Operando High-Resolution Swell Mapping for Mixed Ionic-Electronic Channel

Operando High-Resolution Swell Mapping for Mixed Ionic-Electronic Channel | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Operando High-Resolution Swell Mapping for Mixed Ionic-Electronic Channel Wei Huang, Ziyi Deng, siyu Zhang, Jiahao Wang, Donghao Li, Jinhao Zhou, and 9 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7958348/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract Organic electrochemical transistors (OECTs) and related bioelectronics operate through ionic (de)doping of organic mixed ionic-electronic (semi)conductor (OMIEC) channels with concomitant swelling. However, operando swelling monitoring with high spatiotemporal resolution has remained a challenge owing to the inherent limitations of existing techniques. Here, we introduce an in-situ characterization platform for real-time swelling monitoring of OECT channels by incorporating a laser Doppler vibrometer with a customized testing module. This approach enables dynamic reconstruction of the swelling process with sub-nanometer and sub-microsecond spatiotemporal resolution, revealing apparent inhomogeneity in swelling magnitudes (4 nm ~ 400 nm) in different OMIECs and channel locations, along with distinct ionic (de)doping paths originating from vertical channel edge. Moreover, we identify the Coulomb force between vertically stacked source/drain electrodes as an effective factor for swelling suppression, which enables the demonstration of high-fidelity OECTs (> 15 million full switching cycles) and organic artificial neurons (> 15-day stable operation in 1×PBS). Our work provides a brand-new route for guiding OMIEC synthesis, elucidating underlying mechanisms, and advancing the design of robust (bio)electronic devices. Physical sciences/Materials science/Materials for devices/Electronic devices Physical sciences/Nanoscience and technology/Nanoscale devices/Electronic devices Figures Figure 1 Figure 2 Figure 3 Figure 4 Main Organic electrochemical transistors (OECTs), which show tremendous potential in neuromorphic electronics 1-3 , brain-machine interfaces 4,5 , and implantable sensors 6,7 , depend mainly on organic mixed ionic-electronic conductor (OMIEC) channels. While ionic-electronic coupling of OMIECs leads to apparent swelling, which is essential for device function 8-10 . Therefore, swelling characteristics of OMIEC channels are extremely important for ionic-electronic coupling exploration and material/device performance optimization 11-14 . Various techniques, including electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D) 15 , electrochemical strain microscopy (ESM) 16 , four-dimensional scanning transmission electron microscopy (4D-STEM) 17 , atomic force microscopy (AFM) 18 , and grazing-incidence wide-angle X-ray scattering (GIWAXS) 19 , have been developed to study OMIEC swelling. Nevertheless, GIWAXS, ESM, 4D-STEM, and AFM enable atomic-level microstructure characterization, but are not compatible with dynamic measurements. While EQCM-D holds advantages in dynamically estimating OMIEC mass variations, it is limited in temporal and spatial resolutions. Therefore, in-situ swelling monitoring on operating OECTs with desired temporal (down to milliseconds) and spatial (down to micrometers) resolutions is not accessible, which severely hinders a comprehensive understanding of OMIEC swelling and restricts further material/device optimization and related bioelectronic development. Here, we demonstrate an in-situ channel swelling monitoring platform by constructing a laser Doppler vibrometer (LDV) with a customized monitoring platform holding a vertical OECT (vOECT) structure with a side-gate configuration (named as laser Doppler vibrometer for swell mapping, LDV-M), enabling high temporal (<0.1 ms) and spatial (x-y axis ~3 μm, z axis ~0.6 nm) resolution, along with a wide measurable swelling range up to 1 mm. Moreover, LDV-M is the only platform that can enable in-situ dynamic swelling monitoring (Extended Data Table 1), which is further applied for high-resolution swelling mapping, enabling direct observation of swelling heterogeneity across different OMIECs under different operation conditions (switching frequencies, driving voltages, cycling status, etc). Notably, we unveil previously inaccessible swelling pathways and transient behavior, identifying apparent edge-dominated swelling (up to 389%) that can be effectively inhibited via the Coulomb force between the vertically stacked source and drain electrodes. Leveraging this discovery, by optimizing device encapsulation, enhanced vOECT cyclic stability for more than 15 million full cycles is demonstrated. Furthermore, vOECT-based artificial neurons are fabricated, showing record-high firing frequency (covering the firing spectrum of all human neurons) and sustainability among reported OECT-based organic neurons. These findings provide pivotal guidance for high-fidelity bioelectronic material and device engineering. Design and configuration of the swelling dynamic monitoring system The LDV-M primarily comprises a laser Doppler vibrometer, a magnification objective lens, and a planar electrical positioning stage (Fig. 1a). Leveraging the laser Doppler shift effect and interference principle 20,21 , this system enables non-contact dynamic swelling measurement of the vOECT channel. Specifically, the laser emitted by the laser source is split into reference light and measurement light by a beam splitter. The measurement light, launched through the objective lens, focuses onto the electrode surface of the device to form a 3 μm-diameter spot. Concurrently, a gate voltage ( V G ) is applied to the device to induce doping/dedoping processes. Thus, the resulting channel swelling alters the phase of the reflected light wavefront, generating a Doppler shift. Subsequently, the reflected light returns to the laser source and interferes with the reference light (with a fixed optical length) 22 . The interference signal captured by the detector contains the device’s swelling displacement information, which is then decoded via digital demodulation techniques to output the swelling displacement magnitude (with a resolution of ~0.6 nm, limited mainly by the surrounding environmental vibration noises). Notably, by coordinating with the planar electrical positioning stage (~ 1 μm x/y-axis movement resolution), swelling signals at different positions on the device can be measured, enabling dynamic channel swell mapping. This LDV-M meets the testing requirements for OECTs with micrometer-scale channel dimensions and sub-millisecond-level response times (Fig. 1b). Photographs of the overall LDV-M configuration, along with the zoomed-in vOECT mounting module and vOECT channel with the laser spot focused on, are presented in Fig. 1c-e. The composition of each subsystem is comprehensively detailed in Methods. Single-point swelling monitoring of vOECTs with different OMIECs A side-gated vOECT architecture with 50 μm top (drain) and bottom (source) electrode width is employed (Supplementary Figs. 1 and 2) 23 . A detailed fabrication process can be found in Methods. For the OMIECs, two n-type (BBL, Homo-gDPP) and two p-type (p(g2T-T), gDPP-g2T) materials are adopted, where Homo-gDPP, p(g2T-T), and gDPP-g2T, respectively, are blended with a crosslinker [DtFDA (DA) or DtFGDA (GDA)] holding a mass ratio of 5:1 (Supplementary Figs. 3) 24-28 . First, the transistor performances of all vOECTs are evaluated (Fig. 2a,b, and Extended Data Fig.1), where ~10 5 or higher current on/off ratios and mA-level on currents ( I on ) are obtained in transistors with different channels. Next, single-point swelling monitoring on these vOECTs is conducted with the laser point located approximately at the channel center (Supplementary Figs. 4), where detailed experimental and data analysis methods can be found in Methods. As shown in Fig. 2c,d, and Extended Data Fig.2a-f, the LDV-M demonstrates high temporal resolution and precise z-axis swelling monitoring capability under three different V G switching frequencies (3.3, 11.1, and 111.1 Hz). In the BBL-based channel (Fig. 2c), under a 3.3 Hz switching frequency, active swelling progressively increases during doping along with rising drain current ( I D ), reaching maximum active swelling concurrent with I D saturation, followed by contraction during dedoping (falling I D ). Increasing the frequency to 11.1 Hz yields a comparable active swelling amplitude to that under 3.3 Hz, attributed to complete doping/dedoping processes under both frequencies. Further increase to 111.1 Hz results in incomplete doping/dedoping as demonstrated by I D versus time, accompanied by significantly reduced active swelling. For the p-type p(g2T-T) channel, the active swelling behavior also exhibits a strong correlation with the degree of doping/dedoping (the amplitude of I D ) as the device switching frequency varies (Fig. 2d). All channels with varying materials demonstrate similar active swelling trends, but with different characteristics (Extended Data Fig.2a-f). First, active swelling magnitudes vary tremendously in channels with different materials (Fig. 2e), where n-type vOECTs show overall stronger active swelling. For instance, under 3.3 Hz, 115.9±1.5 nm active swelling is observed in BBL-based vOECT, while only 4.1±0.2 nm is observed in p(g2T-T): DA-based one. This is further verified by EQCM (Supplementary Figs. 5), which shows that the BBL film exhibits a highly pronounced active swelling compared to p(g2T-T), attributable to the ladder polymer structure requiring substantial water influx during doping 18 . Second, when replacing DA with more hydrophilic GDA crosslinker, pronounced active swellings are observed along with faster switching characteristics in p(g2T-T), Homo-gDPP, and gDPP-g2T based vOECTs (Fig. 2e and Supplementary Table 1). Third, when cycling frequency increases, not only is a reduced active swelling amplitude observed, but an overall swelling baseline shift to a higher z plateau is revealed (Supplementary Figs. 6). This indicates that when operating under high switching frequencies, the injected electrolyte cannot be fully ejected from the channel ( vide infra for swell mapping). Next, the transient swelling behavior is analyzed in detail. In the BBL-based vOECT (Fig. 2f), swelling waveforms are consistent with I D curves across all frequencies, transitioning from a near square-wave shape at low frequencies to a triangular-wave shape at high frequencies. Furthermore, the active swelling rate during the doping process is overall slower than that during the dedoping process, which correlates directly with the I D behavior and agrees well with the reported “slow on, fast off” behavior (Supplementary Figs. 7) 29 . Notably, when switching from off to on or from on to off, a sharp decrease or increase spike in I D is observed due to the charging or discharging of the capacitance 24 . While at the same moment, the film active swelling exhibits a “hold” pattern, showing no swelling. However, this is not attributed to capacitance charging/discharging, but due to delayed active swelling of the channel center ( vide infra for swell mapping). Similar active swelling characteristics are observed in p(g2T-T): DA-based vOECT, with one key difference: after the “hold” pattern during the off-to-on process, the film undergoes transient contraction before expansion (Fig. 2g). As shown in Supplementary Figs. 5, unlike that in BBL, p(g2T-T) reveals obvious active swelling either biased positively or negatively, indicating good ionic conductivity for both cations and anions 30 . Consequently, when switching from off to on, counterions [cations for p(g2T-T)] would be ejected first, leading to film contraction first. Then, anions would be injected, leading to film expansion. Such a phenomenon has also been observed in the gDPP-g2T-based channel (Extended Data Fig.2e,f). Note that such a system can also be applied for the swelling monitoring of planar OECTs, but requires good laser light reflection of the channel surface (Extended Data Fig.2g-i). vOECT channel swell mapping By precisely controlling the relative position between the channel and the laser spot using the planar electrical positioning stage (Fig. 3a), high temporal resolution of the single-point channel swelling monitoring can be incorporated with swell mapping capability across the entire vOECT channel. Specifically, a 6×4 measurement grid [(x, y), where x = 1:6, y = 1:4] is constructed over the channel region (80×50 μm 2 ) by scanning the laser spot in defined steps (Extended Data Fig.3). Note, points at (1, y) and (6, y) are located outside the channel with no bottom electrode underneath. Detailed testing protocols can be found in Methods. Swell mappings of different channels are then conducted (Supplementary Videos 1 to 12), demonstrating the unique operando swelling monitoring capability of LDV-M. By extracting specific frames from the mapping movies, the channel swelling behavior can be analyzed with high spatiotemporal resolution. As shown in Fig. 3b,c, and Extended Data Fig.4a,b, obvious swelling in the channel area is observed upon switching, while apparent differences are observed in different channel locations and different driving frequencies. For instance, with 11.1 Hz switching frequency (Fig. 3c), at the initial doping stage ( t 1 to t 2 ), swelling is more pronounced at the channel periphery than at the center; with time progression ( t 3 to t 5 ), swelling propagates from channel edge to channel center, reaching saturation. Upon the dedoping ( t 5 to t 8 ) process, the channel edges obviously contract faster than the channel central region. Such a spatiotemporal dependent swelling characteristic provides the hard evidence that, in vOECTs, the doping/dedoping process always starts from the channel edge and then evolves to the channel bulk. With a higher switching frequency of 111.1 Hz, the swelling difference between channel edge and channel center magnifies, indicating unsaturated doping of the channel bulk, which is further supported by the unsaturated I D (Extended Data Fig.4b). Moreover, upon repeated switching cycles, a gradual swelling baseline shift towards a higher z plateau is also observed under 111.1 Hz switching frequency (Extended Data Fig.4c). Such a phenomenon suggests that both doping and dedoping processes cannot reach saturation under high switching frequencies due to inferior ionic mobility. Next, active swelling behaviors at 3 representative positions are analyzed in detail, which are (1,3), (3,3), and (3,4), representing locations at top electrode edge with no bottom electrode underneath, top electrode edge with bottom electrode underneath, and top electrode above channel center, respectively (Fig. 3d). Obviously, active swelling transient behavior (under 11.1 Hz) at (3,3) is not only lagged (1,3) and (3,4), but also show longer response time [22.2±0.4 ms for (3,3), 10.0±0.3 ms for (1,3), and 10.3±0.2 ms for (3,4), respectively], supporting the ionic doping/dedoping pathway start from the channel edge (Fig. 3e and Supplementary Table 2). While increasing switching frequency from 11.1 Hz to 111.1 Hz, the overall baseline shifts are enhanced, where (1, 3) shows an extraordinary shift of 80.2 nm, while only 46.5 nm and 31.3 nm at (3,4) and (3, 3), respectively, are observed (Fig. 3f,g). In fact, tremendously pronounced swellings at top electrode edge without bottom electrode underneath [(1,y) and (6,y), y = 1:4] are consistently observed, which are 184.2±26.1 nm, 183.4±24.2 nm, and 107.5±31.1 nm for switching frequencies of 3.3 Hz, 11.1 Hz and 111.1 Hz, respectively, while corresponding averaged swelling magnitudes in the channel are only 125.1±22.5 nm, 118.8±21.1 nm, and 33.5±20.1 nm (Fig. 3c, Extended Data Fig.4a,b, and Supplementary Videos 1 to 3). This phenomenon directly indicates that excessive water molecules in the electrolyte solution have been injected into the channel edge (especially the part without the bottom electrodes) during vOECT operation, which could impair cycling stability. In fact, similar swell mapping characteristics are observed in all other polymer channels (Supplementary Videos 4 to 12). Specifically, despite varying swelling magnitudes across different materials, they all exhibit pronounced swelling at the top-electrode edge (Extended Data Fig.5). Especially, up to 380 nm total swelling is observed in p(g2T-T):GDA with an original film thickness of only 80 nm. To probe the origin of such huge swelling at the top electrode edge, source and drain voltages ( V S and V D ) are both set to 0 V during V G switching. As shown in Extended Data Fig.6, for a representative point (3,1), which is located at the top electrode edge with the bottom electrode underneath, enhanced swelling magnitudes are always observed for different channels when no source/drain bias is applied. Especially, apparent baseline shifts are observed with p(g2T-T) and gDPP-g2T-based channels. However, as long as V D is biased, no baseline shifts and reduced swelling magnitudes are observed. It is suggested that, when a vertical electric field is applied, i.e., a weak Coulombic force is formed between two electrodes, channel swelling can be effectively suppressed. Additionally, after 1000 switching cycles in the absence of the Coulombic force in a BBL-based vOECT, distinct wrinkles (> 400 nm in height) in the channel region can be observed by optical microscopy and AFM (Supplementary Figs. 8). Modulation of the swelling in vOECT towards high-fidelity OECN Consequently, to suppress swelling at the critical top electrode edge region, the encapsulation pattern is re-designed by precisely aligning the opening width with that of the bottom electrode(Fig. 4a and Supplementary Fig. 9). As shown in Supplementary Figs. 10 and 11, swelling is effectively suppressed at the top electrode edge, leading to an overall 21% reduction in swelling amplitude compared to that without optimized encapsulation. Consequently, cycling stabilities of vOECTs with different channel materials can be further enhanced, along with a minor effect on transistor transient characteristics (Fig. 4. b,c, and Extended Data Fig.7). Note, the detailed cycling process can be found in Methods. For instance, with switching V G from 0.4 V to -0.6 V, 99.7% I D retention after 100k cycles (1.4 hrs) is obtained for the optimized p(g2T-T):DA-based vOECT, markedly surpassing 63.84% I D retention in the conventionally encapsulated counterpart. Note, channels with GDA crosslinker typically exhibit lower stabilities but faster transient responses than those with DA, which is attributed to the hydrophilic ethylene glycol chain in GDA that facilitates swelling. Moreover, extensively continuous cycling characteristics on vOECTs based on p(g2T-T):DA, Homo-gDPP:DA, and BBL are conducted (Fig. 4d and Extended Data Fig.8). These devices demonstrate stable full switching cycles for 15 million (208.3 hours) and 2.8 million (62.2 hours) for p-type and n-type OECTs, respectively. Note that, in these cycling stability measurements, no measures (for instance, degassing) to avoid side reactions are adopted 31 , while these stabilities are still among the highest reported for OECTs (Fig. 4e and Supplementary Table 3) 28,31-41 . Next, such vOECTs are utilized for the construction of a vertically stacked organic electrochemical neuron (vOECN) based on the axon hillock (A-H) circuit. First, vertically stacked complementary inverters are fabricated using gDPP-g2T:DA and Homo-gDPP:DA as p-/n-type channels, respectively (Supplementary Figs. 12). Corresponding transfer and transient curves demonstrate on/off current ratios of ~10⁶ and transient times of ~ 1 ms, which enable inverters with robust logic switching up to 1250 Hz. Then, vOECNs are further integrated (Fig. 4f, Supplementary Figs. 13, and detailed fabrication process can be found in Methods) and characterized. The present leaky integrate-and-fire (LIF) OECN structure mimics the action potential spikes generated by nerve cells 42 , making the dynamic range of spike frequencies profoundly influence the diversity of neural behaviors 40,43-45 . Thus, spike frequency coverage of the developed vOECNs is systematically investigated. The pulse frequency ( f fire ) of vOECNs can be regulated by the charge-discharge rate of membrane capacitance in the circuit, a process that V DD , C mem , and I IN can all manipulate 2,40,46 . As shown in Fig. 4g, under fixed conditions of C mem = C f = 500 pF and I IN = 1 μA, f fire decreases monotonically from 92.6 Hz to 33.6 Hz as V DD rises from 0.6 V to 0.8 V. This behavior originates from the lower V DD reducing the threshold voltage, enabling capacitors to charge to the threshold more rapidly and trigger spikes. I IN also significantly influences the charge-discharge dynamics of C mem , where higher I IN accelerates the process (Fig. 4h). Furthermore, by adjusting C mem , the frequency range of vOECNs extends from 0.5 Hz to 1.1 kHz, representing the widest bandwidth reported for OECT-based OECNs to date, fully encompassing the firing spectrum of human neurons (Fig. 4i, Extended Data Fig.9, and Supplementary Table 4) 2,40,42,46-52 . This is attributed to high-resolution channel packaging (55 × 105 μm) that reduces parasitic capacitance and integration of smaller external capacitors. Lastly, the stability of vOECN is characterized. Fig. 4j demonstrates that vOECN maintains 100% fire voltage ( V fire ) retention after 155,000 switching cycles, an excellent performance attributed to the optimized encapsulation. Furthermore, no performance degradation (100% V fire and f fire retention) is observed after the vOECN is immersed in 1× PBS solution for 15 days, confirming sustained operation throughout the testing period (Fig. 4k). The combined wide-range spiking capability and exceptional stability metrics fully demonstrate the significant application potential of vOECN in the fields of neuromorphic electronics and brain-computer interfaces. This study introduces a novel in-operando channel swelling monitoring tool, LDV-M, which is currently the sole platform that enables real-time dynamic swelling monitoring in operando conditions. High spatiotemporal resolution swell mapping can be easily accessed, enabling direct observation of swelling behaviors in OMIEC-based vOECTs under diverse conditions (different channel materials, switching frequencies, driving voltages, cycling states, etc.). Apparent differences in swelling magnitudes (from several nm to hundreds of nm) in different channel materials are observed, along with clear ionic doping paths from the vertical channel edge to the channel center. Especially, significant lateral top electrode edge swelling is identified as the primary cause of device degradation, while Coulombic forces between vertically stacked source/drain electrodes effectively suppress such swelling. Consequently, a precise device encapsulation configuration is implemented, enhancing vOECT cyclic stability beyond 15 million full cycles (the highest reported to date). Furthermore, vOECN based on such architecture achieves the broadest f fire range from 0.5 Hz to 1.1 kHz, along with 100% spike sustaining after 155,000 cycles and 15-day immersion in 1×PBS. Overall, LDV-M provides a novel in situ characterization methodology for dissecting OECT operational mechanisms and offers a practical research tool for OMIEC-based bionic neural engineering. Methods Materials gDPP-g2T, Homo-gDPP, DA, and GDA were synthesized via previously reported methods 25,27,28 . p(g2T-T) was purchased from Derthon Optoelectronics Materials Science Technology Co., Ltd. BBL, Ag/AgCl paste, Isopropyl alcohol, methanesulfonic acid, and chloroform were purchased from Sigma-Aldrich. Phosphate buffer saline (0.01 M PBS) supplied by Solarbio was used as the electrolyte. Semiconductor solution preparation gDPP-g2T, Homo-gDPP, DA, and GDA were first dissolved in chloroform, respectively, with a concentration of 20 mg ml −1 . p(g2T-T) was dissolved in chloroform at a concentration of 10 mg ml −1 . Then those solutions were filtered through a 0.45 μm polyvinylidene difluoride filter. Subsequently, gDPP-g2T, Homo-gDPP, or p(g2T-T) solution was mixed with DA or GDA solution in a mass ratio of 5:1. For BBL, it was dissolved in methanesulfonic acid at a concentration of 15 mg ml −1 . Vertical OECT fabrication The vOECT fabrication process is illustrated in Supplementary Figs. 2. First, 3 nm of Cr and 130 nm of Au (rate approximately 0.5–2.0 Å s −1 ) were thermally evaporated on a precleaned Si/100 nm SiO 2 wafer with a shadow mask as the bottom source electrode and gate electrode. Then, the substrates with the bottom electrodes underwent a 15-minute UV-ozone cleaning process. Subsequently, solutions of BBL, Homo-gDPP:GDA, Homo-gDPP:DA, p(g2T-T):GDA, p(g2T-T):DA, gDPP-g2T:GDA, and gDPP-g2T:DA, respectively, were spin-coated at 2,500 rpm for 30 seconds. The films with crosslinkers were then cross-linked by exposure to 365 nm UV light (125 mW/cm 2 ) for 2 min; while BBL film was first subjected to a 15-minute immersion in deionized water and subsequently blow-dried with a nitrogen gun. Then, the semiconductor layer was patterned using an LPKF protolaser R4 at 500 kHz with a power of 0.13 W. Then, the top drain electrode (130 nm Au) was thermally evaporated (rate approximately 0.5–2.0 Å s −1 ) with a shadow mask while maintaining the substrate at a temperature of ~ 5 ℃ with a back water-cooling system. Subsequently, an SU8-2002 solution was spin-coated onto the substrate at 2,000 rpm for 60 s. The sample was then heated on a 95 °C hotplate for 80 s, exposed to light (28 mW/cm²) for 20 s using a shadow mask, and reheated on the 95 °C hotplate for 80 s. The encapsulation layer was then patterned by developing the SU8 in a developer for 10 s, rinsing in isopropanol for 10 s, and blow-drying. Finally, an Ag/AgCl paste was applied onto the gate electrode and vacuum-dried for 30 min, the device was semi-sealed with glass, and 10–30 μL of 1× PBS solution was introduced into the semi-sealed region. Planar OECT fabrication First, 3 nm of Cr and 50 nm of Au (rate approximately 0.5–2.0 Å s −1 ) were thermally evaporated on a precleaned Si/100 nm SiO 2 wafer with a shadow mask as the source, drain, and gate electrodes. Then, the substrates with the electrodes underwent a 15-minute UV-ozone cleaning process. Subsequently, solutions of BBL and p(g2T-T):GDA were spin-coated at 2,500 rpm for 30 seconds. The films with crosslinkers were then cross-linked by exposure to 365 nm UV light (125 mW/cm 2 ) for 2 min; while BBL film was first subjected to a 15-minute immersion in deionized water and subsequently blow-dried with a nitrogen gun. Then, the semiconductor layer was patterned using an LPKF protolaser R4 at 500 kHz with a power of 0.13 W. Subsequently, an SU8-2002 solution was spin-coated onto the substrate at 2,000 rpm for 60 s. The sample was then heated on a 95 °C hotplate for 80 s, exposed to light (28 mW/cm²) for 20 s using a shadow mask, and reheated on the 95 °C hotplate for 80 s. The encapsulation layer was then patterned by developing the SU8 in a developer for 10 s, rinsing in isopropanol for 10 s, and blow-drying. Finally, an Ag/AgCl paste was applied onto the gate electrode and vacuum-dried for 30 min, the device was semi-sealed with glass, and 10–30 μL of 1× PBS solution was introduced into the semi-sealed region. Vertical OECN fabrication vOECN fabrication process can be found in Supplementary Fig. 13. First, 3 nm of Cr and 80 nm of Au (rate approximately 0.5–2.0 Å s −1 ) were thermally evaporated on a precleaned glass substrate with a shadow mask as the bottom electrode. gDPP-g2T:DA blend solution was spin-coated at 2,500 rpm for 20 s. The film was then cross-linked by exposure to 365 nm UV light (125 mW/cm 2 ) for 2 min, and the semiconductor layer was patterned using an LPKF protolaser R4 at 500 kHz with a power of 0.13 W. Next, the middle drain electrode (80 nm Au) was then thermally evaporated (rate approximately 0.5–2.0 Å s −1 ) with a shadow mask while maintaining the substrate at a temperature of ~ 5 ℃ with a back water-cooling system. Then, Homo-gDPP:DA blend solution was spin-coated and photopatterned using the same protocol as the p-type material to form the n-type channels in the amplifier block and T reset regions. The top electrode (GND) was fabricated by thermal evaporation of an 80 nm Au layer through a shadow mask. To expose active channel areas, gate electrodes, and capacitor connection points, the substrate was coated with an SU8-2002 solution via spin-coating at 2,000 rpm for 60 s, followed by a 95 °C hotplate bake for 80 s. The SU8 layer was then exposed to 28 mW/cm² UV light through a shadow mask for 20 s and subjected to a post-exposure bake at 95 °C for 80 s. Patterning development was achieved by immersing the sample in SU8 developer for 10 s, rinsing with isopropanol for 10 s, and drying with compressed air to form the encapsulated structure. Gate electrodes of the amplifier block and T reset were coated with Ag/AgCl paste and vacuum-dried for 30 min. Capacitors were then attached using conductive silver paint. Finally, 1× PBS electrolyte was dropped onto the gate electrodes and adjacent active channel regions to complete device fabrication. LDV-M platform configuration The LDV-M employed a 633 nm wavelength Doppler laser vibrometer (Polytec Inc., VibroFlex Compact), with a ×20 objective lens (VIB-A-20×) mounted on the laser probe to focus the laser spot to be 3 μm diameter. vOECT electrodes were clamped by a 3M chip testing fixture (which is further connected with a semiconductor analyzer) and fixed onto a custom-designed planar electrical positioning stage with micron-level positioning accuracy and multi-axis adjustability (x, y, z, pitch angle). The laser is incident perpendicularly onto the sample surface, while the laser spot position on the surface is real-time monitored by a CMOS color camera integrated into the vibrometer. Additionally, a semiconductor parameter analyzer (FS-Pro) drives the OECT and acquires its electrical signals simultaneously, while the laser vibrometer collects swelling signals. Notably, both the vibrometer and the planar electrical positioning stage are mounted on the same optical table to enhance the signal-to-noise ratio. Electrical measurements Under ambient conditions, the electrical properties of vOECTs, inverters, and vOECNs were characterized using an FS-Pro (PDA) semiconductor analyzer and a probe station (Chengdu Chiptest Technology Co., LTD.). For cycling stability test: first, a transfer curve of the device was measured; then, a rectangular wave pulse with fixed frequency and amplitude was applied to the V G for cyclic stability testing , while V D was 0.1 V and -0.1 V for n-type and p-type OECTs, respectively. This process was repeated multiple times to enable larger cycling numbers and time. Specifically, for p(g2T-T):DA and p(g2T-T):GDA-based vOECT, V G = 0.4 to -0.6 V, frequency = 20 Hz; for BBL-based vOECT, V G = -0.3 to 0.5 V, frequency = 12.5 Hz; for Homo-gDPP:DA-based vOECT, the test conditions in Fig. 4c,d were V G = 0 to 0.9 V at 25 Hz and V G = 0 to 0.8 V at 20 Hz, respectively; for Homo-gDPP:GDA-based vOECT, V G = 0 to 0.9 V, frequency = 25 Hz; for gDPP-g2T:DA and gDPP-g2T:GDA-based vOECT, V G = -0.3 to -0.6 V, frequency = 25 Hz. In Fig. 4c and Extended Data Fig. 7, transfer curves were gathered every 20,000 switching cycles for vOECTs using p(g2T-T):DA/GDA, Homo-gDPP:DA/GDA, or gDPP-g2T:DA/GDA, and every 5,000 switching cycles for BBL-based vOECT. In Fig. 4d and Extended Data Fig. 8, transfer curves were collected every 100,000 switching cycles for vOECTs based on p(g2T-T):DA, and every 50,000 switching cycles for those based on Homo-gDPP:DA and BBL. Notably, to maintain a relatively stable 1× PBS electrolyte concentration, a PDMS well was placed on top of the active region of the device, and ~50 μL of 1× PBS solution was added to restrict electrolyte displacement and slow down electrolyte evaporation. For the voltage transfer characteristic measurement of inverters, the V IN was supplied by the FS-Pro with a step interval of 2 mV, and the output voltage was also recorded by the FS-Pro (PDA). To characterize the frequency response of the inverters, the FS-Pro was used to apply V IN voltages with a fixed amplitude range of 0 to 0.7 V and varying frequencies (50 Hz to 1.25 kHz), while the output characteristics were recorded. For the electrical characterization of vOECNs, the FS-Pro provided different constant I IN = 0.05 to 50 μA and V DD = 0.6 to 0.8 V, with a sampling frequency of 50,000 samples per second during testing. To evaluate the cyclic stability of vOECNs, a constant V DD = 0.7 V and I IN = 1.1 μA were applied via the FS-Pro, and the output characteristics were recorded. Notably, three independent PDMS wells were designed at the electrolyte droplet positions to ensure an adequate volume of 1× PBS solution and prevent short circuits caused by electrolyte mixing. For the storage stability test of vOECNs, a 3D-printed sealed container was employed to house the vOECN, which was immersed in 1× PBS within the container. Before each test, the vOECN was removed, rinsed with deionized water, dried using a nitrogen gun, and then characterized. Vertical OECT swelling measurements For swelling testing of vOECTs, the laser spot position on the vOECT device surface was first observed and adjusted using a CMOS color camera to determine the measured point position (Polytec Inc., VibroFlex Compact). Subsequently, the vOECT is driven by the Fs-Pro semiconductor analyzer, and V G supplied by Fs-Pro is also synchronized with the laser vibrometer. Note, V G switching frequencies of 3.3 Hz, 11.1 Hz, and 111.1 Hz are chosen to minimize the interference of the power line interference (50 Hz). For swell mapping of vOECT channels, the laser spot was first positioned at the lower-left corner of the OECT top electrode (1,1) using a CMOS color camera. A custom-designed planar electrical positioning stage controlled by LabView was used to perform a 6×4 scanning matrix with a 16 μm step size: 5 steps right (80 μm), return to the origin, 1 step up, and 3 steps right (50 μm), scanning from the lower-left to upper-right of the electrode. During scanning, Fs-Pro generated rectangular wave V G signals to switch the device on/off state and record I D ; the laser vibrometer collects the corresponding swelling and V G signals, while the CMOS camera records the position of the laser spot at each step. Planar OECT swelling measurements For swelling testing of planar OECTs, the laser spot position on the planar OECT device surface was first observed and adjusted using a CMOS color camera to determine the measured point position (Polytec Inc., VibroFlex Compact). Subsequently, the planar OECT is driven by the Fs-Pro semiconductor analyzer. Note, V G switching frequency is 3.3 Hz. OECT swelling data analysis For the collected vOECT/planar OECT swelling data, the acquired signals were filtered using a band-stop filter at 24-26 and 49-51 Hz to minimize power line interference (50 Hz). Additionally, as both the source meter (Fs-Pro) and laser vibrometer record V G voltage signals, synchronization of the vOECT switching current with the swelling signal was achieved by aligning the V G voltage traces from both devices. Swelling magnitudes of the vOECT channels contain two parts: active swelling and baseline shift (Fig. 2c and Fig. S6). When analyzing the degree of doping and dedoping of films, swelling from baseline shift is excluded to focus solely on active swelling signals. All swelling data analyses, except those labeled "active swelling", include both baseline shift and active swelling (e.g., 3D swelling distribution maps of devices and swelling across multiple device cycles). EQCM measurements EQCM measurements were performed using a gold‐coated quartz crystal sensor and a quartz crystal microbalance (QCM922A, Princeton Applied Research). The polymer film was patterned to define an active gold area (~0.2 cm²). Before film deposition, the crystal’s fundamental frequency was tested in air and electrolyte (0.01 M PBS) solution environments. After spin-coating and patterning the semiconductor film onto the crystal, the fundamental frequency was retested in the same environments to calculate passive swelling. Finally, the crystal was connected to an Fs-pro semiconductor parameter analyzer via a chip testing fixture, with the Fs-pro generating rectangular wave voltage signals to induce film doping/dedoping while recording current signals. Previous studies have shown that ~100 nm-thick polymer films can be considered “rigid” films 18 , so in this work, mass changes were calculated using the Sauerbrey equation: where Δ f n is the frequency shift of the n th overtone, A is the sensor active area, ρ q is the density of quartz, V q is the shear wave velocity in quartz, f 0 is the fundamental frequency and n is the overtone number (fixed at 1). Relative mass change was calculated as the percentage change in total mass relative to the dry mass: AFM Measurements The film thickness was measured using atomic force microscopy (AFM) in tapping mode, with a Park NX7 AFM equipped with a silicon tip. Specimens for film thickness measurement were prepared following the same fabrication process as that used for the semiconductor layers in each vOECT. Then, the film surface was scratched with tweezers. Subsequently, AFM was used to measure the height difference between the two sides of the scratch, which was taken as the thickness of the film. Declarations Acknowledgments: We thank W. Wang from Polytec China Ltd. for technical support. This work is financially supported by the National Key R&D Program of China (2022YFE0134800), the National Natural Science Foundation of China (No. 62273073, 52273316), the National Key R&D Program of China (2024YFB3211600, 2023YFC2411800), the Aeronautical Science Foundation of China (20230024080002), the Natural Science Foundation of Sichuan (2025ZNSFSC0515), Sichuan Science and Technology Program (2023YFSY0064), Chengdu Science Technology Bureau (2023-YF06-00028-HZ), the Fundamental Research Funds for the Central Universities (ZYGX2025TS009, ZYGX2024XJ029, ZYGX2024XJ031), and Scientific Research Innovation Capability Support Project for Young Faculty (ZYGXQNJSKYCXNLZCXM-M1P). Author contr ibutions: Z.D., C.C., and W.H. conceived the idea and designed the experiments. Z.D. and S.Z. performed OECT fabrication and measurement. Z.D., J.W., M.X., L.H., Y.C., C.C., and W.H. constructed the swelling system. Z.D., S.Z., and D.Z. performed the OECT swelling measurement. Z.D. performed OECN fabrication and measurement. Z.D. and D.L. produced the swelling animation. Y.Z. performed the AFM measurement. Z.D., S.Z., J.Z., and L.-W.F. performed the EQCM measurement. J.C. synthesized the Homo-gDPP and gDPP-g2T. Y.L. and L.-W.F. synthesized the DA and GDA. Z.D. and W.H. wrote the manuscript. All the authors reviewed and approved the manuscript. Competing interests: Z.D., C.C., and W.H. are inventors on patent applications related to the LDV-M platform and designs of high-fidelity OECTs. Data Availability: The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request. References Gkoupidenis, P. et al. Organic mixed conductors for bioinspired electronics. Nat. Rev. Mater. 9 , 134-149 (2023). https://doi.org/10.1038/s41578-023-00622-5 Harikesh, P. C. et al. Ion-tunable antiambipolarity in mixed ion-electron conducting polymers enables biorealistic organic electrochemical neurons. Nat. 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C. et al. Single organic electrochemical neuron capable of anticoincidence detection. Sci. Adv. 11 , eadv3194 (2025). https://doi.org/doi:10.1126/sciadv.adv3194 Additional Declarations Yes there is potential Competing Interest. Z.D., C.C., and W.H. are inventors on patent applications related to the LDV-M platform and designs of high-fidelity OECTs. Supplementary Files MovieS11gDPPg2T11.1hz.mp4 Video S11 MovieS7pg2TT3.3hz.mp4 Video S7 MovieS10gDPPg2T3.3Hz.mp4 Video S10 MovieS2XXXBBL11.1HzXXX.mp4 Video S2 MovieS8pg2TT11.1hz.mp4 Video S8 MovieS1XXXBBL3.3HzXXX.mp4 Video S1 MovieS9pg2TT111.1hz.mp4 Video S9 MovieS12gDPPg2T111.1hz.mp4 Video S12 MovieS6XXXHomogDPP111.1hz.mp4 Video S6 SIdzy251027.docx Supporting Information MovieS4XXXHomogDPP3.3HzXXX.mp4 Video S4 MovieS3XXXBBL111.1HzXXX.mp4 Video S3 MovieS5XXXHomogDPP11.1hzXXX.mp4 Video S5 ExtendedData.docx Cite Share Download PDF Status: Under Review Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7958348","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":538312379,"identity":"28df0fe3-7f42-4b29-9f57-0f6f317fbcd2","order_by":0,"name":"Wei 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configuration of the laser Doppler vibrometer with mapping (LDV-M).\u003c/strong\u003e \u003cstrong\u003ea,\u003c/strong\u003e Main components of the LDV-M.\u003cstrong\u003e b,\u003c/strong\u003e Schematic diagram of LDV linked with planar electrical positioning stage for channel swelling monitoring. \u003cstrong\u003ec,\u003c/strong\u003e Optical image of the LDV-M, along with the zoomed-in \u003cstrong\u003e(d)\u003c/strong\u003e OECT mounting module and \u003cstrong\u003e(e) \u003c/strong\u003etransistor channel with\u003cstrong\u003e \u003c/strong\u003ea measuring laser spot focused on.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7958348/v1/97095bfbe37e033516a4100a.png"},{"id":95224437,"identity":"7d1718a5-187e-4627-8253-1b5ad2205822","added_by":"auto","created_at":"2025-11-05 16:23:46","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":736640,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSingle-point swelling monitoring.\u003c/strong\u003e Transfer curves of vOECTs based on \u003cstrong\u003e(a)\u003c/strong\u003e BBL or \u003cstrong\u003e(b)\u003c/strong\u003e p(g2T-T):DA. Single point swelling behaviors of vOECT channels based on \u003cstrong\u003e(c) \u003c/strong\u003eBBL or \u003cstrong\u003e(d)\u003c/strong\u003e p(g2T-T):DA under different switching frequencies.\u003cstrong\u003e e, \u003c/strong\u003eActive\u003cstrong\u003e \u003c/strong\u003eswelling magnitudes of the vOECT channel center based on different channels under varying frequencies. Representative swelling characteristics within a single switching cycle under different frequencies for vOECTs based on \u003cstrong\u003e(f) \u003c/strong\u003eBBL or \u003cstrong\u003e(g)\u003c/strong\u003e p(g2T-T):DA. \u003cem\u003eV\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e = 0.1 V (n-type) or -0.1 V (p-type).\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7958348/v1/56d537e705540a2da593f414.png"},{"id":95084557,"identity":"02513606-1555-458b-807a-17591e2713bc","added_by":"auto","created_at":"2025-11-04 07:04:31","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":4718784,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSwell mapping of vOECT channel. a,\u003c/strong\u003e Schematic of laser light spot distribution.\u003cstrong\u003e b, \u003c/strong\u003eAn \u003cem\u003eI\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e switching cycle along with\u003cstrong\u003e (c) \u003c/strong\u003ethe corresponding swell mapping frames of a BBL-based vOECT channel. \u003cstrong\u003ed, \u003c/strong\u003eRepresentative mapping point locations, along with \u003cstrong\u003e(e)\u003c/strong\u003e the swelling behavior during a single switching cycle and \u003cstrong\u003e(f,g)\u003c/strong\u003e multiple swelling cycles. Switching Frequencies are 11.1 Hz and 111.1 Hz for \u003cstrong\u003e(e,f)\u003c/strong\u003e and \u003cstrong\u003e(g)\u003c/strong\u003e, respectively.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7958348/v1/91efcde42c2d847c1e00306e.png"},{"id":95084561,"identity":"5d258d49-01a0-45d2-9999-9a15468546bc","added_by":"auto","created_at":"2025-11-04 07:04:32","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":617082,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eDesign and characteristics of vOECTs and high-fidelity vOECNs. a, \u003c/strong\u003eTop view of the channel with conventional or optimized encapsulation. \u003cstrong\u003eb,\u003c/strong\u003e Transfer curves of vOECTs based on p(g2T-T):DA with two different encapsulations after indicated cycle stability measurements. \u003cstrong\u003ec, \u003c/strong\u003eOn current retention ratio for vOECTs based on different channels with different encapsulation methods after 100,000 switching cycles.\u003cstrong\u003e d, \u003c/strong\u003eTransfer curves of vOECTs based on p(g2T-T):DA and Homo-gDPP:DA after indicated switching cycles. \u003cstrong\u003ee, \u003c/strong\u003eComparison of cycling numbers and operation times of reported OECTs.\u003cstrong\u003e f, \u003c/strong\u003eCircuit diagram and\u003cstrong\u003e \u003c/strong\u003eoptical image of a vOECN.\u003cstrong\u003e g,\u003c/strong\u003e vOECN fire frequency modulation under three different \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e configurations and \u003cstrong\u003e(h) \u003c/strong\u003ethe coverage ranges of \u003cem\u003ef\u003c/em\u003e\u003csub\u003efire \u003c/sub\u003eat\u003cstrong\u003e \u003c/strong\u003edifferent \u003cem\u003eI\u003c/em\u003e\u003csub\u003eIN\u003c/sub\u003e with varying \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e (\u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e =0.6 V, 0.7 V, and 0.8 V; \u003cem\u003eC\u003c/em\u003e\u003csub\u003emem\u003c/sub\u003e = \u003cem\u003eC\u003c/em\u003e\u003csub\u003ef\u003c/sub\u003e = 500 pF) or with varying capacitance (\u003cem\u003eC\u003c/em\u003e\u003csub\u003emem\u003c/sub\u003e = \u003cem\u003eC\u003c/em\u003e\u003csub\u003ef\u003c/sub\u003e = 500 pF, 10 nF, or 50 nF; \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e =0.7 V).\u003cstrong\u003e (i) \u003c/strong\u003eFire frequency versus \u003cem\u003eI\u003c/em\u003e\u003csub\u003e\u003cem\u003eIN\u003c/em\u003e\u003c/sub\u003e in this work compared with those from reported OECNs.\u003cstrong\u003e (j) \u003c/strong\u003eCycling stability and \u003cstrong\u003e(k) s\u003c/strong\u003etorage stability of the vOECN with a switching frequency of 34 Hz (\u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e = 0.7 V, 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tremendous potential in neuromorphic electronics\u003csup\u003e1-3\u003c/sup\u003e, brain-machine interfaces\u003csup\u003e4,5\u003c/sup\u003e, and implantable sensors\u003csup\u003e6,7\u003c/sup\u003e, depend mainly on organic mixed ionic-electronic\u0026nbsp;conductor (OMIEC) channels.\u0026nbsp;While\u0026nbsp;ionic-electronic coupling of OMIECs leads to apparent swelling, which is essential for device function\u003csup\u003e8-10\u003c/sup\u003e. Therefore, swelling\u0026nbsp;characteristics\u0026nbsp;of OMIEC channels\u0026nbsp;are\u0026nbsp;extremely important for ionic-electronic coupling exploration and material/device performance optimization\u003csup\u003e11-14\u003c/sup\u003e. Various techniques, including electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D)\u003csup\u003e15\u003c/sup\u003e,\u0026nbsp;electrochemical strain microscopy (ESM)\u003csup\u003e16\u003c/sup\u003e, four-dimensional scanning transmission electron microscopy (4D-STEM)\u003csup\u003e17\u003c/sup\u003e,\u0026nbsp;atomic force microscopy (AFM)\u003csup\u003e18\u003c/sup\u003e, and grazing-incidence wide-angle X-ray scattering (GIWAXS)\u003csup\u003e19\u003c/sup\u003e, have been developed to study OMIEC swelling.\u0026nbsp;Nevertheless, GIWAXS,\u0026nbsp;ESM, 4D-STEM,\u0026nbsp;and AFM enable atomic-level microstructure characterization, but are not compatible with dynamic measurements.\u0026nbsp;While\u0026nbsp;EQCM-D holds advantages in dynamically estimating OMIEC\u0026nbsp;mass variations,\u0026nbsp;it\u0026nbsp;is limited in temporal and spatial resolutions.\u0026nbsp;Therefore, in-situ swelling monitoring on operating OECTs with\u0026nbsp;desired\u0026nbsp;temporal (down to milliseconds) and spatial (down to micrometers) resolutions is not accessible, which severely hinders a comprehensive understanding of OMIEC swelling and restricts further material/device optimization and related bioelectronic development.\u003c/p\u003e\n\u003cp\u003eHere, we demonstrate an in-situ channel swelling monitoring platform by constructing a laser Doppler vibrometer (LDV) with a customized monitoring platform holding a vertical OECT (vOECT) structure with a side-gate configuration (named as laser Doppler vibrometer for swell mapping, LDV-M), enabling high temporal (\u0026lt;0.1 ms) and spatial (x-y axis ~3 \u0026mu;m, z axis ~0.6 nm) resolution, along with a wide measurable swelling range up to 1 mm. Moreover, LDV-M is the only platform that can enable in-situ dynamic swelling monitoring (Extended Data Table 1), which is further applied for high-resolution swelling mapping, enabling direct observation of swelling heterogeneity across different OMIECs under different operation conditions (switching frequencies, driving voltages, cycling status, etc). Notably, we unveil previously inaccessible swelling pathways and transient behavior, identifying apparent edge-dominated swelling (up to 389%) that can be effectively inhibited via the Coulomb force between the vertically stacked source and drain electrodes. Leveraging this discovery, by optimizing device encapsulation, enhanced vOECT cyclic stability for more than 15 million full cycles is demonstrated. Furthermore, vOECT-based artificial neurons are fabricated, showing record-high firing frequency (covering the firing spectrum of all human neurons) and sustainability among reported OECT-based organic neurons. These findings provide pivotal guidance for high-fidelity bioelectronic material and device engineering.\u003c/p\u003e\n\u003cp\u003eDesign and configuration of the swelling dynamic monitoring system\u003c/p\u003e\n\u003cp\u003eThe LDV-M primarily comprises a laser Doppler vibrometer, a magnification objective lens, and a planar electrical positioning stage (Fig. 1a).\u0026nbsp;Leveraging the laser Doppler shift effect and interference principle\u003csup\u003e20,21\u003c/sup\u003e, this system enables non-contact dynamic swelling measurement of the vOECT channel. Specifically, the laser emitted by the laser source is split into reference light and measurement light by a beam splitter. The measurement light, launched through the objective lens, focuses onto the electrode surface of the device to form a 3 \u0026mu;m-diameter spot. Concurrently, a gate voltage (\u003cem\u003eV\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e) is applied to the device to induce doping/dedoping processes. Thus, the resulting channel swelling alters the phase of the reflected light wavefront, generating a Doppler shift. Subsequently, the reflected light returns to the laser source and interferes with the reference light (with a fixed optical length)\u003csup\u003e22\u003c/sup\u003e. The interference signal captured by the detector contains the device\u0026rsquo;s swelling displacement information, which is then decoded via digital demodulation techniques to output the swelling displacement magnitude (with a resolution of ~0.6 nm, limited mainly by the surrounding environmental vibration noises). Notably, by coordinating with the planar electrical positioning stage (~ 1 \u0026mu;m x/y-axis movement resolution), swelling signals at different positions on the device can be measured, enabling dynamic channel swell mapping. This LDV-M meets the testing requirements for OECTs with micrometer-scale channel dimensions and sub-millisecond-level response times (Fig. 1b). Photographs of the overall LDV-M configuration, along with the zoomed-in vOECT mounting module and vOECT channel with the laser spot focused on, are presented in Fig. 1c-e. The composition of each subsystem is comprehensively detailed in Methods.\u003c/p\u003e\n\u003cp\u003eSingle-point swelling monitoring of vOECTs with different OMIECs\u003c/p\u003e\n\u003cp\u003eA side-gated vOECT architecture with 50 \u0026mu;m top (drain) and bottom (source) electrode\u0026nbsp;width\u0026nbsp;is employed\u0026nbsp;(Supplementary Figs. 1 and 2)\u003csup\u003e23\u003c/sup\u003e.\u0026nbsp;A detailed fabrication process can be found in Methods.\u0026nbsp;For the OMIECs, two\u0026nbsp;n-type (BBL, Homo-gDPP) and two\u0026nbsp;p-type\u0026nbsp;(p(g2T-T), gDPP-g2T) materials are adopted, where Homo-gDPP, p(g2T-T), and gDPP-g2T, respectively, are\u0026nbsp;blended with a crosslinker\u0026nbsp;[DtFDA (DA) or DtFGDA (GDA)]\u0026nbsp;holding a mass ratio of 5:1 (Supplementary Figs. 3) \u003csup\u003e24-28\u003c/sup\u003e.\u0026nbsp;First, the transistor performances of all vOECTs are evaluated (Fig. 2a,b, and Extended Data Fig.1), where ~10\u003csup\u003e5\u003c/sup\u003e or higher current on/off ratios and mA-level on currents (\u003cem\u003eI\u003c/em\u003e\u003csub\u003eon\u003c/sub\u003e) are obtained in transistors with different channels.\u003c/p\u003e\n\u003cp\u003eNext, single-point swelling monitoring on these vOECTs is conducted with the laser point located approximately at the channel center (Supplementary Figs. 4), where detailed experimental and data analysis methods can be found in Methods. As shown in Fig. 2c,d, and Extended Data Fig.2a-f, the LDV-M demonstrates high temporal resolution and precise z-axis swelling monitoring capability under three different \u003cem\u003eV\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e switching frequencies (3.3, 11.1, and 111.1 Hz). In the BBL-based channel (Fig. 2c), under a 3.3 Hz switching frequency, active swelling progressively increases during doping along with rising drain current (\u003cem\u003eI\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e), reaching maximum active swelling concurrent with \u003cem\u003eI\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e saturation, followed by contraction during dedoping (falling \u003cem\u003eI\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e). Increasing the frequency to 11.1 Hz yields a comparable active swelling amplitude to that under 3.3 Hz, attributed to complete doping/dedoping processes under both frequencies. Further increase to 111.1 Hz results in incomplete doping/dedoping as demonstrated by \u003cem\u003eI\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e versus time, accompanied by significantly reduced active swelling. For the p-type p(g2T-T) channel, the active swelling behavior also exhibits a strong correlation with the degree of doping/dedoping (the amplitude of \u003cem\u003eI\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e) as the device switching frequency varies (Fig. 2d).\u003c/p\u003e\n\u003cp\u003eAll channels with varying materials demonstrate similar active swelling trends, but with different characteristics (Extended Data Fig.2a-f). First, active swelling magnitudes vary tremendously in channels with different materials (Fig. 2e), where n-type vOECTs show overall stronger active swelling. For instance, under 3.3 Hz, 115.9\u0026plusmn;1.5 nm active swelling is observed in BBL-based vOECT, while only 4.1\u0026plusmn;0.2 nm is observed in p(g2T-T): DA-based one. This is further verified by EQCM (Supplementary Figs. 5), which shows that the BBL film exhibits a highly pronounced active swelling compared to p(g2T-T), attributable to the ladder polymer structure requiring substantial water influx during doping\u003csup\u003e18\u003c/sup\u003e. Second, when replacing DA with more hydrophilic GDA crosslinker, pronounced active swellings are observed along with faster switching characteristics in p(g2T-T), Homo-gDPP, and gDPP-g2T based vOECTs (Fig. 2e and Supplementary Table 1). Third, when cycling frequency increases, not only is a reduced active swelling amplitude observed, but an overall swelling baseline shift to a higher z plateau is revealed (Supplementary Figs. 6). This indicates that when operating under high switching frequencies, the injected electrolyte cannot be fully ejected from the channel (\u003cem\u003evide infra\u003c/em\u003e for swell mapping).\u003c/p\u003e\n\u003cp\u003eNext, the transient swelling behavior is analyzed in detail. In the BBL-based vOECT (Fig. 2f),\u0026nbsp;swelling waveforms are consistent with \u003cem\u003eI\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e curves across all frequencies, transitioning from a near square-wave shape at low frequencies to a triangular-wave shape at high frequencies. Furthermore, the active swelling rate during the doping process is overall slower than that during the dedoping process, which correlates directly with the \u003cem\u003eI\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e behavior and agrees well with the reported \u0026ldquo;slow on, fast off\u0026rdquo; behavior (Supplementary Figs. 7)\u003csup\u003e29\u003c/sup\u003e.\u0026nbsp;Notably, when switching from off to on or from on to off, a sharp decrease or increase spike in \u003cem\u003eI\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e is observed due to the charging or discharging of the capacitance\u003csup\u003e24\u003c/sup\u003e. While at the same moment, the film active swelling exhibits a \u0026ldquo;hold\u0026rdquo; pattern, showing no swelling. However, this is not attributed to capacitance charging/discharging, but due to delayed active swelling of the channel center (\u003cem\u003evide infra\u003c/em\u003e for swell mapping).\u0026nbsp;Similar active swelling characteristics are observed in p(g2T-T): DA-based vOECT, with one key difference: after the \u0026ldquo;hold\u0026rdquo; pattern during the off-to-on process, the film undergoes transient contraction before expansion (Fig. 2g).\u0026nbsp;As shown in Supplementary Figs. 5, unlike that in BBL, p(g2T-T) reveals obvious active swelling either biased positively or negatively, indicating good ionic conductivity for both cations and anions\u003csup\u003e30\u003c/sup\u003e. Consequently, when switching from off to on, counterions [cations for p(g2T-T)] would be ejected first, leading to film contraction first. Then, anions would be injected, leading to film expansion. Such a phenomenon has also been observed in the gDPP-g2T-based channel (Extended Data Fig.2e,f). Note that such a system can also be applied for the swelling monitoring of planar OECTs, but requires good laser light reflection of the channel surface (Extended Data Fig.2g-i).\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003evOECT channel swell mapping\u003c/p\u003e\n\u003cp\u003eBy\u0026nbsp;precisely controlling the relative position between the channel and the laser spot using the\u0026nbsp;planar electrical positioning stage\u0026nbsp;(Fig. 3a), high\u0026nbsp;temporal resolution of the single-point\u0026nbsp;channel\u0026nbsp;swelling\u0026nbsp;monitoring can be incorporated with\u0026nbsp;swell mapping\u0026nbsp;capability\u0026nbsp;across the entire vOECT channel. Specifically, a 6\u0026times;4 measurement grid [(x, y), where x = 1:6, y = 1:4] is constructed over the channel region (80\u0026times;50\u0026nbsp;\u0026mu;m\u003csup\u003e2\u003c/sup\u003e) by scanning the laser spot in defined steps (Extended Data Fig.3). Note, points at (1, y) and (6, y) are located outside the channel with no bottom electrode underneath. Detailed testing protocols can be found in\u0026nbsp;Methods.\u003c/p\u003e\n\u003cp\u003eSwell mappings of different channels are then conducted (Supplementary Videos 1 to 12), demonstrating the unique operando swelling monitoring capability of LDV-M. By extracting specific frames from the mapping movies, the channel swelling behavior can be analyzed with high spatiotemporal resolution. As shown in Fig. 3b,c, and Extended Data Fig.4a,b, obvious swelling in the channel area is observed upon switching, while apparent differences are observed in different channel locations and different driving frequencies. For instance, with 11.1 Hz switching frequency (Fig. 3c), at the initial doping stage (\u003cem\u003et\u003c/em\u003e\u003csub\u003e1\u003c/sub\u003e to \u003cem\u003et\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e), swelling is more pronounced at the channel periphery than at the center; with time progression (\u003cem\u003et\u003c/em\u003e\u003csub\u003e3\u003c/sub\u003e to \u003cem\u003et\u003c/em\u003e\u003csub\u003e5\u003c/sub\u003e), swelling propagates from channel edge to channel center, reaching saturation. Upon the dedoping (\u003cem\u003et\u003c/em\u003e\u003csub\u003e5\u003c/sub\u003e to \u003cem\u003et\u003c/em\u003e\u003csub\u003e8\u003c/sub\u003e) process, the channel edges obviously contract faster than the channel central region. Such a spatiotemporal dependent swelling characteristic provides the hard evidence that, in vOECTs, the doping/dedoping process always starts from the channel edge and then evolves to the channel bulk. With a higher switching frequency of 111.1 Hz, the swelling difference between channel edge and channel center magnifies, indicating unsaturated doping of the channel bulk, which is further supported by the unsaturated \u003cem\u003eI\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e (Extended Data Fig.4b). Moreover, upon repeated switching cycles, a gradual swelling baseline shift towards a higher z plateau is also observed under 111.1 Hz switching frequency (Extended Data Fig.4c). Such a phenomenon suggests that both doping and dedoping processes cannot reach saturation under high switching frequencies due to inferior ionic mobility.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eNext, active swelling behaviors at 3 representative positions are analyzed in detail, which are (1,3), (3,3), and (3,4), representing locations at top electrode edge with no bottom electrode underneath, top electrode edge with bottom electrode underneath, and top electrode above channel center, respectively (Fig. 3d). Obviously, active swelling transient behavior (under 11.1 Hz) at (3,3) is not only lagged (1,3) and (3,4), but also show longer response time [22.2\u0026plusmn;0.4 ms for (3,3), 10.0\u0026plusmn;0.3 ms for (1,3), and 10.3\u0026plusmn;0.2 ms for (3,4),\u0026nbsp;respectively], supporting the ionic doping/dedoping pathway start from the channel edge (Fig. 3e and Supplementary Table 2).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWhile increasing switching frequency from 11.1 Hz to 111.1 Hz, the overall baseline shifts are enhanced, where (1, 3) shows an extraordinary shift of 80.2 nm, while only 46.5 nm and 31.3 nm at (3,4) and (3, 3), respectively, are observed (Fig. 3f,g). In fact, tremendously pronounced swellings at top electrode edge without bottom electrode underneath [(1,y) and (6,y), y = 1:4] are consistently observed, which are 184.2\u0026plusmn;26.1 nm, 183.4\u0026plusmn;24.2 nm, and 107.5\u0026plusmn;31.1 nm for switching frequencies of 3.3 Hz, 11.1 Hz and 111.1 Hz, respectively, while corresponding averaged swelling magnitudes in the channel are only 125.1\u0026plusmn;22.5 nm, 118.8\u0026plusmn;21.1 nm, and 33.5\u0026plusmn;20.1 nm (Fig. 3c, Extended Data Fig.4a,b, and Supplementary Videos 1 to 3). This phenomenon directly indicates that excessive water molecules in the electrolyte solution have been injected into the channel edge (especially the part without the bottom electrodes) during vOECT operation, which could impair cycling stability. In fact, similar swell mapping characteristics are observed in all other polymer channels (Supplementary Videos 4 to 12). Specifically, despite varying swelling magnitudes across different materials, they all exhibit pronounced swelling at the\u0026nbsp;top-electrode edge\u0026nbsp;(Extended Data Fig.5). Especially, up to 380 nm total swelling is observed in p(g2T-T):GDA with an original film thickness of only 80 nm.\u003c/p\u003e\n\u003cp\u003eTo probe the origin of such huge swelling at the top electrode edge, source and drain voltages (\u003cem\u003eV\u003c/em\u003e\u003csub\u003eS\u003c/sub\u003e and \u003cem\u003eV\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e) are both set to 0 V during \u003cem\u003eV\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e switching. As shown in Extended Data Fig.6, for a representative point (3,1), which is located at the top electrode edge with the bottom electrode underneath, enhanced swelling magnitudes are always observed for different channels when no source/drain bias is applied. Especially, apparent baseline shifts are observed with p(g2T-T) and gDPP-g2T-based channels. However, as long as \u003cem\u003eV\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e is biased, no baseline shifts and reduced swelling magnitudes are observed. It is suggested that, when a vertical electric field is applied, i.e., a weak Coulombic force is formed between two electrodes, channel swelling can be effectively suppressed. Additionally, after 1000 switching cycles in the absence of the Coulombic force in a BBL-based vOECT, distinct wrinkles (\u0026gt; 400 nm in height) in the channel region can be observed by optical microscopy and AFM (Supplementary Figs. 8).\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eModulation of the swelling in vOECT towards high-fidelity OECN\u003c/p\u003e\n\u003cp\u003eConsequently, to suppress swelling at the critical top electrode edge region, the encapsulation pattern is re-designed by precisely aligning the opening width with that of the bottom electrode(Fig. 4a and Supplementary Fig. 9). As shown in Supplementary Figs. 10 and 11, swelling is effectively suppressed at the top electrode edge, leading to an overall 21% reduction in swelling amplitude compared to that without optimized encapsulation. Consequently, cycling stabilities of vOECTs with different channel materials can be further enhanced, along with a minor effect on transistor transient characteristics (Fig.\u0026nbsp;4. b,c, and Extended Data Fig.7). Note, the detailed cycling process can be found in Methods. For instance, with switching \u003cem\u003eV\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e from 0.4 V to -0.6 V, 99.7% \u003cem\u003eI\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e retention after 100k cycles (1.4 hrs) is obtained for the optimized p(g2T-T):DA-based vOECT, markedly surpassing 63.84% \u003cem\u003eI\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e retention in the conventionally encapsulated counterpart. Note, channels with GDA crosslinker typically exhibit lower stabilities but faster transient responses than those with DA, which is attributed to the hydrophilic ethylene glycol chain in GDA that facilitates swelling. Moreover, extensively continuous cycling characteristics on vOECTs based on p(g2T-T):DA, Homo-gDPP:DA, and BBL are conducted (Fig. 4d and Extended Data Fig.8). These devices demonstrate stable full switching cycles for 15 million (208.3 hours) and 2.8 million (62.2 hours) for p-type and n-type OECTs, respectively. Note that, in these cycling stability measurements, no measures (for instance, degassing) to avoid side reactions are adopted\u003csup\u003e31\u003c/sup\u003e, while these stabilities are still among the highest reported for OECTs (Fig. 4e and\u0026nbsp;Supplementary Table 3)\u0026nbsp;\u003csup\u003e28,31-41\u003c/sup\u003e.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eNext, such vOECTs are utilized for the construction of a vertically stacked organic electrochemical neuron (vOECN) based on the axon hillock (A-H) circuit. First, vertically stacked complementary inverters are fabricated using gDPP-g2T:DA and Homo-gDPP:DA as p-/n-type channels, respectively (Supplementary Figs. 12). Corresponding transfer and transient curves demonstrate on/off current ratios of ~10⁶ and transient times of ~ 1 ms, which enable inverters with robust logic switching up to 1250 Hz. Then, vOECNs are further integrated (Fig. 4f, Supplementary Figs. 13, and detailed fabrication process can be found in Methods) and characterized. The present leaky integrate-and-fire (LIF) OECN structure mimics the action potential spikes generated by nerve cells\u003csup\u003e42\u003c/sup\u003e, making the dynamic range of spike frequencies profoundly influence the diversity of neural behaviors\u003csup\u003e40,43-45\u003c/sup\u003e. Thus, spike frequency coverage of the developed vOECNs is systematically investigated.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe pulse frequency (\u003cem\u003ef\u003c/em\u003e\u003csub\u003efire\u003c/sub\u003e) of vOECNs can be regulated by the charge-discharge rate of membrane capacitance in the circuit, a process that \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e, \u003cem\u003eC\u003c/em\u003e\u003csub\u003emem\u003c/sub\u003e, and \u003cem\u003eI\u003c/em\u003e\u003csub\u003eIN\u003c/sub\u003e can all manipulate\u003csup\u003e2,40,46\u003c/sup\u003e. As shown in Fig. 4g, under fixed conditions of \u003cem\u003eC\u003c/em\u003e\u003csub\u003emem\u003c/sub\u003e = \u003cem\u003eC\u003c/em\u003e\u003csub\u003ef\u003c/sub\u003e = 500 pF and \u003cem\u003eI\u003c/em\u003e\u003csub\u003eIN\u003c/sub\u003e = 1 \u0026mu;A, \u003cem\u003ef\u003c/em\u003e\u003csub\u003efire\u003c/sub\u003e decreases monotonically from 92.6 Hz to 33.6 Hz as \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e rises from 0.6 V to 0.8 V. This behavior originates from the lower \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e reducing the threshold voltage, enabling capacitors to charge to the threshold more rapidly and trigger spikes. \u003cem\u003eI\u003c/em\u003e\u003csub\u003eIN\u003c/sub\u003e also significantly influences the charge-discharge dynamics of \u003cem\u003eC\u003c/em\u003e\u003csub\u003emem\u003c/sub\u003e, where higher \u003cem\u003eI\u003c/em\u003e\u003csub\u003eIN\u003c/sub\u003e accelerates the process (Fig. 4h). Furthermore, by adjusting \u003cem\u003eC\u003c/em\u003e\u003csub\u003emem\u003c/sub\u003e, the frequency range of vOECNs extends from 0.5 Hz to 1.1 kHz, representing the widest bandwidth reported for OECT-based OECNs to date, fully encompassing the firing spectrum of human neurons (Fig. 4i,\u0026nbsp;Extended Data Fig.9, and\u0026nbsp;Supplementary Table 4)\u003csup\u003e2,40,42,46-52\u003c/sup\u003e. This is attributed to high-resolution channel packaging (55 \u0026times; 105 \u0026mu;m) that reduces parasitic capacitance and integration of smaller external capacitors.\u003c/p\u003e\n\u003cp\u003eLastly, the stability of vOECN is characterized. Fig. 4j demonstrates that vOECN maintains 100% fire voltage (\u003cem\u003eV\u003c/em\u003e\u003csub\u003efire\u003c/sub\u003e) retention after 155,000 switching cycles, an excellent performance attributed to the optimized encapsulation. Furthermore, no performance degradation (100% \u003cem\u003eV\u003c/em\u003e\u003csub\u003efire\u003c/sub\u003e and \u003cem\u003ef\u003c/em\u003e\u003csub\u003efire\u003c/sub\u003e retention) is observed after the vOECN is immersed in 1\u0026times; PBS solution for 15 days, confirming sustained operation throughout the testing period (Fig. 4k). The combined wide-range spiking capability and exceptional stability metrics fully demonstrate the significant application potential of vOECN in the fields of neuromorphic electronics and brain-computer interfaces.\u003c/p\u003e\n\u003cp\u003eThis study introduces a novel in-operando channel swelling monitoring tool, LDV-M, which is currently the sole platform that enables real-time dynamic swelling monitoring in operando conditions. High spatiotemporal resolution swell mapping can be easily accessed, enabling direct observation of swelling behaviors in OMIEC-based vOECTs under diverse conditions (different channel materials, switching frequencies, driving voltages, cycling states, etc.). Apparent differences in swelling magnitudes (from several nm to hundreds of nm) in different channel materials are observed, along with clear ionic doping paths from the vertical channel edge to the channel center. Especially, significant lateral top electrode edge swelling is identified as the primary cause of device degradation, while Coulombic forces between vertically stacked source/drain electrodes effectively suppress such swelling. Consequently, a precise device encapsulation configuration is implemented, enhancing vOECT cyclic stability beyond 15 million full cycles (the highest reported to date). Furthermore, vOECN based on such architecture achieves the broadest\u0026nbsp;\u003cem\u003ef\u003c/em\u003e\u003csub\u003efire\u003c/sub\u003e range from 0.5 Hz to 1.1 kHz, along with 100% spike sustaining after 155,000 cycles and 15-day immersion in 1\u0026times;PBS. Overall, LDV-M provides a novel in situ characterization methodology for dissecting OECT operational mechanisms and offers a practical research tool for OMIEC-based bionic neural engineering.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003cstrong\u003eMaterials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003egDPP-g2T, Homo-gDPP, DA, and GDA were synthesized via previously reported methods\u003csup\u003e25,27,28\u003c/sup\u003e. p(g2T-T) was purchased from Derthon Optoelectronics Materials Science Technology Co., Ltd. BBL, Ag/AgCl paste, Isopropyl alcohol, methanesulfonic acid, and chloroform were purchased from Sigma-Aldrich. Phosphate buffer saline (0.01 M PBS) supplied by Solarbio was used as the electrolyte.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSemiconductor solution preparation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003egDPP-g2T, Homo-gDPP, DA, and GDA were first dissolved in chloroform, respectively, with a concentration of 20 mg ml\u003csup\u003e\u0026minus;1\u003c/sup\u003e. p(g2T-T) was dissolved in chloroform at a concentration of 10 mg ml\u003csup\u003e\u0026minus;1\u003c/sup\u003e. Then those solutions were filtered through a 0.45 \u0026mu;m polyvinylidene difluoride filter. Subsequently, gDPP-g2T, Homo-gDPP, or p(g2T-T) solution was mixed with DA or GDA solution in a mass ratio of 5:1. For BBL, it was dissolved in methanesulfonic acid at a concentration of 15 mg ml\u003csup\u003e\u0026minus;1\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eVertical OECT fabrication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe vOECT fabrication process is illustrated in\u0026nbsp;Supplementary Figs. 2. First, 3 nm of Cr and 130 nm of Au (rate approximately 0.5\u0026ndash;2.0 \u0026Aring; s\u003csup\u003e\u0026minus;1\u003c/sup\u003e) were thermally evaporated on a precleaned Si/100 nm SiO\u003csub\u003e2\u003c/sub\u003e wafer with a shadow mask as the bottom source electrode and gate electrode. Then, the substrates with the bottom electrodes underwent a 15-minute UV-ozone cleaning process. Subsequently, solutions of BBL, Homo-gDPP:GDA,\u0026nbsp;Homo-gDPP:DA, p(g2T-T):GDA, p(g2T-T):DA, gDPP-g2T:GDA, and gDPP-g2T:DA, respectively, were spin-coated at 2,500 rpm for 30 seconds. The films with crosslinkers were then cross-linked by exposure to 365 nm UV light (125 mW/cm\u003csup\u003e2\u003c/sup\u003e) for 2 min; while BBL film was first subjected to a 15-minute immersion in deionized water and subsequently blow-dried with a nitrogen gun. Then, the semiconductor layer was patterned using an LPKF protolaser R4 at 500 kHz with a power of 0.13 W.\u0026nbsp;Then, the top drain electrode (130 nm Au) was thermally evaporated (rate approximately 0.5\u0026ndash;2.0 \u0026Aring; s\u003csup\u003e\u0026minus;1\u003c/sup\u003e) with a shadow mask while maintaining the substrate at a temperature of ~ 5 ℃ with a back water-cooling system. Subsequently, an SU8-2002 solution was spin-coated onto the substrate at 2,000 rpm for 60 s. The sample was then heated on a 95 \u0026deg;C hotplate for 80 s, exposed to light (28 mW/cm\u0026sup2;) for 20 s using a shadow mask, and reheated on the 95 \u0026deg;C hotplate for 80 s. The encapsulation layer was then patterned by developing the SU8 in a developer for 10 s, rinsing in isopropanol for 10 s, and blow-drying. Finally, an Ag/AgCl paste was applied onto the gate electrode and vacuum-dried for 30 min, the device was semi-sealed with glass, and 10\u0026ndash;30 \u0026mu;L of 1\u0026times; PBS solution was introduced into the semi-sealed region.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePlanar OECT fabrication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFirst, 3 nm of Cr and 50 nm of Au (rate approximately 0.5\u0026ndash;2.0 \u0026Aring; s\u003csup\u003e\u0026minus;1\u003c/sup\u003e) were thermally evaporated on a precleaned Si/100 nm SiO\u003csub\u003e2\u003c/sub\u003e wafer with a shadow mask as the source, drain, and gate electrodes. Then, the substrates with the electrodes underwent a 15-minute UV-ozone cleaning process. Subsequently, solutions of BBL and p(g2T-T):GDA were spin-coated at 2,500 rpm for 30 seconds. The films with crosslinkers were then cross-linked by exposure to 365 nm UV light (125 mW/cm\u003csup\u003e2\u003c/sup\u003e) for 2 min; while BBL film was first subjected to a 15-minute immersion in deionized water and subsequently blow-dried with a nitrogen gun. Then, the semiconductor layer was patterned using an LPKF protolaser R4 at 500 kHz with a power of 0.13 W. Subsequently, an SU8-2002 solution was spin-coated onto the substrate at 2,000 rpm for 60 s. The sample was then heated on a 95 \u0026deg;C hotplate for 80 s, exposed to light (28 mW/cm\u0026sup2;) for 20 s using a shadow mask, and reheated on the 95 \u0026deg;C hotplate for 80 s. The encapsulation layer was then patterned by developing the SU8 in a developer for 10 s, rinsing in isopropanol for 10 s, and blow-drying. Finally, an Ag/AgCl paste was applied onto the gate electrode and vacuum-dried for 30 min, the device was semi-sealed with glass, and 10\u0026ndash;30 \u0026mu;L of 1\u0026times; PBS solution was introduced into the semi-sealed region.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eVertical OECN fabrication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003evOECN fabrication process can be found in\u0026nbsp;Supplementary Fig. 13. First, 3 nm of Cr and 80 nm of Au (rate approximately 0.5\u0026ndash;2.0 \u0026Aring; s\u003csup\u003e\u0026minus;1\u003c/sup\u003e) were thermally evaporated on a precleaned glass substrate with a shadow mask as the bottom electrode. gDPP-g2T:DA blend solution was spin-coated at 2,500 rpm for 20 s. The film was then cross-linked by exposure to 365 nm UV light (125 mW/cm\u003csup\u003e2\u003c/sup\u003e) for 2 min, and the semiconductor layer was patterned using an LPKF protolaser R4 at 500 kHz with a power of 0.13 W. Next, the middle drain electrode (80 nm Au) was then thermally evaporated (rate approximately 0.5\u0026ndash;2.0 \u0026Aring; s\u003csup\u003e\u0026minus;1\u003c/sup\u003e) with a shadow mask while maintaining the substrate at a temperature of ~ 5 ℃ with a back water-cooling system. Then, Homo-gDPP:DA blend solution was spin-coated and photopatterned using the same protocol as the p-type material to form the n-type channels in the amplifier block and \u003cem\u003eT\u003c/em\u003e\u003csub\u003ereset\u003c/sub\u003e regions. The top electrode (GND) was fabricated by thermal evaporation of an 80 nm Au layer through a shadow mask. To expose active channel areas, gate electrodes, and capacitor connection points, the substrate was coated with an SU8-2002 solution via spin-coating at 2,000 rpm for 60 s, followed by a 95 \u0026deg;C hotplate bake for 80 s. The SU8 layer was then exposed to 28 mW/cm\u0026sup2; UV light through a shadow mask for 20 s and subjected to a post-exposure bake at 95 \u0026deg;C for 80 s. Patterning development was achieved by immersing the sample in SU8 developer for 10 s, rinsing with isopropanol for 10 s, and drying with compressed air to form the encapsulated structure. Gate electrodes of the amplifier block and \u003cem\u003eT\u003c/em\u003e\u003csub\u003ereset\u003c/sub\u003e were coated with Ag/AgCl paste and vacuum-dried for 30 min. Capacitors were then attached using conductive silver paint. Finally, 1\u0026times; PBS electrolyte was dropped onto the gate electrodes and adjacent active channel regions to complete device fabrication.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLDV-M\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;platform configuration\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe LDV-M employed a 633 nm wavelength Doppler laser vibrometer (Polytec Inc., VibroFlex Compact), with a \u0026times;20 objective lens (VIB-A-20\u0026times;) mounted on the laser probe to focus the laser spot to be 3 \u0026mu;m diameter. vOECT electrodes were clamped by a 3M chip testing fixture (which is further connected with a semiconductor analyzer) and fixed onto a custom-designed planar electrical positioning stage with micron-level positioning accuracy and multi-axis adjustability (x, y, z, pitch angle). The laser is incident perpendicularly onto the sample surface, while the laser spot position on the surface is real-time monitored by a CMOS color camera integrated into the vibrometer. Additionally, a semiconductor parameter analyzer (FS-Pro) drives the OECT and acquires its electrical signals simultaneously, while the laser vibrometer collects swelling signals. Notably, both the vibrometer and the planar electrical positioning stage are mounted on the same optical table to enhance the signal-to-noise ratio.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eElectrical measurements\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eUnder ambient conditions, the electrical properties of vOECTs, inverters, and vOECNs were characterized using an FS-Pro (PDA) semiconductor analyzer and a probe station (Chengdu Chiptest Technology Co., LTD.).\u003c/p\u003e\n\u003cp\u003eFor cycling stability test: first, a transfer curve of the device was measured; then, a rectangular wave pulse with fixed frequency and amplitude was applied to the \u003cem\u003eV\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e for cyclic stability testing\u003cem\u003e,\u0026nbsp;\u003c/em\u003ewhile \u003cem\u003eV\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e was 0.1 V and -0.1 V for n-type and p-type OECTs, respectively. This process was repeated multiple times to enable larger cycling numbers and time. Specifically, for p(g2T-T):DA and p(g2T-T):GDA-based vOECT, \u003cem\u003eV\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e = 0.4 to -0.6 V, frequency = 20 Hz; for BBL-based vOECT, \u003cem\u003eV\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e = -0.3 to 0.5 V, frequency = 12.5 Hz; for Homo-gDPP:DA-based vOECT, the test conditions in Fig. 4c,d were \u003cem\u003eV\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e\u0026nbsp; = 0 to 0.9 V at 25 Hz and \u003cem\u003eV\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e\u0026nbsp; = 0 to 0.8 V at 20 Hz, respectively; for Homo-gDPP:GDA-based vOECT, \u003cem\u003eV\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e = 0 to 0.9 V, frequency = 25 Hz; for gDPP-g2T:DA and gDPP-g2T:GDA-based vOECT, \u003cem\u003eV\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e = -0.3 to -0.6 V, frequency = 25 Hz.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn Fig. 4c and Extended Data Fig. 7, transfer curves were gathered every 20,000 switching cycles for vOECTs using p(g2T-T):DA/GDA, Homo-gDPP:DA/GDA, or gDPP-g2T:DA/GDA, and every 5,000 switching cycles for BBL-based vOECT. In Fig. 4d and\u0026nbsp;Extended Data Fig. 8, transfer curves were collected every 100,000 switching cycles for vOECTs based on p(g2T-T):DA, and every 50,000 switching cycles for those based on Homo-gDPP:DA and BBL. Notably, to maintain a relatively stable 1\u0026times; PBS electrolyte concentration, a PDMS well was placed on top of the active region of the device, and ~50 \u0026mu;L of 1\u0026times; PBS solution was added to restrict electrolyte displacement and slow down electrolyte evaporation.\u003c/p\u003e\n\u003cp\u003eFor the voltage transfer characteristic measurement of inverters, the \u003cem\u003eV\u003c/em\u003e\u003csub\u003eIN\u003c/sub\u003e was supplied by the FS-Pro with a step interval of 2 mV, and the output voltage was also recorded by the FS-Pro (PDA). To characterize the frequency response of the inverters, the FS-Pro was used to apply \u003cem\u003eV\u003c/em\u003e\u003csub\u003eIN\u003c/sub\u003e voltages with a fixed amplitude range of 0 to 0.7 V and varying frequencies (50 Hz to 1.25 kHz), while the output characteristics were recorded.\u003c/p\u003e\n\u003cp\u003eFor the electrical characterization of vOECNs, the FS-Pro provided different constant \u003cem\u003eI\u003c/em\u003e\u003csub\u003eIN\u003c/sub\u003e = 0.05 to 50 \u0026mu;A and \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e = 0.6 to 0.8 V, with a sampling frequency of 50,000 samples per second during testing. To evaluate the cyclic stability of vOECNs, a constant \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e = 0.7 V and \u003cem\u003eI\u003c/em\u003e\u003csub\u003eIN\u003c/sub\u003e = 1.1 \u0026mu;A were applied via the FS-Pro, and the output characteristics were recorded. Notably, three independent PDMS wells were designed at the electrolyte droplet positions to ensure an adequate volume of 1\u0026times; PBS solution and prevent short circuits caused by electrolyte mixing. For the storage stability test of vOECNs, a 3D-printed sealed container was employed to house the vOECN, which was immersed in 1\u0026times; PBS within the container. Before each test, the vOECN was removed, rinsed with deionized water, dried using a nitrogen gun, and then characterized.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eVertical OECT swelling measurements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFor swelling testing of vOECTs, the laser spot position on the vOECT device surface was first observed and adjusted using a CMOS color camera to determine the measured point position (Polytec Inc., VibroFlex Compact). Subsequently, the vOECT is driven by the Fs-Pro semiconductor analyzer, and \u003cem\u003eV\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e supplied by Fs-Pro is also synchronized with the laser vibrometer. Note, V\u003csub\u003eG\u003c/sub\u003e switching frequencies of 3.3 Hz, 11.1 Hz, and 111.1 Hz are chosen to minimize the interference of the power line interference (50 Hz).\u003c/p\u003e\n\u003cp\u003eFor swell mapping of vOECT channels, the laser spot was first positioned at the lower-left corner of the OECT top electrode (1,1) using a CMOS color camera. A custom-designed planar electrical positioning stage controlled by LabView was used to perform a 6\u0026times;4 scanning matrix with a 16 \u0026mu;m step size: 5 steps right (80 \u0026mu;m), return to the origin, 1 step up, and 3 steps right (50 \u0026mu;m), scanning from the lower-left to upper-right of the electrode. During scanning, Fs-Pro generated rectangular wave \u003cem\u003eV\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e signals to switch the device on/off state and record \u003cem\u003eI\u003c/em\u003e\u003csub\u003eD\u003c/sub\u003e; the laser vibrometer collects the corresponding swelling and \u003cem\u003eV\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e signals, while the CMOS camera records the position of the laser spot at each step.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePlanar OECT swelling measurements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFor swelling testing of planar OECTs, the laser spot position on the planar OECT device surface was first observed and adjusted using a CMOS color camera to determine the measured point position (Polytec Inc., VibroFlex Compact). Subsequently, the planar OECT is driven by the Fs-Pro semiconductor analyzer. Note, \u003cem\u003eV\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e switching frequency is 3.3 Hz.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eOECT swelling data analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFor the collected vOECT/planar OECT swelling data, the acquired signals were filtered using a band-stop filter at 24-26 and 49-51 Hz to minimize power line interference (50 Hz). Additionally, as both the source meter (Fs-Pro) and laser vibrometer record \u003cem\u003eV\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e voltage signals, synchronization of the vOECT switching current with the swelling signal was achieved by aligning the \u003cem\u003eV\u003c/em\u003e\u003csub\u003eG\u003c/sub\u003e voltage traces from both devices.\u003c/p\u003e\n\u003cp\u003eSwelling magnitudes of the vOECT channels contain two parts: active swelling and baseline shift (Fig. 2c and Fig. S6). When analyzing the degree of doping and dedoping of films, swelling from baseline shift is excluded to focus solely on active swelling signals. All swelling data analyses, except those labeled \u0026quot;active swelling\u0026quot;, include both baseline shift and active swelling (e.g., 3D swelling distribution maps of devices and swelling across multiple device cycles).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEQCM measurements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEQCM measurements were performed using a gold‐coated quartz crystal sensor and a quartz crystal microbalance (QCM922A, Princeton Applied Research).\u0026nbsp;The polymer film was patterned to define an active gold area (~0.2 cm\u0026sup2;). Before film deposition, the crystal\u0026rsquo;s fundamental frequency was tested in air and electrolyte (0.01 M PBS) solution environments. After spin-coating and patterning the semiconductor film onto the crystal, the fundamental frequency was retested in the same environments to calculate passive swelling. Finally, the crystal was connected to an Fs-pro semiconductor parameter analyzer via a chip testing fixture, with the Fs-pro generating rectangular wave voltage signals to induce film doping/dedoping while recording current signals. Previous studies have shown that ~100 nm-thick polymer films can be considered \u0026ldquo;rigid\u0026rdquo; films\u003csup\u003e18\u003c/sup\u003e, so in this work, mass changes were calculated using the Sauerbrey equation:\u003c/p\u003e\n\u003cp\u003e\u003cimg 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fEIZw95KTbrhkB8lIraM0+m0ZZRKJVc55pFZ4qgZ3mpWVdXyvJIkGRNu+DI7O8tisVhBy7gU83hvWZaZqqpMlmWmKIrl9fgwYPG7yq+m7Y4Nv5qQ8xP8mhEF8irhH3a5i67rxhfA6Re2EfQGFs1vNeYhf+ZFPP5mfMz0VsGXp6TMz2UOVJqmlXydYoqd/zwtIS78NcwB2G4pJ3iGQiEjGEv5ImDm4yE+N/JBu9h7L/aYSo5PrXlYLbvQayCZTGJpaclRPWi3mJubwxdffAFd18sebdBI8XgcPT09NR2FQXa2cDiMx48f4/333wfy9bvNrly5gr6+PkxPT1vWE4EY2ZtZOj/tVrz0cTtFUYq2xnmLJpYvxMNbBU5bKbUUzE+/JqQSsVhsyxmo/Lwnpbmqs/Ps2bOuHzOaSqXQ1taGZDIJmIbOnTx5UtzVaPECwLFjx9Db2wvGGGRZxoULF8Td6+7KlSvUUiIVO3jwIHK5XMmO1+vXr+Po0aPiaiJwTSAPh8PGKA9+GeZG//zzD3K5HHbt2oV4PI6DBw/i2rVrtimV7u5uxGIxIF8Xmk8y6uvrKzoxplYymQzGxsbQ1taGtrY2fPbZZ7h69aq4GyGOybIMXdfxxhtvIBAIYHJy0ljGxsbg9XrR29tbszHsO4rYRG9GiUSCqapq9Hw3Y2eDUzw9hPzIgK0KEZlTK5xWwR3oI5GI8booc6wuf8+KojBd19mhQ4fYm2++Ke5GSNl4lVBzZ6KSrzzYDOlDt2j6QJ7O16XmwbxZ8sP1Uo1AznvlFUVhqqoaEy9gM0zMDv8B5SNXOjs7d3zeUtd1FolEjEqC/AdX13Wjr0Ic2kZIozR9INc0zRgby4cWtZLtBnJd15miKJbHp0031t3qh5G/Ph+WZje7zW6d25lbiPxYJxIJpmka03XdGI/s5qtDsnM0dY48HA5DkiQjN0z1NMp3+/ZtzM/PW/KM7e3tmJ6eNmpULC8vmx5hxevGvPbaa+jp6UE0Gi0oGjY+Pi4+zPUYY0b/hM/nM4a9Tk9Po6OjA7lcTnwIIY0jRvZmwVMpXDpfq3sntv6KEe84YpdP3A6ecrEbzmlutbfSMTcz361JvHsOT09RaoU0g6ZskWcyGZw+fdoytO3BgweWfVqB3+9HPv0Fxhj8fj9WV1ct66phz549xr8zmQw8Hg9eeuklzMzMAIDRCi81TIzLZDIIh8Po7+9Hf38/kJ/wxGu0+P1+R8/TDNbX1yFJEu7evYuvv/7aWL+ysmJUBaxlHRJCnGrKQH727FlEo1HIsmxcvvPx1HbD9EhlHj16BEmS8N577xnr2tvbjR8JfjMBXdfBGHMUtJaXl3Hx4kVEo1EAQCAQQDKZxPDwMGRZxuLiIs6ePSs+rOlkMhksLi4il8uht7fX8rf/+uuvgAsKnJEWIjbRG83uMpZtkQYg5Uvn71FYatQKKiyKxet+iPdF5DVlJEmy7N+MeFrLLq3EO90prUKaRVO1yJPJJK5evWpbR+XZs2fiKrINCwsL2Lt3L0ZGRsRNgKlIf19fn7hpSy+88AIAYO/evejq6jLW86spN3QU3rx5EwAKOnL5rdQ0TXN0hUJIPTRNIE8mkzh8+DB++ukncRMA4I8//gBcPquzWSSTSUxMTBQ91gBw69YtAMCBAwfETS1hbW0NiqIUzCpcWloC8sdFvD0ZIY3S8ECeyWQwNzeHffv2QZIkcTOQrzly7949wHQDBlKZTCaDoaEhrK+vl2xRrq2tAYAlf94qeGem3S3TFhcXAQCvvPIKnj59Km4mpDHEXEs98ZypeRFzsuJ2vtBEjPKZZ8mWwm8ZZpcfdoJPIrJ7PP/8mhkfdml3nCRJYrIsOy5vQEg9NLRF3tHRYRlKxxjD5uamZR9xO1/ES15SWiaTQX9/P4LBoCVvbYePOPn444/FTS1henoajDHb45TNZrG5uVnWrcgIqbWGBnJSHzyIf/PNN7bBKRwOW+5A/vPPPwMA9u/fb9qLENKsXHeHIFIeHsR1XcfevXvFzdjc3EQ2m0U2mwXy9dJlWYaqqlhdXRV3N7YjX4ZUvIJCfuz4zMwMZFnG77//buTik8kk3n77bQBAJBKhVi0h1SLmWsjOYi5dW2wxj9vn46ftbuLL+zR4/0QwGHTUpxEMBgtKC6BIDp0QUj5qkRMLv9+PjY2Noi1t5HPInMfjQSgUMgqbEULqj3LkxMCnpfOKh6KZmRn09vZa1mmahrt371rWEULqiwJ5C1tZWUFbW5vx/4WFBSiKYtu65reW2717t7jJGHNOCGkMCuQt7K+//jIC+dzcHCYmJowJL4QQ96BA3sJUVUU2m0VbWxuSySQePnxI1SUJcSEK5C2sq6vLGHo4PT1dcso+D/DitPRUKlVRYS1CSPVQICeO2XVsRqPRgg5QQkh90fBD4hifDBSLxdDd3Y3JyUncuXPHduIQIaR+KJCTssTjceNuTcVmfxJC6osCOSGEuBzlyAkhxOUokBNCiMtRICeEEJejQE4IIS5HgZwQQlyOAjkhhLgcBXJCCHE5CuSEEOJyFMgJIcTlKJATQojLUSAnhBCXo0BOCCEuR4GcEEJc7v8BE/pNSi/eGf4AAAAASUVORK5CYII=\" width=\"370\" height=\"100\"\u003e\u003c/p\u003e\n\u003cp\u003ewhere \u0026Delta;\u003cem\u003ef\u003c/em\u003e\u003csub\u003en\u003c/sub\u003e is the frequency shift of the \u003cem\u003en\u003c/em\u003eth overtone, \u003cem\u003eA\u003c/em\u003e is the sensor active area, \u003cem\u003e\u0026rho;\u003c/em\u003e\u003csub\u003eq\u003c/sub\u003e is the density of quartz, \u003cem\u003eV\u003c/em\u003eq is the shear wave velocity in quartz, \u003cem\u003ef\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e is the fundamental frequency and \u003cem\u003en\u003c/em\u003e is the overtone number (fixed at 1). Relative mass change was calculated as the percentage change in total mass relative to the dry mass:\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"data:image/png;base64,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\" width=\"433\" height=\"100\"\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAFM Measurements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe film thickness was measured using atomic force microscopy (AFM) in tapping mode, with a Park NX7 AFM equipped with a silicon tip. Specimens for film thickness measurement were prepared following the same fabrication process as that used for the semiconductor layers in each vOECT. Then, the film surface was scratched with tweezers. Subsequently, AFM was used to measure the height difference between the two sides of the scratch, which was taken as the thickness of the film.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eAcknowledgments:\u0026nbsp;We thank\u0026nbsp;W.\u0026nbsp;Wang\u0026nbsp;from Polytec China Ltd. for technical support.\u0026nbsp;This work is financially supported by the National Key R\u0026amp;D Program of China\u0026nbsp;(2022YFE0134800), the National Natural Science Foundation of China (No. 62273073,\u0026nbsp;52273316), the National Key R\u0026amp;D Program of China (2024YFB3211600, 2023YFC2411800), the Aeronautical Science Foundation of China (20230024080002), the Natural Science Foundation of Sichuan (2025ZNSFSC0515),\u0026nbsp;Sichuan Science and Technology Program (2023YFSY0064),\u0026nbsp;Chengdu Science Technology Bureau (2023-YF06-00028-HZ), the Fundamental Research Funds for the Central Universities (ZYGX2025TS009,\u0026nbsp;ZYGX2024XJ029, ZYGX2024XJ031), and\u0026nbsp;Scientific Research Innovation Capability Support Project for Young Faculty (ZYGXQNJSKYCXNLZCXM-M1P).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contr\u003c/strong\u003e\u003cstrong\u003eibutions:\u003c/strong\u003e Z.D.,\u0026nbsp;C.C., and W.H. conceived the idea and designed the experiments.\u0026nbsp;Z.D.\u0026nbsp;and\u0026nbsp;S.Z.\u0026nbsp;performed\u0026nbsp;OECT\u0026nbsp;fabrication\u0026nbsp;and measurement.\u0026nbsp;Z.D.,\u0026nbsp;J.W., M.X., L.H., Y.C., C.C., and\u0026nbsp;W.H.\u0026nbsp;constructed the swelling system.\u0026nbsp;Z.D., S.Z.,\u0026nbsp;and D.Z.\u0026nbsp;performed the OECT\u0026nbsp;swelling measurement. Z.D.\u0026nbsp;performed\u0026nbsp;OECN\u0026nbsp;fabrication\u0026nbsp;and measurement. Z.D. and D.L.\u0026nbsp;produced\u0026nbsp;the swelling animation. Y.Z. performed the AFM measurement. Z.D., S.Z., J.Z., and L.-W.F. performed the EQCM measurement.\u0026nbsp;J.C. synthesized the Homo-gDPP and\u0026nbsp;gDPP-g2T.\u0026nbsp;Y.L. and L.-W.F.\u0026nbsp;synthesized the\u0026nbsp;DA\u0026nbsp;and GDA. Z.D. and W.H. wrote the manuscript. All the authors reviewed and approved the manuscript.\u003c/p\u003e\n\u003cp\u003eCompeting interests:\u0026nbsp;Z.D., C.C., and W.H. are inventors on patent applications related to the LDV-M platform and designs of high-fidelity OECTs.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability:\u0026nbsp;\u003c/strong\u003eThe datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eGkoupidenis, P.\u003cem\u003e et al.\u003c/em\u003e Organic mixed conductors for bioinspired electronics. \u003cem\u003eNat. Rev. Mater.\u003c/em\u003e \u003cstrong\u003e9\u003c/strong\u003e, 134-149 (2023). https://doi.org/10.1038/s41578-023-00622-5\u003c/li\u003e\n\u003cli\u003eHarikesh, P. 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However, operando swelling monitoring with high spatiotemporal resolution has remained a challenge owing to the inherent limitations of existing techniques. Here, we introduce an in-situ characterization platform for real-time swelling monitoring of OECT channels by incorporating a laser Doppler vibrometer with a customized testing module. This approach enables dynamic reconstruction of the swelling process with sub-nanometer and sub-microsecond spatiotemporal resolution, revealing apparent inhomogeneity in swelling magnitudes (4 nm ~ 400 nm) in different OMIECs and channel locations, along with distinct ionic (de)doping paths originating from vertical channel edge. Moreover, we identify the Coulomb force between vertically stacked source/drain electrodes as an effective factor for swelling suppression, which enables the demonstration of high-fidelity OECTs (\u003e 15 million full switching cycles) and organic artificial neurons (\u003e 15-day stable operation in 1×PBS). Our work provides a brand-new route for guiding OMIEC synthesis, elucidating underlying mechanisms, and advancing the design of robust (bio)electronic devices.","manuscriptTitle":"Operando High-Resolution Swell Mapping for Mixed Ionic-Electronic Channel","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-04 07:04:25","doi":"10.21203/rs.3.rs-7958348/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"nature-electronics","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"natelectron","sideBox":"Learn more about [Nature Electronics](http://www.nature.com/natelectron/)","snPcode":"","submissionUrl":"","title":"Nature Electronics","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature Research","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"5c7e86f6-e60e-4ae6-ab18-1244d7f5e3f9","owner":[],"postedDate":"November 4th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":57255959,"name":"Physical sciences/Materials science/Materials for devices/Electronic devices"},{"id":57255960,"name":"Physical sciences/Nanoscience and technology/Nanoscale devices/Electronic devices"}],"tags":[],"updatedAt":"2026-05-09T09:11:54+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-04 07:04:25","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7958348","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7958348","identity":"rs-7958348","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}