Insulating Effect of Alkyl Chains for Low-Power and High-Stability Organic Transistors and Circuits

Insulating Effect of Alkyl Chains for Low-Power and High-Stability Organic Transistors and Circuits | 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 Insulating Effect of Alkyl Chains for Low-Power and High-Stability Organic Transistors and Circuits Liqiang Li, Jiannan Qi, Jialu Xue, Xufan Li, Kai Tie, Zhongwu Wang, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5398767/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract The designability of organic semiconductors (OSCs) enables the tunable properties of organic field-effect transistors (OFETs) with significant potential applications in flexible displays, wearable devices, and bioelectronic devices. The introduction of alkyl chains has been proved to effectively modulate the mobility, crystallinity, solubility, and other optoelectronic properties of OSCs. Here, we revealed that the alkyl chains can function as dielectric components in OFETs due to their insulating effect. The ultrathin alkyl chains are covalently bonded to the OSC backbone, eliminating the heterogeneous charge transport interface and reducing the trap density, which enables low-power and high-stability alkylated-OFETs. The 2,9-didecyldinaphtho[2,3-b:2’,3’-f]thieno[3,2-b]thiophene (C10-DNTT) FET with alkyl chain exhibits a mobility of 11.6 cm2 V−1 s−1 and an ultrahigh intrinsic gain of 7.52×104 at operational voltage of 1 V. The corresponding inverters show exceptional static (small-signal gains of 127.6 and total noise margin of 95.3% at VDD = 2.5 V) and dynamic characteristics (signal-delay time constants of 50 μs at VDD = 1 V) under low voltage. Additionally, the C10-DNTT FETs and inverters demonstrate outstanding operational stability, enduring 30000 seconds of bias stress and cycle tests. This work offers a solution for achieving both low-power and high-stability organic electronic and optoelectronic application. Physical sciences/Materials science/Materials for devices/Electronic devices Physical sciences/Chemistry/Materials chemistry/Electronic materials Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Organic field-effect transistors (OFETs) are considered important building blocks in the burgeoning $20-billion-per-year flexible electronics market 1 , with significant potential applications in flexible display 2 , 3 , wearable devices 4 – 6 , and bioelectronic devices 7 , 8 . The first OFET utilizing polythiophene as an active layer was reported in 1986 9 , exhibiting a mobility ( µ ) of only 10 − 5 cm 2 V − 1 s − 1 under high operating voltage. The poor electrical properties of organic semiconductors (OSCs) and high power are critical challenges faced by OFETs in practical applications. The chemical design of OSCs enables the development of high-performance OFETs 10 , 11 . The introduction of alkyl chains into OSCs is a common strategy in chemical design, often employed to modulate the electronic and optoelectronic properties for OSCs. Yuji Yamaguchi et al. demonstrated that alkyl chains significantly impact solubility, thermal durability, self-organization ability, and carrier transport of OSCs 12 . Hatsumi Mori et al. noted that the length of alkyl chains affects the microstructure of OSC films 13 . Henning Sirringhaus et al. indicated that alkyl chains influence the lattice thermal conductivity of OSC polycrystalline films 14 . Moreover, they observed that while alkyl chains benefit in-plane carrier transport, their insulating effect adversely affects out-of-plane charge transport 15 . However, the utilization of insulating properties for alkyl chains in OSCs has not received widespread attention. In this work, we revealed that the alkyl chains of alkylated OSCs can serve as dielectric components in OFETs due to their insulating effect. The ultra-thin alkyl chains provide barrier of 4.5 eV for carrier tunneling, which is superior to that of Al 2 O 3 (approximately 1–3 eV) 16 – 18 and SiO 2 (3.2 eV) 19 , enabling alkylated-OSCs to function as both active and dielectric components for low-power OFETs. Besides, the traditional heterogeneous charge transport interface present in conventional OFETs is absent in alkylated OFETs, due to the covalent bond connection between the alkyl chains and the OSC backbone. This improves the operational stability of alkylated-OFETs, addresses the stability issues caused by the polarity effects and interface traps in low-power OFETs using high- k dielectric layers 20 – 22 . Furthermore, organic inverters using the insulating effect of alkyl chain exhibit excellent dynamic and static characteristics under low-power conditions while maintaining outstanding operational stability. Low-power alkylated-OFETs with high operational stability are achieved through the appropriate selection of OSC materials. The insulating effect of alkyl chain layers in alkylated FETs To verify the insulating effect of alkyl chains, we selected chemically stable dinaphtho[2,3-b:2’,3’-f]thieno[3,2-b]thiophene (DNTT), 2,9-dihexylnaphtho[2,3-b]naphtho[2’,3’:4,5]thieno[2,3-d]thiophene (C 6 -DNTT), and 2,9-didecyldinaphtho[2,3-b:2’,3’-f]thieno[3,2-b]thiophene (C 10 -DNTT) as OSC layers, and their molecular structures are shown in Fig. 1 a. The OSC layers were prepared by vacuum thermal deposition on heavily doped Si substrates. Octadecyltrichlorosilane (OTS) was modified onto the substrate to promote the vertical growth of the OSC molecules. The Au source-drain electrodes were then deposited to fabricate staggered structure DNTT, C 6 -DNTT, and C 10 -DNTT FETs. I GS typically arises from non-ideal currents generated between the gate and source-drain electrodes due to carrier quantum tunneling through the dielectric layer. Due to the high tunneling barrier of the alkyl chains 19 , alkylated-DNTT (C 6 -DNTT and C 10 -DNTT) FETs can significantly reduce I GS , whereas the DNTT FETs without alkyl chains fail to operate properly due to the large I GS (Fig. 1 b, c). We tested the transfer characteristics of the three OFETs (Fig. 1 d, e and Supplementary Fig. 1a). The I GS in DNTT FETs was even higher than the maximum on-state current, illustrating that without the insulating effect provided by the alkyl chains, the devices could not operate properly (Fig. 1 d). As the alkyl chain length increased, the I GS in C 10 -DNTT FETs was an order of magnitude lower than that in C 6 -DNTT FETs (Fig. 1 e and Supplementary Fig. 1a). The subthreshold slopes ( SS ) of C 6 -DNTT FETs and C 10 -DNTT FETs were 121.8 mV dec − 1 and 79.5 mV dec − 1 , respectively. A lower SS indicates fewer interface defects in C 10 -DNTT FETs compared to C 6 -DNTT FETs. The output characteristics of the three devices were also measured (Fig. 1 f, g and Supplementary Fig. 1b). Due to the high I GS in DNTT FETs, the DNTT device exhibited a high drain-source current ( I DS ) even when drain-source voltage ( V DS ) was zero (Fig. 1 f). In contrast, C 6 -DNTT and C 10 -DNTT FETs could be quickly turned on and saturated at a gate-source voltage ( V GS ) as low as 1 V, demonstrating excellent low-voltage operation characteristics of low-power alkylated-DNTT FETs (Fig. 1 g and Supplementary Fig. 1b). SAM layers are reported and studied as dielectric layers 24 . To further demonstrate that the insulating properties of alkylated-DNTT FETs originate from the alkyl chains, we employed methyltrichlorosilane (MTS) which only contains a methyl group as the SAM layer to modify the OSC molecules stacking. We then fabricated staggered DNTT, C 6 -DNTT, and C 10 -DNTT FETs on the MTS-modified substrate. The transfer characteristics of these three devices were measured (Supplementary Fig. 2). The MTS-alkylated-DNTT devices operated normally whereas the MTS-DNTT devices exhibit no field-effect characteristics. This further confirms that the alkyl chains of the alkylated OSCs provide essential insulation for achieving low-power organic transistors. Characterizations of alkylated-OFETs The size of the alkyl chain length can be determined by the X-ray diffraction (XRD) patterns of OSCs 25 , 26 . The C 6 and C 10 alkyl chain lengths were determined from the d 001 of three OSCs to be 0.61 nm and 1.135 nm, respectively (Supplementary Fig. 3 and Supplementary Note 1). Considering the native oxide of Si (relative dielectric constant is 3.9), OTS, and the alkyl chains (relative dielectric constant is 2.5), the ideal capacitances ( C i ) of the C 6 -DNTT and C 10 -DNTT devices were calculated to be 430.9 nF cm − 2 and 395.1 nF cm − 2 , respectively. The mobility of the alkylated-DNTT devices as a function of gate-source voltage ( V GS ) is plotted in Fig. 2 a and Supplementary Fig. 4. The mobility of C 10 -DNTT FETs is 11.6 cm 2 V − 1 s − 1 . The µ - V GS curve of C 10 -DNTT showed a clear plateau over a broad V GS range, indicating a reliable assessment of mobility. In contrast, the mobility of C 6 -DNTT was slightly lower at 1.3 cm 2 V − 1 s − 1 . As the alkyl chain length increases, OSC molecules form an isolated alkyl chain layer, which effectively raises the cohesive energy within the crystal and enhances the electrical performance of the corresponding OFETs 27 . To investigate the influence of the alkyl chain layer on the operational stability of OFETs, a constant bias was applied to the three OFETs for 30000 seconds. The evolution of the normalized I DS was measured over time, revealing that the I DS of the C 10 -DNTT device retained 99% and 93% of its original value after 10000 and 30000 seconds of operation, respectively. In contrast, the I DS of the DNTT device retained only 8% of its original value after 10000 seconds and less than 1% after 30000 seconds (Fig. 2 b). Additionally, the transfer characteristics of three OFETs were measured under different bias stress time (Fig. 2 c and Supplementary Fig. 5). The threshold voltage of the C 10 -DNTT FETs showed negligible decrease or shift compared to the DNTT and C 6 -DNTT FETs. These results indicate that the operational stability of the devices improves significantly with the increase in alkyl chain length. The weak polarization effect and ability of eliminating heterogeneous carrier transport interfaces of long alkyl chains is the reason for the excellent operational stability of alkylated-DNTT FETs. Moreover, we calculated the energy distribution of trap density of states (trap DOS) within the bandgap using Grünewald's method 28 , 29 (Supplementary Note 2). The trap DOS function was determined by analyzing the dependence of I DS on V GS in the transfer characteristics in the linear regime (Supplementary Fig. 6). The trap DOS of the three devices is plotted in Fig. 2 d. As the alkyl chains are introduced and elongated in OSC molecules, the trap DOS in the OSC layer decreases. Due to the covalent bond connection between the alkyl chains and the OSC backbone, the heterogeneous charge transport interface is eliminated and the carrier traps are decreased by the alkyl chains. These improved electrical performance and operational stability of alkylated-DNTT FETs compared with DNTT FETs. Intrinsic gain is a crucial parameter in the design of high-performance organic electronic devices, as it directly affects the electrical performance and efficiency in practical applications 30 , 31 . It also serves as an indicator of carrier transport properties and interface quality for OFETs. To further assess the performance of alkylated-DNTT devices, the intrinsic gain of C 10 -DNTT was calculated using Eq. 1 according to Fig. 1 e, f. $$\:{A}_{i}={g}_{m}{r}_{0}$$ 1 \(\:{g}_{m}\) denotes the transconductance of OFETs, and \(\:{r}_{0}\) represents the output resistance. As V GS increases, \(\:{g}_{m}\) gradually rises, while the output resistance decreases rapidly (Fig. 2 e). The C 10 -DNTT FETs achieve an intrinsic gain as high as 7.52×10 4 in the subthreshold region. This value significantly surpasses that of inorganic silicon metal-oxide-semiconductor field-effect transistors (Si-MOSFETs) and indium-gallium-zinc-oxide thin-film transistors (IGZO TFTs), and even exceeds that of inorganic Schottky-barrier thin-film transistors (SB-TFTs), which are designed to address the challenge of achieving high gain in inverters 32 , 33 (Fig. 2 f). This demonstrates that high-gain inverters can be realized by C 10 -DNTT FETs. The C 10 -DNTT FETs utilizing the insulating effect of alkyl chains exhibit excellent electrical characteristics, comparable to those of C 10 -DNTT fabricated on high- k dielectric layers 34 . Notably, their stability exceeds that of C 10 -DNTT FETs on high- k dielectric layers, demonstrating the potential of the insulating effect of alkyl chain layers in low-power organic devices. Mechanism and simulation for the insulating effect of alkyl chain To investigate the mechanisms of I GS generation in DNTT and alkylated-DNTT FETs, conductive-probe atomic force microscopy (c-AFM) is employed to evaluate the out-of-plane charge transport characteristics of DNTT and alkylated-DNTT films. The c-AFM technique allows for the simultaneous measurement of both the morphology and current conduction properties of the sample, providing a detailed assessment of its electrical characteristics at the nanoscale and facilitating the analysis of local variations in I GS in the OFETs 35 . We first measured the substrate without the evaporated OSC (Supplementary Fig. 7). An electrically conductive probe (Pt-Ir probe) was used to scan the sample surface while applying a 3 V bias voltage. The current passing through the probe was recorded by a current-voltage preamplifier to form the two-dimensional current maps corresponding to the morphology images. Multiple leakage points were observed on the current map of the OTS-modified substrate. This could be one of the reasons why DNTT devices fail to operate properly. Subsequently, we measured the surfaces of DNTT, C 6 -DNTT, and C 10 -DNTT films. We found that the DNTT samples showed many leakage areas at the grain boundaries, while the I GS of C 6 -DNTT samples at the grain boundaries was significantly reduced, and the I GS of C 10 -DNTT samples was the smallest (Fig. 3 a-c and Supplementary Fig. 8). This proves that alkyl chains can effectively reduce I GS . A technology computer-aided design (TCAD) simulation was employed to further validate our conclusions. TCAD simulations play a crucial role in both device design and technology development. It can be used to explore and understand the relationship between device performance and nanoscale structures 36 , 37 . We performed simulations of devices with DNTT FETs without alkyl chains and C 10 -DNTT FETs with alkyl chains using Silvaco TCAD. Referring to the defect state distribution experimental data shown in Fig. 2 d, the density of the tail distribution of acceptor-like states of alkylated-DNTT is set to be one order of magnitude lower compared to that of DNTT. Three-dimensional carrier concentration ( n ) distributions and two-dimensional cross-sectional carrier concentration distributions in the OSC layer for the simulated DNTT FETs and C 10 -DNTT FETs were obtained (Fig. 3 d, e). Due to the presence of alkyl chains, the carrier concentration near the gate in C 10 -DNTT FETs is three orders of magnitude lower than that near the gate in DNTT FETs (Fig. 3 f), reflected in the transfer characteristics as a lower off-state current (Fig. 3 g). Both experimentally and theoretically results proved that the alkyl chains of alkylated-OSCs can provide an effective insulating effect to reduce I GS . Low-power application of the alkylated-OFETs Low-voltage, high-gain, and stable inverters are crucial in organic logic circuits, enabling large signal amplification, lower power consumption, and simpler circuit design. The electrical performance and stability of each organic transistor component determine the overall performance and stability of organic integrated circuits. Based on the C 10 -DNTT FETs with excellent performance and high stability, a zero- V GS inverter was constructed to evaluate the application potential of alkylated-OSCs. The circuit diagram of the zero- V GS inverter is shown in the inset of Fig. 4 a. Constructing a zero- V GS inverter with superior static and dynamic performance requires enhancement-mode drive transistors and depletion-mode load transistors 38 , 39 . In this configuration, the driver provides a large noise margin, while the load facilitates rapid discharge at the output, ensuring higher gain. In the C 10 -DNTT inverters, enhancement-mode C 10 -DNTT FETs serve as the driver (M1), while depletion-mode C 10 -DNTT FETs with gate and source electrodes interconnected serve as the load (M2) (Fig. 4 a). The input-output characteristics and small-signal gain of the C 10 -DNTT inverter were measured within supply voltages ( V DD ) ranging from 0.4 V to 2.5 V (Fig. 4 b, c). The inverter exhibited significant rail-to-rail inverter characteristics over the range of V DD from 0.4 to 2.5V, with the output voltage rapidly switching from V DD to 0 as the input voltage transitioned from 0 to V DD . Rail-to-rail operation is crucial for digital circuit systems, ensuring that the output voltage of one logic gate can drive the input of the next 39 . Moreover, the C 10 -DNTT inverter demonstrated a wide operating voltage range in the on-state. Benefiting from the low SS and interface trap density of the C 10 -DNTT FETs, the C 10 -DNTT inverter exhibits high small-signal gains of 46.2 at V DD = 1 V and 127.6 at V DD = 2.5 V, making it promising for use in high-performance, low-power applications, such as electronic skin and radio-frequency identification tags. Owing to the high gain of C 10 -DNTT inverter provided by the insulating effect of alkyl chain, the total noise margin ((NM L + NM H )/ V DD ) reaches up to 95.3% at V DD = 2.5 V, demonstrating the high noise tolerance of C 10 -DNTT inverter utilizing the insulating effect of alkyl chain (Fig. 4 d). We also calculate the total noise margins at different V DD values (Supplementary Fig. 9). The noise margins exceed 80% across V DD ranging from 0.5 V to 2.5 V, demonstrating the robustness of the C 10 -DNTT inverters utilizing the insulating effect of alkyl chain in multistage operations. Although the zero- V GS inverter exhibited excellent static performance, its dynamic performance is compromised due to significant signal delay compared to bias-load and saturated-load architectures, where the load transistor is driven at higher bias voltages 40 . The characteristic signal-delay time constants (τ) of the C 10 -DNTT inverter at 2500 Hz are 50 µs for the low-to-high transition (τ rise ) and the high-to-low transition (τ fall ), which benefit from the low interface trap density of the alkyl chains (Fig. 4 e). Moreover, the C 10 -DNTT inverter has both excellent dynamic and static characteristics, which is one of the exceptional performances reported in the existing literature 1 , 32 , 38 , 41 – 49 (Supplementary Table 1). This demonstrates the insulating effect of alkyl chain can be utilized to achieve low-power integrated circuits. Inverters, as the fundamental units of logic circuits, must maintain their operational stability under continuous power supply to effectively prevent logic circuit failure caused by electrical performance drift 40 . To evaluate the operational stability of organic inverters, we continuously applied V DD and varied V in to repeatedly turn the inverter on and off for over 50 cycles. The input-output characteristics of C 10 -DNTT inverter at both V DD = 1 V and 2.5 V exhibited almost no drift (Fig. 4 f and Supplementary Fig. 10). The zero- V GS DNTT inverter was measured to demonstrate that the operational stability of the organic inverters is attributed to the alkyl chain layer (Supplementary Fig. 11). The increase in V out in the off-state of DNTT inverter may be caused by I GS at the load. Additionally, the gain decreases and the off-state voltages rise for the DNTT inverter after cycle tests, likely due to the operational instability of DNTT FETs. This demonstrates that the introduction of alkyl chains not only reduces I GS but also successfully enhances the operational stability of single OFET and organic logic circuits. The insulating effect of alkyl chains provides a straightforward method for fabricating low-power and high-stability organic transistors, making them promising candidates for low-power organic circuits. Discussion We have demonstrated that the alkyl chains which were conventionally designed to improve the electrical and optoelectrical properties in alkylated OSCs, could be suitable as dielectric components for OFETs and organic circuits due to their insulating effect. The alkylated OSCs could function as both active and dielectric components. Besides, the nanoscale-thick alkyl chains are covalently bonded to backbones of OSC molecules, effectively eliminating the impact of the heterogeneous charge transport interface which is present in traditional OFETs on operational stability of OFETs. This reduces the density of traps at OSC/dielectric interface and the thickness of dielectric layer, enabling the fabrication of low-power and operational stable OFETs. Herein, C 10 -DNTT FETs with the ultrathin C 10 alkyl chains show excellent electrical performance, characterized by a mobility of 11.6 cm 2 V − 1 s − 1 and the high operational stability with negligible current degradation during a 30000-second constant bias test. Furthermore, C 10 -DNTT inverters, composed of C 10 -DNTT FETs with high performance and excellent stability, achieve a small-signal gain of 46.2 and switching time of 50 µs at V DD = 1 V, exhibiting both superior static and dynamic characteristics, which represents one of the exceptional performances reported in the current literature. The strategy of utilizing the insulating effect of alkyl chains addresses the challenge of OFETs with high- k dielectrics in achieving high operational stability and opens new avenues for low-power and highly stable organic circuit applications. Declarations Acknowledgments This work was supported by the National Natural Science Foundation of China (52225304, 52073210, 52203236, 52473193, 52403243, 52121002), and the Fundamental Research Funds for the Central Universities. Author contributions X. C., L. L. and W. H. conceived the study. J. Q. and J. X. fabricated the films and the devices and performed the electrical and structure characteristics. J. Q., J. X, Z. W, Y.N. H and Y. H. analyzed the characterization data. X. L performed TCAD simulation. X.C., L.L., J.Q. and J. X. wrote the manuscript. X. C., L. L. and W.H. supervised this work. All authors contributed to data analysis and manuscript preparation and commented on the manuscript. Additional information Supplementary information is available for this paper at XXX Correspondence and requests for materials should be addressed to L. L. Peer review information Nature Communications thanks the anonymous reviewers for their contribution to the peer review of this work. Reprints and permissions information is available at XXX. References Borchert JW et al (2020) Flexible low-voltage high-frequency organic thin-film transistors. Sci Adv 6:eaaz5156 Zhang Z et al (2022) High-brightness all-polymer stretchable LED with charge-trapping dilution. Nature 603:624–630 Han L et al (2023) Wafer-scale organic-on-III-V monolithic heterogeneous integration for active-matrix micro-LED displays. Nat Commun 14:6985 Nawaz A, Merces L, Ferro LM, Sonar P, Bufon CC (2023) Impact of planar and vertical organic field-effect transistors on flexible electronics. Adv Mater 35:2204804 Xie Y et al (2024) Organic transistor-based integrated circuits for future smart life. Smartmat, e1261 Wang B et al (2023) On-chip fluorescent sensor for chemical vapor detection. Adv Mater Technol 8:2300609 Shi W, Guo Y, Liu Y (2020) When flexible organic field-effect transistors meet biomimetics: a prospective view of the internet of things. Adv Mater 32:1901493 Nawaz A, Liu Q, Leong WL, Fairfull-Smith KE, Sonar P (2021) Organic electrochemical transistors for in vivo bioelectronics. Adv Mater 33:2101874 Tsumura A, Koezuka H, Ando T (1986) Macromolecular electronic device: Field-effect transistor with a polythiophene thin film. Appl Phys Lett 49:1210–1212 Henson ZB, Müllen K, Bazan GC (2012) Design strategies for organic semiconductors beyond the molecular formula. Nat Chem 4:699–704 Bronstein H, Nielsen CB, Schroeder BC, McCulloch I (2020) The role of chemical design in the performance of organic semiconductors. Nat Rev Chem 4:66–77 Yamaguchi Y et al (2020) Solution-Processable Organic Semiconductors Featuring S-Shaped Dinaphthothienothiophene (S-DNTT): Effects of Alkyl Chain Length on Self-Organization and Carrier Transport Properties. Chem Mater 32:5350–5360 Zhang D et al (2020) Effect of alkyl chain length on charge transport property of anthracene-based organic semiconductors. ACS Appl Mater Inter 13:989–998 Selezneva E et al (2021) Strong Suppression of Thermal Conductivity in the Presence of Long Terminal Alkyl Chains in Low-Disorder Molecular Semiconductors. Adv Mater 33:2008708 Hu Y et al (2018) Effect of Alkyl-Chain Length on Charge Transport Properties of Organic Semiconductors and Organic Field‐Effect Transistors. Adv Electron Mater 4:1800175 Koberidze M, Puska M, Nieminen R (2018) Structural details of Al/Al 2 O 3 junctions and their role in the formation of electron tunnel barriers. Phys Rev B 97:195406 Ma P et al (2019) Electron transport mechanism through ultrathin Al 2 O 3 films grown at low temperatures using atomic–layer deposition. Semicond Sci Technol 34:105004 Wilt J, Sakidja R, Goul R, Wu JZ (2017) Effect of an interfacial layer on electron tunneling through atomically thin Al 2 O 3 tunnel barriers. ACS Appl Mater Inter 9:37468–37475 Boulas C, Davidovits J, Rondelez F, Vuillaume D (1996) Suppression of charge carrier tunneling through organic self-assembled monolayers. Phys Rev Lett 76:4797 Först CJ, Ashman CR, Schwarz K, Blöchl PE (2004) The interface between silicon and a high-k oxide. Nature 427:53–56 Wang B et al (2018) High-k gate dielectrics for emerging flexible and stretchable electronics. Chem Rev 118:5690–5754 Palumbo F et al (2020) A review on dielectric breakdown in thin dielectrics: silicon dioxide, high-k, and layered dielectrics. Adv Funct Mater 30:1900657 Chen X et al (2022) Balancing the film strain of organic semiconductors for ultrastable organic transistors with a five-year lifetime. Nat Commun 13:1480 Casalini S, Bortolotti CA, Leonardi F, Biscarini F (2017) Self-assembled monolayers in organic electronics. Chem Soc Rev 46:40–71 Oliver RC et al (2013) Dependence of micelle size and shape on detergent alkyl chain length and head group. PLoS ONE 8:e62488 Zhou C et al (2023) Hybrid organic-inorganic two-dimensional metal carbide MXenes with amido- and imido-terminated surfaces. Nat Chem 15 Inoue S et al (2015) Effects of substituted alkyl chain length on solution-processable layered organic semiconductor crystals. Chem Mater 27:3809–3812 Grünewald M, Thomas P, Würtz D (1980) A simple scheme for evaluating field effect data. Phys Status Solidi (B) 100:K139–K143 Haneef HF, Zeidell AM, Jurchescu OD (2020) Charge carrier traps in organic semiconductors: a review on the underlying physics and impact on electronic devices. J Mater Chem C 8:759–787 Cheng M et al (2024) Low-voltage polymer monolayer transistors for high-gain unipolar and complementary logic inverters. J Mater Chem C 12:9562–9570 Wang S et al (2023) Ultrahigh-gain organic transistors based on van der Waals metal-barrier interlayer-semiconductor junction. Sci Adv 9:eadj4656 Jiang C et al (2019) Printed subthreshold organic transistors operating at high gain and ultralow power. Science 363:719–723 Lee S, Nathan A (2016) Subthreshold Schottky-barrier thin-film transistors with ultralow power and high intrinsic gain. Science 354:302–304 Luo Z et al (2021) Sub-thermionic, ultra-high-gain organic transistors and circuits. Nat Commun 12:1928 Si H et al (2020) Emerging conductive atomic force microscopy for metal halide perovskite materials and solar cells. Adv Energy Mater 10:1903922 Lee J (2021) Physical modeling of charge transport in conjugated polymer field-effect transistors. J Phys D: Appl Phys 54:143002 Boubaker A, Hafsi B, Lmimouni K, Kalboussi A (2017) A comparative TCAD simulations of a P-and N-type organic field effect transistors: field-dependent mobility, bulk and interface traps models. J Mater Sci -Mater Electron 28:7834–7843 Haldar T et al (2023) High-gain, low-voltage unipolar logic circuits based on nanoscale flexible organic thin-film transistors with small signal delays. Sci Adv 9:eadd3669 Shiwaku R et al (2017) Printed Organic Inverter Circuits with Ultralow Operating Voltages. Adv Electron Mater 3:1600557 Li J et al (2012) A stable solution-processed polymer semiconductor with record high-mobility for printed transistors. Sci Rep 2:754 Chi L-J, Yu M-J, Chang Y-H, Hou T-H (2016) 1-V full-swing depletion-load a-In–Ga–Zn–O inverters for back-end-of-line compatible 3D integration. IEEE Electr Device Lett 37:441–444 Dai Z, Wang Z, He X, Zhang XX, Alshareef HN (2017) Large-Area Chemical Vapor Deposited MoS 2 with Transparent Conducting Oxide Contacts toward Fully Transparent 2D Electronics. Adv Funct Mater 27:1703119 Fukuda K et al (2014) Fully-printed high-performance organic thin-film transistors and circuitry on one-micron-thick polymer films. Nat Commun 5:1–8 Huang W et al (2023) Vertical organic electrochemical transistors for complementary circuits. Nature 613:496–502 Ji D et al (2018) Copolymer dielectrics with balanced chain-packing density and surface polarity for high-performance flexible organic electronics. Nat Commun 9:2339 Park H et al (2024) Organic flexible electronics with closed-loop recycling for sustainable wearable technology. Nat Electron 7:39–50 Sun D-m et al (2011) Flexible high-performance carbon nanotube integrated circuits. Nat Nanotechnol 6:156–161 Wachter S, Polyushkin DK, Bethge O, Mueller T (2017) A microprocessor based on a two-dimensional semiconductor. Nat Commun 8:14948 Wang M et al (2016) Threshold voltage tuning in a-IGZO TFTs with ultrathin SnO x capping layer and application to depletion-load inverter. IEEE Electr Device Lett 37:422–425 Methods Fabrication of OFETs The OFETs adopted bottom-gate and top-contact configurations. Highly doped Si wafers were used as substrates and gate electrodes. OTS, purchased from Aldrich, was modified into the O 2 plasma-treated Si wafers (treated at 100W for 1min) in a vacuum for 10 min at 60 ℃. Triple-sublimed grade DNTT, C 6 -DNTT, and C 10 -DNTT purchased from Sigma-Aldrich were deposited by vacuum thermal evaporation at a rate of approximately 0.1 Å s −1 under 10 −4 Pa to fabricate the 20 nm OSC layers. The thickness and deposition rate were monitored by quartz-crystal microbalances. 30 nm Au electrodes were deposited to the OSC layers via shadow masks as the source and drain electrodes at a rate of approximately 0.1 Å s −1 under 10 −4 Pa. Characterization of the OFETs Both the electrical characteristics of the OFETs and the static characteristics of organic inverters were measured by an Agilent B1500A in a probe station system under dark air conditions. The dynamic characteristics of organic inverters were measured by PDA FS-Pro connected to a probe station system under dark air conditions. Structure Characteristics XRD measurements are measured in reflection mode with Cu kα radiation using an X-ray diffractometer (RIGAKU SMARTLAB 9KW). c-AFM were performed in tapping mode using a Bruker Dimension ICON-PT instrument equipped with a c-AFM sensor and Pt-Ir-coated conducting probes (SCM-PIT-V2 from Bruker). Additional Declarations There is NO Competing Interest. Supplementary Files SI.docx Cite Share Download PDF Status: Posted 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. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-5398767","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":377806784,"identity":"2360a1e0-218b-413c-8bb2-b6f2da3df9be","order_by":0,"name":"Liqiang Li","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAq0lEQVRIiWNgGAWjYBACPmbmBoYPDGwgtgFxWtiYGRsYZySQpIWBsYGZJ4GBFC3sjI23bX/wJTawN2+TYKi5Q5TDmq1zEtgSG3iOlUkwHHtGlJY2abAWiRwzCcaGw0RqsQBpkX9DihYGsC08xGtptuxJYzNu40krtkg4RoQWfv7DB2/8sDkm289+eOONDzVEaAEBCQaGY5D4TyBOA1hLDbFqR8EoGAWjYCQCAMrWLjnHIyOwAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0001-8399-3957","institution":"Tianjin University","correspondingAuthor":true,"prefix":"","firstName":"Liqiang","middleName":"","lastName":"Li","suffix":""},{"id":377806785,"identity":"849b194b-e7ee-4151-b174-1adc165a9175","order_by":1,"name":"Jiannan Qi","email":"","orcid":"","institution":"Tianjin University","correspondingAuthor":false,"prefix":"","firstName":"Jiannan","middleName":"","lastName":"Qi","suffix":""},{"id":377806786,"identity":"1ce4fafd-eaf8-4e46-a6a0-96a36ef919a4","order_by":2,"name":"Jialu Xue","email":"","orcid":"","institution":"Tianjin University","correspondingAuthor":false,"prefix":"","firstName":"Jialu","middleName":"","lastName":"Xue","suffix":""},{"id":377806787,"identity":"4031ce5a-19cb-4bcf-a4c6-78706567ea5f","order_by":3,"name":"Xufan Li","email":"","orcid":"https://orcid.org/0009-0003-5197-1974","institution":"Institute of Microelectronics, Chinese Academy of Sciences","correspondingAuthor":false,"prefix":"","firstName":"Xufan","middleName":"","lastName":"Li","suffix":""},{"id":377806788,"identity":"cadeb5c9-0e8d-4f3e-9d3a-6080ab9f4390","order_by":4,"name":"Kai Tie","email":"","orcid":"","institution":"Tianjin University","correspondingAuthor":false,"prefix":"","firstName":"Kai","middleName":"","lastName":"Tie","suffix":""},{"id":377806789,"identity":"7240a5a7-5607-4bd6-87f8-eab1a93e6c5d","order_by":5,"name":"Zhongwu Wang","email":"","orcid":"https://orcid.org/0000-0002-1331-9796","institution":"Tianjin University","correspondingAuthor":false,"prefix":"","firstName":"Zhongwu","middleName":"","lastName":"Wang","suffix":""},{"id":377806790,"identity":"c124159d-d7f1-464d-bf92-8cbe93e459e9","order_by":6,"name":"Yinan Huang","email":"","orcid":"","institution":"Tianjin University","correspondingAuthor":false,"prefix":"","firstName":"Yinan","middleName":"","lastName":"Huang","suffix":""},{"id":377806791,"identity":"40ea1fab-ff4f-450c-9028-61c99a5bedae","order_by":7,"name":"Yongxu Hu","email":"","orcid":"","institution":"Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Institute of Molecular Aggregation Science","correspondingAuthor":false,"prefix":"","firstName":"Yongxu","middleName":"","lastName":"Hu","suffix":""},{"id":377806792,"identity":"6038189b-ad28-4a61-98dd-79251cf3b332","order_by":8,"name":"Xiaosong Chen","email":"","orcid":"https://orcid.org/0000-0002-3055-8852","institution":"Tianjin University","correspondingAuthor":false,"prefix":"","firstName":"Xiaosong","middleName":"","lastName":"Chen","suffix":""},{"id":377806793,"identity":"4cb7925e-ed29-4ca1-ae44-f8ef805f9b2a","order_by":9,"name":"Wenping Hu","email":"","orcid":"https://orcid.org/0000-0001-5686-2740","institution":"Tianjin University","correspondingAuthor":false,"prefix":"","firstName":"Wenping","middleName":"","lastName":"Hu","suffix":""}],"badges":[],"createdAt":"2024-11-06 02:20:17","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5398767/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5398767/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":69058551,"identity":"13c7a881-3390-4a32-8d69-3f01d4ac6169","added_by":"auto","created_at":"2024-11-15 07:04:27","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":2816076,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eModel OFETs with and without alkyl chain layers. a\u003c/strong\u003e The molecular structure of DNTT, C\u003csub\u003e6\u003c/sub\u003e-DNTT, and C\u003csub\u003e10\u003c/sub\u003e-DNTT. The conductive region (CR) is the core structure of the OSC molecule represented by the blue region, while the non-conductive region (NCR) is the alkyl chains represented by the orange region. \u003cstrong\u003eb, c\u003c/strong\u003e Schematic diagram of the DNTT FETs without alkyl chain layers (\u003cstrong\u003eb\u003c/strong\u003e) and the alkylated-DNTT FETs with alkyl chain layers (\u003cstrong\u003ec\u003c/strong\u003e). A trace dispersion of Au nanoparticles from the electrodes can improve carrier injection\u003csup\u003e23\u003c/sup\u003e. \u003cstrong\u003ed, e\u003c/strong\u003e The transfer characteristics of the DNTT (\u003cstrong\u003ed\u003c/strong\u003e) and C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs (\u003cstrong\u003ee\u003c/strong\u003e). \u003cstrong\u003ef, g\u003c/strong\u003e The output characteristics of the DNTT (\u003cstrong\u003ef\u003c/strong\u003e) and C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs (\u003cstrong\u003eg\u003c/strong\u003e).\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-5398767/v1/b7d8d6cad46648a8943dc759.png"},{"id":69058555,"identity":"7dc77f04-48ef-4257-af51-e117ad27cfb4","added_by":"auto","created_at":"2024-11-15 07:04:27","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":469229,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThe electrical characteristics and operational stability of DNTT and alkylated-DNTT FETs.\u003c/strong\u003e \u003cstrong\u003ea\u003c/strong\u003e The extract mobility as a function of \u003cem\u003eV\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e for C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs.\u0026nbsp; \u003cstrong\u003eb\u003c/strong\u003e Temporal evolution of the normalized \u003cem\u003eI\u003c/em\u003e\u003csub\u003eDS\u003c/sub\u003e of DNTT and alkylated-DNTT FETs. \u003cem\u003eV\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e = −1 V, \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDS\u003c/sub\u003e = −0.1 V. \u003cstrong\u003ec\u003c/strong\u003e Transfer characteristics of C\u003csub\u003e10\u003c/sub\u003e-DNTT under different stress time. \u003cstrong\u003ed\u003c/strong\u003e The trap DOS in the band gap of DNTT and alkylated-DNTT is calculated by Grünewald’s method. \u003cstrong\u003ee\u003c/strong\u003e \u003cem\u003eg\u003c/em\u003e\u003csub\u003em\u003c/sub\u003e and \u003cem\u003er\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e of the C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs as a function of \u003cem\u003eV\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e. \u003cstrong\u003ef\u003c/strong\u003e The intrinsic gain as a function of \u003cem\u003eV\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-5398767/v1/6a00dde8ffa8ddfebb0cab8a.png"},{"id":69059573,"identity":"3c0548fa-fcc5-4147-9914-ee586ab94ec7","added_by":"auto","created_at":"2024-11-15 07:12:27","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":5374811,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eThe characteristics and TCAD simulation of DNTT and alkylated-DNTT FETs.\u003c/strong\u003e \u003cstrong\u003ea-c\u003c/strong\u003e The current map of DNTT (\u003cstrong\u003ea\u003c/strong\u003e), C\u003csub\u003e6\u003c/sub\u003e-DNTT (\u003cstrong\u003eb\u003c/strong\u003e), and C\u003csub\u003e10\u003c/sub\u003e-DNTT films (\u003cstrong\u003ec\u003c/strong\u003e) measured by c-AFM.\u0026nbsp; \u003cstrong\u003ed, e\u003c/strong\u003e The carrier concentration distributions of OSC layers for a simulated DNTT FET without the alkyl chain layer (\u003cstrong\u003ed\u003c/strong\u003e) and C\u003csub\u003e10\u003c/sub\u003e-DNTT FET with the alkyl chain layer (\u003cstrong\u003ee\u003c/strong\u003e). \u003cstrong\u003ef\u003c/strong\u003e The carrier concentration of simulated DNTT and C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs as a function of distance from the gate electrode. \u003cstrong\u003eg\u003c/strong\u003e Transfer characteristics of the simulated DNTT and C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs. The simulated C\u003csub\u003e10\u003c/sub\u003e-DNTT FET has lower \u003cem\u003eI\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e compared with the simulated DNTT FET.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-5398767/v1/0ab6c6a600d3f6a1a68768b0.png"},{"id":69058553,"identity":"ffd94686-f7b7-491c-adb0-b6ffca5cef0b","added_by":"auto","created_at":"2024-11-15 07:04:27","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":443563,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eStatic and dynamic characteristics and operational stability of C\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003e10\u003c/strong\u003e\u003c/sub\u003e\u003cstrong\u003e-DNTT inverter.\u003c/strong\u003e \u003cstrong\u003ea\u003c/strong\u003e Transfer characteristics of M1 and M2 in C\u003csub\u003e10\u003c/sub\u003e-DNTT inverter. The insert is the circuit diagram of the zero-voltage inverter. M1: \u003cem\u003eL\u003c/em\u003e/\u003cem\u003eW\u003c/em\u003e = 200 μm/1000 μm; M2: \u003cem\u003eL\u003c/em\u003e/\u003cem\u003eW\u003c/em\u003e = 30 μm/1000 μm. \u003cstrong\u003eb\u003c/strong\u003e Input-output characteristics of the C\u003csub\u003e10\u003c/sub\u003e-DNTT inverter at \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e from 0.4 to 2.5 V.\u003cstrong\u003e c\u003c/strong\u003e The small-signal gain of the C\u003csub\u003e10\u003c/sub\u003e-DNTT inverter at \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e from 0.4 to 2.5 V. \u003cstrong\u003ed\u003c/strong\u003e Input-output characteristics and their mirror image of the C\u003csub\u003e10\u003c/sub\u003e-DNTT inverter at \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e = 2.5 V.\u003cem\u003e V\u003c/em\u003e\u003csub\u003eIL\u003c/sub\u003e, and \u003cem\u003eV\u003c/em\u003e\u003csub\u003eIH\u003c/sub\u003e represent the maximum low input voltage and minimum high input voltage, respectively. \u003cem\u003eV\u003c/em\u003e\u003csub\u003eOH \u003c/sub\u003eand \u003cem\u003eV\u003c/em\u003e\u003csub\u003eOL\u003c/sub\u003e correspond to the minimum high output voltage and maximum low output voltage, respectively.\u003cem\u003e \u003c/em\u003eThe noise margin is obtained by fitting the largest square (grey shading). The dashed lines are used as guides to determine the values of \u003cem\u003eV\u003c/em\u003e\u003csub\u003eOH\u003c/sub\u003e,\u003cem\u003e V\u003c/em\u003e\u003csub\u003eOL\u003c/sub\u003e, \u003cem\u003eV\u003c/em\u003e\u003csub\u003eIL\u003c/sub\u003e, and \u003cem\u003eV\u003c/em\u003e\u003csub\u003eIH\u003c/sub\u003e. \u003cstrong\u003ee\u003c/strong\u003e Dynamic characteristics of the C\u003csub\u003e10\u003c/sub\u003e-DNTT inverter at \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e =1 V in response to a square-wave input signal with a frequency of 2500 Hz. \u003cstrong\u003ef\u003c/strong\u003e The 50-cycle input-output characteristics of the C\u003csub\u003e10\u003c/sub\u003e-DNTT inverter at \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e = 1V.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-5398767/v1/22600956399629cf7be80819.png"},{"id":70674436,"identity":"fd606966-477e-4dc2-87f5-8ba9ac6b732f","added_by":"auto","created_at":"2024-12-05 13:38:51","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":9046927,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5398767/v1/1f85d45e-e2ba-4fb6-8b35-71b9741bd6b6.pdf"},{"id":69058554,"identity":"1e352836-3570-459a-af76-cc676a38a8f5","added_by":"auto","created_at":"2024-11-15 07:04:27","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":1954226,"visible":true,"origin":"","legend":"","description":"","filename":"SI.docx","url":"https://assets-eu.researchsquare.com/files/rs-5398767/v1/afa9efa691d4ec8686a8b4fb.docx"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Insulating Effect of Alkyl Chains for Low-Power and High-Stability Organic Transistors and Circuits","fulltext":[{"header":"Introduction","content":"\u003cp\u003eOrganic field-effect transistors (OFETs) are considered important building blocks in the burgeoning $20-billion-per-year flexible electronics market\u003csup\u003e \u003cspan class=\"CitationRef\"\u003e1\u003c/span\u003e \u003c/sup\u003e, with significant potential applications in flexible display\u003csup\u003e \u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e \u003c/sup\u003e, wearable devices\u003csup\u003e \u003cspan class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e6\u003c/span\u003e \u003c/sup\u003e, and bioelectronic devices\u003csup\u003e \u003cspan class=\"CitationRef\"\u003e7\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e8\u003c/span\u003e \u003c/sup\u003e. The first OFET utilizing polythiophene as an active layer was reported in 1986\u003csup\u003e9\u003c/sup\u003e, exhibiting a mobility (\u003cem\u003e\u0026micro;\u003c/em\u003e) of only 10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003e cm\u003csup\u003e \u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e \u003c/sup\u003e V\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e s\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e under high operating voltage. The poor electrical properties of organic semiconductors (OSCs) and high power are critical challenges faced by OFETs in practical applications.\u003c/p\u003e\n\u003cp\u003eThe chemical design of OSCs enables the development of high-performance OFETs\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e10\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e. The introduction of alkyl chains into OSCs is a common strategy in chemical design, often employed to modulate the electronic and optoelectronic properties for OSCs. Yuji Yamaguchi et al. demonstrated that alkyl chains significantly impact solubility, thermal durability, self-organization ability, and carrier transport of OSCs\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e. Hatsumi Mori et al. noted that the length of alkyl chains affects the microstructure of OSC films\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. Henning Sirringhaus et al. indicated that alkyl chains influence the lattice thermal conductivity of OSC polycrystalline films\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e. Moreover, they observed that while alkyl chains benefit in-plane carrier transport, their insulating effect adversely affects out-of-plane charge transport\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e. However, the utilization of insulating properties for alkyl chains in OSCs has not received widespread attention.\u003c/p\u003e\n\u003cp\u003eIn this work, we revealed that the alkyl chains of alkylated OSCs can serve as dielectric components in OFETs due to their insulating effect. The ultra-thin alkyl chains provide barrier of 4.5 eV for carrier tunneling, which is superior to that of Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e (approximately 1\u0026ndash;3 eV)\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e16\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e and SiO\u003csub\u003e2\u003c/sub\u003e (3.2 eV)\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e, enabling alkylated-OSCs to function as both active and dielectric components for low-power OFETs. Besides, the traditional heterogeneous charge transport interface present in conventional OFETs is absent in alkylated OFETs, due to the covalent bond connection between the alkyl chains and the OSC backbone. This improves the operational stability of alkylated-OFETs, addresses the stability issues caused by the polarity effects and interface traps in low-power OFETs using high-\u003cem\u003ek\u003c/em\u003e dielectric layers\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. Furthermore, organic inverters using the insulating effect of alkyl chain exhibit excellent dynamic and static characteristics under low-power conditions while maintaining outstanding operational stability. Low-power alkylated-OFETs with high operational stability are achieved through the appropriate selection of OSC materials.\u003c/p\u003e\n\u003ch3\u003eThe insulating effect of alkyl chain layers in alkylated FETs\u003c/h3\u003e\n\u003cp\u003eTo verify the insulating effect of alkyl chains, we selected chemically stable dinaphtho[2,3-b:2\u0026rsquo;,3\u0026rsquo;-f]thieno[3,2-b]thiophene (DNTT), 2,9-dihexylnaphtho[2,3-b]naphtho[2\u0026rsquo;,3\u0026rsquo;:4,5]thieno[2,3-d]thiophene (C\u003csub\u003e6\u003c/sub\u003e-DNTT), and 2,9-didecyldinaphtho[2,3-b:2\u0026rsquo;,3\u0026rsquo;-f]thieno[3,2-b]thiophene (C\u003csub\u003e10\u003c/sub\u003e-DNTT) as OSC layers, and their molecular structures are shown in Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ea. The OSC layers were prepared by vacuum thermal deposition on heavily doped Si substrates. Octadecyltrichlorosilane (OTS) was modified onto the substrate to promote the vertical growth of the OSC molecules. The Au source-drain electrodes were then deposited to fabricate staggered structure DNTT, C\u003csub\u003e6\u003c/sub\u003e-DNTT, and C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eI\u003c/em\u003e \u003csub\u003eGS\u003c/sub\u003e typically arises from non-ideal currents generated between the gate and source-drain electrodes due to carrier quantum tunneling through the dielectric layer. Due to the high tunneling barrier of the alkyl chains\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e, alkylated-DNTT (C\u003csub\u003e6\u003c/sub\u003e-DNTT and C\u003csub\u003e10\u003c/sub\u003e-DNTT) FETs can significantly reduce \u003cem\u003eI\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e, whereas the DNTT FETs without alkyl chains fail to operate properly due to the large \u003cem\u003eI\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eb, c). We tested the transfer characteristics of the three OFETs (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ed, e and Supplementary Fig.\u0026nbsp;1a). The \u003cem\u003eI\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e in DNTT FETs was even higher than the maximum on-state current, illustrating that without the insulating effect provided by the alkyl chains, the devices could not operate properly (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ed). As the alkyl chain length increased, the \u003cem\u003eI\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e in C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs was an order of magnitude lower than that in C\u003csub\u003e6\u003c/sub\u003e-DNTT FETs (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ee and Supplementary Fig.\u0026nbsp;1a). The subthreshold slopes (\u003cem\u003eSS\u003c/em\u003e) of C\u003csub\u003e6\u003c/sub\u003e-DNTT FETs and C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs were 121.8 mV dec\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and 79.5 mV dec\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, respectively. A lower \u003cem\u003eSS\u003c/em\u003e indicates fewer interface defects in C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs compared to C\u003csub\u003e6\u003c/sub\u003e-DNTT FETs. The output characteristics of the three devices were also measured (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ef, g and Supplementary Fig.\u0026nbsp;1b). Due to the high \u003cem\u003eI\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e in DNTT FETs, the DNTT device exhibited a high drain-source current (\u003cem\u003eI\u003c/em\u003e\u003csub\u003eDS\u003c/sub\u003e) even when drain-source voltage (\u003cem\u003eV\u003c/em\u003e\u003csub\u003eDS\u003c/sub\u003e) was zero (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ef). In contrast, C\u003csub\u003e6\u003c/sub\u003e-DNTT and C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs could be quickly turned on and saturated at a gate-source voltage (\u003cem\u003eV\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e) as low as 1 V, demonstrating excellent low-voltage operation characteristics of low-power alkylated-DNTT FETs (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003eg and Supplementary Fig.\u0026nbsp;1b).\u003c/p\u003e\n\u003cp\u003eSAM layers are reported and studied as dielectric layers\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e. To further demonstrate that the insulating properties of alkylated-DNTT FETs originate from the alkyl chains, we employed methyltrichlorosilane (MTS) which only contains a methyl group as the SAM layer to modify the OSC molecules stacking. We then fabricated staggered DNTT, C\u003csub\u003e6\u003c/sub\u003e-DNTT, and C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs on the MTS-modified substrate. The transfer characteristics of these three devices were measured (Supplementary Fig.\u0026nbsp;2). The MTS-alkylated-DNTT devices operated normally whereas the MTS-DNTT devices exhibit no field-effect characteristics. This further confirms that the alkyl chains of the alkylated OSCs provide essential insulation for achieving low-power organic transistors.\u003c/p\u003e"},{"header":"Characterizations of alkylated-OFETs ","content":"\u003cp\u003eThe size of the alkyl chain length can be determined by the X-ray diffraction (XRD) patterns of OSCs\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e25\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e. The C\u003csub\u003e6\u003c/sub\u003e and C\u003csub\u003e10\u003c/sub\u003e alkyl chain lengths were determined from the \u003cem\u003ed\u003c/em\u003e\u003csub\u003e001\u003c/sub\u003e of three OSCs to be 0.61 nm and 1.135 nm, respectively (Supplementary Fig.\u0026nbsp;3 and Supplementary Note 1). Considering the native oxide of Si (relative dielectric constant is 3.9), OTS, and the alkyl chains (relative dielectric constant is 2.5), the ideal capacitances (\u003cem\u003eC\u003c/em\u003e\u003csub\u003ei\u003c/sub\u003e) of the C\u003csub\u003e6\u003c/sub\u003e-DNTT and C\u003csub\u003e10\u003c/sub\u003e-DNTT devices were calculated to be 430.9 nF cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e and 395.1 nF cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e, respectively. The mobility of the alkylated-DNTT devices as a function of gate-source voltage (\u003cem\u003eV\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e) is plotted in Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003ea and Supplementary Fig.\u0026nbsp;4. The mobility of C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs is 11.6 cm\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e V\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e s\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. The \u003cem\u003e\u0026micro;\u003c/em\u003e-\u003cem\u003eV\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e curve of C\u003csub\u003e10\u003c/sub\u003e-DNTT showed a clear plateau over a broad \u003cem\u003eV\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e range, indicating a reliable assessment of mobility. In contrast, the mobility of C\u003csub\u003e6\u003c/sub\u003e-DNTT was slightly lower at 1.3 cm\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e V\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e s\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. As the alkyl chain length increases, OSC molecules form an isolated alkyl chain layer, which effectively raises the cohesive energy within the crystal and enhances the electrical performance of the corresponding OFETs\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTo investigate the influence of the alkyl chain layer on the operational stability of OFETs, a constant bias was applied to the three OFETs for 30000 seconds. The evolution of the normalized \u003cem\u003eI\u003c/em\u003e\u003csub\u003eDS\u003c/sub\u003e was measured over time, revealing that the \u003cem\u003eI\u003c/em\u003e\u003csub\u003eDS\u003c/sub\u003e of the C\u003csub\u003e10\u003c/sub\u003e-DNTT device retained 99% and 93% of its original value after 10000 and 30000 seconds of operation, respectively. In contrast, the \u003cem\u003eI\u003c/em\u003e\u003csub\u003eDS\u003c/sub\u003e of the DNTT device retained only 8% of its original value after 10000 seconds and less than 1% after 30000 seconds (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003eb). Additionally, the transfer characteristics of three OFETs were measured under different bias stress time (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003ec and Supplementary Fig.\u0026nbsp;5). The threshold voltage of the C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs showed negligible decrease or shift compared to the DNTT and C\u003csub\u003e6\u003c/sub\u003e-DNTT FETs. These results indicate that the operational stability of the devices improves significantly with the increase in alkyl chain length. The weak polarization effect and ability of eliminating heterogeneous carrier transport interfaces of long alkyl chains is the reason for the excellent operational stability of alkylated-DNTT FETs. Moreover, we calculated the energy distribution of trap density of states (trap DOS) within the bandgap using Gr\u0026uuml;newald's method\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e28\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e (Supplementary Note 2). The trap DOS function was determined by analyzing the dependence of \u003cem\u003eI\u003c/em\u003e\u003csub\u003eDS\u003c/sub\u003e on \u003cem\u003eV\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e in the transfer characteristics in the linear regime (Supplementary Fig.\u0026nbsp;6). The trap DOS of the three devices is plotted in Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003ed. As the alkyl chains are introduced and elongated in OSC molecules, the trap DOS in the OSC layer decreases. Due to the covalent bond connection between the alkyl chains and the OSC backbone, the heterogeneous charge transport interface is eliminated and the carrier traps are decreased by the alkyl chains. These improved electrical performance and operational stability of alkylated-DNTT FETs compared with DNTT FETs.\u003c/p\u003e\n\u003cp\u003eIntrinsic gain is a crucial parameter in the design of high-performance organic electronic devices, as it directly affects the electrical performance and efficiency in practical applications\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e30\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e31\u003c/span\u003e\u003c/sup\u003e. It also serves as an indicator of carrier transport properties and interface quality for OFETs. To further assess the performance of alkylated-DNTT devices, the intrinsic gain of C\u003csub\u003e10\u003c/sub\u003e-DNTT was calculated using Eq.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e according to Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003ee, f.\u003c/p\u003e\n\u003cdiv id=\"Equ1\" class=\"Equation\"\u003e\n\u003cdiv id=\"FileID_Equ1\" class=\"mathdisplay\"\u003e$$\\:{A}_{i}={g}_{m}{r}_{0}$$\u003c/div\u003e\n\u003cdiv class=\"EquationNumber\"\u003e1\u003c/div\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e \u003cspan class=\"mathinline\"\u003e\\(\\:{g}_{m}\\)\u003c/span\u003e \u003c/span\u003e denotes the transconductance of OFETs, and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{r}_{0}\\)\u003c/span\u003e\u003c/span\u003e represents the output resistance. As \u003cem\u003eV\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e increases, \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{g}_{m}\\)\u003c/span\u003e\u003c/span\u003e gradually rises, while the output resistance decreases rapidly (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003ee). The C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs achieve an intrinsic gain as high as 7.52\u0026times;10\u003csup\u003e4\u003c/sup\u003e in the subthreshold region. This value significantly surpasses that of inorganic silicon metal-oxide-semiconductor field-effect transistors (Si-MOSFETs) and indium-gallium-zinc-oxide thin-film transistors (IGZO TFTs), and even exceeds that of inorganic Schottky-barrier thin-film transistors (SB-TFTs), which are designed to address the challenge of achieving high gain in inverters\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e32\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003ef). This demonstrates that high-gain inverters can be realized by C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs. The C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs utilizing the insulating effect of alkyl chains exhibit excellent electrical characteristics, comparable to those of C\u003csub\u003e10\u003c/sub\u003e-DNTT fabricated on high-\u003cem\u003ek\u003c/em\u003e dielectric layers\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e34\u003c/span\u003e\u003c/sup\u003e. Notably, their stability exceeds that of C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs on high-\u003cem\u003ek\u003c/em\u003e dielectric layers, demonstrating the potential of the insulating effect of alkyl chain layers in low-power organic devices.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMechanism and simulation for the insulating effect of alkyl chain\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo investigate the mechanisms of \u003cem\u003eI\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e generation in DNTT and alkylated-DNTT FETs, conductive-probe atomic force microscopy (c-AFM) is employed to evaluate the out-of-plane charge transport characteristics of DNTT and alkylated-DNTT films. The c-AFM technique allows for the simultaneous measurement of both the morphology and current conduction properties of the sample, providing a detailed assessment of its electrical characteristics at the nanoscale and facilitating the analysis of local variations in \u003cem\u003eI\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e in the OFETs\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e. We first measured the substrate without the evaporated OSC (Supplementary Fig.\u0026nbsp;7). An electrically conductive probe (Pt-Ir probe) was used to scan the sample surface while applying a 3 V bias voltage. The current passing through the probe was recorded by a current-voltage preamplifier to form the two-dimensional current maps corresponding to the morphology images. Multiple leakage points were observed on the current map of the OTS-modified substrate. This could be one of the reasons why DNTT devices fail to operate properly. Subsequently, we measured the surfaces of DNTT, C\u003csub\u003e6\u003c/sub\u003e-DNTT, and C\u003csub\u003e10\u003c/sub\u003e-DNTT films. We found that the DNTT samples showed many leakage areas at the grain boundaries, while the \u003cem\u003eI\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e of C\u003csub\u003e6\u003c/sub\u003e-DNTT samples at the grain boundaries was significantly reduced, and the \u003cem\u003eI\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e of C\u003csub\u003e10\u003c/sub\u003e-DNTT samples was the smallest (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003ea-c and Supplementary Fig.\u0026nbsp;8). This proves that alkyl chains can effectively reduce \u003cem\u003eI\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e.\u003c/p\u003e\n\u003cp\u003eA technology computer-aided design (TCAD) simulation was employed to further validate our conclusions. TCAD simulations play a crucial role in both device design and technology development. It can be used to explore and understand the relationship between device performance and nanoscale structures\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e36\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e. We performed simulations of devices with DNTT FETs without alkyl chains and C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs with alkyl chains using Silvaco TCAD. Referring to the defect state distribution experimental data shown in Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003ed, the density of the tail distribution of acceptor-like states of alkylated-DNTT is set to be one order of magnitude lower compared to that of DNTT. Three-dimensional carrier concentration (\u003cem\u003en\u003c/em\u003e) distributions and two-dimensional cross-sectional carrier concentration distributions in the OSC layer for the simulated DNTT FETs and C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs were obtained (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003ed, e). Due to the presence of alkyl chains, the carrier concentration near the gate in C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs is three orders of magnitude lower than that near the gate in DNTT FETs (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003ef), reflected in the transfer characteristics as a lower off-state current (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003eg). Both experimentally and theoretically results proved that the alkyl chains of alkylated-OSCs can provide an effective insulating effect to reduce \u003cem\u003eI\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e.\u003c/p\u003e"},{"header":"Low-power application of the alkylated-OFETs","content":"\u003cp\u003eLow-voltage, high-gain, and stable inverters are crucial in organic logic circuits, enabling large signal amplification, lower power consumption, and simpler circuit design. The electrical performance and stability of each organic transistor component determine the overall performance and stability of organic integrated circuits. Based on the C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs with excellent performance and high stability, a zero-\u003cem\u003eV\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e inverter was constructed to evaluate the application potential of alkylated-OSCs. The circuit diagram of the zero-\u003cem\u003eV\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e inverter is shown in the inset of Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003ea. Constructing a zero-\u003cem\u003eV\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e inverter with superior static and dynamic performance requires enhancement-mode drive transistors and depletion-mode load transistors\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e38\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e39\u003c/span\u003e\u003c/sup\u003e. In this configuration, the driver provides a large noise margin, while the load facilitates rapid discharge at the output, ensuring higher gain. In the C\u003csub\u003e10\u003c/sub\u003e-DNTT inverters, enhancement-mode C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs serve as the driver (M1), while depletion-mode C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs with gate and source electrodes interconnected serve as the load (M2) (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003ea). The input-output characteristics and small-signal gain of the C\u003csub\u003e10\u003c/sub\u003e-DNTT inverter were measured within supply voltages (\u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e) ranging from 0.4 V to 2.5 V (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003eb, c). The inverter exhibited significant rail-to-rail inverter characteristics over the range of \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e from 0.4 to 2.5V, with the output voltage rapidly switching from \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e to 0 as the input voltage transitioned from 0 to \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e. Rail-to-rail operation is crucial for digital circuit systems, ensuring that the output voltage of one logic gate can drive the input of the next\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e39\u003c/span\u003e\u003c/sup\u003e. Moreover, the C\u003csub\u003e10\u003c/sub\u003e-DNTT inverter demonstrated a wide operating voltage range in the on-state. Benefiting from the low \u003cem\u003eSS\u003c/em\u003e and interface trap density of the C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs, the C\u003csub\u003e10\u003c/sub\u003e-DNTT inverter exhibits high small-signal gains of 46.2 at \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e = 1 V and 127.6 at \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e = 2.5 V, making it promising for use in high-performance, low-power applications, such as electronic skin and radio-frequency identification tags. Owing to the high gain of C\u003csub\u003e10\u003c/sub\u003e-DNTT inverter provided by the insulating effect of alkyl chain, the total noise margin ((NM\u003csub\u003eL\u003c/sub\u003e + NM\u003csub\u003eH\u003c/sub\u003e)/ \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e) reaches up to 95.3% at \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e = 2.5 V, demonstrating the high noise tolerance of C\u003csub\u003e10\u003c/sub\u003e-DNTT inverter utilizing the insulating effect of alkyl chain (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003ed). We also calculate the total noise margins at different \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e values (Supplementary Fig.\u0026nbsp;9). The noise margins exceed 80% across \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e ranging from 0.5 V to 2.5 V, demonstrating the robustness of the C\u003csub\u003e10\u003c/sub\u003e-DNTT inverters utilizing the insulating effect of alkyl chain in multistage operations.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAlthough the zero-\u003cem\u003eV\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e inverter exhibited excellent static performance, its dynamic performance is compromised due to significant signal delay compared to bias-load and saturated-load architectures, where the load transistor is driven at higher bias voltages\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e40\u003c/span\u003e\u003c/sup\u003e. The characteristic signal-delay time constants (\u0026tau;) of the C\u003csub\u003e10\u003c/sub\u003e-DNTT inverter at 2500 Hz are 50 \u0026micro;s for the low-to-high transition (\u0026tau;\u003csub\u003erise\u003c/sub\u003e) and the high-to-low transition (\u0026tau;\u003csub\u003efall\u003c/sub\u003e), which benefit from the low interface trap density of the alkyl chains (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003ee). Moreover, the C\u003csub\u003e10\u003c/sub\u003e-DNTT inverter has both excellent dynamic and static characteristics, which is one of the exceptional performances reported in the existing literature\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e1\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e32\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e38\u003c/span\u003e,\u003cspan class=\"CitationRef\"\u003e41\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e49\u003c/span\u003e\u003c/sup\u003e (Supplementary Table\u0026nbsp;1). This demonstrates the insulating effect of alkyl chain can be utilized to achieve low-power integrated circuits.\u003c/p\u003e\n\u003cp\u003eInverters, as the fundamental units of logic circuits, must maintain their operational stability under continuous power supply to effectively prevent logic circuit failure caused by electrical performance drift\u003csup\u003e\u003cspan class=\"CitationRef\"\u003e40\u003c/span\u003e\u003c/sup\u003e. To evaluate the operational stability of organic inverters, we continuously applied \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e and varied \u003cem\u003eV\u003c/em\u003e\u003csub\u003ein\u003c/sub\u003e to repeatedly turn the inverter on and off for over 50 cycles. The input-output characteristics of C\u003csub\u003e10\u003c/sub\u003e-DNTT inverter at both \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e = 1 V and 2.5 V exhibited almost no drift (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003ef and Supplementary Fig.\u0026nbsp;10). The zero-\u003cem\u003eV\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e DNTT inverter was measured to demonstrate that the operational stability of the organic inverters is attributed to the alkyl chain layer (Supplementary Fig.\u0026nbsp;11). The increase in \u003cem\u003eV\u003c/em\u003e\u003csub\u003eout\u003c/sub\u003e in the off-state of DNTT inverter may be caused by \u003cem\u003eI\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e at the load. Additionally, the gain decreases and the off-state voltages rise for the DNTT inverter after cycle tests, likely due to the operational instability of DNTT FETs. This demonstrates that the introduction of alkyl chains not only reduces \u003cem\u003eI\u003c/em\u003e\u003csub\u003eGS\u003c/sub\u003e but also successfully enhances the operational stability of single OFET and organic logic circuits. The insulating effect of alkyl chains provides a straightforward method for fabricating low-power and high-stability organic transistors, making them promising candidates for low-power organic circuits.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eWe have demonstrated that the alkyl chains which were conventionally designed to improve the electrical and optoelectrical properties in alkylated OSCs, could be suitable as dielectric components for OFETs and organic circuits due to their insulating effect. The alkylated OSCs could function as both active and dielectric components. Besides, the nanoscale-thick alkyl chains are covalently bonded to backbones of OSC molecules, effectively eliminating the impact of the heterogeneous charge transport interface which is present in traditional OFETs on operational stability of OFETs. This reduces the density of traps at OSC/dielectric interface and the thickness of dielectric layer, enabling the fabrication of low-power and operational stable OFETs. Herein, C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs with the ultrathin C\u003csub\u003e10\u003c/sub\u003e alkyl chains show excellent electrical performance, characterized by a mobility of 11.6 cm\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e V\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e s\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e and the high operational stability with negligible current degradation during a 30000-second constant bias test. Furthermore, C\u003csub\u003e10\u003c/sub\u003e-DNTT inverters, composed of C\u003csub\u003e10\u003c/sub\u003e-DNTT FETs with high performance and excellent stability, achieve a small-signal gain of 46.2 and switching time of 50 \u0026micro;s at \u003cem\u003eV\u003c/em\u003e\u003csub\u003eDD\u003c/sub\u003e = 1 V, exhibiting both superior static and dynamic characteristics, which represents one of the exceptional performances reported in the current literature. The strategy of utilizing the insulating effect of alkyl chains addresses the challenge of OFETs with high-\u003cem\u003ek\u003c/em\u003e dielectrics in achieving high operational stability and opens new avenues for low-power and highly stable organic circuit applications.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by the National Natural Science Foundation of China (52225304, 52073210, 52203236, 52473193, 52403243, 52121002), and the Fundamental Research Funds for the Central Universities.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eX.\u0026nbsp;C., L.\u0026nbsp;L. and W.\u0026nbsp;H. conceived the study. J.\u0026nbsp;Q. and\u0026nbsp;J. X.\u0026nbsp;fabricated the films\u0026nbsp;and\u0026nbsp;the devices\u0026nbsp;and performed the electrical\u0026nbsp;and structure\u0026nbsp;characteristics.\u0026nbsp;J.\u0026nbsp;Q.,\u0026nbsp;J. X,\u0026nbsp;Z. W, Y.N. H and Y. H. analyzed the\u0026nbsp;characterization data.\u0026nbsp;X. L\u0026nbsp;performed\u0026nbsp;TCAD\u0026nbsp;simulation.\u0026nbsp;X.C., L.L.,\u0026nbsp;J.Q. and\u0026nbsp;J. X.\u0026nbsp;wrote the manuscript. X.\u0026nbsp;C.,\u0026nbsp;L.\u0026nbsp;L.\u0026nbsp;and W.H.\u0026nbsp;supervised\u0026nbsp;this work. All authors contributed to data analysis and manuscript preparation and commented on the manuscript.\u003c/p\u003e\n\u003cp\u003eAdditional information\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSupplementary information\u003c/strong\u003e is available for this paper at\u0026nbsp;XXX\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCorrespondence\u003c/strong\u003e and requests for materials should be addressed to L. L.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePeer review information\u003c/strong\u003e \u003cem\u003eNature\u0026nbsp;\u003c/em\u003e\u003cem\u003eCommunications\u003c/em\u003e thanks the anonymous reviewers for their contribution to the peer review of this work.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eReprints and permissions information\u003c/strong\u003e is available at XXX.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eBorchert JW et al (2020) Flexible low-voltage high-frequency organic thin-film transistors. Sci Adv 6:eaaz5156\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang Z et al (2022) High-brightness all-polymer stretchable LED with charge-trapping dilution. Nature 603:624\u0026ndash;630\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHan L et al (2023) Wafer-scale organic-on-III-V monolithic heterogeneous integration for active-matrix micro-LED displays. Nat Commun 14:6985\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNawaz A, Merces L, Ferro LM, Sonar P, Bufon CC (2023) Impact of planar and vertical organic field-effect transistors on flexible electronics. Adv Mater 35:2204804\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXie Y et al (2024) Organic transistor-based integrated circuits for future smart life. Smartmat, e1261\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang B et al (2023) On-chip fluorescent sensor for chemical vapor detection. Adv Mater Technol 8:2300609\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShi W, Guo Y, Liu Y (2020) When flexible organic field-effect transistors meet biomimetics: a prospective view of the internet of things. Adv Mater 32:1901493\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNawaz A, Liu Q, Leong WL, Fairfull-Smith KE, Sonar P (2021) Organic electrochemical transistors for in vivo bioelectronics. Adv Mater 33:2101874\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTsumura A, Koezuka H, Ando T (1986) Macromolecular electronic device: Field-effect transistor with a polythiophene thin film. Appl Phys Lett 49:1210\u0026ndash;1212\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHenson ZB, M\u0026uuml;llen K, Bazan GC (2012) Design strategies for organic semiconductors beyond the molecular formula. Nat Chem 4:699\u0026ndash;704\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBronstein H, Nielsen CB, Schroeder BC, McCulloch I (2020) The role of chemical design in the performance of organic semiconductors. Nat Rev Chem 4:66\u0026ndash;77\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYamaguchi Y et al (2020) Solution-Processable Organic Semiconductors Featuring S-Shaped Dinaphthothienothiophene (S-DNTT): Effects of Alkyl Chain Length on Self-Organization and Carrier Transport Properties. Chem Mater 32:5350\u0026ndash;5360\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang D et al (2020) Effect of alkyl chain length on charge transport property of anthracene-based organic semiconductors. ACS Appl Mater Inter 13:989\u0026ndash;998\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSelezneva E et al (2021) Strong Suppression of Thermal Conductivity in the Presence of Long Terminal Alkyl Chains in Low-Disorder Molecular Semiconductors. Adv Mater 33:2008708\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHu Y et al (2018) Effect of Alkyl-Chain Length on Charge Transport Properties of Organic Semiconductors and Organic Field‐Effect Transistors. Adv Electron Mater 4:1800175\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKoberidze M, Puska M, Nieminen R (2018) Structural details of Al/Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e junctions and their role in the formation of electron tunnel barriers. Phys Rev B 97:195406\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMa P et al (2019) Electron transport mechanism through ultrathin Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e films grown at low temperatures using atomic\u0026ndash;layer deposition. Semicond Sci Technol 34:105004\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWilt J, Sakidja R, Goul R, Wu JZ (2017) Effect of an interfacial layer on electron tunneling through atomically thin Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e tunnel barriers. ACS Appl Mater Inter 9:37468\u0026ndash;37475\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBoulas C, Davidovits J, Rondelez F, Vuillaume D (1996) Suppression of charge carrier tunneling through organic self-assembled monolayers. Phys Rev Lett 76:4797\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eF\u0026ouml;rst CJ, Ashman CR, Schwarz K, Bl\u0026ouml;chl PE (2004) The interface between silicon and a high-k oxide. Nature 427:53\u0026ndash;56\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang B et al (2018) High-k gate dielectrics for emerging flexible and stretchable electronics. Chem Rev 118:5690\u0026ndash;5754\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePalumbo F et al (2020) A review on dielectric breakdown in thin dielectrics: silicon dioxide, high-k, and layered dielectrics. Adv Funct Mater 30:1900657\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen X et al (2022) Balancing the film strain of organic semiconductors for ultrastable organic transistors with a five-year lifetime. Nat Commun 13:1480\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCasalini S, Bortolotti CA, Leonardi F, Biscarini F (2017) Self-assembled monolayers in organic electronics. Chem Soc Rev 46:40\u0026ndash;71\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOliver RC et al (2013) Dependence of micelle size and shape on detergent alkyl chain length and head group. PLoS ONE 8:e62488\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhou C et al (2023) Hybrid organic-inorganic two-dimensional metal carbide MXenes with amido- and imido-terminated surfaces. Nat Chem 15\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eInoue S et al (2015) Effects of substituted alkyl chain length on solution-processable layered organic semiconductor crystals. Chem Mater 27:3809\u0026ndash;3812\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGr\u0026uuml;newald M, Thomas P, W\u0026uuml;rtz D (1980) A simple scheme for evaluating field effect data. Phys Status Solidi (B) 100:K139\u0026ndash;K143\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHaneef HF, Zeidell AM, Jurchescu OD (2020) Charge carrier traps in organic semiconductors: a review on the underlying physics and impact on electronic devices. J Mater Chem C 8:759\u0026ndash;787\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCheng M et al (2024) Low-voltage polymer monolayer transistors for high-gain unipolar and complementary logic inverters. J Mater Chem C 12:9562\u0026ndash;9570\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang S et al (2023) Ultrahigh-gain organic transistors based on van der Waals metal-barrier interlayer-semiconductor junction. Sci Adv 9:eadj4656\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJiang C et al (2019) Printed subthreshold organic transistors operating at high gain and ultralow power. Science 363:719\u0026ndash;723\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLee S, Nathan A (2016) Subthreshold Schottky-barrier thin-film transistors with ultralow power and high intrinsic gain. Science 354:302\u0026ndash;304\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLuo Z et al (2021) Sub-thermionic, ultra-high-gain organic transistors and circuits. Nat Commun 12:1928\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSi H et al (2020) Emerging conductive atomic force microscopy for metal halide perovskite materials and solar cells. Adv Energy Mater 10:1903922\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLee J (2021) Physical modeling of charge transport in conjugated polymer field-effect transistors. J Phys D: Appl Phys 54:143002\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBoubaker A, Hafsi B, Lmimouni K, Kalboussi A (2017) A comparative TCAD simulations of a P-and N-type organic field effect transistors: field-dependent mobility, bulk and interface traps models. J Mater Sci -Mater Electron 28:7834\u0026ndash;7843\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHaldar T et al (2023) High-gain, low-voltage unipolar logic circuits based on nanoscale flexible organic thin-film transistors with small signal delays. Sci Adv 9:eadd3669\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShiwaku R et al (2017) Printed Organic Inverter Circuits with Ultralow Operating Voltages. Adv Electron Mater 3:1600557\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi J et al (2012) A stable solution-processed polymer semiconductor with record high-mobility for printed transistors. Sci Rep 2:754\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChi L-J, Yu M-J, Chang Y-H, Hou T-H (2016) 1-V full-swing depletion-load a-In\u0026ndash;Ga\u0026ndash;Zn\u0026ndash;O inverters for back-end-of-line compatible 3D integration. IEEE Electr Device Lett 37:441\u0026ndash;444\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDai Z, Wang Z, He X, Zhang XX, Alshareef HN (2017) Large-Area Chemical Vapor Deposited MoS\u003csub\u003e2\u003c/sub\u003e with Transparent Conducting Oxide Contacts toward Fully Transparent 2D Electronics. Adv Funct Mater 27:1703119\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFukuda K et al (2014) Fully-printed high-performance organic thin-film transistors and circuitry on one-micron-thick polymer films. Nat Commun 5:1\u0026ndash;8\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHuang W et al (2023) Vertical organic electrochemical transistors for complementary circuits. Nature 613:496\u0026ndash;502\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJi D et al (2018) Copolymer dielectrics with balanced chain-packing density and surface polarity for high-performance flexible organic electronics. Nat Commun 9:2339\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePark H et al (2024) Organic flexible electronics with closed-loop recycling for sustainable wearable technology. Nat Electron 7:39\u0026ndash;50\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSun D-m et al (2011) Flexible high-performance carbon nanotube integrated circuits. Nat Nanotechnol 6:156\u0026ndash;161\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWachter S, Polyushkin DK, Bethge O, Mueller T (2017) A microprocessor based on a two-dimensional semiconductor. Nat Commun 8:14948\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang M et al (2016) Threshold voltage tuning in a-IGZO TFTs with ultrathin SnO\u003csub\u003ex\u003c/sub\u003e capping layer and application to depletion-load inverter. IEEE Electr Device Lett 37:422\u0026ndash;425\u003c/span\u003e\u003c/li\u003e \u003c/ol\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003cstrong\u003eFabrication of OFETs\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe OFETs adopted bottom-gate and top-contact configurations. Highly doped Si wafers were used as substrates and gate electrodes. OTS, purchased from Aldrich, was modified into the\u0026nbsp;O\u003csub\u003e2\u003c/sub\u003e plasma-treated\u0026nbsp;Si wafers\u0026nbsp;(treated at 100W for 1min)\u0026nbsp;in a vacuum for 10 min at 60 ℃. Triple-sublimed grade DNTT, C\u003csub\u003e6\u003c/sub\u003e-DNTT, and C\u003csub\u003e10\u003c/sub\u003e-DNTT purchased from Sigma-Aldrich were deposited by vacuum thermal evaporation at a rate of approximately 0.1 Å s\u003csup\u003e\u0026minus;1\u003c/sup\u003e under 10\u003csup\u003e\u0026minus;4\u0026nbsp;\u003c/sup\u003ePa to fabricate the 20 nm OSC layers. The thickness and deposition rate were monitored by quartz-crystal microbalances. 30 nm Au electrodes were deposited to the OSC layers via shadow masks as the source and drain electrodes at a rate of approximately 0.1 Å s\u003csup\u003e\u0026minus;1\u003c/sup\u003e under 10\u003csup\u003e\u0026minus;4\u0026nbsp;\u003c/sup\u003ePa.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCharacterization of the OFETs\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBoth the electrical characteristics of the OFETs and the static characteristics of organic inverters were measured by an Agilent B1500A in a probe station system\u0026nbsp;under\u0026nbsp;dark air conditions. The dynamic characteristics of organic inverters were measured by PDA FS-Pro connected to a probe station system\u0026nbsp;under\u0026nbsp;dark air conditions.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStructure Characteristics\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eXRD measurements are measured in reflection mode with Cu k\u0026alpha; radiation using an X-ray diffractometer (RIGAKU SMARTLAB 9KW). c-AFM were performed in tapping mode using a Bruker Dimension ICON-PT instrument equipped with a c-AFM sensor and Pt-Ir-coated conducting probes (SCM-PIT-V2 from Bruker).\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":false,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-5398767/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5398767/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"The designability of organic semiconductors (OSCs) enables the tunable properties of organic field-effect transistors (OFETs) with significant potential applications in flexible displays, wearable devices, and bioelectronic devices. The introduction of alkyl chains has been proved to effectively modulate the mobility, crystallinity, solubility, and other optoelectronic properties of OSCs. Here, we revealed that the alkyl chains can function as dielectric components in OFETs due to their insulating effect. The ultrathin alkyl chains are covalently bonded to the OSC backbone, eliminating the heterogeneous charge transport interface and reducing the trap density, which enables low-power and high-stability alkylated-OFETs. The 2,9-didecyldinaphtho[2,3-b:2’,3’-f]thieno[3,2-b]thiophene (C10-DNTT) FET with alkyl chain exhibits a mobility of 11.6 cm2 V−1 s−1 and an ultrahigh intrinsic gain of 7.52×104 at operational voltage of 1 V. The corresponding inverters show exceptional static (small-signal gains of 127.6 and total noise margin of 95.3% at VDD = 2.5 V) and dynamic characteristics (signal-delay time constants of 50 μs at VDD = 1 V) under low voltage. Additionally, the C10-DNTT FETs and inverters demonstrate outstanding operational stability, enduring 30000 seconds of bias stress and cycle tests. This work offers a solution for achieving both low-power and high-stability organic electronic and optoelectronic application.","manuscriptTitle":"Insulating Effect of Alkyl Chains for Low-Power and High-Stability Organic Transistors and Circuits","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-11-15 07:04:22","doi":"10.21203/rs.3.rs-5398767/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"e4e82103-2f31-49e1-8646-b37e8bd201ea","owner":[],"postedDate":"November 15th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":40228890,"name":"Physical sciences/Materials science/Materials for devices/Electronic devices"},{"id":40228891,"name":"Physical sciences/Chemistry/Materials chemistry/Electronic materials"}],"tags":[],"updatedAt":"2026-01-06T16:26:44+00:00","versionOfRecord":[],"versionCreatedAt":"2024-11-15 07:04:22","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5398767","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5398767","identity":"rs-5398767","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}