Rapid and Sensitive Carbon Monoxide Detection Using Novel SnO 2 /PEDOT-PSS Nanocomposite Gas Sensors

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Farea, N Yusof, Mohammad N. Murshed, Hamed Y Mohammed, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7444081/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 8 You are reading this latest preprint version Abstract The development of reliable, rapid, and sensitive sensors for carbon monoxide (CO) detection remains critical due to the toxic and pervasive nature of this gas in industrial and urban environments. This study reports a novel gas sensing device based on a SnO₂PEDOT:PSS nanocomposite, fabricated via a simple sol-gel and solution mixing method. Comprehensive structural, morphological, and optical characterizations using XRD, FTIR, Raman, UV–Vis spectroscopy, and FE-SEM confirm the successful integration of crystalline SnO₂ nanoparticles within the PEDOT:PSS matrix. The sensor demonstrates markedly enhanced chemosensitivity to CO, with a maximum response of 114% at 300 ppm and a substantial improvement in response and recovery times (47 s and 44 s, respectively) compared to the pristine polymer. This enhancement is attributed to the synergistic effects between the semiconducting SnO₂ and the conductive PEDOT:PSS, which facilitate improved charge transfer and gas adsorption. Additionally, the sensor exhibits excellent selectivity towards CO over other gases and maintains stable performance over 50 days, underscoring its practical viability. These findings position the SnO₂/PEDOT:PSS nanocomposite as a promising material for next-generation, room-temperature CO sensing applications. Gas Sensors SnO2/PEDOT-PSS Carbon Monoxide sensor Ultrafast Response Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 1. Introduction Over the past century, the swift development of urbanization, industry, and transportation has unquestionably changed human existence by bringing forth previously unheard-of levels of ease and economic expansion. However, the release of dangerous gases has resulted in a decline in air quality, which is a major cost of this achievement. Among these pollutants, carbon monoxide (CO) stands out as one of the most dangerous and pervasive threats to human health and the environment. CO is a colourless, odourless, and tasteless gas, making it particularly insidious as it can accumulate to lethal concentrations without immediate detection [ 1 – 3 ]. It is mostly created when carbon-based fuels, including those found in automobiles, factories, and home heating systems, burn incompletely. According to the World Health Organization (WHO), exposure to CO levels as low as 25 ppm for more than 8 hours can lead to adverse health effects, including headaches, dizziness, and impaired cognitive function, while concentrations exceeding 150 ppm can be fatal within hours. The environmental impact of CO is equally concerning, as it contributes to the formation of ground-level ozone and indirectly exacerbates climate change by influencing the atmospheric lifetime of methane [ 4 , 5 ]. A variety of dependable, sensitive, and reasonably priced gas sensors for CO detection is crucial given the serious effects of exposure to this gas. Traditional methods for CO monitoring, such as electrochemical and optical sensors, have been widely used but are often limited by high costs, complex fabrication processes, and susceptibility to environmental interference. Chemoresistive gas sensors have become a viable substitute in recent years because of their ease of use, low power consumption, and scalability. These sensors are ideal for real-time monitoring applications, as they operate based on changes in electrical resistance upon exposure to target gases. Metal oxides and conducting polymers have garnered considerable interest among the various materials investigated for chemoresistive sensing due to their unique properties and potential for synergy [ 6 – 8 ]. Metal oxides, such as tin(IV) oxide (SnO₂), are renowned for their high sensitivity, thermal stability, and wide bandgap, which make them excellent candidates for gas sensing. SnO₂, in particular, has been extensively studied for its ability to detect reducing gases like CO through surface redox reactions. However, the actual usefulness of pure SnO₂ sensors is limited due to their sluggish response/recovery times, high working temperatures, and poor selectivity. Conversely, conducting polymers, including poly(3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS), have flexible mechanical properties, adjustable electrical characteristics, and room-temperature functioning. Notwithstanding these advantages, limited sensitivity and long-term stability are problems for PEDOT:PSS-based sensors, especially in humid conditions [ 9 , 10 ]. Researchers have been concentrating more on hybrid materials that combine the advantages of conducting polymers and metal oxides in order to overcome these constraints. The integration of SnO₂ nanoparticles into PEDOT:PSS matrices has shown great promise in enhancing sensor performance by improving charge transfer, surface area, and gas adsorption properties. For instance, studies have demonstrated that SnO₂/PEDOT:PSS nanocomposites exhibit superior sensitivity, selectivity, and response and recovery times compared to their individual components. However, despite these advancements, significant research gaps remain, particularly in optimizing the nanocomposite's composition, understanding the underlying sensing mechanisms, and achieving long-term stability under real-world conditions [ 11 ]. By producing a unique SnO₂/PEDOT:PSS nanocomposite gas sensor for the quick and accurate detection of CO, our work seeks to close these gaps. We begin by exploring the sensing performance of pure PEDOT:PSS, followed by a systematic investigation of the effect of SnO₂ nanoparticles on enhancing key sensor metrics, including selectivity, sensitivity, and stability. The novelty of this work lies in the rational design and optimization of the nanocomposite, utilizing the complementary actions of PEDOT:PSS and SnO₂ to achieve previously unattained sensing performance. Furthermore, this research addresses critical environmental and societal needs by providing a cost-effective and scalable solution for CO monitoring, which is essential for safeguarding public health and mitigating environmental pollution. The production and characterisation of the SnO₂/PEDOT:PSS nanocomposite, the construction of the gas sensor, and the performance assessment utilizing a chemoresistive approach are all covered in depth in this publication. Through a combination of experimental and analytical approaches, we demonstrate the potential of this nanocomposite to revolutionize CO detection, offering a robust and reliable tool for environmental monitoring and industrial safety applications. By addressing the limitations of existing technologies and paving the way for future innovations, this work contributes to the broader goal of creating a safer and more environmentally friendly planet. 2. Experimental and Evaluation 2.1. SnO₂ Preparation Using a modified sol-gel technique, SnO₂ nanoparticles have been prepared [ 12 ]. In brief, 100 mL of DI water was used to dissolve 5 g of SnCl₄·5H₂O while being continuously stirred magnetically at room temperature until a clear solution was achieved. To aid in the hydrolysis and condensation processes, 50 mL of 0.5 M NaOH solution was then added dropwise to the SnCl₄ solution while being vigorously stirred. The mixture was stirred for 2 hours at 60°C to ensure complete precipitation of Sn(OH)₄. Centrifugation at 10,000 rpm for 10 minutes was used to collect the resultant white precipitate, which was then repeatedly cleaned with DI water to get rid of contaminants. To produce crystalline SnO₂ nanoparticles, the cleaned precipitate was dried for 12 hours at 80°C and then calcined for 2 hours at 500°C in a muffle furnace. 2.2. Preparation of the nanocomposite The SnO₂/PEDOT:PSS nanocomposite was produced by dispersing the synthesized SnO₂ nanoparticles into a PEDOT:PSS solution [ 13 ]. To produce a uniform suspension, 0.1 g of SnO₂ nanoparticles were first ultrasonically dispersed in 50 mL of DI water for 30 minutes. 40 mL of DI water was used to dilute 10 mL of PEDOT:PSS solution, which was then agitated for 15 minutes. The diluted PEDOT:PSS solution was then continuously stirred while the SnO₂ suspension was added dropwise. To guarantee that the SnO₂ nanoparticles were evenly distributed throughout the PEDOT:PSS matrix, the mixture was agitated for two more hours at room temperature. For later usage, the resultant SnO₂/PEDOT:PSS nanocomposite solution was kept at 4°C. 2.3. Fabrication of Sensor Devices The SnO₂/PEDOT:PSS nanocomposite was deposited over interdigitated electrode substrates that had been previously designed in order to create the gas sensor device. After being cleaned in an ultrasonic bath for 15 minutes each with acetone, ethanol, and DI water, the substrates were dried under a nitrogen stream. To create a consistent thin layer, the SnO₂/PEDOT:PSS solution was drop-cast onto the substrates. To enhance film adherence and eliminate any remaining solvents, the coated substrates were dried for an hour at 60°C. A specially designed gas sensing measurement setup was used to assess the manufactured device's gas sensing capabilities. A sealed gas chamber, a mass flow controller (MFC) for accurate gas concentration management, and a Keithley 2400 source meter for determining the sensor's electrical resistance made up the setup. A steady stream of dry air was used to capture the baseline resistance while the sensor was within the chamber. The MFC was used to mix CO gas with dry air to bring target CO gas concentrations (between 5 ppm and 300 ppm) into the chamber. The response of the sensor was determined as the relative change in resistance (ΔR/R₀)*100, where R₀ is the baseline resistance in dry air and ΔR is the change in resistance following exposure to CO gas. The time it took the sensor to attain 90% of its maximum response and 10% of its baseline resistance, respectively, was used to calculate the response and recovery times. Every measurement was carried out at room temperature, or 25°C. 3. Results and discussion 3.1. XRD study X-ray diffraction (XRD) was used to examine the synthetic materials' structural characteristics, as seen in Fig. 1 . The π-π stacking of polymer chains is responsible for the large peak at 25° in the XRD pattern of pure PEDOT:PSS, which is indicative of its semi-crystalline structure [ 14 ]. On the other hand, the SnO₂ nanoparticles exhibit distinct diffraction peaks at 26.5°, 33.8°, 37.9°, 51.7°, 54.7°, and 57.8°, which correspond to the tetragonal rutile structure's (110), (101), (200), (211), (220), and (002) planes (JCPDS card no. 41-1445) [ 15 ]. The intense peak at 26.5° indicates preferential growth along the (110) plane, confirming the high crystallinity of SnO₂. The high scattering intensity of the crystalline SnO₂ phase causes the SnO₂/PEDOT:PSS nanocomposite's XRD pattern to maintain the dominating peaks of SnO₂, especially at 26.5° and 33.8°. Additionally, a small peak at 25° corresponding to PEDOT:PSS is observed, confirming its presence in the composite. This shows that SnO₂ nanoparticles have been successfully incorporated into the PEDOT:PSS matrix without affecting either component's crystalline structure. The presence of both phases points to a synergistic combination of PEDOT:PSS flexibility and SnO₂ structural stability, which should improve the gas sensing capability. 3.2. FT-IR analysis FTIR spectroscopy was employed to further investigate the chemical structure and functional groups of the produced materials, as illustrated in Fig. 2 . The FTIR spectra of PEDOT:PSS show distinctive peaks at 2925 cm⁻¹ and 2840 cm⁻¹, which correspond to C-H stretching modes in the polymer backbone, and at 3400 cm⁻¹, which are ascribed to O-H stretching vibrations. Furthermore, PEDOT:PSS -typical C = C stretching and C-S-C deformation vibrations are linked to maxima at 1380 cm⁻¹ and 850 cm⁻¹, respectively [ 16 ]. These peaks attest to the existence of the functional groups and conductive polymer, which are necessary for its electrical characteristics. Broad peaks are seen in the SnO₂ FTIR spectra at 3400 cm⁻¹ and 2300 cm⁻¹, which correspond to O-H stretching vibrations and adsorbed water molecules on the metal oxide's surface [ 17 ]. The nonappearance of sharp peaks in the SnO₂ spectrum is consistent with its inorganic nature and the dominance of metal-oxygen bonds, which are less active in the IR region compared to organic functional groups. A combined set of characteristics from both components may be seen in the SnO₂/PEDOT:PSS nanocomposite's FTIR spectrum. Because of the high concentration of the metal oxide in the composite, the peaks at 3400 cm⁻¹ and 2300 cm⁻¹, which are typical of SnO₂, dominate the spectra. However, the minor but noticeable peaks at 2925 cm⁻¹ and 2840 cm⁻¹, which correspond to C-H stretching vibrations, also clearly show the existence of PEDOT:PSS. These peaks' persistence in the composite indicates that PEDOT:PSS was successfully incorporated into the SnO₂ matrix without undergoing any notable chemical changes. This implies that the functional groups of both materials are preserved in the nanocomposite, which is essential for producing synergistic effects in gas sensing applications. 3.3. UV–Visible spectra study UV-Vis spectroscopy was used to examine the optical characteristics of the produced materials, as shown in Fig. 3 . The π-π* transitions in the conjugated polymer backbone are responsible for the absorption peaks in the UV-Vis spectra of pure PEDOT:PSS, which are located at 290 and 263 nm [ 18 ]. These peaks are characteristic of PEDOT:PSS and indicate its strong absorption in the UV region, consistent with its conductive properties. On the other hand, SnO₂'s UV-Vis spectrum displays a noticeable absorption peak around 210 nm as well as a wide hump that extends into the visible spectrum. The bandgap absorption of SnO₂, which results from electron transitions from the valence band to the conduction band, is shown by the peak at 210 nm [ 19 ]. The broad hump is indicative of light scattering due to the nanoparticle size and surface defects, which is typical for metal oxide nanostructures. With a wide hump and a pronounced peak at 210 nm, the SnO₂/PEDOT:PSS nanocomposite's UV-Vis spectrum closely mimics that of SnO₂, indicating that SnO₂ largely affects the composite's optical characteristics. However, the presence of PEDOT:PSS is subtly reflected in the slight shoulder near 263 nm, confirming its integration into the composite. The retention of SnO₂'s strong absorption and the contribution of PEDOT:PSS 's optical properties highlight the successful formation of the nanocomposite. This combination is expected to enhance the material's light-harvesting and charge transfer capabilities. 3.4. Raman spectra study Raman spectroscopy was utilized further to investigate the synthetic materials' structural and vibrational characteristics, as seen in Fig. 4 . The Cα = Cβ symmetric stretching and oxyethylene ring deformation modes are represented by the strong peaks in the Raman spectra of pure PEDOT:PSS at 1420 cm⁻¹ and 830 cm⁻¹, respectively [ 20 ]. These peaks validate the conductive polymer's molecular structure and are distinctive to it. There are noticeable peaks in the Raman spectra for SnO₂ at 420 cm⁻¹, 835 cm⁻¹, 1418 cm⁻¹, and 1901 cm⁻¹. The Eg mode, which represents the vibration of oxygen atoms in the SnO₂ lattice, is ascribed to the peak at 420 cm⁻¹. The A1g and B2g modes, which are linked to the symmetric and asymmetric stretching of Sn-O bonds, respectively, are represented by the peaks at 835 cm⁻¹ and 1418 cm⁻¹ [ 21 ]. The peak confirms the high crystallinity and vibrational modes of the SnO₂ nanoparticles at 1901 cm⁻¹, which is ascribed to second-order Raman scattering. The prominent peaks at 420 cm⁻¹, 835 cm⁻¹, and 1418 cm⁻¹ in the SnO₂/PEDOT:PSS nanocomposite's Raman spectra closely mimic those of pure SnO₂, suggesting that the composite maintains the metal oxide's vibrational characteristics. However, the presence of PEDOT:PSS is evident through the small but distinct peak at 1420 cm⁻¹, which aligns with the characteristic peak of the polymer. This demonstrates that SnO₂ nanoparticles were successfully incorporated into the PEDOT:PSS matrix without interfering with either component's vibrational modes. The coexistence of these peaks suggests a synergistic interaction between SnO₂ and PEDOT:PSS. 3.5. Morphology studies FESEM was used to examine the surface morphology and structural characteristics of the produced materials, as seen in Fig. 5 . Figure 5 a depicts the FESEM image of pure PEDOT:PSS, revealing a spherical and homogeneous surface typical of the polymer film. The uniform morphology is consistent with the amorphous nature of PEDOT:PSS, which is essential for its conductive properties and film-forming ability [ 22 ]. The FESEM picture of the SnO₂/PEDOT:PSS nanocomposite, on the other hand, is displayed in Fig. 5 b, where it is obvious that SnO₂ nanoparticles have been incorporated into the PEDOT:PSS matrix. The image reveals a more textured and heterogeneous surface, with SnO₂ nanoparticles dispersed uniformly within the polymer matrix. The nanoparticles appear as bright spots, indicating their presence and distribution throughout the composite. 3.6. Performance of the gas sensor 3.6.1. Study of the I-V characteristics Since the interaction between the target gas and the sensing layer directly affects the charge carrier transport, the electrical characteristics of sensing materials are crucial in defining their gas sensing effectiveness. This was assessed by measuring the current-voltage (I-V) properties of the SnO₂/PEDOT:PSS composite and pure PEDOT:PSS, as illustrated in Fig. 6 a. The I-V curve of pure PEDOT:PSS exhibits a linear ohmic behavior, indicating its intrinsic conductive nature due to the delocalized π-electrons in the polymer backbone [ 23 ]. However, the conductivity is greatly increased when SnO₂ nanoparticles are added to the PEDOT:PSS matrix, as evidenced by the higher current values observed in the SnO₂/PEDOT:PSS composite. This enhancement is due to the synergistic interaction between PEDOT:PSS and SnO₂, where the metal oxide nanoparticles facilitate efficient charge transfer by providing additional pathways for electron conduction [ 24 ]. A major contributor to better gas sensing performance is the composite's increased conductivity, which guarantees quicker reaction and recovery times in addition to increased sensitivity to the target gas. These findings open the door for more sophisticated gas sensing applications by highlighting the significance of integrating conductive polymers and metal oxides to optimize the electrical characteristics of sensing materials. 3.6.2. Validation of Dynamic Gas Sensing By subjecting the sensors to different CO gas concentrations (5–300 ppm), with dry air serving as the baseline, the dynamic gas detecting capabilities of pure PEDOT:PSS and the SnO₂/PEDOT:PSS composite were assessed. To make sure that any adsorbed contaminants were eliminated, the sensing components were stabilized in air for 20 minutes before each measurement. As shown in Fig. 6 b, pure PEDOT:PSS exhibits a moderate response to CO gas, reaching a maximum response of 27% at 300 ppm. This reaction is explained by the way CO molecules interact with the conductive polymer, changing the PEDOT:PSS matrix's charge carrier density. However, the very small surface area and absence of active sites for gas adsorption in pure PEDOT:PSS restrict the reaction [ 25 ]. On the other hand, as shown in Fig. 6 c, the SnO₂/PEDOT:PSS composite exhibits a notable improvement in gas sensing ability, reaching a response of 114% at 300 ppm. The synergistic interaction between the PEDOT:PSS matrix and SnO₂ nanoparticles is responsible for this notable improvement. Being an n-type semiconductor, SnO₂ enables effective charge transfer at the interface between SnO₂ and PEDOT:PSS and adds more active sites for gas adsorption. The introduction of CO gas causes a reduction process that releases electrons into the SnO₂ conduction band by interacting with the oxygen species adsorbed on the surface. These electrons are then transferred to the PEDOT:PSS matrix, enhancing its conductivity and resulting in a higher response [ 26 ]. By taking into account the p-n heterojunction that forms between p-type PEDOT:PSS and n-type SnO₂, the sensing process may be further clarified. When CO, a reducing gas, is present, the composite's resistance drops because its electron density rises. This is due to the fact that CO molecules release electrons into the conduction band when they combine with pre-adsorbed oxygen ions (O₂⁻ or O⁻) on the SnO₂ surface. These electrons are then transferred to the PEDOT:PSS matrix, reducing its resistance and amplifying the overall response. The composite's sensitivity is further increased by the additional active sites for gas adsorption that the large surface area of SnO₂ nanoparticles affords [ 27 ]. Additionally, the addition of SnO₂ to PEDOT:PSS enhances response and recovery times, among other gas sensing characteristics. The enhanced recovery is ascribed to the desorption of CO molecules from the active sites, which is made possible by the porous structure of the composite. The quick response is caused by the effective charge transfer made possible by SnO₂. This combination of improved sensitivity, selectivity, and quicker kinetics makes the SnO₂/PEDOT:PSS composite an attractive choice for CO gas sensing applications. The dynamic gas sensing study demonstrates that the SnO₂/PEDOT:PSS composite performs better than pure PEDOT:PSS. The enhanced response is a result of the synergistic interaction between SnO₂ and PEDOT:PSS, which improves charge transfer, surface reactivity, and gas adsorption. These findings underscore the importance of material engineering in developing advanced gas sensors with high performance and reliability. We also investigated the response/recovery time, repeatability, reproducibility, selectivity, and stability of the SnO₂/PEDOT:PSS composite gas sensing capability at a concentration of 50 ppm CO. These characteristics are essential for evaluating the usefulness of gas sensors in actual settings. Response and recovery periods for the SnO₂/PEDOT:PSS composite are shown in Fig. 7 a and are 51 s and 48 s, respectively. These values indicate a rapid and efficient interaction between the sensing material and CO gas, highlighting the composite's ability to detect and recover from gas exposure quickly. The fast response time is attributed to the enhanced charge transfer facilitated by the incorporation of SnO₂ nanoparticles, while the effective desorption of CO molecules from the composite's active spots is what caused the speedy recovery. The reaction and recovery durations for a variety of CO concentrations (5–300 ppm) are further illustrated in Fig. 7 b. The response times increase from 31.9 s at 5 ppm to 88 s at 300 ppm, while the recovery times range from 29.7 s to 100.1 s. This trend is expected, as higher gas concentrations require more time for complete adsorption and desorption processes. However, the composite's applicability for real-time gas monitoring applications is highlighted by the very quick response and recovery periods across all concentrations. The repeatability of the SnO₂/PEDOT:PSS composite was evaluated by exposing the sensor to 50 ppm CO over seven consecutive cycles, as shown in Fig. 7 c. The results reveal high repeatability with negligible degradation, indicating the composite's robustness and reliability under repeated gas exposure. In real-world gas sensing applications, where sensors are often subjected to changing gas concentrations, this characteristic is crucial for guaranteeing reliable performance. Reproducibility studies were carried out employing many sensing devices in the same experimental setup to further confirm the composite's dependability. As depicted in Fig. 7 d, The findings provide essentially comparable response values, demonstrating the consistency of the sensing material and the repeatability of the production process. This reproducibility is a key factor for the large-scale deployment of gas sensors, as it ensures consistent presentation among several devices. By subjecting the sensor to a range of interfering gases, such as NH₃, SO₂, H₂S, CO₂, and CO at a concentration of 50 ppm, the selectivity of the SnO₂/PEDOT:PSS composite was assessed. As shown in Fig. 7 e, The sensor's exceptional selectivity is demonstrated by its noticeably greater sensitivity to CO when compared to the other gases. The distinct electrical characteristics of the composite and the particular interaction between CO molecules and the oxygen species adsorbed on the SnO₂ surface are responsible for this selectivity. The ability to distinguish CO from other gases is crucial for avoiding false alarms and ensuring accurate detection in complex environments. Finally, under the same experimental settings, measurements were made every six days for 50 days to evaluate the SnO₂/PEDOT:PSS composite's long-term stability. As illustrated in Fig. 7 f, With only a modest early deterioration and steady performance over time, the composite shows outstanding stability. Pure PEDOT:PSS, on the other hand, degrades significantly, illustrating one of the fundamental disadvantages of conducting polymers. The enhanced stability of the composite is attributed to the structural reinforcement provided by SnO₂ nanoparticles, which mitigate the degradation of the polymer matrix. This long-term stability is a serious requirement for gas sensors used in continuous monitoring applications. The SnO₂/PEDOT:PSS nanocomposite-based CO gas sensor's detecting capabilities were contrasted with those of other materials' previously published CO sensors. Compared to the PANI/CNTsensor, which has a considerably longer response time of 5.5 minutes, our sensor shows a speedy reaction time of 47 seconds and a recovery time of 44 seconds [ 28 ]. Furthermore, Our sensor reaches an impressive level of sensitivity of up to 87% for CO detection, outperforming the Pd/SnO ₂sensor, which shows a sensitivity of only 0.5 at 18 ppm [ 29 ]. Additionally, our sensor operates efficiently at room temperature, unlike the PPy@PEDOT:PSS sensor, which exhibits a lower response of 9.8% and a longer response time of 121 seconds [ 30 ]. This comparative analysis highlights that the SnO₂/PEDOT:PSS nanocomposite sensor not only matches but surpasses the performance of existing technologies, giving it a very practical way to detect CO in a variety of environmental conditions. The findings highlight the significant shortcomings of previously published sensors by demonstrating that our sensor provides improved sensitivity in addition to remarkably quick response and recovery times at ambient temperature. Conclusion We effectively developed a high-performance CO gas sensor in this work using a SnO₂/PEDOT:PSS nanocomposite, exhibiting remarkable stability, sensitivity, and selectivity. The effective incorporation of SnO₂ nanoparticles inside the PEDOT:PSS matrix was validated by thorough analysis utilizing XRD, FE-SEM, UV–Vis, Raman, and FTIR. At 300 ppm CO, the sensor had an impressive 87% response, much surpassing that of pure PEDOT:PSS. It also demonstrated outstanding repeatability and reproducibility, with fast reaction and recovery times of 47 and 44 seconds, respectively. Furthermore, the sensor demonstrated excellent selectivity against common interfering gases, including NH₃, SO₂, H₂S, and CO₂, along with outstanding stability over 50 days. With its room-temperature operation, scalability, and rapid detection capability, the SnO₂/PEDOT:PSS nanocomposite sensor presents a highly promising solution for real-time CO monitoring in environmental and industrial applications. This work contributes to The development of technologies for gas detection, offering a reliable and efficient approach to detecting toxic gases and enhancing public safety. Declarations Author Contribution M.A.F. conceived and designed the research, carried out the synthesis and characterization of the nanocomposite, and wrote the initial draft of the manuscript. N.Y. contributed to data analysis, interpretation of the sensing performance, and assisted in manuscript preparation. M.N.M. performed spectroscopic analysis and contributed to the discussion of the structural results. H.Y.M. assisted with experimental validation and supported the analysis of gas sensing behavior. A.A.O. contributed to the morphological analysis and critically reviewed the manuscript. D.A. assisted with data curation, figure preparation, and literature review. A.A.A.B. provided supervision, project administration, and critical revision of the manuscript. All authors reviewed and approved the final version of the manuscript. Acknowledgements: The authors extend their appreciation to the Deanship of Research and Graduate Studies at King Khalid University for funding this work through large group Research Project under grant number RGP2/360/46. References J. Yang, Y. Wang, C. Tang, Z. Zhang, Can digitalization reduce industrial pollution? Roles of environmental investment and green innovation, Environ Res 240 (2024) 117442. https://doi.org/10.1016/J.ENVRES.2023.117442. M.A. Farea, H.Y. Mohammed, S.M. Shirsat, Z.M. Ali, M.L. Tsai, I.S. Yahia, H.Y. Zahran, M.D. Shirsat, Impact of reduced graphene oxide on the sensing performance of Poly (3, 4–ethylenedioxythiophene) towards highly sensitive and selective CO sensor: A comprehensive study, Synth Met 291 (2022) 117166. https://doi.org/10.1016/J.SYNTHMET.2022.117166. H.M. Ragab, G.M. Aleid, F.A. Hamada, R.A. Aziz, M.A. Farea, M.A. Shimaa, Catalyzing Sensitivity: Exploring CuO’s Influence on PVA/PPy Films to Enhance its Performance for NO2 Gas Detection, J Inorg Organomet Polym Mater 34 (2024) 3995–4004. https://doi.org/10.1007/S10904-024-03052-0/FIGURES/7. T.E. Barnett, B.A. Curbow, E.K. Soule, S.L. Tomar, D.L. Thombs, Carbon Monoxide Levels Among Patrons of Hookah Cafes, Am J Prev Med 40 (2011) 324–328. https://doi.org/10.1016/J.AMEPRE.2010.11.004. M.A. Farea, H.Y. Mohammed, P.W. sayyad, N.N. Ingle, T. Al‑Gahouari, M.M. Mahadik, G.A. Bodkhe, S.M. Shirsat, M.D. Shirsat, Carbon monoxide sensor based on polypyrrole–graphene oxide composite: a cost-effective approach, Appl Phys A Mater Sci Process 127 (2021) 1–12. https://doi.org/10.1007/S00339-021-04837-7/FIGURES/13. J.F. Currie, A. Essalik, J.C. Marusic, Micromachined thin film solid state electrochemical CO2, NO2 and SO2 gas sensors, Sens Actuators B Chem 59 (1999) 235–241. https://doi.org/10.1016/S0925-4005(99)00227-0. P. Li, J. Li, S. Song, J. Chen, N. Zhong, Q. Xie, Y. Liu, B. Wan, Y. He, H. Karimi-Maleh, Recent advances in optical gas sensors for carbon dioxide detection, Measurement 239 (2025) 115445. https://doi.org/10.1016/J.MEASUREMENT.2024.115445. A. Turlybekuly, Y. Shynybekov, B. Soltabayev, G. Yergaliuly, A. Mentbayeva, The Cross-Sensitivity of Chemiresistive Gas Sensors: Nature, Methods, and Peculiarities: A Systematic Review, ACS Sens 50 (2024) 51. https://doi.org/10.1021/ACSSENSORS.4C02097/ASSET/IMAGES/LARGE/SE4C02097_0004.JPEG. M.A. Farea, N. Yusof, H.Y. Mohammed, M.N. Murshed, A. Samir, A. Hendi, A.M. Osman, Enhanced NO2 sensing performance of CdS nanoparticle-modified PEDOT:PSS composite: A systematic study of ultrasensitivity and reliability, Colloids Surf A Physicochem Eng Asp 703 (2024) 135305. https://doi.org/10.1016/J.COLSURFA.2024.135305. W. Zeng, Y. Liu, J. Mei, C. Tang, K. Luo, S. Li, H. Zhan, Z. He, Hierarchical SnO2–Sn3O4 heterostructural gas sensor with high sensitivity and selectivity to NO2, Sens Actuators B Chem 301 (2019) 127010. https://doi.org/10.1016/J.SNB.2019.127010. B.S. Dakshayini, K.R. Reddy, A. Mishra, N.P. Shetti, S.J. Malode, S. Basu, S. Naveen, A. V. Raghu, Role of conducting polymer and metal oxide-based hybrids for applications in ampereometric sensors and biosensors, Microchemical Journal 147 (2019) 7–24. https://doi.org/10.1016/J.MICROC.2019.02.061. M. Aziz, S. Saber Abbas, W.R. Wan Baharom, Size-controlled synthesis of SnO2 nanoparticles by sol–gel method, Mater Lett 91 (2013) 31–34. https://doi.org/10.1016/J.MATLET.2012.09.079. A.M. Díez-Pascual, Environmentally Friendly Synthesis of Poly(3,4-Ethylenedioxythiophene): Poly(Styrene Sulfonate)/SnO2 Nanocomposites, Polymers 2021, Vol. 13, Page 2445 13 (2021) 2445. https://doi.org/10.3390/POLYM13152445. T. Horii, H. Hikawa, M. Katsunuma, H. Okuzaki, Synthesis of highly conductive PEDOT:PSS and correlation with hierarchical structure, Polymer (Guildf) 140 (2018) 33–38. https://doi.org/10.1016/J.POLYMER.2018.02.034. T.M. Al-Saadi, B.H. Hussein, A.B. Hasan, A.A. Shehab, Study the Structural and Optical Properties of Cr doped SnO2 Nanoparticles Synthesized by Sol-Gel Method, Energy Procedia 157 (2019) 457–465. https://doi.org/10.1016/J.EGYPRO.2018.11.210. M. Reyes-Reyes, I. Cruz-Cruz, R. López-Sandoval, Enhancement of the electrical conductivity in PEDOT: PSS films by the addition of dimethyl sulfate, Journal of Physical Chemistry C 114 (2010) 20220–20224. https://doi.org/10.1021/JP107386X/ASSET/IMAGES/LARGE/JP-2010-07386X_0005.JPEG. F. Berger, E. Beche, R. Berjoan, D. Klein, A. Chambaudet, An XPS and FTIR study of SO2 adsorption on SnO2 surfaces, Appl Surf Sci 93 (1996) 9–16. https://doi.org/10.1016/0169-4332(95)00319-3. R. Gangopadhyay, B. Das, M.R. Molla, How does PEDOT combine with PSS? Insights from structural studies, RSC Adv 4 (2014) 43912–43920. https://doi.org/10.1039/C4RA08666J. P. Chetri, A. Choudhury, Investigation of optical properties of SnO2 nanoparticles, Physica E Low Dimens Syst Nanostruct 47 (2013) 257–263. https://doi.org/10.1016/J.PHYSE.2012.11.011. M. Stavytska-Barba, A.M. Kelley, Surface-enhanced raman study of the interaction of PEDOT: PSS with plasmonically active nanoparticles, Journal of Physical Chemistry C 114 (2010) 6822–6830. https://doi.org/10.1021/JP100135X/SUPPL_FILE/JP100135X_SI_001.PDF. J.X. Zhou, M.S. Zhang, J.M. Hong, J.L. Fang, Z. Yin, Structural and spectral properties of SnO2 nanocrystal prepared by microemulsion technique, Appl Phys A Mater Sci Process 81 (2005) 177–182. https://doi.org/10.1007/S00339-004-2742-7/METRICS. K.M. Alam, P. Kar, U.K. Thakur, R. Kisslinger, N. Mahdi, A. Mohammadpour, P.A. Baheti, P. Kumar, K. Shankar, Remarkable self-organization and unusual conductivity behavior in cellulose nanocrystal-PEDOT: PSS nanocomposites, Journal of Materials Science: Materials in Electronics 30 (2019) 1390–1399. https://doi.org/10.1007/S10854-018-0409-Y/FIGURES/8. S. Khasim, A. Pasha, M. Lakshmi, P. Chellasamy, M. Kadarkarai, A.A.A. Darwish, T.A. Hamdalla, S.A. Al-Ghamdi, S. Alfadhli, Post treated PEDOT-PSS films with excellent conductivity and optical properties as multifunctional flexible electrodes for possible optoelectronic and energy storage applications, Opt Mater (Amst) 125 (2022) 112109. https://doi.org/10.1016/J.OPTMAT.2022.112109. A. Vázquez-López, A. Yaseen, D. Maestre, J. Ramírez-Castellanos, E.S. Marstein, S.Z. Karazhanov, A. Cremades, Synergetic Improvement of Stability and Conductivity of Hybrid Composites formed by PEDOT:PSS and SnO Nanoparticles, Molecules 2020, Vol. 25, Page 695 25 (2020) 695. https://doi.org/10.3390/MOLECULES25030695. A. Vázquez-López, J. Bartolomé, D. Maestre, A. Cremades, Gas Sensing and Thermoelectric Properties of Hybrid Composite Films Based on PEDOT:PSS and SnO or SnO2 Nanostructures, Physica Status Solidi (a) 219 (2022) 2100794. https://doi.org/10.1002/PSSA.202100794. A. Alhameed, A. Hameed, · J F Mohammad, I.M. Ibrahim, A.A.A. Hameed, High sensitivity of UV photodetector based on SnO2-ZnO/P-Si heterojunctions prepared by hydrothermal method, Optical and Quantum Electronics 2025 57:1 57 (2025) 1–17. https://doi.org/10.1007/S11082-024-08031-W. J. Kim, W. Jo, Engineering of buried interfaces in perovskites: advancing sustainable photovoltaics, Nano Converg 11 (2024) 1–26. https://doi.org/10.1186/S40580-024-00464-Z/METRICS. A. Roy, A. Ray, P. Sadhukhan, K. Naskar, G. Lal, R. Bhar, C. Sinha, S. Das, Polyaniline-multiwalled carbon nanotube (PANI-MWCNT): Room temperature resistive carbon monoxide (CO) sensor, Synth Met 245 (2018) 182–189. https://doi.org/10.1016/J.SYNTHMET.2018.08.024. B. Kim, Y. Lu, A. Hannon, M. Meyyappan, J. Li, Low temperature Pd/SnO2 sensor for carbon monoxide detection, Sens Actuators B Chem 177 (2013) 770–775. https://doi.org/10.1016/J.SNB.2012.11.020. K.S. Pasupuleti, N.H. Bak, K.R. Peta, S.G. Kim, H.D. Cho, M.D. Kim, Enhanced sensitivity of langasite-based surface acoustic wave CO gas sensor using highly porous Ppy@PEDOT:PSS hybrid nanocomposite, Sens Actuators B Chem 363 (2022) 131786. https://doi.org/10.1016/J.SNB.2022.131786. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 11 Oct, 2025 Reviews received at journal 17 Sep, 2025 Reviewers agreed at journal 08 Sep, 2025 Reviewers agreed at journal 07 Sep, 2025 Reviewers invited by journal 06 Sep, 2025 Editor assigned by journal 06 Sep, 2025 Submission checks completed at journal 30 Aug, 2025 First submitted to journal 24 Aug, 2025 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-7444081","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":511781220,"identity":"3063b308-db41-47f6-95cb-ed56b35cb944","order_by":0,"name":"Maamon A. Farea","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5klEQVRIiWNgGAWjYBADfjD5AYjZ2InUItkAJBhngLQwk6KFmQfEJKRFt/3ww0c3Ku5I8M8+fPCzza9t8nzMDIwfPubg1mJ2Js3YOOfMMwmJc2nJ0rl9tw3bmBmYJWduw6PlQIKZdG7b4TqGMzwG0rk9txmBWtiYefFpOf/8G0iLhPwZ/s+/LXtu2xPWciMHbIuEwRkeNmmGH7cTidDyphjol8MShmfYzCx7G24ntzEzNuP3y/n0jY9zKg5LyJ1hfnzjx5/btvPbmw9++IhHCypgbAOTDcSqB4E/pCgeBaNgFIyCkQIAYgNRfE0BxskAAAAASUVORK5CYII=","orcid":"","institution":"Universiti Sultan Zainal Abidin","correspondingAuthor":true,"prefix":"","firstName":"Maamon","middleName":"A.","lastName":"Farea","suffix":""},{"id":511781221,"identity":"20d2e5eb-7913-4898-8d43-c8c406aa9ede","order_by":1,"name":"N Yusof","email":"","orcid":"","institution":"Universiti Sultan Zainal Abidin","correspondingAuthor":false,"prefix":"","firstName":"N","middleName":"","lastName":"Yusof","suffix":""},{"id":511781222,"identity":"315a3eb5-82bb-4147-b34a-0ac3bd17e52d","order_by":2,"name":"Mohammad N. Murshed","email":"","orcid":"","institution":"Applied College, King Khalid University Mohayil Asir Abha","correspondingAuthor":false,"prefix":"","firstName":"Mohammad","middleName":"N.","lastName":"Murshed","suffix":""},{"id":511781223,"identity":"8b31ffcd-aadd-44de-88d9-0434f8e520e0","order_by":3,"name":"Hamed Y Mohammed","email":"","orcid":"","institution":"Taiz University","correspondingAuthor":false,"prefix":"","firstName":"Hamed","middleName":"Y","lastName":"Mohammed","suffix":""},{"id":511781224,"identity":"0cb429f7-b81f-44c2-a25c-673a61da97da","order_by":4,"name":"A . AL OJEERY","email":"","orcid":"","institution":"University of Jeddah","correspondingAuthor":false,"prefix":"","firstName":"A","middleName":". AL","lastName":"OJEERY","suffix":""},{"id":511781227,"identity":"69f03853-d3af-467f-bf5a-d604d1fbe7a5","order_by":5,"name":"Doaa Abdelhameed","email":"","orcid":"","institution":"Prince Sattam Bin Abdulaziz University","correspondingAuthor":false,"prefix":"","firstName":"Doaa","middleName":"","lastName":"Abdelhameed","suffix":""},{"id":511781229,"identity":"611ed4fd-56fb-45db-87a4-76262e6b9842","order_by":6,"name":"Ahmad Ashrif","email":"","orcid":"","institution":"Universiti Kebangsaan Malaysia","correspondingAuthor":false,"prefix":"","firstName":"Ahmad","middleName":"","lastName":"Ashrif","suffix":""}],"badges":[],"createdAt":"2025-08-24 04:38:11","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7444081/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7444081/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":91155713,"identity":"d7b1a8af-f61c-408b-9f0f-6c204edcb511","added_by":"auto","created_at":"2025-09-12 08:07:18","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":61712,"visible":true,"origin":"","legend":"\u003cp\u003eXRD pattern of PEDOT-PSS, SnO\u003csub\u003e2\u003c/sub\u003e, and SnO\u003csub\u003e2\u003c/sub\u003e/PEDOT-PSS nanocomposite\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7444081/v1/b84f31e534c708cb8e8f6ee8.png"},{"id":91155714,"identity":"0e16a0ca-34ca-4531-974e-f8f2e3310afd","added_by":"auto","created_at":"2025-09-12 08:07:18","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":66161,"visible":true,"origin":"","legend":"\u003cp\u003eFTIR spectra comparing PEDOT:PSS, SnO₂, and the SnO₂/PEDOT:PSS composite\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7444081/v1/b355da288b9a9a63a2035b28.png"},{"id":91155715,"identity":"a8844f54-9b70-4887-b8dd-f026c622eff2","added_by":"auto","created_at":"2025-09-12 08:07:18","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":56152,"visible":true,"origin":"","legend":"\u003cp\u003eUV–vis spectra comparing PEDOT:PSS, SnO₂, and the SnO₂/PEDOT:PSS composite\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7444081/v1/df5298c58a4b346009132ea9.png"},{"id":91156677,"identity":"4c156daf-45c8-452f-a103-99b9aefc5962","added_by":"auto","created_at":"2025-09-12 08:15:18","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":69630,"visible":true,"origin":"","legend":"\u003cp\u003eRaman shift spectra comparing PEDOT:PSS, SnO₂, and the SnO₂/PEDOT:PSS composite\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7444081/v1/9e9a4499a682278c895b24bf.png"},{"id":91155718,"identity":"9cd08867-4eed-4b24-a970-6d70428b329d","added_by":"auto","created_at":"2025-09-12 08:07:18","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":504818,"visible":true,"origin":"","legend":"\u003cp\u003eFe-SEM images showing (a) the surface morphology of pure PEDOT:PSS and (b) the microstructural features of the SnO₂/PEDOT:PSS composite.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7444081/v1/bce7cce3a29c7786a275ae8f.png"},{"id":91155719,"identity":"8dec4ab7-a264-4de2-92f3-4da953537ed3","added_by":"auto","created_at":"2025-09-12 08:07:18","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":171929,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Current-voltage (I–V) characteristics of PEDOT:PSS and SnO₂/PEDOT:PSS composite, (b) dynamic gas response of PEDOT:PSS, (c) dynamic response of the SnO₂/PEDOT:PSS sensor, and (d) comparison of normalized sensor responses for both materials under identical testing conditions\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-7444081/v1/c93198cfe725bf1937047eb6.png"},{"id":91158361,"identity":"1885cf8b-906c-4f7f-9963-0a6bfa16538e","added_by":"auto","created_at":"2025-09-12 08:31:19","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1461735,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7444081/v1/c23ed99b-f110-4591-ae18-d635899abd8d.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Rapid and Sensitive Carbon Monoxide Detection Using Novel SnO 2 /PEDOT-PSS Nanocomposite Gas Sensors","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eOver the past century, the swift development of urbanization, industry, and transportation has unquestionably changed human existence by bringing forth previously unheard-of levels of ease and economic expansion. However, the release of dangerous gases has resulted in a decline in air quality, which is a major cost of this achievement. Among these pollutants, carbon monoxide (CO) stands out as one of the most dangerous and pervasive threats to human health and the environment. CO is a colourless, odourless, and tasteless gas, making it particularly insidious as it can accumulate to lethal concentrations without immediate detection [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. It is mostly created when carbon-based fuels, including those found in automobiles, factories, and home heating systems, burn incompletely. According to the World Health Organization (WHO), exposure to CO levels as low as 25 ppm for more than 8 hours can lead to adverse health effects, including headaches, dizziness, and impaired cognitive function, while concentrations exceeding 150 ppm can be fatal within hours. The environmental impact of CO is equally concerning, as it contributes to the formation of ground-level ozone and indirectly exacerbates climate change by influencing the atmospheric lifetime of methane [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eA variety of dependable, sensitive, and reasonably priced gas sensors for CO detection is crucial given the serious effects of exposure to this gas. Traditional methods for CO monitoring, such as electrochemical and optical sensors, have been widely used but are often limited by high costs, complex fabrication processes, and susceptibility to environmental interference. Chemoresistive gas sensors have become a viable substitute in recent years because of their ease of use, low power consumption, and scalability. These sensors are ideal for real-time monitoring applications, as they operate based on changes in electrical resistance upon exposure to target gases. Metal oxides and conducting polymers have garnered considerable interest among the various materials investigated for chemoresistive sensing due to their unique properties and potential for synergy [\u003cspan additionalcitationids=\"CR7\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eMetal oxides, such as tin(IV) oxide (SnO₂), are renowned for their high sensitivity, thermal stability, and wide bandgap, which make them excellent candidates for gas sensing. SnO₂, in particular, has been extensively studied for its ability to detect reducing gases like CO through surface redox reactions. However, the actual usefulness of pure SnO₂ sensors is limited due to their sluggish response/recovery times, high working temperatures, and poor selectivity. Conversely, conducting polymers, including poly(3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS), have flexible mechanical properties, adjustable electrical characteristics, and room-temperature functioning. Notwithstanding these advantages, limited sensitivity and long-term stability are problems for PEDOT:PSS-based sensors, especially in humid conditions [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eResearchers have been concentrating more on hybrid materials that combine the advantages of conducting polymers and metal oxides in order to overcome these constraints. The integration of SnO₂ nanoparticles into PEDOT:PSS matrices has shown great promise in enhancing sensor performance by improving charge transfer, surface area, and gas adsorption properties. For instance, studies have demonstrated that SnO₂/PEDOT:PSS nanocomposites exhibit superior sensitivity, selectivity, and response and recovery times compared to their individual components. However, despite these advancements, significant research gaps remain, particularly in optimizing the nanocomposite's composition, understanding the underlying sensing mechanisms, and achieving long-term stability under real-world conditions [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eBy producing a unique SnO₂/PEDOT:PSS nanocomposite gas sensor for the quick and accurate detection of CO, our work seeks to close these gaps. We begin by exploring the sensing performance of pure PEDOT:PSS, followed by a systematic investigation of the effect of SnO₂ nanoparticles on enhancing key sensor metrics, including selectivity, sensitivity, and stability. The novelty of this work lies in the rational design and optimization of the nanocomposite, utilizing the complementary actions of PEDOT:PSS and SnO₂ to achieve previously unattained sensing performance. Furthermore, this research addresses critical environmental and societal needs by providing a cost-effective and scalable solution for CO monitoring, which is essential for safeguarding public health and mitigating environmental pollution.\u003c/p\u003e\u003cp\u003eThe production and characterisation of the SnO₂/PEDOT:PSS nanocomposite, the construction of the gas sensor, and the performance assessment utilizing a chemoresistive approach are all covered in depth in this publication. Through a combination of experimental and analytical approaches, we demonstrate the potential of this nanocomposite to revolutionize CO detection, offering a robust and reliable tool for environmental monitoring and industrial safety applications. By addressing the limitations of existing technologies and paving the way for future innovations, this work contributes to the broader goal of creating a safer and more environmentally friendly planet.\u003c/p\u003e"},{"header":"2. Experimental and Evaluation","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1. SnO₂ Preparation\u003c/h2\u003e\u003cp\u003eUsing a modified sol-gel technique, SnO₂ nanoparticles have been prepared [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. In brief, 100 mL of DI water was used to dissolve 5 g of SnCl₄\u0026middot;5H₂O while being continuously stirred magnetically at room temperature until a clear solution was achieved. To aid in the hydrolysis and condensation processes, 50 mL of 0.5 M NaOH solution was then added dropwise to the SnCl₄ solution while being vigorously stirred. The mixture was stirred for 2 hours at 60\u0026deg;C to ensure complete precipitation of Sn(OH)₄. Centrifugation at 10,000 rpm for 10 minutes was used to collect the resultant white precipitate, which was then repeatedly cleaned with DI water to get rid of contaminants. To produce crystalline SnO₂ nanoparticles, the cleaned precipitate was dried for 12 hours at 80\u0026deg;C and then calcined for 2 hours at 500\u0026deg;C in a muffle furnace.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2. Preparation of the nanocomposite\u003c/h2\u003e\u003cp\u003eThe SnO₂/PEDOT:PSS nanocomposite was produced by dispersing the synthesized SnO₂ nanoparticles into a PEDOT:PSS solution [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. To produce a uniform suspension, 0.1 g of SnO₂ nanoparticles were first ultrasonically dispersed in 50 mL of DI water for 30 minutes. 40 mL of DI water was used to dilute 10 mL of PEDOT:PSS solution, which was then agitated for 15 minutes. The diluted PEDOT:PSS solution was then continuously stirred while the SnO₂ suspension was added dropwise. To guarantee that the SnO₂ nanoparticles were evenly distributed throughout the PEDOT:PSS matrix, the mixture was agitated for two more hours at room temperature. For later usage, the resultant SnO₂/PEDOT:PSS nanocomposite solution was kept at 4\u0026deg;C.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3. Fabrication of Sensor Devices\u003c/h2\u003e\u003cp\u003eThe SnO₂/PEDOT:PSS nanocomposite was deposited over interdigitated electrode substrates that had been previously designed in order to create the gas sensor device. After being cleaned in an ultrasonic bath for 15 minutes each with acetone, ethanol, and DI water, the substrates were dried under a nitrogen stream. To create a consistent thin layer, the SnO₂/PEDOT:PSS solution was drop-cast onto the substrates. To enhance film adherence and eliminate any remaining solvents, the coated substrates were dried for an hour at 60\u0026deg;C.\u003c/p\u003e\u003cp\u003eA specially designed gas sensing measurement setup was used to assess the manufactured device's gas sensing capabilities. A sealed gas chamber, a mass flow controller (MFC) for accurate gas concentration management, and a Keithley 2400 source meter for determining the sensor's electrical resistance made up the setup. A steady stream of dry air was used to capture the baseline resistance while the sensor was within the chamber. The MFC was used to mix CO gas with dry air to bring target CO gas concentrations (between 5 ppm and 300 ppm) into the chamber. The response of the sensor was determined as the relative change in resistance (ΔR/R₀)*100, where R₀ is the baseline resistance in dry air and ΔR is the change in resistance following exposure to CO gas. The time it took the sensor to attain 90% of its maximum response and 10% of its baseline resistance, respectively, was used to calculate the response and recovery times. Every measurement was carried out at room temperature, or 25\u0026deg;C.\u003c/p\u003e\u003c/div\u003e"},{"header":"3. Results and discussion","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003e3.1. XRD study\u003c/h2\u003e\u003cp\u003eX-ray diffraction (XRD) was used to examine the synthetic materials' structural characteristics, as seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The π-π stacking of polymer chains is responsible for the large peak at 25\u0026deg; in the XRD pattern of pure PEDOT:PSS, which is indicative of its semi-crystalline structure [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. On the other hand, the SnO₂ nanoparticles exhibit distinct diffraction peaks at 26.5\u0026deg;, 33.8\u0026deg;, 37.9\u0026deg;, 51.7\u0026deg;, 54.7\u0026deg;, and 57.8\u0026deg;, which correspond to the tetragonal rutile structure's (110), (101), (200), (211), (220), and (002) planes (JCPDS card no. 41-1445) [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. The intense peak at 26.5\u0026deg; indicates preferential growth along the (110) plane, confirming the high crystallinity of SnO₂.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe high scattering intensity of the crystalline SnO₂ phase causes the SnO₂/PEDOT:PSS nanocomposite's XRD pattern to maintain the dominating peaks of SnO₂, especially at 26.5\u0026deg; and 33.8\u0026deg;. Additionally, a small peak at 25\u0026deg; corresponding to PEDOT:PSS is observed, confirming its presence in the composite. This shows that SnO₂ nanoparticles have been successfully incorporated into the PEDOT:PSS matrix without affecting either component's crystalline structure. The presence of both phases points to a synergistic combination of PEDOT:PSS flexibility and SnO₂ structural stability, which should improve the gas sensing capability.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e3.2. FT-IR analysis\u003c/h2\u003e\u003cp\u003eFTIR spectroscopy was employed to further investigate the chemical structure and functional groups of the produced materials, as illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The FTIR spectra of PEDOT:PSS show distinctive peaks at 2925 cm⁻\u0026sup1; and 2840 cm⁻\u0026sup1;, which correspond to C-H stretching modes in the polymer backbone, and at 3400 cm⁻\u0026sup1;, which are ascribed to O-H stretching vibrations. Furthermore, PEDOT:PSS -typical C\u0026thinsp;=\u0026thinsp;C stretching and C-S-C deformation vibrations are linked to maxima at 1380 cm⁻\u0026sup1; and 850 cm⁻\u0026sup1;, respectively [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. These peaks attest to the existence of the functional groups and conductive polymer, which are necessary for its electrical characteristics. Broad peaks are seen in the SnO₂ FTIR spectra at 3400 cm⁻\u0026sup1; and 2300 cm⁻\u0026sup1;, which correspond to O-H stretching vibrations and adsorbed water molecules on the metal oxide's surface [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. The nonappearance of sharp peaks in the SnO₂ spectrum is consistent with its inorganic nature and the dominance of metal-oxygen bonds, which are less active in the IR region compared to organic functional groups.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eA combined set of characteristics from both components may be seen in the SnO₂/PEDOT:PSS nanocomposite's FTIR spectrum. Because of the high concentration of the metal oxide in the composite, the peaks at 3400 cm⁻\u0026sup1; and 2300 cm⁻\u0026sup1;, which are typical of SnO₂, dominate the spectra. However, the minor but noticeable peaks at 2925 cm⁻\u0026sup1; and 2840 cm⁻\u0026sup1;, which correspond to C-H stretching vibrations, also clearly show the existence of PEDOT:PSS. These peaks' persistence in the composite indicates that PEDOT:PSS was successfully incorporated into the SnO₂ matrix without undergoing any notable chemical changes. This implies that the functional groups of both materials are preserved in the nanocomposite, which is essential for producing synergistic effects in gas sensing applications.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e\u003ch2\u003e3.3. UV\u0026ndash;Visible spectra study\u003c/h2\u003e\u003cp\u003eUV-Vis spectroscopy was used to examine the optical characteristics of the produced materials, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. The π-π* transitions in the conjugated polymer backbone are responsible for the absorption peaks in the UV-Vis spectra of pure PEDOT:PSS, which are located at 290 and 263 nm [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. These peaks are characteristic of PEDOT:PSS and indicate its strong absorption in the UV region, consistent with its conductive properties.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eOn the other hand, SnO₂'s UV-Vis spectrum displays a noticeable absorption peak around 210 nm as well as a wide hump that extends into the visible spectrum. The bandgap absorption of SnO₂, which results from electron transitions from the valence band to the conduction band, is shown by the peak at 210 nm [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. The broad hump is indicative of light scattering due to the nanoparticle size and surface defects, which is typical for metal oxide nanostructures.\u003c/p\u003e\u003cp\u003eWith a wide hump and a pronounced peak at 210 nm, the SnO₂/PEDOT:PSS nanocomposite's UV-Vis spectrum closely mimics that of SnO₂, indicating that SnO₂ largely affects the composite's optical characteristics. However, the presence of PEDOT:PSS is subtly reflected in the slight shoulder near 263 nm, confirming its integration into the composite. The retention of SnO₂'s strong absorption and the contribution of PEDOT:PSS 's optical properties highlight the successful formation of the nanocomposite. This combination is expected to enhance the material's light-harvesting and charge transfer capabilities.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\u003ch2\u003e3.4. Raman spectra study\u003c/h2\u003e\u003cp\u003eRaman spectroscopy was utilized further to investigate the synthetic materials' structural and vibrational characteristics, as seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. The Cα\u0026thinsp;=\u0026thinsp;Cβ symmetric stretching and oxyethylene ring deformation modes are represented by the strong peaks in the Raman spectra of pure PEDOT:PSS at 1420 cm⁻\u0026sup1; and 830 cm⁻\u0026sup1;, respectively [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. These peaks validate the conductive polymer's molecular structure and are distinctive to it.\u003c/p\u003e\u003cp\u003eThere are noticeable peaks in the Raman spectra for SnO₂ at 420 cm⁻\u0026sup1;, 835 cm⁻\u0026sup1;, 1418 cm⁻\u0026sup1;, and 1901 cm⁻\u0026sup1;. The Eg mode, which represents the vibration of oxygen atoms in the SnO₂ lattice, is ascribed to the peak at 420 cm⁻\u0026sup1;. The A1g and B2g modes, which are linked to the symmetric and asymmetric stretching of Sn-O bonds, respectively, are represented by the peaks at 835 cm⁻\u0026sup1; and 1418 cm⁻\u0026sup1; [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. The peak confirms the high crystallinity and vibrational modes of the SnO₂ nanoparticles at 1901 cm⁻\u0026sup1;, which is ascribed to second-order Raman scattering.\u003c/p\u003e\u003cp\u003eThe prominent peaks at 420 cm⁻\u0026sup1;, 835 cm⁻\u0026sup1;, and 1418 cm⁻\u0026sup1; in the SnO₂/PEDOT:PSS nanocomposite's Raman spectra closely mimic those of pure SnO₂, suggesting that the composite maintains the metal oxide's vibrational characteristics. However, the presence of PEDOT:PSS is evident through the small but distinct peak at 1420 cm⁻\u0026sup1;, which aligns with the characteristic peak of the polymer. This demonstrates that SnO₂ nanoparticles were successfully incorporated into the PEDOT:PSS matrix without interfering with either component's vibrational modes. The coexistence of these peaks suggests a synergistic interaction between SnO₂ and PEDOT:PSS.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003e3.5. Morphology studies\u003c/h2\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eFESEM was used to examine the surface morphology and structural characteristics of the produced materials, as seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e. Figure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ea depicts the FESEM image of pure PEDOT:PSS, revealing a spherical and homogeneous surface typical of the polymer film. The uniform morphology is consistent with the amorphous nature of PEDOT:PSS, which is essential for its conductive properties and film-forming ability [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe FESEM picture of the SnO₂/PEDOT:PSS nanocomposite, on the other hand, is displayed in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eb, where it is obvious that SnO₂ nanoparticles have been incorporated into the PEDOT:PSS matrix. The image reveals a more textured and heterogeneous surface, with SnO₂ nanoparticles dispersed uniformly within the polymer matrix. The nanoparticles appear as bright spots, indicating their presence and distribution throughout the composite.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003e3.6. Performance of the gas sensor\u003c/h2\u003e\u003cdiv id=\"Sec13\" class=\"Section3\"\u003e\u003ch2\u003e3.6.1. Study of the I-V characteristics\u003c/h2\u003e\u003cp\u003eSince the interaction between the target gas and the sensing layer directly affects the charge carrier transport, the electrical characteristics of sensing materials are crucial in defining their gas sensing effectiveness. This was assessed by measuring the current-voltage (I-V) properties of the SnO₂/PEDOT:PSS composite and pure PEDOT:PSS, as illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ea. The I-V curve of pure PEDOT:PSS exhibits a linear ohmic behavior, indicating its intrinsic conductive nature due to the delocalized π-electrons in the polymer backbone [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. However, the conductivity is greatly increased when SnO₂ nanoparticles are added to the PEDOT:PSS matrix, as evidenced by the higher current values observed in the SnO₂/PEDOT:PSS composite. This enhancement is due to the synergistic interaction between PEDOT:PSS and SnO₂, where the metal oxide nanoparticles facilitate efficient charge transfer by providing additional pathways for electron conduction [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. A major contributor to better gas sensing performance is the composite's increased conductivity, which guarantees quicker reaction and recovery times in addition to increased sensitivity to the target gas. These findings open the door for more sophisticated gas sensing applications by highlighting the significance of integrating conductive polymers and metal oxides to optimize the electrical characteristics of sensing materials.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec14\" class=\"Section3\"\u003e\u003ch2\u003e3.6.2. Validation of Dynamic Gas Sensing\u003c/h2\u003e\u003cp\u003eBy subjecting the sensors to different CO gas concentrations (5\u0026ndash;300 ppm), with dry air serving as the baseline, the dynamic gas detecting capabilities of pure PEDOT:PSS and the SnO₂/PEDOT:PSS composite were assessed. To make sure that any adsorbed contaminants were eliminated, the sensing components were stabilized in air for 20 minutes before each measurement. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eb, pure PEDOT:PSS exhibits a moderate response to CO gas, reaching a maximum response of 27% at 300 ppm. This reaction is explained by the way CO molecules interact with the conductive polymer, changing the PEDOT:PSS matrix's charge carrier density. However, the very small surface area and absence of active sites for gas adsorption in pure PEDOT:PSS restrict the reaction [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eOn the other hand, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003ec, the SnO₂/PEDOT:PSS composite exhibits a notable improvement in gas sensing ability, reaching a response of 114% at 300 ppm. The synergistic interaction between the PEDOT:PSS matrix and SnO₂ nanoparticles is responsible for this notable improvement. Being an n-type semiconductor, SnO₂ enables effective charge transfer at the interface between SnO₂ and PEDOT:PSS and adds more active sites for gas adsorption. The introduction of CO gas causes a reduction process that releases electrons into the SnO₂ conduction band by interacting with the oxygen species adsorbed on the surface. These electrons are then transferred to the PEDOT:PSS matrix, enhancing its conductivity and resulting in a higher response [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eBy taking into account the p-n heterojunction that forms between p-type PEDOT:PSS and n-type SnO₂, the sensing process may be further clarified. When CO, a reducing gas, is present, the composite's resistance drops because its electron density rises. This is due to the fact that CO molecules release electrons into the conduction band when they combine with pre-adsorbed oxygen ions (O₂⁻ or O⁻) on the SnO₂ surface. These electrons are then transferred to the PEDOT:PSS matrix, reducing its resistance and amplifying the overall response. The composite's sensitivity is further increased by the additional active sites for gas adsorption that the large surface area of SnO₂ nanoparticles affords [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAdditionally, the addition of SnO₂ to PEDOT:PSS enhances response and recovery times, among other gas sensing characteristics. The enhanced recovery is ascribed to the desorption of CO molecules from the active sites, which is made possible by the porous structure of the composite. The quick response is caused by the effective charge transfer made possible by SnO₂. This combination of improved sensitivity, selectivity, and quicker kinetics makes the SnO₂/PEDOT:PSS composite an attractive choice for CO gas sensing applications.\u003c/p\u003e\u003cp\u003eThe dynamic gas sensing study demonstrates that the SnO₂/PEDOT:PSS composite performs better than pure PEDOT:PSS. The enhanced response is a result of the synergistic interaction between SnO₂ and PEDOT:PSS, which improves charge transfer, surface reactivity, and gas adsorption. These findings underscore the importance of material engineering in developing advanced gas sensors with high performance and reliability.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eWe also investigated the response/recovery time, repeatability, reproducibility, selectivity, and stability of the SnO₂/PEDOT:PSS composite gas sensing capability at a concentration of 50 ppm CO. These characteristics are essential for evaluating the usefulness of gas sensors in actual settings.\u003c/p\u003e\u003cp\u003eResponse and recovery periods for the SnO₂/PEDOT:PSS composite are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003ea and are 51 s and 48 s, respectively. These values indicate a rapid and efficient interaction between the sensing material and CO gas, highlighting the composite's ability to detect and recover from gas exposure quickly. The fast response time is attributed to the enhanced charge transfer facilitated by the incorporation of SnO₂ nanoparticles, while the effective desorption of CO molecules from the composite's active spots is what caused the speedy recovery. The reaction and recovery durations for a variety of CO concentrations (5\u0026ndash;300 ppm) are further illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003eb. The response times increase from 31.9 s at 5 ppm to 88 s at 300 ppm, while the recovery times range from 29.7 s to 100.1 s. This trend is expected, as higher gas concentrations require more time for complete adsorption and desorption processes. However, the composite's applicability for real-time gas monitoring applications is highlighted by the very quick response and recovery periods across all concentrations.\u003c/p\u003e\u003cp\u003eThe repeatability of the SnO₂/PEDOT:PSS composite was evaluated by exposing the sensor to 50 ppm CO over seven consecutive cycles, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003ec. The results reveal high repeatability with negligible degradation, indicating the composite's robustness and reliability under repeated gas exposure. In real-world gas sensing applications, where sensors are often subjected to changing gas concentrations, this characteristic is crucial for guaranteeing reliable performance. Reproducibility studies were carried out employing many sensing devices in the same experimental setup to further confirm the composite's dependability. As depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003ed, The findings provide essentially comparable response values, demonstrating the consistency of the sensing material and the repeatability of the production process. This reproducibility is a key factor for the large-scale deployment of gas sensors, as it ensures consistent presentation among several devices.\u003c/p\u003e\u003cp\u003eBy subjecting the sensor to a range of interfering gases, such as NH₃, SO₂, H₂S, CO₂, and CO at a concentration of 50 ppm, the selectivity of the SnO₂/PEDOT:PSS composite was assessed. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003ee, The sensor's exceptional selectivity is demonstrated by its noticeably greater sensitivity to CO when compared to the other gases. The distinct electrical characteristics of the composite and the particular interaction between CO molecules and the oxygen species adsorbed on the SnO₂ surface are responsible for this selectivity. The ability to distinguish CO from other gases is crucial for avoiding false alarms and ensuring accurate detection in complex environments.\u003c/p\u003e\u003cp\u003eFinally, under the same experimental settings, measurements were made every six days for 50 days to evaluate the SnO₂/PEDOT:PSS composite's long-term stability. As illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003ef, With only a modest early deterioration and steady performance over time, the composite shows outstanding stability. Pure PEDOT:PSS, on the other hand, degrades significantly, illustrating one of the fundamental disadvantages of conducting polymers. The enhanced stability of the composite is attributed to the structural reinforcement provided by SnO₂ nanoparticles, which mitigate the degradation of the polymer matrix. This long-term stability is a serious requirement for gas sensors used in continuous monitoring applications.\u003c/p\u003e\u003cp\u003eThe SnO₂/PEDOT:PSS nanocomposite-based CO gas sensor's detecting capabilities were contrasted with those of other materials' previously published CO sensors. Compared to the PANI/CNTsensor, which has a considerably longer response time of 5.5 minutes, our sensor shows a speedy reaction time of 47 seconds and a recovery time of 44 seconds [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Furthermore, Our sensor reaches an impressive level of sensitivity of up to 87% for CO detection, outperforming the Pd/SnO ₂sensor, which shows a sensitivity of only 0.5 at 18 ppm [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Additionally, our sensor operates efficiently at room temperature, unlike the PPy@PEDOT:PSS sensor, which exhibits a lower response of 9.8% and a longer response time of 121 seconds [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. This comparative analysis highlights that the SnO₂/PEDOT:PSS nanocomposite sensor not only matches but surpasses the performance of existing technologies, giving it a very practical way to detect CO in a variety of environmental conditions. The findings highlight the significant shortcomings of previously published sensors by demonstrating that our sensor provides improved sensitivity in addition to remarkably quick response and recovery times at ambient temperature.\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eWe effectively developed a high-performance CO gas sensor in this work using a SnO₂/PEDOT:PSS nanocomposite, exhibiting remarkable stability, sensitivity, and selectivity. The effective incorporation of SnO₂ nanoparticles inside the PEDOT:PSS matrix was validated by thorough analysis utilizing XRD, FE-SEM, UV\u0026ndash;Vis, Raman, and FTIR. At 300 ppm CO, the sensor had an impressive 87% response, much surpassing that of pure PEDOT:PSS. It also demonstrated outstanding repeatability and reproducibility, with fast reaction and recovery times of 47 and 44 seconds, respectively. Furthermore, the sensor demonstrated excellent selectivity against common interfering gases, including NH₃, SO₂, H₂S, and CO₂, along with outstanding stability over 50 days. With its room-temperature operation, scalability, and rapid detection capability, the SnO₂/PEDOT:PSS nanocomposite sensor presents a highly promising solution for real-time CO monitoring in environmental and industrial applications. This work contributes to The development of technologies for gas detection, offering a reliable and efficient approach to detecting toxic gases and enhancing public safety.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eM.A.F. conceived and designed the research, carried out the synthesis and characterization of the nanocomposite, and wrote the initial draft of the manuscript. N.Y. contributed to data analysis, interpretation of the sensing performance, and assisted in manuscript preparation. M.N.M. performed spectroscopic analysis and contributed to the discussion of the structural results. H.Y.M. assisted with experimental validation and supported the analysis of gas sensing behavior. A.A.O. contributed to the morphological analysis and critically reviewed the manuscript. D.A. assisted with data curation, figure preparation, and literature review. A.A.A.B. provided supervision, project administration, and critical revision of the manuscript. All authors reviewed and approved the final version of the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgements:\u003c/h2\u003e\u003cp\u003eThe authors extend their appreciation to the Deanship of Research and Graduate Studies at King Khalid University for funding this work through large group Research Project under grant number RGP2/360/46.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eJ. Yang, Y. Wang, C. Tang, Z. Zhang, Can digitalization reduce industrial pollution? Roles of environmental investment and green innovation, Environ Res 240 (2024) 117442. https://doi.org/10.1016/J.ENVRES.2023.117442.\u003c/li\u003e\n \u003cli\u003eM.A. Farea, H.Y. Mohammed, S.M. Shirsat, Z.M. Ali, M.L. Tsai, I.S. Yahia, H.Y. Zahran, M.D. Shirsat, Impact of reduced graphene oxide on the sensing performance of Poly (3, 4\u0026ndash;ethylenedioxythiophene) towards highly sensitive and selective CO sensor: A comprehensive study, Synth Met 291 (2022) 117166. https://doi.org/10.1016/J.SYNTHMET.2022.117166.\u003c/li\u003e\n \u003cli\u003eH.M. Ragab, G.M. Aleid, F.A. Hamada, R.A. Aziz, M.A. Farea, M.A. Shimaa, Catalyzing Sensitivity: Exploring CuO\u0026rsquo;s Influence on PVA/PPy Films to Enhance its Performance for NO2 Gas Detection, J Inorg Organomet Polym Mater 34 (2024) 3995\u0026ndash;4004. https://doi.org/10.1007/S10904-024-03052-0/FIGURES/7.\u003c/li\u003e\n \u003cli\u003eT.E. Barnett, B.A. Curbow, E.K. Soule, S.L. Tomar, D.L. Thombs, Carbon Monoxide Levels Among Patrons of Hookah Cafes, Am J Prev Med 40 (2011) 324\u0026ndash;328. https://doi.org/10.1016/J.AMEPRE.2010.11.004.\u003c/li\u003e\n \u003cli\u003eM.A. Farea, H.Y. Mohammed, P.W. sayyad, N.N. Ingle, T. Al‑Gahouari, M.M. Mahadik, G.A. Bodkhe, S.M. Shirsat, M.D. Shirsat, Carbon monoxide sensor based on polypyrrole\u0026ndash;graphene oxide composite: a cost-effective approach, Appl Phys A Mater Sci Process 127 (2021) 1\u0026ndash;12. https://doi.org/10.1007/S00339-021-04837-7/FIGURES/13.\u003c/li\u003e\n \u003cli\u003eJ.F. Currie, A. Essalik, J.C. Marusic, Micromachined thin film solid state electrochemical CO2, NO2 and SO2 gas sensors, Sens Actuators B Chem 59 (1999) 235\u0026ndash;241. https://doi.org/10.1016/S0925-4005(99)00227-0.\u003c/li\u003e\n \u003cli\u003eP. Li, J. Li, S. Song, J. Chen, N. Zhong, Q. Xie, Y. Liu, B. Wan, Y. He, H. Karimi-Maleh, Recent advances in optical gas sensors for carbon dioxide detection, Measurement 239 (2025) 115445. https://doi.org/10.1016/J.MEASUREMENT.2024.115445.\u003c/li\u003e\n \u003cli\u003eA. Turlybekuly, Y. Shynybekov, B. Soltabayev, G. Yergaliuly, A. Mentbayeva, The Cross-Sensitivity of Chemiresistive Gas Sensors: Nature, Methods, and Peculiarities: A Systematic Review, ACS Sens 50 (2024) 51. https://doi.org/10.1021/ACSSENSORS.4C02097/ASSET/IMAGES/LARGE/SE4C02097_0004.JPEG.\u003c/li\u003e\n \u003cli\u003eM.A. Farea, N. Yusof, H.Y. Mohammed, M.N. Murshed, A. Samir, A. Hendi, A.M. Osman, Enhanced NO2 sensing performance of CdS nanoparticle-modified PEDOT:PSS composite: A systematic study of ultrasensitivity and reliability, Colloids Surf A Physicochem Eng Asp 703 (2024) 135305. https://doi.org/10.1016/J.COLSURFA.2024.135305.\u003c/li\u003e\n \u003cli\u003eW. Zeng, Y. Liu, J. Mei, C. Tang, K. Luo, S. Li, H. Zhan, Z. He, Hierarchical SnO2\u0026ndash;Sn3O4 heterostructural gas sensor with high sensitivity and selectivity to NO2, Sens Actuators B Chem 301 (2019) 127010. https://doi.org/10.1016/J.SNB.2019.127010.\u003c/li\u003e\n \u003cli\u003eB.S. Dakshayini, K.R. Reddy, A. Mishra, N.P. Shetti, S.J. Malode, S. Basu, S. Naveen, A. V. Raghu, Role of conducting polymer and metal oxide-based hybrids for applications in ampereometric sensors and biosensors, Microchemical Journal 147 (2019) 7\u0026ndash;24. https://doi.org/10.1016/J.MICROC.2019.02.061.\u003c/li\u003e\n \u003cli\u003eM. Aziz, S. Saber Abbas, W.R. Wan Baharom, Size-controlled synthesis of SnO2 nanoparticles by sol\u0026ndash;gel method, Mater Lett 91 (2013) 31\u0026ndash;34. https://doi.org/10.1016/J.MATLET.2012.09.079.\u003c/li\u003e\n \u003cli\u003eA.M. D\u0026iacute;ez-Pascual, Environmentally Friendly Synthesis of Poly(3,4-Ethylenedioxythiophene): Poly(Styrene Sulfonate)/SnO2 Nanocomposites, Polymers 2021, Vol. 13, Page 2445 13 (2021) 2445. https://doi.org/10.3390/POLYM13152445.\u003c/li\u003e\n \u003cli\u003eT. Horii, H. Hikawa, M. Katsunuma, H. Okuzaki, Synthesis of highly conductive PEDOT:PSS and correlation with hierarchical structure, Polymer (Guildf) 140 (2018) 33\u0026ndash;38. https://doi.org/10.1016/J.POLYMER.2018.02.034.\u003c/li\u003e\n \u003cli\u003eT.M. Al-Saadi, B.H. Hussein, A.B. Hasan, A.A. Shehab, Study the Structural and Optical Properties of Cr doped SnO2 Nanoparticles Synthesized by Sol-Gel Method, Energy Procedia 157 (2019) 457\u0026ndash;465. https://doi.org/10.1016/J.EGYPRO.2018.11.210.\u003c/li\u003e\n \u003cli\u003eM. Reyes-Reyes, I. Cruz-Cruz, R. L\u0026oacute;pez-Sandoval, Enhancement of the electrical conductivity in PEDOT: PSS films by the addition of dimethyl sulfate, Journal of Physical Chemistry C 114 (2010) 20220\u0026ndash;20224. https://doi.org/10.1021/JP107386X/ASSET/IMAGES/LARGE/JP-2010-07386X_0005.JPEG.\u003c/li\u003e\n \u003cli\u003eF. Berger, E. Beche, R. Berjoan, D. Klein, A. Chambaudet, An XPS and FTIR study of SO2 adsorption on SnO2 surfaces, Appl Surf Sci 93 (1996) 9\u0026ndash;16. https://doi.org/10.1016/0169-4332(95)00319-3.\u003c/li\u003e\n \u003cli\u003eR. Gangopadhyay, B. Das, M.R. Molla, How does PEDOT combine with PSS? Insights from structural studies, RSC Adv 4 (2014) 43912\u0026ndash;43920. https://doi.org/10.1039/C4RA08666J.\u003c/li\u003e\n \u003cli\u003eP. Chetri, A. Choudhury, Investigation of optical properties of SnO2 nanoparticles, Physica E Low Dimens Syst Nanostruct 47 (2013) 257\u0026ndash;263. https://doi.org/10.1016/J.PHYSE.2012.11.011.\u003c/li\u003e\n \u003cli\u003eM. Stavytska-Barba, A.M. Kelley, Surface-enhanced raman study of the interaction of PEDOT: PSS with plasmonically active nanoparticles, Journal of Physical Chemistry C 114 (2010) 6822\u0026ndash;6830. https://doi.org/10.1021/JP100135X/SUPPL_FILE/JP100135X_SI_001.PDF.\u003c/li\u003e\n \u003cli\u003eJ.X. Zhou, M.S. Zhang, J.M. Hong, J.L. Fang, Z. Yin, Structural and spectral properties of SnO2 nanocrystal prepared by microemulsion technique, Appl Phys A Mater Sci Process 81 (2005) 177\u0026ndash;182. https://doi.org/10.1007/S00339-004-2742-7/METRICS.\u003c/li\u003e\n \u003cli\u003eK.M. Alam, P. Kar, U.K. Thakur, R. Kisslinger, N. Mahdi, A. Mohammadpour, P.A. Baheti, P. Kumar, K. Shankar, Remarkable self-organization and unusual conductivity behavior in cellulose nanocrystal-PEDOT: PSS nanocomposites, Journal of Materials Science: Materials in Electronics 30 (2019) 1390\u0026ndash;1399. https://doi.org/10.1007/S10854-018-0409-Y/FIGURES/8.\u003c/li\u003e\n \u003cli\u003eS. Khasim, A. Pasha, M. Lakshmi, P. Chellasamy, M. Kadarkarai, A.A.A. Darwish, T.A. Hamdalla, S.A. Al-Ghamdi, S. Alfadhli, Post treated PEDOT-PSS films with excellent conductivity and optical properties as multifunctional flexible electrodes for possible optoelectronic and energy storage applications, Opt Mater (Amst) 125 (2022) 112109. https://doi.org/10.1016/J.OPTMAT.2022.112109.\u003c/li\u003e\n \u003cli\u003eA. V\u0026aacute;zquez-L\u0026oacute;pez, A. Yaseen, D. Maestre, J. Ram\u0026iacute;rez-Castellanos, E.S. Marstein, S.Z. Karazhanov, A. Cremades, Synergetic Improvement of Stability and Conductivity of Hybrid Composites formed by PEDOT:PSS and SnO Nanoparticles, Molecules 2020, Vol. 25, Page 695 25 (2020) 695. https://doi.org/10.3390/MOLECULES25030695.\u003c/li\u003e\n \u003cli\u003eA. V\u0026aacute;zquez-L\u0026oacute;pez, J. Bartolom\u0026eacute;, D. Maestre, A. Cremades, Gas Sensing and Thermoelectric Properties of Hybrid Composite Films Based on PEDOT:PSS and SnO or SnO2 Nanostructures, Physica Status Solidi (a) 219 (2022) 2100794. https://doi.org/10.1002/PSSA.202100794.\u003c/li\u003e\n \u003cli\u003eA. Alhameed, A. Hameed, \u0026middot; J F Mohammad, I.M. Ibrahim, A.A.A. Hameed, High sensitivity of UV photodetector based on SnO2-ZnO/P-Si heterojunctions prepared by hydrothermal method, Optical and Quantum Electronics 2025 57:1 57 (2025) 1\u0026ndash;17. https://doi.org/10.1007/S11082-024-08031-W.\u003c/li\u003e\n \u003cli\u003eJ. Kim, W. Jo, Engineering of buried interfaces in perovskites: advancing sustainable photovoltaics, Nano Converg 11 (2024) 1\u0026ndash;26. https://doi.org/10.1186/S40580-024-00464-Z/METRICS.\u003c/li\u003e\n \u003cli\u003eA. Roy, A. Ray, P. Sadhukhan, K. Naskar, G. Lal, R. Bhar, C. Sinha, S. Das, Polyaniline-multiwalled carbon nanotube (PANI-MWCNT): Room temperature resistive carbon monoxide (CO) sensor, Synth Met 245 (2018) 182\u0026ndash;189. https://doi.org/10.1016/J.SYNTHMET.2018.08.024.\u003c/li\u003e\n \u003cli\u003eB. Kim, Y. Lu, A. Hannon, M. Meyyappan, J. Li, Low temperature Pd/SnO2 sensor for carbon monoxide detection, Sens Actuators B Chem 177 (2013) 770\u0026ndash;775. https://doi.org/10.1016/J.SNB.2012.11.020.\u003c/li\u003e\n \u003cli\u003eK.S. Pasupuleti, N.H. Bak, K.R. Peta, S.G. Kim, H.D. Cho, M.D. Kim, Enhanced sensitivity of langasite-based surface acoustic wave CO gas sensor using highly porous Ppy@PEDOT:PSS hybrid nanocomposite, Sens Actuators B Chem 363 (2022) 131786. https://doi.org/10.1016/J.SNB.2022.131786.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"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":"polymer-bulletin","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pobu","sideBox":"Learn more about [Polymer Bulletin](http://link.springer.com/journal/289)","snPcode":"289","submissionUrl":"https://submission.nature.com/new-submission/289/3","title":"Polymer Bulletin","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Gas Sensors, SnO2/PEDOT-PSS, Carbon Monoxide sensor, Ultrafast Response","lastPublishedDoi":"10.21203/rs.3.rs-7444081/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7444081/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe development of reliable, rapid, and sensitive sensors for carbon monoxide (CO) detection remains critical due to the toxic and pervasive nature of this gas in industrial and urban environments. This study reports a novel gas sensing device based on a SnO₂PEDOT:PSS nanocomposite, fabricated via a simple sol-gel and solution mixing method. Comprehensive structural, morphological, and optical characterizations using XRD, FTIR, Raman, UV–Vis spectroscopy, and FE-SEM confirm the successful integration of crystalline SnO₂ nanoparticles within the PEDOT:PSS matrix. The sensor demonstrates markedly enhanced chemosensitivity to CO, with a maximum response of 114% at 300 ppm and a substantial improvement in response and recovery times (47 s and 44 s, respectively) compared to the pristine polymer. This enhancement is attributed to the synergistic effects between the semiconducting SnO₂ and the conductive PEDOT:PSS, which facilitate improved charge transfer and gas adsorption. Additionally, the sensor exhibits excellent selectivity towards CO over other gases and maintains stable performance over 50 days, underscoring its practical viability. These findings position the SnO₂/PEDOT:PSS nanocomposite as a promising material for next-generation, room-temperature CO sensing applications.\u003c/p\u003e","manuscriptTitle":"Rapid and Sensitive Carbon Monoxide Detection Using Novel SnO 2 /PEDOT-PSS Nanocomposite Gas Sensors","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-12 08:07:13","doi":"10.21203/rs.3.rs-7444081/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-10-12T02:46:31+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-09-17T18:08:37+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"149087531101016637059169491209420798461","date":"2025-09-08T09:20:19+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"132690786636332514857365540450542647783","date":"2025-09-07T11:55:24+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-09-07T02:48:43+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-09-07T00:26:30+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-08-30T09:33:29+00:00","index":"","fulltext":""},{"type":"submitted","content":"Polymer Bulletin","date":"2025-08-24T04:33:34+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"polymer-bulletin","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"pobu","sideBox":"Learn more about [Polymer Bulletin](http://link.springer.com/journal/289)","snPcode":"289","submissionUrl":"https://submission.nature.com/new-submission/289/3","title":"Polymer Bulletin","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"e6705f7e-4d41-4bf7-a6ad-85dc79742d12","owner":[],"postedDate":"September 12th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-12-14T06:08:13+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-12 08:07:13","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7444081","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7444081","identity":"rs-7444081","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}