CTAB modified SnO₂ PEDOT PSS heterojunction humidity sensor with enhanced sensitivity stability and machine learning evaluation
Abstract This study presents the development of a high-performance resistive humidity sensor based on a cetyltrimethylammonium bromide (CTAB)-assisted tin oxide (SnO₂) nanostructured thin film integrated with a Poly(3,4-ethylenedioxythiophene): Poly(styrenesulfonate) (PEDOT: PSS)/SnO₂ heterojunction...
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Nature Portfolio
2025-08-01
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| Online Access: | https://doi.org/10.1038/s41598-025-14184-9 |
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| author | Poundoss Chellamuthu Kirubaveni Savarimuthu M Gulam Nabi Alsath R. Krishnamoorthy Yuvaraj T Feras Alnaimat Mohammad Shabaz |
| author_facet | Poundoss Chellamuthu Kirubaveni Savarimuthu M Gulam Nabi Alsath R. Krishnamoorthy Yuvaraj T Feras Alnaimat Mohammad Shabaz |
| author_sort | Poundoss Chellamuthu |
| collection | DOAJ |
| description | Abstract This study presents the development of a high-performance resistive humidity sensor based on a cetyltrimethylammonium bromide (CTAB)-assisted tin oxide (SnO₂) nanostructured thin film integrated with a Poly(3,4-ethylenedioxythiophene): Poly(styrenesulfonate) (PEDOT: PSS)/SnO₂ heterojunction. The sensor design incorporates CTAB at varying weight percentages (0%, 6%, 11%, 16%, and 20%) during the hydrothermal synthesis of SnO₂ to regulate crystal growth, morphology, and surface area. The sample with 20 wt% CTAB (SnO-5) exhibited a flower-like stacked nanostructure, confirmed via field emission scanning electron microscopy (FESEM), which significantly enhanced water molecule adsorption and charge transport pathways. X-ray diffraction (XRD) analysis confirmed the tetragonal rutile phase of SnO₂ with decreasing crystallite size from 12.2 nm (nm) to 4.8 nm as CTAB concentration increased. The incorporation of PEDOT: PSS, a p-type conducting polymer, onto the SnO₂ layer via spin coating formed a p–n heterojunction, which improved charge separation and reduced recombination, thereby enhancing electrical conductivity and sensor performance. Electrochemical impedance spectroscopy (EIS) and current-voltage (J-V) measurements demonstrated that SnO-5 exhibited a low internal resistance (1.1 kilo ohms (kΩ)), a minimal cut-in voltage (0.071 Volts (V)), and a high current response (2.645 micro Amps.(µA)), indicating efficient carrier transport. The optimized SnO-5 sensor achieved a high sensitivity of 85.7%, a rapid response time of 14 s (s), and a quick recovery time of 7 s, with low hysteresis (1.60%) across a broad humidity range (5–97% Relative Humidity (RH)), outperforming several existing humidity sensing platforms. The synergistic effects of CTAB-induced nanostructuring and heterojunction engineering played a pivotal role in improving moisture interaction, charge mobility, and structural stability. Furthermore, to validate real-time application feasibility, machine learning (ML) algorithms were implemented to model and predict sensor behavior. Among the tested models, Random Forest (RF) Regression achieved the highest predictive accuracy (R² = 0.99), confirming the sensor’s robustness and reproducibility in dynamic environments. The proposed sensor’s outstanding performance, in combination with ML-enhanced evaluation, positions it as a promising candidate for next-generation humidity monitoring systems in industrial, environmental, and biomedical applications, including respiratory diagnostics and non-invasive health monitoring. |
| format | Article |
| id | doaj-art-be6a392d01e84f54aaa6c88a79b344bd |
| institution | Kabale University |
| issn | 2045-2322 |
| language | English |
| publishDate | 2025-08-01 |
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| spelling | doaj-art-be6a392d01e84f54aaa6c88a79b344bd2025-08-20T03:46:08ZengNature PortfolioScientific Reports2045-23222025-08-0115112010.1038/s41598-025-14184-9CTAB modified SnO₂ PEDOT PSS heterojunction humidity sensor with enhanced sensitivity stability and machine learning evaluationPoundoss Chellamuthu0Kirubaveni Savarimuthu1M Gulam Nabi Alsath2R. Krishnamoorthy3Yuvaraj T4Feras Alnaimat5Mohammad Shabaz6Centre for Smart Energy Systems, Chennai Institute of TechnologyDepartment of Electronics and Communication Engineering, College of Engineering, Anna University, GuindyDepartment of Electronics and Communication Engineering, College of Engineering, Anna University, GuindyCentre for Advanced Wireless Integrated Technology, Chennai Institute of TechnologyCentre for Smart Energy Systems, Chennai Institute of TechnologyFaculty of Engineering, Hourani Center for Applied Scientific Research, Al-Ahliyya Amman UniversityMarwadi University Research Center, Department of Computer Engineering, Faculty of Engineering and Technology, Marwadi UniversityAbstract This study presents the development of a high-performance resistive humidity sensor based on a cetyltrimethylammonium bromide (CTAB)-assisted tin oxide (SnO₂) nanostructured thin film integrated with a Poly(3,4-ethylenedioxythiophene): Poly(styrenesulfonate) (PEDOT: PSS)/SnO₂ heterojunction. The sensor design incorporates CTAB at varying weight percentages (0%, 6%, 11%, 16%, and 20%) during the hydrothermal synthesis of SnO₂ to regulate crystal growth, morphology, and surface area. The sample with 20 wt% CTAB (SnO-5) exhibited a flower-like stacked nanostructure, confirmed via field emission scanning electron microscopy (FESEM), which significantly enhanced water molecule adsorption and charge transport pathways. X-ray diffraction (XRD) analysis confirmed the tetragonal rutile phase of SnO₂ with decreasing crystallite size from 12.2 nm (nm) to 4.8 nm as CTAB concentration increased. The incorporation of PEDOT: PSS, a p-type conducting polymer, onto the SnO₂ layer via spin coating formed a p–n heterojunction, which improved charge separation and reduced recombination, thereby enhancing electrical conductivity and sensor performance. Electrochemical impedance spectroscopy (EIS) and current-voltage (J-V) measurements demonstrated that SnO-5 exhibited a low internal resistance (1.1 kilo ohms (kΩ)), a minimal cut-in voltage (0.071 Volts (V)), and a high current response (2.645 micro Amps.(µA)), indicating efficient carrier transport. The optimized SnO-5 sensor achieved a high sensitivity of 85.7%, a rapid response time of 14 s (s), and a quick recovery time of 7 s, with low hysteresis (1.60%) across a broad humidity range (5–97% Relative Humidity (RH)), outperforming several existing humidity sensing platforms. The synergistic effects of CTAB-induced nanostructuring and heterojunction engineering played a pivotal role in improving moisture interaction, charge mobility, and structural stability. Furthermore, to validate real-time application feasibility, machine learning (ML) algorithms were implemented to model and predict sensor behavior. Among the tested models, Random Forest (RF) Regression achieved the highest predictive accuracy (R² = 0.99), confirming the sensor’s robustness and reproducibility in dynamic environments. The proposed sensor’s outstanding performance, in combination with ML-enhanced evaluation, positions it as a promising candidate for next-generation humidity monitoring systems in industrial, environmental, and biomedical applications, including respiratory diagnostics and non-invasive health monitoring.https://doi.org/10.1038/s41598-025-14184-9CTAB-assisted SnO2 nanostructuresHydrothermal synthesisPEDOT:PSS heterojunctionFlower-like morphologyResistive humidity sensingSensitivity and hysteresis analysis |
| spellingShingle | Poundoss Chellamuthu Kirubaveni Savarimuthu M Gulam Nabi Alsath R. Krishnamoorthy Yuvaraj T Feras Alnaimat Mohammad Shabaz CTAB modified SnO₂ PEDOT PSS heterojunction humidity sensor with enhanced sensitivity stability and machine learning evaluation Scientific Reports CTAB-assisted SnO2 nanostructures Hydrothermal synthesis PEDOT:PSS heterojunction Flower-like morphology Resistive humidity sensing Sensitivity and hysteresis analysis |
| title | CTAB modified SnO₂ PEDOT PSS heterojunction humidity sensor with enhanced sensitivity stability and machine learning evaluation |
| title_full | CTAB modified SnO₂ PEDOT PSS heterojunction humidity sensor with enhanced sensitivity stability and machine learning evaluation |
| title_fullStr | CTAB modified SnO₂ PEDOT PSS heterojunction humidity sensor with enhanced sensitivity stability and machine learning evaluation |
| title_full_unstemmed | CTAB modified SnO₂ PEDOT PSS heterojunction humidity sensor with enhanced sensitivity stability and machine learning evaluation |
| title_short | CTAB modified SnO₂ PEDOT PSS heterojunction humidity sensor with enhanced sensitivity stability and machine learning evaluation |
| title_sort | ctab modified sno₂ pedot pss heterojunction humidity sensor with enhanced sensitivity stability and machine learning evaluation |
| topic | CTAB-assisted SnO2 nanostructures Hydrothermal synthesis PEDOT:PSS heterojunction Flower-like morphology Resistive humidity sensing Sensitivity and hysteresis analysis |
| url | https://doi.org/10.1038/s41598-025-14184-9 |
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