# Polymer-Based Chemicapacitive Hybrid Sensor Array for Improved Selectivity in e-Nose Systems

## TL;DR

This paper introduces a new polymer-based sensor array that improves the accuracy of detecting volatile organic compounds, which is important for health, environment, and industry.

## Contribution

The novel contribution is a hybrid sensor array that integrates virtual sensor arrays with advanced electrode geometry for enhanced VOC detection accuracy.

## Key findings

- Hybrid sensor arrays (HSAs) achieved 100% accuracy in identifying VOC compounds.
- VSAs using PMMA and PVP polymers reached 100% and 98% prediction accuracy respectively.
- HSAs outperformed traditional multi-sensor arrays and virtual sensor arrays in VOC detection.

## Abstract

Detecting volatile organic compounds (VOCs) is essential for health, environmental protection, and industrial safety. VOCs contribute to air pollution, pose health risks, and can indicate leaks or contamination in industries. Applications include air quality monitoring, disease diagnosis, and food safety. This paper focuses on polymer-based hybrid sensor arrays (HSAs) utilizing interdigitated electrode (IDE) geometries for VOC detection. Achieving high selectivity and sensitivity in gas sensing remains a challenge, particularly in complex environments. To address this, we propose HSAs as an innovative solution to enhance sensor performance. IDE-based sensors are designed and fabricated using the Polysilicon Multi-User MEMS process (PolyMUMPs). Experimental evaluations are performed by exposing sensors to VOCs under controlled conditions. Traditional multi-sensor arrays (MSAs) achieve 82% prediction accuracy, while virtual sensor arrays (VSAs) leveraging frequency dependence improve performance: PMMA-VSA and PVP-VSA predict compounds with 100% and 98% accuracy, respectively. The proposed HSA, integrating these VSAs, consistently achieves 100% accuracy in compound identification and concentration estimation, surpassing MSA and VSA performance. These findings demonstrate that proposed polymer-based HSAs and VSAs, particularly with advanced IDE geometries, significantly enhance selectivity and sensitivity, advancing e-Nose technology for more accurate and reliable VOC detection across diverse applications.