High-Performance Nitric Oxide Gas Sensors Based on an Ultrathin Nanoporous Poly(3-hexylthiophene) Film

Abstract

Conjugated polymer (CP)-based organic field-effect transistors (OFETs) have been considered a potential sensor platform for detecting gas molecules because they can amplify sensing signals by controlling the gate voltage. However, these sensors exhibit significantly poorer oxidizing gas sensing performance than their inorganic counterparts. This paper presents a high-performance nitric oxide (NO) OFET sensor consisting of a poly(3-hexylthiophene) (P3HT) film with an ultrathin nanoporous structure. The ultrathin nonporous structure of the P3HT film was created via deposition through the shear-coating-assisted phase separation of polymer blends and selective solvent etching. The ultrathin nonporous structure of the P3HT film enhanced NO gas diffusion, adsorption, and desorption, resulting in the ultrathin nanoporous P3HT-film-based OFET gas sensor exhibiting significantly better sensing performance than pristine P3HT-film-based OFET sensors. Additionally, upon exposure to 10 ppm NO at room temperature, the nanoporous P3HT-film-based OFET gas sensor exhibited significantly better sensing performance (i.e., responsivity ≈ 42%, sensitivity ≈ 4.7% ppm−1, limit of detection ≈ 0.5 ppm, and response/recovery times ≈ 6.6/8.0 min) than the pristine P3HT-film-based OFET sensors.