The Polymer Society of Korea

Abstract

This study enhances organic field-effect transistor (OFET) gas sensor performance by introducing porosity into poly(3-hexylthiophene) (P3HT) thin films(< 10nm) via non-solvent immersion. We correlated film morphology and electrical properties to gas sensing performance using various non-solvents. Hexane created wide, deep 3D pores, maximizing the specific surface area. This resulted in a 357% sensitivity enhancement (1.37 %/ppm) to NO₂ over pristine films and a 0.002 ppm limit of detection (LOD). Conversely, H₂O formed shallow pores with limited sensitivity but uniquely improved charge carrier mobility by 2.4% via polymer chain rearrangement. Our work proves that non-solvent immersion is an effective strategy to selectively control the porous structure and microscopic crystallinity of the active layer, offering a key strategy for designing high-performance organic gas sensors.