Preparation of conjugated polymer/reduced graphene oxide nanocomposites for high-performance volatile organic compound sensors

[Display omitted] •Conjugated polymer/rGO composites with high sensitivity to VOCs are created.•Photoirradiation facilitates nucleation and growth of polymer aggregates on rGO.•The composites show enhanced charge mobility and interfacial charge interactions.•Composite-based OFET sensors exhibit excellent responsivity to polar VOCs.•Rapid response/recovery behaviors are observed in the OFET sensors. We have reported a facile approach to fabricate poly(3-hexylthiophene)/reduced graphene oxide (P3HT/rGO) composite films via the photoirradiation of the corresponding composite solutions. The films are applied to organic field-effect transistor (OFET) sensors for the high-performance detection of volatile organic compounds (VOCs). The photoirradiation of the composite solutions and the presence of rGO act synergistically to facilitate the molecular ordering of P3HT. Thus, the P3HT/rGO composite films containing 20 wt% rGO exhibit a maximized charge carrier mobility of ~0.18 cm2 V−1 s−1, which is 6-folds higher than that of pristine P3HT films. The interfacial interactions between rGO and P3HT are enhanced by the favorable π − π and electrostatic interactions following photoirradiation. The OFET sensors based on the P3HT/rGO composites consistently show enhanced sensitivity to polar VOCs (methanol, acetone, ethanol, and isopropyl alcohol) compared to those based on the pristine P3HT, photoirradiated bare P3HT, and pristine P3HT/rGO composites. In particular, the photoirradiated P3HT/rGO-based OFET sensors achieve significantly improved responsivity (~110.6%) to methanol vapors (10 ppm) under rapid on/off pulses of 60 s, compared to those based on pristine P3HT (~6.8%), photoirradiated bare P3HT (~20.8%), and pristine P3HT/rGO (~55.1%) composites. Finally, excellent response and recovery behaviors (e.g., ~15 s and ~42 s, respectively) are also observed.