Improved NO<sub>2</sub> Gas-Sensing Performance of an Organic Field-Effect Transistor Based on Reduced Graphene Oxide-Incorporated Nanoporous Conjugated Polymer Thin Films
Seo Young Shin, Ganghoon Jeong, Nann Aye Mya Mya Phu, Hyeonseo Cheon, Vinh Van Tran, Hyeonseok Yoon, Mincheol Chang
Abstract
In this study, we have described a simple method for enhancing the NO 2 -sensing performance of the organic field-effect transistor (OFET) sensors at room temperature through reduced graphene oxide (rGO)-incorporated nanoporous P3HT films using the shear coating-assisted phase separation technique. The morphologies, microstructures, photophysical properties, and electrical properties of rGO-incorporated nanoporous P3HT films were investigated by atomic force microscopy, optical microscopy, ultraviolet–visible spectroscopy, X-ray diffraction analysis, Raman spectroscopy, and charge-carrier mobility measurements. The synergistic effect of P3HT pores acting as analyte diffusion pathways and rGO acting as adsorption sites resulted in a significant variation of the electrical properties of nanoporous P3HT/rGO OFETs upon exposure to NO 2 gas molecules, indicating the potential of OFETs as efficient NO 2 sensors. Specifically, the new nanoporous OFET sensors based on rGO-incorporated nanoporous P3HT films exhibited significantly improved responsivity with a value of ∼61.3% for 10 ppm NO 2 gas compared to those based on nonporous P3HT/PS/rGO composite films (∼17.7%). Moreover, excellent response and recovery behaviors (response time = ∼62 s and recovery time = ∼145 s), high sensitivity (∼1.48 ppm –1 ), and good selectivity were observed.