title: Ammonia gas sensors based on poly (3-hexylthiophene)-molybdenum disulfide film transistors.
abstract: In this work, in order to enhance the recovery performance of organic thin film transistors (OTFTs) ammonia (NH3) sensors, poly (3-hexylthiophene) (P3HT) and molybdenum disulfide (MoS2) were combined as sensitive materials. Different sensitive film structures as active layers of OTFTs, i.e., P3HT-MoS2 composite film, P3HT/MoS2 bilayer film and MoS2/P3HT bilayer film were fabricated by spray technology. OTFT gas sensors based on P3HT-MoS2 composite film showed a shorter recovery time than others when the ammonia concentration changed from 4 to 20 ppm. Specifically, x-ray diffraction (XRD), Raman and UV-visible absorption were employed to explore the interface properties between P3HT and single-layer MoS2. Through the complementary characterization, a mechanism based on charge transfer is proposed to explain the physical originality of these OTFT gas sensors: closer interlayer d-spacing and better π-π stacking of the P3HT chains in composite film have ensured a short recovery time of OTFT gas sensors. Moreover, sensing mechanisms of OTFTs were further studied by comparing the device performance in the presence of nitrogen or dry air as a carrier gas. This work not only strengthens the fundamental understanding of the sensing mechanism, but provides a promising approach to optimizing the OTFT gas sensors.
authors.affiliation: School of Optoelectronic Information, State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China (UESTC), Chengdu, 610054, People's Republic of China.
authors.forename: Tao
authors.initials: T
authors.lastname: Xie
authors.forename: Guangzhong
authors.initials: G
authors.lastname: Xie
authors.forename: Yuanjie
authors.initials: Y
authors.lastname: Su
authors.forename: Du
authors.initials: D
authors.lastname: Hongfei
authors.forename: Zongbiao
authors.initials: Z
authors.lastname: Ye
authors.forename: Yadong
authors.initials: Y
authors.lastname: Jiang