Improved NO2 gas sensing performance of nanoporous conjugated polymer (CP) thin films by incorporating preformed CP nanowires

• Published in: Dyes and pigments 2023-06, Vol.214, p.111235, Article 111235
• Main Authors: Jeong, Ganghoon, Cheon, Hyeong Jun, Shin, Seo Young, Wi, Eunsol, Kyokunzire, Proscovia, Cheon, Hyeonseo, Van Tran, Vinh, Vu, Trang Thi, Chang, Mincheol
• Format: Article
• Language: English
• Subjects: Conjugated polymers; Gas sensors; Nanoporous films; Nitrogen dioxides; Poly(3-hexylthiophene) nanowires
• ISSN: 0143-7208; 1873-3743
• DOI: 10.1016/j.dyepig.2023.111235

Conjugated polymer (CP)-based organic field-effect transistor (OFET) gas sensors can detect gas molecules at room temperature with high sensitivity and selectivity. However, their performance, particularly when detecting oxidizing gases, has fallen behind that of their metal oxide counterparts. Hence, improving their sensing performance as well as understanding the correlation between it and the structural and electrical properties of the sensing materials is necessary. Herein, we demonstrate that gas sensing performance of an OFET sensor based on nanoporous poly(3-hexylthiophene) (P3HT) films can be improved simply by incorporating preformed P3HT nanowires (NWs), which act as an efficient charge transport pathway. It detects nitrogen dioxide (NO2) molecules with high sensitivity due to the efficient charge transport pathway as well as ultrathin nanoporous structure of the P3HT films. Upon exposure to 10 ppm NO2 at room temperature, the OFET gas sensor based on the P3HT-NW embedded nanoporous P3HT film exhibits excellent responsivity (34%), fast response and recovery times (∼69 and ∼133 s, respectively), and a low limit of detection of under 0.1 ppm, which are comparable to those of conventional metal oxide-based gas sensors. Based on the correlation study between the morphology, charge transport ability, and sensing performance of the P3HT-NWs embedded nanoporous P3HT films, it is revealed that the efficient charge transport ability is an important factor for realizing high-performance CP-based OFET gas sensors, along with excellent morphological features such as thinness and high pore density. [Display omitted] •Preformed P3HT NW-incorporated ultrathin nanoporous P3HT films were created.•P3HT NWs facilitated effective charge transport in the resulting porous P3HT films.•The ultrathin nanoporous structure enabled enhanced interaction of NO2 with P3HT.•New P3HT film-based OFET sensors exhibited excellent performance in NO2 sensing.