Ammonia Gas Sensing Characteristic of P3HT-rGO-MWCNT Composite Films

• Main Authors: Tran Si Trong Khanh, Tran Quang Trung, Le Thuy Thanh Giang, Tran Quang Nguyen, Nguyen Dinh Lam, Nguyen Nang Dinh
• Format: Article
• Language: English
• Published: MDPI AG 2021-07-01
• Series: Applied Sciences
• Subjects: P3HT-rGO-MWCNT nanocomposite; drop-casting; heterojunction; NH₃ gas sensors; response time; sensitivity
• Online Access: https://www.mdpi.com/2076-3417/11/15/6675

In this work, the P3HT:rGO:MWCNTs (PGC) nanocomposite film applied to the ammonia gas sensor was successfully fabricated by a drop-casting technique. The results demonstrated that the optimum weight ratio of the PGC nanocomposite gas sensor is 20%:60%:20% as the weight ratio of P3HT:rGO:MWCNTs (called PGC-60). This weight ratio leads to the formation of nanostructured composites, causing the efficient adsorption/desorption of ammonia gas in/out of the film surface. The sensor based on PGC-60 possessed a response time of 30 s, sensitivity up to 3.6% at ammonia gas concentration of 10 ppm, and relative sensitivity of 0.031%/ppm. These results could be attributed to excellent electron transportation of rGO, the main adsorption activator to NH₃ gas of P3HT, and holes move from P3HT to the cathodes, which works as charge “nano-bridges” carriers of Multi-Walled Carbon Nanotubes (MWCNTs). In general, these three components of PGC sensors have significantly contributed to the improvement of both the sensitivity and response time in the NH₃ gas sensor.