Conducting Polymers Incorporated with Related Graphene Compound Films for Use for Humidity and NH3 Gas Sensing

Using spin-coating technique, PEDOT:PSS + GQD + CNT (GPC), PEDOT:PSS + GQD + AgNW (GPA) films used for humidity sensors and P3HT + rGO + CNT (P3GC) films used for NH3 gas sensors were prepared. At room temperature and atmospheric pressure, all the sensing devices have extremely simple structure and they respond well to the humidity change (for GPC and GPA) and NH3 gas (for P3GC). The sensitivity of both the GPC and GPA humidity sensing devices was found to be dependent on the additives of CNT or AgNW. For the GPA sensors, the best sensitivity attained a value as large as 15.2% with a response time of 30 s. For the NH3 gas sensors made from P3GC films with a content of 20 wt.% of rGO and 10% of CNTs, the best performance parameters were obtained, such as responding time of ca. 30 s, sensing response of 0.8% at ammonia gas concentration of 10 ppm and a relative sensitivity of 0.05%/ppm. The fact that the P3HT + rGO + CNT sensors do not respond to humidity suggests useful applications in gas thin-film sensors for selectively sensing ammonia gas in a humid environment.