Highly sensitive and flexible ammonia sensor based on S and N co-doped graphene quantum dots/polyaniline hybrid at room temperature

Abstract

Here we present an innovative flexible ammonia (NH3) sensor based on S and N co-doped graphene quantum dots (S, N: GQDs)/polyaniline (PANI) hybrid loading on flexible polyethylene terephthalate thin film by chemical oxidative polymerization. The sensor exhibited not only excellent response, good selectivity and fast response and recovery time at room temperature but also flexibility, low cost and wearable characteristics. The experimental results reveal that the response of S, N: GQDs/PANI hybrid was about 5 fold higher than that of pure PANI at 100ppm of NH3 and the attained gas-sensing performance may be attributed to the increased hole like carriers by S, N: GQDs and enhanced interactions between the hybrid sensing film and NH3 molecules via π electron networks. The NH3-sensing mechanisms of the flexible S, N: GQDs/PANI gas sensor based on acid-base doping/de-doping process, carriers mobility, and swelling process are highlighted.