▎ 摘　　要

Reduced graphene oxide (rGO) has attracted an enormous interest as a promising candidate material for gas detection due to its unique atomic structure. In the present work, rGO films were fabricated by the layer-by-layer (LBL) self-assembly and thermal reduction method for detecting ammonia (NH3) gas at room temperature. The single-and multi-layer rGO films exhibited high sensitivity and fast sensing performance to 5-50 ppm NH3, among which bi-layer rGO film showed the best sensitivity, recovery and the shortest response/recovery time to different concentrations of NH3. For bi-layer rGO film, the shortest response time to 50 ppm NH3 was 24 s and the recovery rate to 5 ppm NH3 was 98%, respectively. The sensing mechanism is attributed to the thinner rGO films and a larger specific surface area offered by the LBL self-assembly.