UV light driven high-performance room temperature surface acoustic wave NH3 gas sensor using sulfur-doped g-C3N4 quantum dots

Nanomaterials integrated surface acoustic wave (SAW) gas sensing technology has emerged as a promising candidate for realtime toxic gas sensing applications for environmental and human health safety. However, the development of novel chemical interface based on two-dimensional (2D) sensing materials for SAW sensors for the rapid and sensitive detection of NH3 gas at room temperature (RT) still remains challenging. Herein, we report a highly selective RT NH3 gas sensor based on sulfur-doped graphitic carbon nitride quantum dots (S@g-C3N4 QD) coated langasite (LGS) SAW sensor with enhanced sensitivity and recovery rate under ultraviolet (UV) illumination. Fascinatingly, the sensitivity of the S@g-C3N4 QD/LGS SAW sensor to NH3 (500 ppb) at RT is dramatically enhanced by ∼ 4.5-fold with a low detection limit (∼ 85 ppb), high selectivity, excellent reproducibility, and fast response/recovery time (70 s/79 s) under UV activation (365 nm) as compared to dark condition. Additionally, the proposed sensor exhibited augmented NH3 detection capability across the broad range of relative humidity (20