Design of p–p heterojunctions based on CuO decorated WS <sub>2</sub> nanosheets for sensitive NH <sub>3</sub> gas sensing at room temperature
Hanyu Luo, Jia Shi, Chao Liu, Xinwei Chen, Wen Lv, Yuchen Zhou, Min Zeng, Jianhua Yang, Hao Wei, Zhihua Zhou, Yanjie Su, Nantao Hu, Zhi Yang
Abstract
Abstract Tungsten disulfide (WS 2 ) nanosheets (NSs) have become a promising room-temperature gas sensor candidate due to their inherent high surface-to-volume ratio, tunable electrical properties, and high on-state current density. For further practical applications of WS 2 -based gas sensors, it is still necessary to overcome the insensitive response and incomplete recovery at room temperature. In this work, we controllably synthesized high-performance ammonia (NH 3 ) gas sensor based on CuO decorated WS 2 NSs. The optimized p–p WS 2 /CuO heterojunctions improve the surface catalytic effect, thereby enhancing the gas-sensing performance. The pure WS 2 NSs-based gas sensors showed a low response and an incomplete recovery in the case of NH 3 sensing. After the functionalization of CuO nanoparticles, the WS 2 /CuO heterostructure-based gas sensor exhibits an improved response value of 40.5% to 5 ppm NH 3 and full recoverability without any external assistance. Density functional theory calculations illustrate that the adsorption of CuO for NH 3 is much superior to WS 2 . The p–p heterojunctions strategy demonstrated in this work has great potential in the design of sensitive materials for gas sensors, and provides useful guidance for enhancing the room-temperature sensitivity and recoverability.