Multiple Photo-Excited NH3 Gas Sensors Based on WS2/CuO Heterostructures With High Sensitivity and Reliable Anti-Humidity Ability

Nanosensors based on high-performance materials can be utilized for efficient detection of specific gases. In this study, tungsten disulfide/copper (II) oxide (WS
₂
/CuO) composite materials are successfully prepared. The optimal operating temperature of the formed materials is room temperature. When the molar ratio of Cu to WS
₂
is 5%, the fabricated sensor exhibits the highest sensitivity to ammonia. The performance of the sensor is tested under six light conditions, respectively, and the optimal excitation wavelength is proven to be 650 nm. With the illumination of 650-nm light, the sensing properties of the WS
₂
/CuO sensor are enhanced. The response value to 10-ppm NH
₃
is 194.9%, and the response/recover time is 112/115 s. In addition, the sensor with 650-nm light illumination is tested to have the anti-humidity ability, owing to its full recoverability and slight response value drift (16.9%) at the relative humidity between 10% and 75%. Moreover, the sensor exhibits great repeatability, selectivity, and stability. The sensing results show that light activation is a great method to enhance the sensing properties of WS
₂
/CuO hybrid.