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

Abstract

Nanosensors based on high performance materials can be utilized for efficient detection of specific gases. In this study, WS2/CuO composite materials are successfully prepared. The optimal operating temperature of the formed materials is room temperature. When the molar ratio of Cu to WS2 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 WS2/CuO sensor are enhanced. The response value to 10 ppm NH3 is 194.9%, and the response/recover time is 112 s/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 WS2/CuO hybrid.