Triethylamine (TEA) is internationally recognized as a common industrial waste gas, necessitating the urgent development of gas sensors with high selectivity and sensitivity. Here, the gas sensor derived from ZIF-L modified with PbS quantum dots (QDs) was designed and prepared. The photo-generated charge under UV light interacts with the adsorbed oxygen on the ZnO/PbS surface, resulting in the formation of alternating cycles. The p-n nano heterojunction created at the ZnO/PbS interface facilitates rapid carrier transfer. Therefore, the ZnO/PbS-0.2 sensor exhibits a response to TEA under UV light is as high as 13,600 (Ra/Rg), which is 5 times greater than that of ZnO, and 16 times higher than that of ZnO/PbS-0.2 sensor in darkness. Moreover, the response of ZnO/PbS-0.2 to TEA under UV light is at least 8 times that of the other 7 types of volatile organic compounds (VOCs). In addition, the detection limits of ZnO/PbS-0.2 under UV light are as low as 198 ppb, far below the internationally emission limit value (1 ppm). The ppb-level detection, super-high responsiveness, and outstanding selectivity of ZnO/PbS-0.2 sensor are result from the synergistic effect of the p-n nano heterojunction at the PbS-ZnO interface and abundant photo-generated charge carriers generated under UV light.
Read full abstract