Enhanced xylene detection performance of colloidal quantum dots modified tungsten oxide composites

Abstract

Surface modification of sensitive materials is an effective strategy for building high-performance sensors. In this work, NH4Cl acted as structure-directing agent and corrosive was utilizing in the fabrication of WO3 nanoplates with neat grooves. The prepared Co3O4 colloid quantum dots were uniformly dispersed on the WO3 surface to construct the gas sensor with excellent sensing performance. The intrinsic properties, such as crystal structures, surface adsorption states, and chemical states of all samples, were analyzed. Compared with the sensor without Co3O4, the sensing performance of the Co3O4 functionalized sensor towards xylene was significantly improved. Compared with the pristine WO3 sensor, the optimal working temperature of the Co3O4 functionalized sensor (S4) was low (240 ℃), and the response value was as high as 24.63. Combined with material characterization, device testing, and the first-principles analysis, the improved sensor performance is mainly attributed to the following points: the oxygen-adsorbing capacity of grooved WO3 is stronger than smooth WO3 nanoplates, the formation of the p-n junction between Co3O4 and WO3 increased the width of the depletion layer, and oxygen vacancy-rich Co3O4 have preferential adsorption on xylene.