N719-dye sensitized amorphous zinc oxide films for NO2 detection under visible-light illumination

摘要

In this paper, a room-temperature NO2 gas sensor has been developed based on dye sensitized amorphous ZnO (a-ZnO) film. The dye sensitized a-ZnO sensor shows a remarkable reduction of base resistance under visible light illumination. The sensor resistance is firstly reduced by the photogenerated electrons transferred from the dye to the a-ZnO, and then reduced by desorption of oxygen on a-ZnO surface under light illumination. The dye sensitized sensors show significant responses to low concentration NO2 and the sensor response increases linearly with the NO2 concentration. The use of dye makes the a-ZnO sensors have significant responses to NO2 at room temperature under visible light illumination, which paves a new way to develop room temperature gas sensors based on wide-gap semiconductors.