Carambola-like Zn-doped In2O3 structures with conductometric ethanol sensing properties

Novel carambola-like Zn-doped In2O3 structures were prepared by a facile solvothermal method. The morphology and phase composition of the Zn-doped In2O3 were controlled by simply adjusting the Zn/In ratio. Compared to pure ZnO, pure In2O3, and snow cake-like Zn-doped In2O3 structures, the carambola-like Zn-doped In2O3 structures prepared with the Zn/In ratio of 1/1 exhibit the highest response and best selectivity to ethanol. Specifically, the carambola-like Zn-doped In2O3 structures show a high response value (R-a/R-g) of 203 and a fast response/recovery speed of 15/15 s to 50 ppm ethanol at the operating temperature of 220 degrees C, and the detection limit is as low as 1 ppm. The carambola-like Zn-doped In2O3 structures display outstanding repeatability and long-term stability. In addition, they still maintain a high response to ethanol at high relative humidity. The conductometric sensing performance of the carambola-like Zn-doped In2O3 structures is attributed to their large specific surface areas, abundant adsorbed oxygen species on the surface, and the incorporation of Zn dopant. The excellent ethanol sensing properties endow the carambola-like Zn-doped In2O3 structures promising for practical application in ethanol detection.