Influence of ion-doping on the photoelectric properties of mesoporous ZnO thin films

Sn, Al, Y-doped mesoporous ZnO(doping with 5 at.%) thin films (M-ZnO-5%X, X= (Sn, Al, Y))with regular mesoporous structures were successfully prepared through sol-gel and spin-coating methods, as evidenced from small angle X-ray diffraction (SAXRD) and scanning electron microscopy (SEM). The diameter/d value is about 8 nm calculated by Bragg equation. Influences of ion-doping on the photoluminescence spectra of mesoporous ZnO thin films were investigated. The energy gaps of Y, Al, Sn-doped mesoporous ZnO increase from 3.0 eV (the energy gap of undoped ZnO thin film) to 3.05, 3.08 and 3.15 eV, respectively. Dye-sensitized solar cells (DSSCs) based on Sn, Al, Y-doped ZnO photoelectrodes were structured and the properties of the cells were studied. Compared with undoped ZnO film, M-ZnO-5%Sn film showed higher solar-to-electric conversion efficiency, which may come from the broader absorbance.