Investigation on effect of blocking layer in perovskite sensitized pure and aluminium doped ZnO photoanode solar cell

Abstract

ZnO is a promising candidate as low cost, porous semiconductor material for photoanodes in a dye sensitized solar cell. In this work, we investigate the performance of pure ZnO nanoparticles (ZNPs), Al2O3 doped ZnO (Al@ZNPs) and ZnO/Nb2O5 core–shell structure of photoanode material. These electrodes were sensitized with a pervoskite CH3NH3SnCl3 sensitizer. To study the effect of the Al2O3, Nb2O5 treatment with ZnO, the J–V and EIS parameters, the current density (Jsc),Open circuit voltage (Voc), fill factor (FF), electron life time (τn), electron mobility (µ) and charge collection efficiency (ƞcc) are calculated for the fabricated solar cells and the results are compared. It was found that the Al2O3 doped ZnO with the sensitizer CH3NH3Sncl2 showed the highest efficiency of 9.41% under 100 mW/cm2 irradiation. The electron impedance spectroscopy revealed that the charge collection efficiency (ƞcc) of the solar cells is in the order of PSSC3 > PSSC4 > PSSC2 > PSSC1. In this work, the effect of blocking layer (Ta2O5) is also discussed. From the J–V and EIS analysis, the effect of blocking layer is appreciable and it is useful to increase the efficiency of the solar cell by the way of reducing the recombination of charge carriers process. Therefore, the increase of photocurrent is mainly due to the combined effect of the sensitizer competence and blocking layer.