Efficiency enhancement of hole-conductor-free perovskite solar cell based on ZnO nanostructure by Al doping in ZnO

Hole-conductor-free perovskite solar cells were fabricated with Al-doped ZnO (AZO) nanostructure as electron collector layer and low-cost carbon paste as counter electrode. AZO nanostructure layer deposited by spray pyrolysis method with different Al doping content from 0 to 10%. The current–voltage characteristics, incident-photon-to-current conversion efficiency (IPCE), electrochemical impedance spectroscopy (EIS), Fields emission scanning electron spectroscopy (FESEM) and X-ray diffraction analysis were carried out to study the effect of Al doping content on the cell performance. The fill factor (FF), short circuit current density (Jsc) and power conversion efficiency (PCE) values exhibit clear dependence on the Al doping content. With the increasing of Al doping content from 0% to 5%, the FF, Jsc and PCE values enhanced whereas these values decreased as the increasing of Al doping content from 5 to 10%. The PCE of 8.23% has been achieved under optimized conditions with Al doping content of 5%. Also the fabricated cell with 5% Al doping content reveals the lowest series resistance and highest recombination resistance. [Display omitted] •Hole conductor free perovskite solar cells were fabricated by Al doped ZnO.•The low cost carbon electrode is applied as counter electrode.•Photovoltaic performance of fabricated devices depended on Al doping content.•Highest efficiency of 8.23% is obtained for fabricated device with 5% Al.