Sputtered indium zinc oxide rear electrodes for inverted semitransparent perovskite solar cells without using a protective buffer layer

Abstract In this work, we demonstrate inverted semitransparent perovskite solar cells (PSC) comprising an indium zinc oxide (IZO) layer sputtered at room temperature without a protective buffer layer between the organic electron transport layers (ETL) and the transparent sputtered electrode. The damage done to the ETL layer during sputtering is cured with a short annealing step at a moderate temperature and semitransparent PSCs with fill factors of almost 70% and with power conversion efficiencies (PCE) over 13% are achieved with negligible hysteresis. We investigate the influence of the layer thicknesses of the ETL double layer consisting of PCBM and BCP on the solar cell characteristics as well as the influence of the illumination direction of the bifacial device.