Preparation of ultra-thin and high-quality WO3 compact layers and comparision of WO3 and TiO2 compact layer thickness in planar perovskite solar cells

•Preparation of ultra-thin and high-quality WO3 compact layers.•Perovskite solar cell with 15 nm-thick WO3 compact layer achieved PCE of 10.14%.•Perovskite solar cell with 60 nm-thick TiO2 compact layer achieved PCE of 12.64%.

In this paper, the ultra-thin and high-quality WO3 compact layers were successfully prepared by spin-coating-pyrolysis method using the tungsten isopropoxide solution in isopropanol. The influence of WO3 and TiO2 compact layer thickness on the photovoltaic performance of planar perovskite solar cells was systematically compared, and the interface charge transfer and recombination in planar perovskite solar cells with TiO2 compact layer was analyzed by electrochemical impedance spectroscopy. The results revealed that the optimum thickness of WO3 and TiO2 compact layer was 15 nm and 60 nm. The planar perovskite solar cell with 15 nm WO3 compact layer gave a 9.69% average and 10.14% maximum photoelectric conversion efficiency, whereas the planar perovskite solar cell with 60 nm TiO2 compact layer achieved a 11.79% average and 12.64% maximum photoelectric conversion efficiency.

Graphical abstractThe planar perovskite solar cell with 15 nm WO3 compact layer gave a 9.69% average and 10.14% maximum photoelectric conversion efficiency, whereas the planar perovskite solar cell with 60 nm TiO2 compact layer achieved a 11.79% average and 12.64% maximum photoelectric conversion efficiency.Figure optionsDownload full-size imageDownload as PowerPoint slide