Despite the successful enhancement in the high-power conversion efficiency (PCE) of perovskite solar cells (PSCs), the poor stability of PSCs is one of the major issues preventing their commercialization. The attenuation of PSCs may be due to the lower heat resistance of the organic charge transport layer and the tendency to aggregate at high temperatures. Here we report cerium oxide (CeOx) as an electron transport layer (ETL) prepared through a simple solution processed at a low temperature (∼100 °C) to replace the organic charge transport layer on top of the inverted planar PSCs. The CeOx layer has excellent charge selectivity and can provide the perovskite film with protection against moisture and metal reactions with the electrode. The solar cell with CeOx as the electron transport layer has a power conversion efficiency of 17.47%. These results may prove a prospect for practical applications.
