High efficiency planar perovskite solar cell by surface disorder removal on mesoporous tin oxide

•Ethanol is introduced to remove the surface disorder of mesoporous SnO2.•The charge transport is enhanced at interface and high-quality perovskite film is obtained.•The device after ethanol treatment exhibits a high PCE from 20.70% to 21.62%.•Long term stability of devices with ethanol treatment are promoted, especially for light and thermal duration.