Chemical bath deposition of mesoporous SnO2 to improve interface adhesion and device operational stability

The material and microstructure of the carrier-selective layers in the perovskite solar cells are important to determining their efficiency and stability. Planar SnO 2 is the most commonly used inorganic electron transport layer, but there are few reports of its mesoporous structure because of the degradation of hole-blocking property after high temperature sintering. Here, the chemical bath deposition method was optimized to realize low-temperature in-situ deposition of mesoporous SnO 2 layer on FTO substrates. On one hand, the increased interface contact area improves electron injection from the perovskite layer to the SnO 2 , yielding an impressive increase of the power conversion efficiency from 22.09% to 24.11%. And on the other hand, thanks to the increased mechanical strength of the interface, the device with mesoporous SnO 2 retains 90% of its initial power conversion efficiency after 1000 h operation under continuous one-sun illumination.