Hollow TiO2 spheres as mesoporous layer for better efficiency and stability of perovskite solar cells

Hollow TiO 2 spheres were synthesized by template method, with the diameters was 200 nm and the thickness of shell about 30 nm. The high-quality perovskite films fabricated on the hollow TiO 2 mesoporous layer demonstrate smooth surface and large grain size, resulting in the better scattering light ability and fewer defects. The efficiency of the perovskite solar cells prepared on hollow mesoporous layer can reach 17.60%, which is an approximately 14% higher than the PCE of conventional mesoporous layer devices under the same condition. Importantly, the solar cells with hollow TiO 2 can exhibit better stability than the cells with mesoporous TiO 2 after aging 30 days in 65% relative humidity under dark conditions. The results indicate that the hollow TiO 2 mesoporous layer will be a candidate for better efficient and stable CH 3 NH 3 PbI 3 perovskite solar cells, and this structure provides a direction for the design of novel mesoporous layers for perovskite solar cells in future.