In-situ facile deposition of TiO2 hole blocking layers for efficient hole-conductor-free perovskite solar cells

A compact hole blocking layer is necessary for high efficient perovskite solar cell, which was usually fabricated by spin coating or spray pyrolysis with the followed annealing process, or vacuum deposition. Here, we deposited TiO2 compact layers by an in-situ room-temperature solvent method, which were applied as an effective hole blocking layer for hole-conductor-free perovskite solar cells with carbon electrodes. The thickness of the TiO2 compact layer can be easily regulated by the depositing time. By optimizing the TiO2 depositing time, the power conversion efficiency of hole-conductor-free perovskite solar cells was up to 10.66%.