All-Inorganic Perovskite CsPbI2Br Through Co-evaporation for Planar Heterojunction Solar Cells

All-inorganic perovskite CsPbI2Br thin films are formed by the dual-source thermal evaporation of CsBr and PbI2. The resultant perovskite layers possess a uniform and dense microstructure with a bandgap of 1.97eV. Planar heterojunction perovskite solar cells are fabricated using TiO2 and spiro-OMeTAD charge-transporting layers in the regular n-i-p form. The devices exhibit a best efficiency of 5.7%. Thermal stability evaluation is performed at 85 degrees C under atmosphere, and 85% of the initial efficiency is maintained after [GRAPHICS] .