Thermally Stable, Efficient, Vapor Deposited Inorganic Perovskite Solar Cells

We report on thermally stable inorganic mixed halide perovskite solar cells deposited using a vapor deposition technique with no loss in device performance at 200 degrees C for 72 h. X-ray diffraction analysis confirms no compositional degradation of the perovskite layer up to 200 degrees C anneals. We use a layer-by-layer vapor deposition technique with thin layers (several nanometers) of PbI2 and CsBr precursors to fabricate inorganic mixed halide perovskite solar cells with a photoconversion efficiency of 11.8%. We study the effect of several key parameters of the perovskite fabrication process that control the intermixing of the perovskite layer and their effect on device efficiency and hysteresis. The thermal stability of the perovskite material and its energy band gap of 1.87 eV makes it appropriate for use in tandem junction cells for use in real-life environments with high solar illuminance where the ambient temperatures exceed 55 degrees C in the summer, and silicon cell module temperatures approach 86 degrees C.