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We report on the properties and stability of inorganic perovskite CsPbBr3 fabricated using vapor deposition. We have obtained the highest voltage ever recorded, exceeding 1.6V, in this material. The material was deposited using vapor deposition process, followed by post-deposition anneal at 450 C. Both layer by layer, and sequential anneal processes were sued for growing the material. After growth and anneals, the material was tested for thermal stability at temperatures of 300 C, and the x-ray data showed that there was no degradation of the material even at this high temperature. n-i-p superstrate devices were fabricated on FTO substrates coated with either TiO2 or n-CdS. The p layer was P3HT or PTAA. The devices showed an open-circuit voltage of 1.62V, the highest ever reported in this material. The devices were exposed to humid room air for 25 days, and showed no degradation at all in its performance. Detailed material measurements such as subgap quantum efficiency and deep defects were measured. The Urbach energy for valence band tails is found to be 22 meV and mid-gap defect density in the range of few 1015/cm3. 

We report on the growth, grain enhancement, doping, and electron mobility of cadmium selenide (CdSe) thin films deposited using the thermal evaporation method. The optical measurement shows CdSe is a direct bandgap material with an optical bandgap (Egap) of 1.72 eV. CdSe thin films were deposited on fluorine doped tin oxide glass substrates with different thicknesses, and grain size and mobility were measured on the films. CdCl2 was deposited on the films, and the films were subjected to high temperature treatment for several hours. It was found that both grain sizes increased significantly after CdCl2 treatment. The mobility of electrons was measured using the space charge limited current technique, and it was found that the mobility increased significantly after CdCl2 treatment. It was discovered that postdeposition selenization further improved the electrical properties of CdSe thin films by increasing the electron mobility-lifetime product and the photo/dark conductivity ratio. CdSe films after postselenization also showed significantly lower values for midgap states and Urbach energies for valence band tail states.