Application of Inorganic Hole Transporting Materials in Perovskite Solar Cells SEPALAGEGAVESHANA ANURADHA 2017 Despite their rapid increase in device performances, organic-inorganic hybrid “perovskite” solar cells are costly and suffer from low stability of organic hole transporting materials (HTMs) and toxicity of lead. This thesis presents the application of inorganic HTMs as alternatives to organic HTMs, development of deposition techniques for inorganic HTMs and the role of HTMs on the performance and long-term stability of devices. Record power conversion efficiencies were achieved for planar structured inorganic HTMs based devices and their stability at different illumination and temperature conditions have been investigated. Moreover, a novel bismuth-based perovskite has been investigated as a replacement for the Pb-based perovskite.