My work seeks to reveal the influence of novel precursor solutions for efficient thin-film deposition of CuI compounds as p-type semiconductors. On the synthetic side, a series of not only hybrid organic/inorganic Copper (I) iodides but also polyiodides with diammonium cations have been synthesized. In the end, multiple characterization techniques both morphologically and spectroscopically are exploited in order to evaluate the applicability of the materials in perovskite solar cells.