 Organo-metal perovskite materials are promising candidates for solar energy conversion due to their high efficiency and stability. We conducted electronic structure calculations on 240 different perovskite compounds consisting of CS, CH3 and H3, and HC, and H2, 2 is a cation, SN or Pb as bion, and combinations of Cl, Br, and I as anions. Our results show that the band gap of these materials can vary significantly depending on the composition and crystal structure. Additionally, the band gap increases with increasing electronegativity of the constituents and decreases with increasing lattice constant. These findings suggest that further optimization of the material composition and crystalline structure could lead to even higher efficiencies in solar energy conversion. This article was authored by Ivano E. Costelli, one Maria Garcia-Lastra, Christian S. Tijson, and others.