CH3NH3Cd0.875Pb0.125I3 perovskite as potential photovoltaic materials

The band structure, electronic and optical properties of the perovskite CH3NH3CdxPb1-xI3 are predicted using density functional theory. When Cd content is not over Pb content, the band gap of CH3NH3CdxPb1-xI3 is larger than that of CH3NH3PbI3, and the smallest band gap appears in CH3NH3Cd0.875Pb0.125I3 compound. In the wavelength range of 500-800 nm, the optical absorption coefficients of three kinds of composition CH3NH3CdxPb1-xI3 (x=5,6,7) are much larger than those of CH3NH3PbI3. Compared to CH3NH3PbI3, the absorption coefficients of CH3NH3Cd0.875Pb0.125I3 increase averagely 3.54 times in the visible light spectrum and the latter can absorb much more solar energy in infrared range than the former. The CH3NH3Cd0.875Pb0.125I3 compound is exceptional candidates of photovoltaic materials