Investigation of Optoelectronics, Thermoelectric, Structural and Photovoltaic Properties of CH3NH3SnBr3 Lead-Free Organic Perovskites

To develop the lead-free organic perovskites, the crystal CH3NH3SnBr3 was selected for their computational exploration which has a vast functional application in optoelectronic area as functional materials.First of all, the electronics band structures, the total density of state, the partial density of state and optical properties were investigated by DFT functional for CH3NH3SnBr3. In general, the band gap of CH3NH3SnBr3was calculated at 1.421 eV by Generalized Gradient Approximation (GGA) with Perdew Burke Ernzerhof (PBE) functional, and the energy gap and open circuit voltage was evaluated. The density of states (DOS) and partial density of states (PDOS) were evaluated to show that how each atom can be contributed to their electronic structure. The optical properties, for instance absorption, reflection, refractive index, conductivity, dielectric function, and loss function were estimated.Further, Sn atom was substituted to design the lead-free molecule, CH3NH3SnBr3 that passed good optoelectronic and optical properties. It can be concluded that Sn atoms containing organic crystal, CH3NH3SnBr3, show narrow band gap in comparison to lead or other heavy metals containing crystals although Sn is smaller in atomic size than Pd atom.