  To be able to increase the efficiency of perovskite solar cells which is one
of the most substantial challenges ahead in photovoltaic industry, the
structural and optical properties of perovskite CH3NH3PbI3-xBrx for values
x=1-3 have been studied employing density functional theory (DFT). Using the
optical constants extracted from DFT calculations, the amount of light
reflectance and ideal current density of a simulated single-junction perovskite
solar cell have been investigated. The results of DFT calculations indicate
that adding halogen bromide to CH3NH3PbI3 compound causes the relocation of
energy bands in band structure which its consequence is increasing the bandgap.
In addition, the effect of increasing Br in this structure can be seen as a
reduction in lattice constant, refractive index, extinction and absorption
coefficient. As well, results of the simulation suggest a significant current
density enhancement as much as 22% can be achieved by an optimized array of
Platinum nanoparticles that is remarkable. This plan is able to be a prelude
for accomplishment of solar cells with higher energy conversion efficiency.
