The perovskite, the subject of investigation in this study, is a mineral that has gained
attention due to its use as an active layer in the fabrication of high-efficiency photovoltaic
solar cells. The main objective here is to investigate the structural and electronic properties
of certain perovskite halides, utilizing the methodology of Density Functional Theory
(DFT) to solve the Schr ̈odinger equation. The obtained results include calculations of lattice
parameters, energy gaps, density of states (DOS), and the corresponding Projection of
Density of States (PDOS). Our results reveal that the cubic structure is not the one of lowest
energy for lead methylammonium iodide (CH3NH3P bI3), lead methylammonium chloride
(CH3NH3P bCl3), or lead methylammonium bromide (CH3NH3P bBr3). These halides
can also crystallize in orthorhombic and tetragonal phases. In all cases, the calculations
show that the electronic states in the bandgap do not have contributions from the organic
part of these perovskites. Additionally, we demonstrate the dependence of the energy gap
values on the substitution of I by Br or Cl, as well as the variation with the geometry of
the studied crystals.
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