Análisis teórico de las perovskitas híbridas MA₂BX₄ LIBRE de Pb

Resumen

This work presents a comparative theoretical study of a series of Ruddlesden Popper hybrid perovskites with the general formula MA₂BX₄, where B = Ge or Pb and X = Br or I. In the first stage, the density of states and band gap energies of MA₂GeI₄, MA₂GeBr₄, MA₂PbBr₄, and MA₂PbI₄ were calculated to evaluate the effects of metal-site and halide substitutions on the electronic properties. These compounds exhibited relatively wide band gaps, making them less suitable for photovoltaic applications. In contrast, MA₂GeI₄ showed a direct band gap of 1.37 eV, which is within the optimal range for solar energy conversion. Based on this finding, a detailed analysis of the structural, electronic, optical, and photovoltaic properties of MA₂GeI₄ was performed using Density Functional Theory (DFT) and the Spectroscopic Limited Maximum Efficiency (SLME) model. The results indicate that MA₂GeI₄ combines high theoretical efficiency (32.6%), good structural stability, and lead-free composition, establishing it as a promising material for sustainable solar cell applications.