Modeling of organic-inorganic halide perovskites for applications in the use of solar energy

S. TINTE

Bariloche

Workshop; NEUROCOMEN-2023; 2023

HORIZON-EU programs: MSCA-RISE-ENGIMA, MSCA-RISE-MELON and WIDERA-TALENTS-FerroChiral

Among renewable energies, solar photovoltaic is one that has grown the most in recent years, since it supplies around 3.7% of the electrical energy consumed globally. Solar cells based on semiconductors with perovskite structure have shown accelerated growth in their light-to-energy conversion efficiency, currently reaching more than 25%. Hybrid organic-inorganic perovskites ABX3 with A an organic cation (methylammonium, CH3NH3 or MA+, and formamidinium, CH(NH2)2 or FA+), B a metal (Pb, Sn) and X an halide (Cl, Br, I) have become an ideal replacement for silicon, being methylammonium lead triiodide (MAPbI3) and formamidinium lead triiodide (FAPbI3) the most promising candidates. These materials are very attractive for their low cost synthesis and excellent optoelectronics properties, such as direct bandgap which can be tuned by compositional engineering, high absorption coefficient, low effective masses, and long carrier diffusion. However, before thinking in industrial manufacturing some drawbacks must be solved, such as poor stability to external agents, low phase stability, light induced trap formation, among others. We have used computational methods to investigate the structural and optoelectronic properties of these materials. In this talk, I will present (i) results based on ab-initio methods on the investigation of the mixture of organic cations (MA+ and FA+) at the A-site as a stabilization strategy, and report the effects on the inorganic sublattice Pb-I and how hydrogen bonds stabilize nonbonding I-5p orbitals; (ii) ab-initio simulated optical spectra through the imaginary part of the dielectric function of pure MAPI in the room-temperature tetragonal phase, that helped to clarify the extinction coefficient peaks obtained from Reflectance and Transmittance measurements performed in the laboratories from our Institute.