Stabilizing tetramethylammonium lead iodide perovskite and exploring its electronic and optical absorption for solar...

Modeling perovskites as solar cell absorbers has become popular due to the breakthrough of methylammonium lead iodide (CH₃NH₃PbI₃). In this study, we modeled a tetramethylammonium lead iodide (CH₃)₄NPbI₃ structure. We further confirmed the stability of the structure by determining the phonon dispersion using density functional perturbation theory. We calculated the spin-orbit and non-spin-orbit coupling-based electronic structure using the Perdew-Burke-Ernzerhof exchange-correlation functional within the generalized gradient approximation of the density functional theory and the self-consistent GW quasiparticle methods. Similarly, the absorption spectra were calculated from the real and imaginary parts of the dielectric tensor obtained from solving the Bethe-Salpeter equation using the GW quasiparticle database. The solar cell absorber spectroscopic limited maximum efficiency was calculated at 293.15 K. The self-consistent GW method without spin-orbit coupling reported bandgaps of 2.63 eV and 2.89 eV for GW₀ and GW methods, respectively, in agreement with experimental reports. The phonon dispersion showed positive phonon modes across the high symmetry point, which attest to its thermodynamic stability. The absorption coefficient on the order of 10⁵ was reported along the ultraviolet region. The standard limited maximum efficiency between 7% and 12% was recorded at 293.15 K between 0.01 and 100 μm absorber thicknesses. The thermodynamic stability, high absorption coefficient, and low transmittance indicated exciting prospects for a non-transparent (CH₃)₄NPbI₃ solar cell absorber.