Theoretical investigation on structure and optoelectronic performance of two-dimensional fluorbenzidine perovskites

Abstract

Two-dimensional lead halide perovskite solar cell has shown great potential applications because of its relatively high stability in comparison with normal three-dimensional perovskite. More and more two-dimensional lead halide perovskites are used as absorbers in solar cells, but theoretical study on the structure-performance relationship of two-dimensional lead halide perovskites is still lacking. Therefore, starting form 3 kinds of fluorobenzylamine perovskites, first-principle calculations are carried out. By comparing their crystal structures, non-covalent interactions, formation energy, band structures, exciton binding energy, carrier mobilities of theses perovskites, and short-circuit current densities of their corresponding solar cells, the influences caused by organic spacers on the structural and electronic properties are studied. This research shows that the more negative the formation energy, the higher the stability of the optoelectronic device is, and the smaller the exciton binding energy, the larger the short-circuit current of the optoelectronic device is. A relationship for quantitative prediction of short-circuit current is proposed, and substitution with electron-withdrawing groups at the end of the spacer is expected to improve both the stability and short-circuit current density of optoelectronic device. The research results of this work can contribute to the design of new perovskite solar cells with high conversion efficiency.