First-principles investigation on the thickness-dependent optoelectronic properties of two-dimensional perovskite BA2SnI4

Abstract Recently, Sn-based two-dimensional layered halide perovskites(Sn-2DLHP) with fine light-harvesting performances and longstanding stabilities have attracted considerable interests. However, the impact of thickness on the optoelectronic properties of Sn-2DLHP is still insufficiently known. In this work, we take BA2SnI4(BA=C4H9NH3+) as a representative to present theoretical studies of electronic structure, carrier mobilities, optical absorption, and exciton-binding energy to reveal the effect of thickness on the optoelectronic properties of Sn-2DLHP. Results show that the 2D-layered BA2SnI4 are direct bandgap semiconductors with absorption coefficients of up to 105 cm−1 and appreciable carrier mobilities, which all can be significantly modified by tuning thickness. Notably, the 2D-layered BA2SnI4 have large and thickness-dependent exciton-binding energies, indicating the 2D-layered BA2SnI4 may have more application potential in optoelectronic devices. Our theoretical work paves a theoretical foundation of potential applications for other Sn-2DLHP in optoelectronic devices.