Layer-dependent transport and optoelectronic property in two-dimensional perovskite: (PEA)₂PbI₄

Recently, two-dimensional (2D) layered organic-inorganic hybrid perovskites have attracted a huge amount of interest due to their unique layered structure, and potential optical properties. However, amongst researchers it has long been disputed as to whether it is suitable for use as a photovoltaic material or light-emitting device. Here, we present a detailed theoretical investigation to discuss the photovoltaic and optoelectronic properties of a novel synthetic 2D layered perovskite (PEA)2PbI4. Based on the calculated geometric and electronic structure, charge carrier mobilities of the 2D layered (PEA)2PbI4 are predicted theoretically. In addition, the linear dichroism and exciton binding energies are also calculated. We found that the carrier mobilities of the 2D layered (PEA)2PbI4 reach the same order of magnitude as those of the optoelectronic material MoS2, but smaller than those of the photovoltaic material MAPbI3 and Si crystal, whereas exciton binding energies (Eb) enlarge with the thinning layers, being obviously higher than MAPbI3 and Si crystal. Moreover, the system exhibits a strong linear dichroism, suggesting weak absorption along the c axis in the visible spectrum, which is detrimental to photovoltaics. Our work provides a theoretical basis to prove that ultrathin two-dimensional (2D) materials may be potential candidates for optoelectronic detection devices, rather than solar absorbers.