Nonradiative Energy Transfer and Selective Charge Transfer in TMDC/2D perovskite Heterostructures

Van der Waals heterostructures are currently the focus of intense investigation; this is essentially due to the unprecedented flexibility offered by total relaxation of lattice matching requirements and their new and exotic properties compared to the individual layers. Here, we investigate hybrid transition-metal dichalcogenide (TMDC)/2D perovskite heterostructures. We present the first density functional theory (DFT) calculations of a such ensembles, which reveal a novel band alignment, where direct electron transfer is blocked by the organic spacer of the 2D perovskite. In contrast, the valence band forms a cascade from TMDC through the organic linkers to the inorganic part of the perovskite allowing a hole transfer. These predictions are supported by optical spectroscopy studies, which provide compelling evidence for both charge transfer and nonradiative transfer of the excitation (energy transfer) between the layers. Our results show that TMDC/2D perovskite heterostructures provide a flexible and convenient way to engineer the band alignment.