Organic Cation Modulation of Interlayer Exciton Emission in Two-Dimensional Perovskite/Monolayer Transition Metal Dichalcogenide Heterostructures

摘要

Interlayer excitons (IXs) are demonstrated in two-dimensional (2D)perovskite/transition-metal dichalcogenide (TMD) heterostructuresregardless of the lattice match, momentum mismatch, and thermal annealingprocesses. The broad selection of 2D perovskites and TMDs together with therobust interlayer coupling between constituent layers make 2Dperovskite/TMD heterostructures an attractive platform for studying IXs.However, studies on IXs in 2D perovskite/TMD heterostructures are still intheir infancy, and how the organic cation affects the IXs in 2Dperovskite/TMD heterostructures remains elusive. Herein, this article reportson IXs emission from heterostructures consisting of monolayer WSe_2 and 2Dperovskites with different organic cations. Notably, by temperature-dependentphotoluminescence studies on (EA)2PbI4/WSe_2 and (PEA)2PbI_4/WSe_2heterostructures (EA = ethylamine and PEA = phenylethylammonium), it isfound that the organic cations of 2D perovskites can effectively change theexciton binding energy of the Ixs and thus the emission peak of the Ixs. Theobserved difference can be ascribed to the significant dielectric constantdifference between their organic cations. Furthermore, the change in theorganic cations can also affect the dipole–dipole interaction and lifetime ofIxs. The findings provide critical insights into the 2D perovskite/TMDheterointerfaces and also open up new opportunities for exploiting tunableexciton devices based on Ixs.