Exciton Energy Routing via Defect Networks in hBN/2D Perovskite Hybrids.

Excitons in two-dimensional Ruddlesden-Popper perovskites (RPPs) exhibit large and tunable binding energies, making them promising candidates for optoelectronic applications. In particular, long-range exciton energy transfer in these materials holds potential for light-harvesting technologies and nanoscale interconnects. Here, using cathodoluminescence spectroscopy, we demonstrate that exciton energy can be transferred over ultralong distances─up to 150 μm─in heterostructures composed of hexagonal boron nitride (hBN) and RPPs. This transfer is enabled by efficient exciton coupling to defect centers in hBN and subsequent defect-defect interactions. This mechanism not only facilitates long-range energy transfer but also leads to enhanced luminescence intensity, narrower emission line widths, extended exciton lifetimes, and reduced electron beam-induced degradation. Owing to the high density of emitters within the hBN layers, the investigated van der Waals heterostructure emerges as a robust and stable hybrid platform. Our findings enable room-temperature excitonic devices with enhanced performance, including quantum transducers, light-harvesting systems, and optoelectronic interconnects.