Controlling exciton recombination in atomically thin semiconductors is central to their optoelectronic functionality, as the competition between radiative and non-radiative decay channels governs emission efficiency. Existing approaches, such as defect passivation, chemical doping, dielectric engineering, and strain tuning, primarily aim to suppress non-radiative losses. Here, we report a pronounced ∼6-fold enhancement of room-temperature A-exciton emission in a type-I MoSe2/PdSe2 van der Waals heterostructure, yielding a photoluminescence quantum yield of 6 %, compared to ∼1 % for as-exfoliated monolayer MoSe2. This enhancement is accompanied by strong quenching of the B-exciton, consistent with interlayer electronic coupling that redistributes exciton populations toward the radiative A-exciton channel. Power- and temperature-dependent measurements reveal a suppression of exciton-exciton annihilation and a crossover to quenched emission at low temperature, indicating a redistribution of exciton relaxation pathways. Photoluminescence excitation spectroscopy further reveals a broadband enhancement spanning 450-725 nm, ruling out a resonance-specific mechanism. These results demonstrate that interlayer electronic coupling can be used as an efficient means to redirect exciton populations toward radiative channels, enhancing emission efficiency in two-dimensional semiconductors without chemical modification or strain.
@article{arxiv.2605.13211,
title = {Highly Efficient Exciton Modulation in MoSe$_2$/PdSe$_2$ Heterostructures},
author = {Petr Rozhin and Emma Contin and Danae Katrisioti and Till Weickhardt and Muhammad Sufyan Ramzan and Micol Bertolotti and Nouha Loudhaief and Bing Wu and Zdeněk Sofer and Takashi Taniguchi and Kenji Watanabe and Leonardo Puppulin and Stefano Dal Conte and Caterina Cocchi and Ioannis Paradisanos and Giancarlo Soavi and Giovanni Antonio Salvatore and Domenico De Fazio},
journal= {arXiv preprint arXiv:2605.13211},
year = {2026}
}