A technical paper titled “Excitation-Dependent High-Lying Excitonic Exchange via Interlayer Energy Transfer from Lower-to-Higher Bandgap 2D Material” was published by researchers at University of Warsaw, Brookhaven National Laboratory, and National Institute for Materials Science (Japan).
“High light absorption (∼15%) and strong photoluminescence (PL) emission in monolayer (1L) transition metal dichalcogenides (TMDs) make them ideal candidates for optoelectronic device applications. Competing interlayer charge transfer (CT) and energy transfer (ET) processes control the photocarrier relaxation pathways in TMD heterostructures (HSs). In TMDs, long-distance ET can survive up to several tens of nm, unlike the CT process. Our experiment shows that an efficient ET occurs from the 1Ls WSe2-to-MoS2 with an interlayer hexagonal boron nitride (hBN), due to the resonant overlapping of the high-lying excitonic states between the two TMDs, resulting in enhanced HS MoS2 PL emission. This type of unconventional ET from the lower-to-higher optical bandgap material is not typical in the TMD HSs. With increasing temperature, the ET process becomes weaker due to the increased electron-phonon scattering, destroying the enhanced MoS2 emission. Our work provides new insight into the long-distance ET process and its effect on the photocarrier relaxation pathways.”
Find the technical paper here. Published June 2023. Read this related news article from Brookhaven National Laboratory.
Arka Karmakar, Tomasz Kazimierczuk, Igor Antoniazzi, Mateusz Raczyński, Suji Park, Houk Jang, Takashi Taniguchi, Kenji Watanabe, Adam Babiński, Abdullah Al-Mahboob, and Maciej R. Molas, Nano Letters 2023 23 (12), 5617-5624, DOI: 10.1021/acs.nanolett.3c01127
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