Research Team from Department of Physics and Chemical Engineering and Materials Science at Ewha Suggests a Strategy ...
Research Team from Department of Physics and Chemical Engineering and Materials Science at Ewha Suggests a Strategy to Enable Exciton Funneling and Boost Visible Light Emission in 2D Inorganic Semiconductors
A joint research team at Ewha reports rapid transfer of photogenerated excitons and enhanced light emission from 2D inorganic semiconductors integrated with blue-fluorescent organic molecules. The results of the study, which highlights a strategy to develop a new type of optoelectronic devices, were published in the online edition of Advanced Science (IF: 16.806), a world-renowned academic journal within the top 4.4% in the field of materials science, on June 16 (Thu.).
(from left) Prof. Youngmin You, Prof. Dong-Wook Kim, Dr. Soyeong Kwon
The team led by Professors Dong-Wook Kim at the Department of Physics and Youngmin You at the Department of Chemical Engineering and Materials Science confirmed the enhancement of luminescence due to exciton transfers in heterostructure interfaces comprised of two-dimensional semiconductor transition metal dichalcogenides (TMD) and fluorescent organic molecules.
Professor Kim fabricated heterostructures by stacking evaporated thin films of DY1 fluorescent molecules on TMD MoS2 monolayers. The DY1 fluorescent molecules used in the process were obtained by the team led by Prof. You during the team’s OLED development researches. Optical characterizations and probe-based surface charge distribution measurements revealed exciton transfer from DY1 molecules to the MoS2 monolayers, which led to 1.7-fold enhanced light emission from MoS2. It has been reported that charge transfer rather than exciton transfer is dominant at the interfaces of different TMD materials. This work successfully demonstrated exciton transfers in the hybrid heterostructures by stacking fluorescent organic molecules on TMDs. The team could also propose a way to identify the transfer process of charges and excitons, based on the complementary use of measuring optical properties and analyzing scanning probe microscopes.
(Left) A schematic diagram to illustrate the transfer of excitons generated from DY1, a self-developed fluorescent organic molecule, to an adjacent two-dimensional semiconductor MoS2 monolayer.
(Right) Enhanced light emission characteristics and extension of exciton lifetime of the DY1/MoS2 hybrid heterostructure (small figure).
Dr. Soyeong Kwon at the Department of Physics remarked as the first author of the paper, “Given the various trials and errors as well as numerous difficulties that I went through while studying the novel research subject of organic and inorganic heterostructures over the last two years of my Ph.D. course, I feel an even deeper sense of satisfaction and fulfillment. I also hope that our findings will be followed by many follow-up studies.”
The paper, titled “Exciton Transfer at Heterointerfaces of MoS2 Monolayers and Fluorescent Molecular Aggregates,” was conducted through collaborative research by the Department of Physics at Ewha (Professor Seokhyun Yoon and Taeyoung Choi), the Institute of Basic Science at Sungkyunkwan University (Professor Ji-Hee Kim and Ki Kang Kim), and the Department of Physics at Chungnam National University (Professor Ki-ju Yee), with support from the National Research Foundation of Korea and the Institute for Basic Science. Professors Dong-Wook Kim and Youngmin You, the corresponding authors of this paper, are supported by the Basic Research Laboratory grant.