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|
| Type |
Poster Presentation |
| Area |
Physical Chemistry |
| Room No. |
Grand Ballroom |
| Time |
10월 19일 (금요일) 11:00~12:30 |
| Code |
PHYS.P-201 |
| Subject |
Formation of Two-Dimensional Tetracene Crystals and their Photoluminescence Behavior on Graphene Substrates |
| Authors |
Seonghyun Koo, Sunmin Ryu*
Department of Chemistry, Pohang University of Science and Technology, Korea
|
| Abstract |
Wave function and binding energy of an exciton are largely affected by not only its dielectric but also geometric environments. Excitons may be further confined in two-dimensional (2D) molecular crystals because of reduced dielectric screening. However, it has been a challenge to realize such molecular systems in a reproducible and spectroscopy-compatible manner. In this study, we created 2D tetracene films sandwiched between two graphene or hexagonal boron nitride (hBN) layers with high chemical stability and mechanical strength. To form such a vertical heterostructure, a top graphene (hBN) layer was dry-transferred onto tetracene film thermally evaporated on a bottom graphene (hBN) layer. Besides being a confining wall, graphene and hBN also served as an ideal ‘spectroscopic window’ due to their high optical transparency. Tetracene formed flat films with multiples of its minimum molecular layer and were found stable in the ambient conditions and even under intense laser irradiation. PL intensity substantially decreased when supported on graphene compared to on hBN, which indicates efficient energy transfer between tetracene and metallic materials. Efficiency of the PL quenching was also investigated as a function of number of graphene layers by steady-state emission measurements. Polarization-resolved PL analysis revealed a long-range order suggesting crystalline nature of 2D tetracene. We will discuss structural details and excitonic dynamics that will be probed by time-resolved spectroscopy. The demonstrated method will be highly useful in investigating the behavior of confined molecules and interactions between molecules and 2D materials. |
| E-mail |
shkoo@postech.ac.kr |
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122nd General Meeting of the KCS