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|
| Type |
Poster Presentation |
| Area |
Physical Chemistry |
| Room No. |
Event Hall |
| Time |
4월 20일 (금요일) 11:00~12:30 |
| Code |
PHYS.P-82 |
| Subject |
Mechanistic Study for Photochemical Oxidation of Thin Layered Chromium Thiophosphate (CrPS4) |
| Authors |
Suhyeon Kim, Sunmin Ryu*
Department of Chemistry, Pohang University of Science and Technology, Korea
|
| Abstract |
Two-dimensional (2D) semiconductors represented by transition metal dichalcogenides have optical bandgaps in the visible or near IR-range. Because of their thickness-dependent bandgaps and strong absorption, they stand as a promising candidate for optoelectronic devices. Despite this potential, however, photooxidations of 2D semiconductors are not well understood or controversial in their mechanistic details. In this work, we investigated photoreaction mechanisms of atomically thin chromium thiophosphate (CrPS4), an antiferromagnetic semiconductor, using Raman and photoluminescence spectroscopy. Few-layer CrPS4 underwent photodegradation which accelerated with increasing molar fraction of O2. Topographic analysis by atomic force microscopy showed that 2D CrPS4 is highly susceptible to the photooxidation even at ~2 % of the laser power density required for 2D MoS2. This observation suggested that a novel photooxidation mechanism may be operative for CrPS4 other than the photothermal mechanism for 2D MoS2. Indeed, the early-time reaction rate of 2D CrPS4 was linearly proportional to the photon exposure, but exhibited negligible dependence on the power density. Based on these results, we propose a one-photon photochemical process that is mediated by CrPS4-sensitized generation of singlet O2 and will present preliminary results to support it. Additionally, protection of CrPS4 layers with thin Al2O3 films will be discussed. |
| E-mail |
suhkim@postech.ac.kr |
|
121st General Meeting of the KCS