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  • 02월 19일 23시 이후 : 초록수정 불가능, 일정확인 및 검색만 가능

제119회 대한화학회 학술발표회, 총회 및 기기전시회 안내 Singly and Doubly Occupied Higher Quantum States in Nanocrystals

등록일
2017년 3월 21일 11시 05분 53초
접수번호
5218
발표코드
KCS.O-8 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
발표시간
목 11시 : 16분
발표형식
구두발표
발표분야
한국다우케미칼 우수논문상 수상자 구두발표
저자 및
공동저자
정주연, 윤빛나, 권영완1,*, 최동선, 정광섭*
고려대학교 화학과, Korea
1KU KIST 융합대학원, Korea

Colloidal quantum dot (CQD) has been rigorously studied for the last three decades due to its tunable optical and electrical properties by varying the nanocrystal size. Since the CQD is semiconducting material, doping density can determine the CQD device performance. Therefore, it is very important to finely control the doping density of the CQD for manipulating the electric, optical and magnetic properties of CQDs. Previous work has shown the tunable intraband transition of mercury chalcogenide CQD by varying the nanocrystal size. Here, we firstly report HgSe CQDs with zero, one (unpaired) or two (paired) electrons occupying the lowest quantum state of the conduction band (1Se), which has been a long-standing challenge in the colloidal nanocrystal research. The number of electrons in the 1Se state is determined by nanocrystal growth time directly involved in the stoichiometry of the metal-chalcogenide CQD. The singly-occupied-quantum-state (SOQS), when an electron fills the 1Se state in stable under ambient conditions, was confirmed by carrying out the electron paramagnetic resonance spectroscopy. Furthermore, the diamagnetism was observed when zero or two electrons are occupied in the 1Se state, corresponding to doubly-occupied-quantum-state (DOQS). Strikingly, superparamagnetism was identified by performing SQUID for the SOQS HgSe CQDs with varying temperature down to 4 K. The number of electrons in the 1Se state, moreover, can be controlled by surface treatment. The SOQS and DOQS of CQD will be a promising magnetic feature for future spin based applications such as nonvolatile memory, infrared optoelectronics, catalysts, optomagneto-imaging and quantum computing.


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