Luminescence mechanism of colloidal graphene quantum dots and its correlation with conjugated oxygen-functional groups콜로이드 그래핀 양자점 발광 메커니즘과 결합된 산소 기능기의 관련성 연구

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Graphene quantum dot is defined as a graphene sheet with lateral dimension less than 100 nm and with few layers. The graphene quantum dots have a lot of advantages, including not only an eco-friendly property, a low toxicity, a good solubility, and a high biocompatibility for various bio-appications, but also a broad range of optical absorptivity and a stable photoluminescence without blinking for optoelectronic devices. However, the GQDs have been leaving many questions unanswered. Therefore, it is very important to reveal a comprehensive luminescence origin and mechanisms in the GQDs to improve quantum efficiency and design a new strucutral GQD for applications. In this thesis, we have studied the luminescence mechanisms and origins in the GQDs by both ways of experimental approaches through various optical measurements and theoretical approaches through density functional theory. As a result, we suggested that the GQDs mostly have two luminescence origins, which called as an ‘extrinsic state’ formed by oxygen-functional groups and an ‘intrinsic state’ based on a crystalline structure of graphene with nanoscale. Our research is to verify the luminescence mechanisms in the GQDs through the various optical characterizations such as PL, PL excitation, and time-resolved PL, the theoretical calculation of structural model, and the design of GQDs structure for selectively controlling of oxygen-functional groups. Our results can lead to future development of novel strategies for guiding the synthesis of the GQDs and engineering the properties of GQDs toward various applications such as bioimaging, sensor, biological labeling, and functional nanoscale devices.
Advisors
Cho, Yong Hoonresearcher조용훈researcher
Description
한국과학기술원 :물리학과,
Publisher
한국과학기술원
Issue Date
2017
Identifier
325007
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 물리학과, 2017.2,[x, 118 p. :]

Keywords

Graphene; Graphene quantum dots; Graphene oxide quantum dots; optical chearacterization; nanoparticle; 그래핀; 그래핀 양자점; 산화 그래핀 양자점; 광분석; 나노 입자

URI
http://hdl.handle.net/10203/241779
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=675683&flag=dissertation
Appears in Collection
PH-Theses_Ph.D.(박사논문)
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