Metallic phase transition metal dichalcogenide quantum dots showing di…
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논문명 | Metallic phase transition metal dichalcogenide quantum dots showing different optical charge excitation and decay pathways |
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저자 | Bo-Hyun Kim, Min-Ho Jang, Hyewon Yoon, Hyun Jun Kim, Yong-Hoon Cho, Seokwoo Jeon and Sung-Ho Song |
저널명 | NPG Asia Materials |
게재년월 | 2021/4/23 |
Vol. pp |
The charge excitation and decay pathways of two-dimensional heteroatomic quantum dots (QDs) are affected by the
quantum confinement effect, bandgap structure and strong exciton binding energy. Recently, semiconducting
transition metal dichalcogenides (TMDs) have been intensively studied; however, the charge dynamics of metallic
phase QDs (mQDs) of TMDs remain relatively unknown. Herein, we investigate the photophysical properties of TMDmQDs of two sizes, where the TMD-mQDs show different charge excitation and decay pathways that are mainly
ascribed to the defect states and valence band splitting, resulting in a large Stokes shift and two excitation bands for
maximum photoluminescence (PL). Interestingly, the dominant excitation band redshifts as the size increases, and the
time-resolved PL peak redshifts at an excitation wavelength of 266 nm in the smaller QDs. Additionally, the lifetime is
shortened in the larger QDs. From the structural and theoretical analysis, we discuss that the charge decay pathway in
the smaller QDs is predominantly affected by edge oxidation, whereas the vacancies play an important role in the
larger QDs.