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Water‐Soluble Monolayer Molybdenum Disulfide Quantum Dots with Upconversion Fluorescence
Author(s) -
Huang Hao,
Du Cuicui,
Shi Hongyan,
Feng Xun,
Li Jin,
Tan Yanlei,
Song Wenbo
Publication year - 2015
Publication title -
particle and particle systems characterization
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 56
eISSN - 1521-4117
pISSN - 0934-0866
DOI - 10.1002/ppsc.201400101
Subject(s) - monolayer , molybdenum disulfide , photoluminescence , quantum dot , photochemistry , fluorescence , band gap , quantum yield , luminescence , materials science , stokes shift , reagent , chemistry , nanotechnology , optoelectronics , optics , physics , metallurgy
Uniform water‐soluble monolayer MoS 2 quantum dots (MQDs) with lateral sizes of ≈2.1 nm, a clearly zigzag‐terminated edge, and a hexagonal lattice structure are achieved using ammonium molybdate, thiourea, and N‐acetyl‐ l ‐cysteine (NAC) as precursors and the capping reagent in a facile one‐pot hydrothermal approach. MQDs have good dispersity and high stability in aqueous suspension and exhibit a significantly larger direct bandgap (3.96 eV) compared to monolayer MoS 2 nanosheets (1.89 eV). Pronounced blue‐shifts in the wavelengths of both the excitonic absorption and intrinsic state emission with activated strong luminescence at room temperature beyond monolayer MoS 2 nanosheets is demonstrated. Unusual upconversion photoluminescence is also observed and is caused by two successive transfers of energy from the near‐infrared (NIR) absorption generated by the NAC capping reagent to the hexagonal structure of MQDs. Additional optical properties of MQDs may provide numerous exciting technological applications. Here, MQDs are demonstrated as a highly selective fluorescent reagent for detecting tetracycline hydrochloride under UV and NIR irradiation.