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Hydrothermal synthesis for high‐quality glutathione‐capped Cd x Zn 1 – x Se and Cd x Zn 1 – x Se/ZnS alloyed quantum dots and its application in Hg(II) sensing
Author(s) -
Lai Lu,
Sheng SiYu,
Mei Ping,
Liu Yi,
Guo QingLian
Publication year - 2017
Publication title -
luminescence
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.428
H-Index - 45
eISSN - 1522-7243
pISSN - 1522-7235
DOI - 10.1002/bio.3174
Subject(s) - photoluminescence , quantum dot , analytical chemistry (journal) , full width at half maximum , x ray photoelectron spectroscopy , high resolution transmission electron microscopy , materials science , fourier transform infrared spectroscopy , spectroscopy , quantum yield , transmission electron microscopy , chemistry , fluorescence , nanotechnology , optoelectronics , chemical engineering , nuclear magnetic resonance , physics , chromatography , quantum mechanics , engineering
High‐quality Cd x Zn 1 – x Se and Cd x Zn 1 – x Se/ZnS core/shell quantum dots (QDs) emitting in the violet–green spectral range have been successfully prepared using hydrothermal methods. The obtained aqueous Cd x Zn 1 – x Se and Cd x Zn 1 – x Se/ZnS QDs exhibit a tunable photoluminescence (PL) emission (from 433.5 nm to 501.2 nm) and a favorable narrow photoluminescence bandwidth [full width at half maximum (FWHM): 30–42 nm]. After coating with a ZnS shell, the quantum yield increases from 40.2% to 48.1%. These Cd x Zn 1 – x Se and Cd x Zn 1 – x Se/ZnS QDs were characterized by transmission electron microscopy, X‐ray diffraction, X‐ray photoelectron spectroscopy and Fourier transform infrared (FTIR) spectroscopy. To further understand the alloying mechanism, the growth kinetics of Cd x Zn 1 – x Se were investigated through measuring the fluorescence spectra and X‐ray diffraction spectra at different growth intervals. The results demonstrate that the inverted ZnSe/CdSe core/shell structure is formed initially after the injection of Cd 2 + . With further heating, the core/shell structured ZnSe/CdSe is transformed into alloyed Cd x Zn 1 – x Se QDs with the diffusion of Cd 2 + into ZnSe matrices. With increasing the reaction temperature from 100 °C to 180 °C, the duration time of the alloying process decreases from 210 min to 20 min. In addition, the cytotoxicity of Cd x Zn 1 – x Se and Cd x Zn 1 – x Se/ZnS QDs were investigated. The results indicate that the as‐prepared Cd x Zn 1 – x Se/ZnS QDs have low cytotoxicity, which makes them a promising probe for cell imaging. Finally, the as‐prepared Cd x Zn 1 – x Se/ZnS QDs were utilized to ultrasensitively and selectively detect Hg 2 + ions with a low detection limit (1.8 nM).