Journal of Inorganic Materials, Volume. 35, Issue 4, 439(2020)
Cu-In-Zn-S (CIZS) quantum dots (QDs) are considered as promising fluorescent materials owing to their low toxicity, wide emission range and large Stokes shifts, which have a wide prospect in lighting field. CIZS QDs were prepared via ionic liquid assisted microwave method in aqueous solution. The effects of reaction time, addition amount of ligand and pH of precursor solution on phase composition, microscopic morphology and photoluminescence (PL) property were investigated. Results showed that the reaction rate could be accelerated with the assistance of ionic liquid, i.e. the reaction time reducing from 180 min to 30 min. The size of QDs gradually increased with the increase of reaction time, resulting in red shift of emission peak from 609.2 to 634.6 nm. Moreover, the particle size of CIZS QDs increased with the increase of nGSH/n(CuInZn) ratios, resulting in the red shift of emission peak from 622.6 nm to 631.6 nm. Meanwhile, the PL intensity of QDs increased and reached the maximum at nGSH/n(CuInZn)=15. Furthermore, the surface defect state was effectively passivated with the increase of pH of precursor solution due to enhanced bonding force between deprotonized groups (-SH, -NH2) and QDs, resulting in enhancement of PL intensity. And the optimal pH was 8.5. The average hydrodynamic size of CIZS QDs increased from 99 nm to 241 nm with the increase of pH, and the relative Zeta potential ranged from -27.7 mV to -41.1 mV, indicating the excellent stability of CIZS QDs solution. Emission intensity of QDs could be enhanced significantly after coating with ZnS shells. White LED device was fabricated by combining CIZS QDs and a blue chip, the color rendering index and luminous efficiency of device were 85.6 and 34.8 lm/W, respectively, which provided a reference for the application of water soluble multiple QDs in white LEDs.
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Ting CHEN, Yanqiao XU, Weihui JIANG, Zhixiang XIE, Lianjun WANG, Wan JIANG.
Category: RESEARCH PAPER
Received: May. 30, 2019
Accepted: --
Published Online: Mar. 1, 2021
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