Synthesis of high quality and stability CdS quantum dots with overlapped nucleation-growth process in large scale.
A low-cost, green, and reproducibly non-injection one-pot synthesis of high-quality CdS quantum dots (QDs) is reported. The synthesis was performed in the open air by mixing precursors cadmium stearate and S powder into a new solvent N-oleoylmorpholine. An overlapped nucleation-growth stage followed by a dominated growth stage was observed. The resulting QDs exhibited well-resolved absorption fine substructure and a dominant band-edge emission with a narrow size distribution (the full width at half maximum (fwhm) was only 22-24nm). The maximum photoluminescence (PL) quantum yield (QY) was as high as 46.5%. Highly monodispersed CdS QDs with tunable sizes and similar PL fwhm and QYs could also be obtained from the CdS QDs in a large-scale synthesis. The high-resolution transmission electron microscopy (HRTEM) images and powder X-ray diffraction (XRD) pattern suggested that the as-prepared QDs with high crystallinity had a cubic structure. A significant PL improvement and a continuous QY increase for the CdS QDs were observed during a long storage time in air and in a glovebox under room temperature. A slow surface reconstruction was proposed to be the cause for the PL enhancement of CdS QDs.
School of Materials Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China.
Xinmei
X
Liu
Yang
Y
Jiang
Xinzheng
X
Lan
Shanying
S
Li
Di
D
Wu
Tingting
T
Han
Honghai
H
Zhong
Zhongping
Z
Zhang
D019187:Cadmium Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D019411:Clinical Laboratory Techniques / Q000191:economics; D049449:Luminescence; D045663:Quantum Dots; D013440:Sulfides / Q000138:chemical synthesis* / Q000737:chemistry
D019187:Cadmium Compounds; D013440:Sulfides; C034939:cadmium sulfide