Aqueous synthesis of Cu-doped ZnCdS/ZnS core/shell nanocrystals with a new and highly reactive sulfur source

• Published in: Nanotechnology Vol. 25; no. 13; pp. 135602 - 9
• Main Authors: Zeng, Ruosheng, Shen, Rongan, Zhao, Yunqiang, Li, Xingsheng, Sun, Zhiguo, Shen, Yayun
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 04.04.2014; Institute of Physics
• Subjects: aqueous synthesis; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Copper; core/shell; Cross-disciplinary physics: materials science; rheology; Cu:ZnCdS; doped nanocrystals; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Fullerenes and related materials; General studies of phase transitions; Materials science; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; new sulfur source; Nucleation; Optical properties; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures; Physics; Shells; Spectra; Sulfides; Sulfur; Synthesis; Visible and ultraviolet spectra; Zinc sulfides; Temperature dependence; pH value; Nucleation; Zinc additions; Core shell structure; Doping; Photoluminescence; XRD; Quantum yield; Precursor; Sulfides; Experimental result; Transmission electron microscopy; II-VI semiconductors; Optical properties; Ultraviolet visible spectrum; Absorption spectra; Nanostructured materials; Nanocrystal; X-ray photoelectron spectra
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/0957-4484/25/13/135602

A new sulfur precursor with a highly reactive chemical nature was prepared with S powder and NaBH4 at the high temperature of 180 °C in a closed autoclave and made it possible to carry out the synthesis of high quality metal sulfide nanocrystals (NCs) with diverse composition and structure. Using this new sulfur source, we demonstrated aqueous synthesis of colloidal Cu-doped ZnCdS NCs (d-dots) with pure, color-tunable photoluminescence (PL) in a wide spectral range (from 517 to 650 nm) based on the 'co-nucleation doping' strategy. The influences of the various experimental variables, including Cd Zn ratio, Cu-doping concentration, pH value and amount of mercaptopropionic acid (MPA), on the optical properties of Cu-doped ZnCdS NCs were systematically investigated. Furthermore, highly efficient and stable dopant emission from Cu:ZnCdS ZnS core/shell d-dots with PL quantum yield as high as 40% was achieved by the deposition of a ZnS shell around the bare Cu:ZnCdS cores; this is the highest reported to date for aqueous doped NCs. The optical properties and structure of the d-dots were characterized by UV-vis absorption spectra, PL spectra, x-ray photoelectron spectroscopy, powder x-ray diffraction, and transmission electron microscopy. The experimental results indicated that this facile synthesis route would provide a versatile approach for the preparation of other water-soluble sulfide NCs.