Preparation and purification of l-cysteine capped CdTe quantum dots and its self-recovery of degenerate fluorescence

• Published in: Journal of luminescence 2010-10, Vol.130 (10), p.1935-1940
• Main Authors: Li, Mengying, Zhou, Huameng, Zhang, Hongyan, Sun, Pan, Yi, Kuiyu, Wang, Meng, Dong, Zaizheng, Xu, Shukun
• Format: Article
• Language: English
• Subjects: Bio-compatibility; Cadmium tellurides; Capping; CdTe QDs; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Covalent bonds; Exact sciences and technology; Fluorescence; l-cysteine; Ligands; 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; Purification; Purification of QDs; Quantum dots; Self-recovery; Spectra
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2010.05.008

l-cysteine capped CdTe quantum dots (QDs) were prepared in aqueous solution by a simple and efficient method, showing many advantages such as short synthesis period, the broaden range of starting pH value and the wide fluorescence emission wavelength range. A novel purification process was designed to remove excess Cd 2+ which has potential cytotoxicity for bio-analysis. Three-dimensional fluorescence charts of pre- and post-purification showed that the purified QDs were of better luminescent performance. The prepared QDs were of cubic crystal structure with an average size of 2–6 nm, which were characterized by XRD and HRTEM. It is confirmed by IR spectra that the l-cysteine ligands were conjugated with CdTe cores via covalent bond. The degenerate fluorescence of QDs can be self-recovered in the presence of l-cysteine without other processing steps.