Emission characteristics of SPAN-80 activated ZnS nanocolloids

• Published in: Journal of luminescence 2012-08, Vol.132 (8), p.2135-2142
• Main Authors: Ngo, Thu Huong, Bui, Hong Van, Pham, Van Ben, Tran, Thi Hong, Ngac, An Bang, Hoang, Nam Nhat
• Format: Article
• Language: English
• Subjects: Band spectra; Bands; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Copper; Exact sciences and technology; Manganese; Nanocolloid; Nanocrystals and nanoparticles; Nanomaterials; Nanostructure; 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; Photoluminescence; Physics; Spectra; TD-DFT; Zinc sulfides; ZnS
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2012.03.052

Quantum surface effects (new emission bands, blueshifts, intensity enhancement) were observed in SPAN-80 activated ZnS nanocolloids and explained in terms of time-dependent density functional theory. The experimental evidences were demonstrated for both undoped and Cu, Mn-doped colloidal phases. The photoluminescence spectra of these materials showed a new green band at 520nm (ZnS:Cu) and a yellow-orange band at 576nm (ZnS:Mn) besides a blue band at 465nm. All bands lie in the visible region and are blueshifted, show sharp emissions with narrow widths and have approximately 20-times stronger intensities in comparison with those of the bulk samples. The time-resolved luminescence spectra showed that the life-times of free electrons were 0.12μs and 1.9ms in ZnS:Cu and ZnS:Mn correspondingly. ► Novel SPAN-80 activated ZnS nanocolloids with new observables. ► Enhanced emission intensity of colloidal systems activated by SPAN-80. ► Quantum surface effects explained on basis of time-dependent density functional theory.