Enhanced upconversion in Dy super(3+), Yb super(3+) co-doped Gd sub(2)O sub(3) monodisperse nanocrystals

• Published in: Journal of sol-gel science and technology Vol. 78; no. 2; pp. 307 - 312
• Main Authors: Peng, Lingling, Huang, Min, Cao, Shixiu, Liu, Bitao, Han, Tao, Zhao, Cong
• Format: Journal Article
• Language: English
• Published: 01.05.2016
• Subjects: Annealing; Doping; Nanocrystals; Sodium; Sol gel process; Sulfonates; Surfactants; Upconversion
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-015-3952-5

Dy super(3+)/Yb super(3+) co-doped Gd sub(2)O sub(3) monodispersed nanocrystals have been synthesized using the sodium dodecyl benzene sulfonate (SDBS) as the surfactant. The SDBS surfactant plays a critical role in the forming of monodisperse Gd sub(2)O sub(3) structures with sphere-like morphologies. The growth mechanism of the nanocrystals was proposed in detail. The samples annealed at 400 degree C for 4 h exhibit good crystallinity and narrow size distribution with average size of 6-9 nm. Green and red emission of Dy super(3+) related to super(4)G sub(11/2)- super(6)H sub(11/2) and super(4)G sub(11/2)- super(6)H sub(9/2) transition was observed under the laser excitation at 980 nm. An involvement of three photons has been observed for these emissions. The energy distribution of upconversion spectra depended on doping concentration and the intensity changed with the increasing of Dy super(3+) concentration. The mechanisms of upconversion by multi-photon absorption and energy transfer processes transitions were interpreted and explained.