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Upconversion luminescence of Er, Yb – doped nanolanganite powders synthesized by a citrate sol-gel method

A. M. VOICULESCU1,* , S. GEORGESCU1, O. TOMA1, S. NASTASE1, R. BIRJEGA1, L. PETRESCU2, I. ENCULESCU3, E. MATEI3

Affiliation

  1. National Institute for Laser, Plasma and Radiation Physics, Măgurele, Ilfov, Romania
  2. Faculty of Biology, University of Bucharest, Bucharest, Romania
  3. National Institute for Materials Physics, Măgurele, Ilfov, Romania

Abstract

Langanite nanopowders doped with erbium and ytterbium were prepared by a citrate sol–gel method and annealed in air at various temperatures between 700ºC and 1000ºC. For annealing temperatures 900ºC and 1000ºC, part of the langanite transforms in perovskite (LaGaO3), as evidenced in XRD spectra. The reddish color of the powders due to color centers associated to oxygen defects intensifies with increasing annealing temperature. Green and red luminescence was obtained for IR (933 nm) pumping and only green for UV pump. The mechanisms involved in luminescence and energy transfer processes are presented and discussed..

Keywords

Langanite, Er3+. Yb3+, Upconversion, Luminescence.

Citation

A. M. VOICULESCU, S. GEORGESCU, O. TOMA, S. NASTASE, R. BIRJEGA, L. PETRESCU, I. ENCULESCU, E. MATEI, Upconversion luminescence of Er, Yb – doped nanolanganite powders synthesized by a citrate sol-gel method, Optoelectronics and Advanced Materials - Rapid Communications, 5, 11, November 2011, pp.1170-1173 (2011).

Submitted at: Oct. 31, 2011

Accepted at: Nov. 23, 2011