Open AccessEfficient up-conversion red emission from TiO_2:Yb,Er nanocrystals
Author(s) -
Yangqing Wu,
Shaobing Lin,
Jingjing Liu,
Yang Ji,
Jun Xu,
Ling Xu,
Kunji Chen
Publication year - 2017
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.25.022648
Subject(s) - nanocrystal , materials science , thulium , ion , annealing (glass) , doping , fluoride , amplified spontaneous emission , emission spectrum , emission intensity , optics , optoelectronics , nanotechnology , laser , spectral line , inorganic chemistry , chemistry , physics , organic chemistry , astronomy , composite material
Usually, up-conversion (UC) green emission is easily observed by using rare-earth doped fluoride nanocrystals. However, preferential red emission is desired for some actual applications especially in biological field. Here, we demonstrated that the dominant UC red emission can be realized by preparing TiO 2 :Yb,Er nanocrystals under 980 nm exciation. By controlling the crystal symmetry and size via the annealing temperature and Yb 3+ ions concentration, the enhanced UC red emission is achieved. The multi-photon relaxation and cross-relaxation mechanisms may be responsible for the energy transform process and in turn the UC emission.