Morphology and phase control of fluorides nanocrystals activated by lanthanides with two-model luminescence propertiesElectronic supplementary information (ESI) available. See DOI: 10.1039/c2nr30998j

• Main Authors: Dong, Guoping, Chen, Binbin, Xiao, Xiudi, Chai, Guanqi, Liang, Qiming, Peng, Mingying, Qiu, Jianrong
• Format: Journal Article
• Language: English
• Published: 12.07.2012
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c2nr30998j

The morphology, size and phase control of luminescent fluoride nanocrystals through doping has become a new research hotspot due to their improved properties. In this work, Yb 3+ ions, as one of the most efficient sensitizers for various lanthanide activators, were doped in NaGd(Y)F 4 nanocrystals. The results show that no obvious influence was observed for Yb 3+ -doped NaYF 4 nanocrystals, while the influence of Yb 3+ doping on NaGdF 4 nanocrystals was remarkable. The NaGd 1 x Yb x F 4 nanocrystals were synthesized by a hydrothermal route and had a morphology of rice-like nanorods. By controlling the synthesis parameters, the average size and slenderness of the nanocrystals increased gradually with addition of Yb 3+ ions. In contrast, the NaGd 1 x Yb x F 4 nanocrystals maintained a hexagonal phase, which is more beneficial for application as a luminescent host, until the content of Yb 3+ ions reached x = 0.9. The growth and transformation mechanism of NaGd 1 x Yb x F 4 nanocrystals was proposed to be a result of the competition between ion diffusion and an Oswald ripening process. Photoluminescence (PL) spectra confirm the efficient up-conversion and near-infrared (NIR) two-model luminescence properties of Er 3+ (Tm 3+ ) activated NaGd(Y) 1 x Yb x F 4 nanocrystals. Simulated analysis results indicate that a colloidal solution of mixed luminescent nanocrystals is expected to find application as the activated medium of three dimensional displays and a broadband optical amplifier. The multi-color up-conversion luminescence of Er 3+ (Tm 3+ ) activated NaGd(Y) 1 x Yb x F 4 nanocrystals could cover the entire visible region by fine tuning the composition of the nanocrystals.