White light upconversion in Yb-sensitized (Tm, Ho)-doped KLu(WO4)2 nanocrystals: the effect of Eu incorporation
| Autor: | Francesc Díaz, Marco Bettinelli, Rosa Maria Solé, Xavier Mateos, Jaume Massons, Magdalena Aguiló, E. W. Barrera, Adolfo Speghini, Joan J. Carvajal, Maria Cinta Pujol, Concepción Cascales |
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| Rok vydání: | 2013 |
| Předmět: |
Materials science
Light Analytical chemistry General Physics and Astronomy chemistry.chemical_element Lutetium Tungsten law.invention Holmium Europium law TRANSITION-METAL Physical and Theoretical Chemistry Chromaticity Particle Size Ytterbium Power density LUMINESCENCE THULIUM business.industry Laser Nanocrystalline material Photon upconversion Thulium chemistry Excited state Optoelectronics Nanoparticles Luminescence business |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| ISSN: | 1463-9084 |
| Popis: | Monoclinic Yb-sensitized (Tm, Ho)-doped KLu(WO4)2 nanocrystals of ∼100 nm size have been synthesized by the modified Pechini sol-gel method. Their diode laser near-infrared (∼980 nm) excited upconversion emission properties have been characterized at power densities in the range 30-355 W cm-2. Bright white light composed of blue ∼475 nm, green ∼540 nm, and red ∼650 nm emissions, corresponding to Tm 3+ 1G4 → 3H6, Ho 3+ 5S2, 5F4 → 5I8, and Ho3+ 5F5 → 5I8 electronic transitions, respectively, was generated by adjusting the Yb, Tm, and Ho contents in KLu(WO4)2 nanocrystalline samples. Chromaticity coordinates of the emitted white light can be tuned by modifying the excitation power density. The effect of Tm and Ho on the luminescence dynamics has been described by analyzing the upconverted emission intensity dependence on the excitation power, as well as from Stokes and decay time measurements. The effect on upconversion properties of further codoping with Eu in these (Tm, Ho, Yb)-doped KLu(WO4)2 nanocrystals has also been studied. This work is supported by the Spanish Government under projects, MAT2011-29255-C02-01-02, TEC2010-21574-C02-02 and PI09/90527; and the Catalan Government under project 2009SGR235. EW Barrera is supported by Catalan Government for the fund provided through the fellowship 2012FI_B200136. The support of the COST Action CM1006 by the STSM-CM1006-050512-017263 grant is gratefully acknowledged. |
| Databáze: | OpenAIRE |
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