Enhanced upconversion luminescence induced by structrual evolution of lanthanum niobate phosphor
| Autor: | Panpan Sun, Xintong Zhang, Chengjiu Zhao, Jikai Yang, Pengpeng Dai |
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| Rok vydání: | 2015 |
| Předmět: |
Materials science
Process Chemistry and Technology Analytical chemistry chemistry.chemical_element Mineralogy Phosphor Fergusonite Photon upconversion Surfaces Coatings and Films Electronic Optical and Magnetic Materials Tetragonal crystal system chemistry Phase (matter) Materials Chemistry Ceramics and Composites Lanthanum Luminescence Monoclinic crystal system |
| Zdroj: | Ceramics International. 41:3009-3016 |
| ISSN: | 0272-8842 |
| DOI: | 10.1016/j.ceramint.2014.10.136 |
| Popis: | A series of Yb 3+ -Er 3+ coactivated La(Nb 1-x V x )O 4 (0≤ x ≤1) upconversion (UC) emission phosphors are prepared by high-temperature solid-state reaction method. Experimental results demonstrate that the introduction of V 5+ expands and distorts the unit cell volume of LaNbO 4 , and induces structural transformation of LaNbO 4 from Phase 1 with monoclinic fergusonite structure (0 x ≤0.2) to Phase 2 with tetragonal scheelite structure (0.25≤ x ≤0.5) to Phase 3 with monoclinic monazite structure ( x =1). Under 976 nm excitation, continuously enhanced green UC emission is observed in Phase 1 with gradual replacement of Nb 5+ with the V 5+ (0 x ≤0.2). At x =0.2, the luminescence intensity is enhanced 1.3 times than that of the pristine sample. In Phase 2 and Phase 3, the intensity of green UC emission is decreased gradually with increasing the V 5+ concentration. Based on the XRD results and crystal structural analysis, the enhanced luminescence is attributed to the lowered symmetry around La 3+ ions (Er 3+ ions), which relaxes the parity-forbidden selection rules of Er 3+ luminescent centers. This study provides a useful approach in developing UC luminescence materials with controllable optical properties based on variations in local coordination environments through composition substitutions. |
| Databáze: | OpenAIRE |
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