Appearance of efficient luminescence energy transfer in doped orthovanadate nanocrystals

This paper reports the detailed synthesis mechanism and the structural, morphological and optical characterization of ultraviolet (?311?nm) excitable samarium doped gadolinium yttrium orthovanadate, (Gd,Y)VO₄:Sm³⁺, nanocrystals. X-ray diffraction and Rietveld refinement studies confirmed that the synthesized samples crystallize in a tetragonal structure with I41/amd space group. The enhanced photoluminescence intensity of (Gd,Y)VO₄:Sm³⁺ compared with the existing YVO₄:Sm³⁺ phosphor clearly indicates the significant role of Gd³⁺ ions. This has been attributed to the sensitization of the ⁶P_J energy level of Gd³⁺ ions by energy transfer from orthovanadate (VO₄^3-) ions and subsequent energy trapping by Sm³⁺ ions. The energy transfer from VO₄^3- to Sm³⁺via Gd³⁺ ions as intermediates and concentration quenching of Gd³⁺ luminescence are discussed in detail. The optical band gap of the as-prepared nanocrystals has been estimated using UV-vis-NIR absorption spectroscopy, which reveals a slightly higher band gap (3.75?eV) for YVO₄ as compared to GdYVO₄ (3.50?eV). Furthermore, confocal microcopy, decay parameters and Commission Internationale de l'Eclairage chromatic coordinates have supplemented these studies, which established the suitability of these nanophosphors for achieving spectral conversion in silicon solar cells.Efficient luminescence energy transfer in doped orthovanadate nanocrystals is reported.