The Synthesize And Photoluminescence Study Of Rare-earth Ion Doped GdVO₄ Nanocrystals

Luminescence materials have found wide applications in many fields, such as display, illumination and photo-electronic devices. With the rapid development of nanotechnology, nanoscaled luminescence materials have drawn much attention and been the hot topic because these materials have many miraculous properties compared with the bulk materials. Rare earth activated LnVO₄ phosphor has been attracting more atention in recent years because of their high luminescent intensities and stability under UV or VUV excitation as comparison with the conventional phosphors. Due to these advantages, the phosphor has been potential luminescent materials for new flat displays, such as plasma display panel (PDP), field emission displays(FED ). In order to explore novel luminescence systems with high efficiency, in this thesis, we synthesized vanadate nanomaterials by combustion method and studied their luminescence properties systemically.The main contents and the important results are listed as followings:1. Nanocrystal rare earth gadolinium vanadate was synthesized by combustion method. The Structure,crystal size and morphology of GdVO₄:Tm at different annealing temperatures were analysed by XRD and SEM; Theresults show that GdVO₄:Tm is tetragonal, its crystal size is under 60 nm.GdVO₄:Tm can be excited by 250-350 nm ultraviolet radiation. It emits bright blue fluorescence when excited by 320 nm ultraviolet radiation. The higher properties of the luminescence is shown under the condition of annealing temperature 1000℃and the concentration of 0.4 mol % Tm³⁺2.Green luminescent material YVO₄:Er has a broad excitation spectra located between 250 -350nm in ultraviolet region, and has a intensive emission spectra between 510-560nm, which has two peaks located at 530 nm and 560 nm respectively. Under 320 nm excitation, the optimal intensity is obtained when the content of Er³⁺ is 0.4 mol %.3.Nanocrystalline rare-earth gadolinium vanadate doped with Er³⁺ and Yb³⁺ ions was synthesized by combustion method. The up-conversion emission spectrum of the sample was measured under the excitation of a 980 nm continuous wave diode laser. The intense green emissions around 526 nm and 553 nm corresponding to the ²H_11/2→⁴I_15/2, ⁴S_3/2→⁴I_15/2 transitions of Er³⁺ ions were observed under excitation at 980 nm. The most efficient luminescence emission of GdVO₄(V.Er³⁺,Yb³⁺ is shown under the condition of the annealing temperature 1000℃and of the concentration of 1 mol% Er³⁺ and 4 mol% Yb³⁺.4. In this paper a certain degree of analysis about luminescent mechanism was made based on the experiment.