Sol-gel Preparation And Photoluminescence Properties Of Alkaline Earth Codoped YVO₄:Eu³⁺ Particles

Rare earth doped luminescence materials have been widely used in color TVs, high pressure mercury lamps, laser materials, display devices and so on. Owing to their chemical stablility and good application prospects, rare earth doped oxide nanomaterials have received intensive attention in recent years. Among oxide matrix, the rare earth Eu3+doped YVO4(YV04:Eu3+) is a common red phosphor material, which has outstanding photoluminescence properties, excellent color purity, and good stability. Alkaline earth co-dopants can substantially improve the photoluminescence properties of YVO4:Eu3+luminescent materials. In this thesis, alkaline earth (Sr2+Ba2+) co-doped YVO4:Eu3+luminescent particles and thin films were prepared by the sol-gel method for the first time, and their photoluminescence properties were systematically investigated. This thesis includes the following research work and results:1) The effect of different annealing temperatures on earth metal doped YVO4:Eu3+luminescent materials structure and performance:a) The structure and morphology:As-prepared at500℃, YVO4:Eu3+luminescent particles had good crystallinity, structural integrity. Their particle size was about20nm. Then these samples were post-annealled at700℃,800℃,900℃and1000℃, respectively. When post-annealed at900℃, the alkaline earth doped YVO4:Eu3+luminescent materials had a particle size about60nm. These particles rapidly grew larger and became aggregated when post-annealed at1000℃.b) Photoluminescence properties:While the post-anneallcd temperature became higher, the luminous intensity much better. And alkaline earth doping samples had similar properties with the change of temperature.2) The effect of different substances and doping concentration on the YVO4:Eu3+luminescent particles performance:The results show that when the doping Sr2+, Ba2+, Eu3+concentrations were0.05, 0.03and0.07mol, the crystallization and the luminous intensity would get the best effect, alkaline earth (Sr2+, Ba2+) co-doped YVO4:Eu3+can improve the photoluminescence properties of YVO4:Eu3+luminescent particles. And their photoluminesence intensity was improved by2.38times.3) Comparative experiment:YVO4:Eu3+, Sr2+luminescent particles prepared by sol-gel method and hydrothermal method, respectively.The results showed that:the structure and properties of the alkaline earth metal Sr2+doped YVO4:Eu3+phosphor by the two methods had no obvious difference. The samples prepared by sol-gel were nanoscale and by hydrothermal were micronscale.4) Alkaline earth doping YVO4:Eu3+luminescent thin film preparation and performance:On quartz substrates deposited YVO4:Eu3+,YVO4:Eu3+,Ba2+, YVO4:Eu3+,Sr2+series luminescent film, reseach the effect on YVO4:Eu3+film about film thickness, annealing temperature and doping substances.The results showed that:thin film has grow on (200),(400) orientation direction, the higher of annealing temperature and spin-coating, the samples crystalline and particle size was much better. Doped Ba2+or Sr2+can improved the photoluminescence properties of YVO4:Eu3+film. And their photoluminesence intensity was improved by1.69times.