Preparation And Characterization Of Ca₂Si₅N₈:Eu²⁺ And Ca_2-xSr_xSi₅N₈:Eu²⁺

Ca2Si5N8:Eu2+phosphors were prepared successfully by the high temperature solid-state method. The effect of best calcining temperature, holding time, graphite addition, fluxing agent and the concentration of Eu2+on the crystal structure and luminescence properties was studied systematically. The samples were analyzed by XRD and fluorescence spectrophotometer. The results show that the optimum graphite addition is Ca: C=1.5, calcining temperature is1600℃, holding6h, with N2and H2flowing rate200L/h, the concentration of Eu2+is25mol%, without fluxing agent NH4Cl, and the preferable luminescence properties is obtained. The emission spectrum is a broad band spectrum, with the peaks at585nm. The excitation spectrum is also a broad band spectrum between400nm and560nm.A series of Ca2-xSrxSi5N8:Eu2+solid solution were synthesized by the high temperature solid-state method in the best technological conditions of Ca2Si5Ng:Eu2+phosph-or. Using metal nitrides as raw materials, the synthetized Ca2-xSrxSi5N8:Eu2+has lower concentration of oxygen. The testing results show that, with the change of x, luminescence properties and crystal structures are subsequently changing regularly. When x=1.0,the phosphor have the best luminescent properties and comprehensive crystal structure. The emission spectrum is a broad band spectrum, with two peaks at610nm and635nm.The excitation spectrum is also a broad band spectrum between400nm and560nm.