Luminescence Properties Of Rare-earth/transition Metal Ions Co-doped Fluorosilicate Glass Ceramics

The thesis briefly describes the theories spectrum of ions and Foster resonance energy transfer, introduces the up-conversion mechanism and gives an overview of the recent advances on the materials of spectrum modulation. The Yb3+/Tm3+ Yb3+/Er3+ co-doped contain SrF2 nanocrystals and Er3+/Yb3+ Cr3+/Yb3+. and Bi/Yb3+ co-doped contain CaF2 nanocrystals fluorosilicate glasses and glass ceramics had been synthesized. DTA, XRD. TEM and photoluminescence spectroscopy (PL) were used to investigate the microstructure and luminescence property of the products.Yb3+/Tm3+ and Yb3+/Er3+co-doped fluorosilicate glass and glass ceramics have been prepared. TEM results showed SrF2 nanocrystals were precipitated in glass ceramics’ matrix; excited by 980 nm LD, Yb3+-Tm3+ and Yb3+-Er3+ could occur upconversion process, and the main mechanism of the upconvsion were Yb3+-Yb3+’s cooperative upconvesion, Yb3+-Tm3+ and Tm3+-Tm3+’s cross relaxation and Yb3+-Er3+ s energy transfer upconversion.Er3+/Yb3+ co-doped fluorosilicate glass and glass ceramics have been prepared. HRTEM results showed CaF2 nanocrystals were precipitated in glass ceramic matrix; excited by 1450 nm LD, Er3+ ions transfer from ground state to 4IH/2. through FRET process, Yb3+ ions transfer from 2F5/2 to F7/2 then broadband emission from 900 nm to 1100 nm was detected.Cr3+/Yb3+ co-doped fluorosilicate glass and glass ceramics have been prepared. The energy transfers (ET) from Cr3+:2E(G) to Yb3+:2F5/2 in the samples were confirmed by the 980 nm Yb3+ emission under the broadband excitation assigned to Cr3+. The Cr3+:2E(G) lifetime decreased with the Yb3+concentration, and the ET efficiency from Cr3+ to Yb3+ was up to higher than 84.83%. The glass ceramics containing CaF2 nanocrystals were obtained by annealing and their 980 nm emission were enhanced by six times intense than the precursor glass.Bi/Yb3+ co-doped fluorosilicate glass and glass ceramics have been prepared. The energy transfers from Bi+:3P0 to Yb3+:2F5/2 in the samples can be confirmed by the 980 nm Yb3+emission under the excitation assigned to Bi+; the dependence of the intensity of upconversion emissions upon the excitation power of 1319 nm LD suggested that two-photon absorption process Bi/Yb3+ codoped glass in 20 K.