Synthesis And Study The Conversion Luminescent Materials Based On Oxide

Rare-earth (RE) doped up-conversion (UC) luminescent materials have been paid moreattention due to their potential applications in biology medical, three-dimensional displays, solar cell, infrared (IR) radicalization detection and so on. It is known that host materials play a key role in up-conversion process. Host materials with low phonon energy can reduce non-radiative losses of multiphonon relaxation and realize efficient UC luminescence. In this work, we developed some novel oxide hosts phosphors with excellent physical and chemical stabilities and prepared by wet chemical methods.In2O3:Yb3+/Er3+and Yb2O3:Er3+particles with different morphologies were obtained by homogeneous precipitation in aqueous solutions through reaction with the thermal decomposition products of urea. The effects of concentration, reaction temperature, and aging time on the shapes of particles were investigated. Precursors converted to In2O3:Yb3+/Er3+and Yb2O3:Er3+by an annealing process, which does not change original morphologies. Under the980nm excitation, the up-conversion mechanism has also been discussed.A series of BaRE2Zn05:Yb3+/Pr3+(RE=Y, Gd) and CaLa2Zn05:Yb3+/RE3+(RE=Er3+Ho3+) up-conversion phosphors were successfully synthesized by a modified sol-gel method. The processing parameters and optimal concentration were determined. The structures and luminescent properties of samples were characterized by X-ray diffraction (XRD) and photoluminescence spectra (PL). With the excitation of980nm laser, UC spectra show five prominent emission bands centered at484(1I6â†'3H4),514(3P1â†'3H4),546(3P0â†'3H5),656(3P0â†'3F2) and670nm(3P0â†'3F3) in BaRE2Zn05:Yb3+/Pr3+(RE=Y, Gd). CaLa2Zn05: Yb3+/Er3+UC spectra are composed of strong greed emission (524,547nm) and weak red emission (672nm), and the temperature dependence of fluorescence intensity ratio (FIR) of the two green UC emission bands peaked at524and547nm was studied in the range of298-513K. Results suggest that phosphor is a promising candidate for optical temperature sensors. CaLa2ZnO5:Yb3+/Ho3+emission spectra consist of two prominent emission bands centered at545and662nm originating from5F4,5S2â†'5I8and5F5â†'5I8transitions of Ho3+ion, respectively. The possible UC mechanism was proposed, and lifetime measurements were also carried out to support our proposal.