Photoluminescence properties of the material based on SiO2-Y2O3:Eu3+, Tb3+under different in situ temperature prepared by the sol-gel process

The codoped SiO2-Y2O3:Tb3+,Eu3+ (x(Tb): 1.0 mol%; x(Eu): 0.1; 0.2; 0.5; 0.7 and 1.0 mol%) nanomaterials were prepared at room temperature by sol-gel process and heat treated at 900 and 1000 degrees C during 4 h, under air atmosphere. The materials were characterized by X-ray powder diffraction (XRD) and UV excited photoluminescence. The material exhibits Y2O3 cubic, one peak positioned around 26 degrees assigned to the cristobalite SiO2 phase and amorphous SiO2 phases due to the Y2O3 and SiO2 presences. The emission bands observed in the emission spectra under excitation at 301 are assigned to the Tb3+ and Eu(3+ )ions, with clear evidence of energy transfer from Tb3+ to Eu3+. The line assigned to the D-5(0) -> F-7(2) transition (Eu3+) increase the intensity as a function of Eu3+ concentration. The sensibility under controlled temperature variation was investigate. The Eu3+: 0.5 mol% doped material (annealed @900 degrees C) exhibited higher thermic sensitivity (with maximum relative sensitivity 0.294% K-1 in 303 K). Under excitation at 395 nm, the red color emission increases the intensity due the thermal treatment. Furthermore, CIE parameters and the color correlated temperature (CCT) are discussed in order to characterize the greenish color emission. Based on the results, these luminescence materials may be potential candidates for optical thermometry diodes, solid-state lighting and nano in vivo biological system.