resumo
Upconverter materials based on Y0.983-xYb0.012Ho0.005TmxO3, x = 0.000 - 0.012, were synthesized by conventional coprecipitation method followed by calcination process at different temperatures: 900, 1000, and 1100 degrees C for 4 h under air atmosphere. The materials were characterized by XRD, SEM, and PL. The effects of the dopant concentration and calcination temperature on the upconversion emission quantum yield were investigated upon excitation with CW laser diode at 980 nm, with tunable laser power pump. Predominant emission narrow bands arising from Ho3+ transitions (5F4,5S2 & RARR;5I8) in the green region and Tm3+ (1G4 & RARR;3H6) in the blue spectral region, and (3H4 & RARR; 4H6) in the infrared region, were observed. The material containing Yb3+, Ho3+ presented values of relative sensitivity (SR) from 1.3 K-1 (13 K) to 0.00119 K-1 (450 K) while the presence of the Yb3+, Ho3+, and Tm3+ in material exhibited 1.2 K-1 (13 K) to 0.00097 K-1 (450 K). The system showed emission via upconversion mechanism, even suspended in aqueous medium. Furthermore, the concentration of Tm3+ showed to be crucial for the change in the upconversion intensity of the present materials. These outcomes strongly suggest that the tri-doped Ho3+, Yb3+, and Tm3+ materials discussed here may be suitable for optical temperature sensing and PDT.
palavras-chave
LUMINESCENCE; TM3+; PHOTOLUMINESCENCE; NANOSTRUCTURES; THERMOMETRY; LANTHANIDE; EMISSION; POWDERS; SENSOR; IONS
categoria
Materials Science; Physics
autores
Perrella, RV; Debasu, ML; Rezende, TKL; Carneiro, JA; Barbosa, HP; Ferreirab, RAS; Carlos, LD; Ferrari, JL
nossos autores
Luís Carlos
Professor Catedráticoagradecimentos
The authors would like to acknowledge FAPEMIG, FINEP and CNPq. This work is a collaboration research project of members of the Rede Mineira de Quimica (RQ-MG) supported by FAPEMIG (Project: CEX-RED-00010- 14,) . This study was financed in part by the Coordenaca o de Aperfeicoamento de Pessoal de Nivel Superior-Brasil (CAPES) -Finance Code 001. Prof. J.L. Ferrari would like to thank for Prof. Rute A. S. Ferreira and Luis D. Carlos for the support laboratory to perform this work and collaboration.