Sol-gel synthesized rare earth La3+ ions doped Zn2SiO4 phosphors for lighting applications

Abstract

In this study, Zn2-xLaxSiO4 (x = 0.00, 0.02, 0.04, and 0.06) materials with varying weight percentages of lanthanum (La) in zinc silicate (Zn2SiO4) were synthesized using the sol-gel process. The effect of La dopant on the structure, morphology, and optical characteristics of Zn2SiO4 was investigated through various analytical and spectroscopical techniques. According to PXRD measurements, La3+ ions were incorporated into the host materials of Zn2SiO4, considerably affecting their crystallinity. Irregular granular and pebble stone-like morphology was observed in the FESEM analysis. The optical energy bandgap of La-doped Zn2SiO4 materials decreased from 5.09 eV to 3.80 eV while increasing the La dopant into Zn2SiO4 host systems. The photoluminescence (PL) spectra and photoluminescence quantum yield (PLQY) confirmed the increase of luminescent peak intensity at 730 nm. A tri-exponential fitting technique was used to determine the luminescence decay lifetime of the significant emissions of La-doped Zn2SiO4, and the average lifetime was found to be 30.4 ns. Dosimetry could benefit significantly from the thermoluminescence investigation conducted for the La-doped Zn2SiO4 phosphor at a linear heating rate of 8 °C/s.