Síntese e geração de luz visível em nanocristais de LaF3 dopados com disprósio e térbio

Abstract

Novel materials suitable for the development of solid-state visible and white light sources based upon UV excited rare-earth doped phosphors have drawn much scientific and technological interest lately, owing to their potential applications in color displays technology, assay of biological compounds, remote sensors, optical data storage, optical printing, etc. Considering solid-state hosts, nanoglasses have recently emerged as a viable alternative for photonic and biophotonics applications. Visible light emission and Dy-Tb energy-transfer processes was examined in Dy/Tb - codoped LaF 3 nanocrystals obtained by the copreciptation method. The phosphor was synthesized, and the light emission feature was examined under UV excitation. Emission 484, 576, 663, and 754 nm due to dysprosium, and 488, 545, 588, 620, 647, 669 and 679 nm owing to terbium ions, was observed as a function of excitation wavelength. Terbium-dysprosium energy-transfer processes were also observed and analyzed. The excitation spectrum was examined and showed resonances around 385 nm for the Dy (573 nm emission) and 375 nm for the Tb (540 nm emission). Results indicated that the polychromatic light phosphor herein reported produced light with a color tone tunable either by excitation wavelength or active ions concentration, which lays within the region of the white-light boundary in the CIE- 1931 chromaticity diagram.