Tailoring the emission of Eu based hybrid materials for light-emitting diodes application

The rare-earth elements (REEs) derived phosphors play an essential role in light-emitting diodes. Many approaches have been proposed for tailoring the emission color of lamp phosphors by tuning the contents and valances of REEs (such as Ce3+, Tb3+, Eu3+). As we know, the separation and purifying of REEs from waste phosphors usually requires high cost and complicated operations. Here we report the phosphor only based on Eu doped in different matrices with manipulated color for the first time, which will minimize the environmental challenges present in the transition to a green economy. The hybrid material is manufactured by mixing (SAOE) SrAl2O4:Eu2+ and (TTAE) Eu(TTA)3phen (TTA = 2-thenoyltrifluoroacetone, phen = 1,10-phenanthroline) in different mass ratios. The optical properties of the resulting phosphor materials are determined by photoluminescence (PL). Eu doped in alkaline earth aluminates (SrAl2O4) has strong green (510 nm) emission, meanwhile the Eu exhibits enhanced red (612 nm) luminescence upon bonding with TTA (thenoyltrifluoroacetone) and phen ligands. By adjusting the mass ratios of SAOE and TTAE, the emission colors of the hybrid materials can be tuned from red to green. The chromaticity coordinates are calculated, which fell well in the red, orange, yellow and green regions of 1931 CIE chromaticity diagram. According to the spectroscopic studies, the absorption almost have no overlap on the emissions of SAOE and TTAE powders, leading to efficient PL emitting with high photoluminescence quantum yields of 24-68%. Through deposition of the hybrid materials with polydimethylsiloxane (PDMS) onto the 365 nm UV-LED chip, tunable color light-emitting diodes are fabricated, they show excellent luminescence properties, indicating their potential application in optical device and offering a novel approach for designing multi-color phosphor materials.