Stable efficient CdSe/CdS/ZnS core/multi-shell nanophosphors fabricated through a phosphine-free route for white light-emitting-diodes with high color rendering properties

Abstract

Highly-fluorescent CdSe/CdS/ZnS core/multi-shell quantum dot (QD) nanophosphors were successfully synthesized via a phosphine-free and continual precursor injection method in paraffin liquid for the first time. The as-prepared cubic zinc blended QDs showed high photoluminescent quantum yield (PLQY) and excellent optical stability. We also fabricated QDs/epoxy composites by directly dispersing the core/multi-shell QDs into epoxy resin as the encapsulating and light conversion materials for the application on the white light LED, and the as-prepared composites possessed even better stability against UV radiation and heating. Moreover, a white light LED was fabricated by combining QDs/epoxy composites incorporated with green, yellow and red emission QDs with blue InGaN LED, and the resulting four-band RYGB QD-WLED showed good performance with a CIE-1931 coordinates of (0.35, 0.37), Ra of 88, T_c of 3865 K and the power efficiency (PE) of 32 lm W⁻¹ at 100 mA, indicating that the combination of highly fluorescent CdSe/CdS/ZnS core/multi-shell QDs in LEDs can be a promising solution for white light sources with high color rendering properties.