Highly luminescent quantum dots in remote-type liquid-phase color converters for white light-emitting diodes

Abstract

Quantum dots (QDs) can be integrated into a solid-phase color converter (SCC) for white light-emitting diodes (WLEDs). However, the development of QD-based SCCs is prevented by the limitations of the QDs themselves, nonuniform dispersion or aggregation of the QDs, and heat accumulation by low thermal conductivity of the solid matrix. Herein, the development of new high-quality CdZnSeS/ZnS QDs in a one spot synthesis is reported that have high photoluminescence quantum yield (up to 100% for green wavelengths), narrow emission spectra (full width at half maximum < 27.3 nm), and good color tunability in the green region, 496-586 nm. Seven different color QDs are used to fabricate liquid-phase color converters (LCCs) for application in WLEDs with a remote configuration. The best LCC-based WLEDs show not only intense bright day white light (correlated color temperature = 6029 K) with a maximum luminous efficacy of 222.7 lm W-1, but also excellent color quality (color rendering index = 95.1, as well as R9 = 94.4, and R13 = 97.1), which is very important in medical diagnostic lighting, dressing and display room lighting, painting and accent lighting. These results indicate remarkable progress both in the synthesis of high-quality QDs and in the development of WLEDs for high-performance commercial lighting devices.