High-performance, environmentally friendly solid-phase color converted-based quantum dots white light-emitting diodes

Abstract

Quantum dots (QDs) have been widely used in solid-phase color converter for white light-emitting diodes (WLEDs). However, further applications of these WLEDs are prevented by the limitations of the toxicity of QDs and the poor performance of devices. We herein explore highly luminescent InP/ZnS and AgInS2/ZnS core/shell QDs to solve these issues. We have synthesized high quality InP/ZnS QDs with widely tunable green emission wavelength, high PL QYs (>70%) and narrow PL peak width (∼40 nm). The prepared AgInS2/ZnS QDs achieve a wide emission coverage from 515 to 804 nm, large Stokes shift (>100 nm) and wide PL linewidth (110–160 nm) by adjusting the Ag/In content. Finally, warm-white LEDs were fabricated by combing green-emitting InP/ZnS and AgInS2/ZnS (560–690 nm) QDs with a blue GaN chip. The best WLED exhibits not only bright warm white light (correlated color temperature = 3114 K) with a maximum luminous efficacy of 75.2 lm W−1, but also excellent color quality (color rendering index Ra = 97.52, R9 = 91.5, and R13 = 99.4) and good stability.