The role of deep-red emission CuInS2/ZnS QDs in white light emitting diodes

Abstract

CuInS2/ZnS quantum dots (QDs) have been regarded as a promising alternative to the material of II–IV systems owing to their attractive optoelectronic properties and deficiency of highly toxic elements. Red spectra are important components for white light sources with high color rendering index (CRI). In this paper, red emission CuInS2/ZnS QDs with high luminescence are synthesized using the hot-injection method in organic solvent and the peak wavelength (λp) can be tuned in the range of 630 ∼ 730 nm by controlling the ratio of copper and indium. These red emission CuInS2/ZnS QDs, combined with green rare-earth phosphor, are used as down converters to fabricate white light emitting diodes (WLEDs), and the luminescent properties of the resulting devices are also characterized. With a Cu:In ratio of 1:4, deep-red emission CuInS2/ZnS QDs with λp of 680 nm are prepared, and the resulting WLED exhibits a high CRI value of 91, a correlated color temperature (CCT) of 6347 K, and a satisfactory luminous efficiency of 23.9 lm W−1, suggesting that highly luminous deep-red emission CuInS2/ZnS QDs have great potential for providing WLEDs with high CRI.