Efficient red luminescence in Eu3+ doped CdSe/CdS all-inorganic quantum dots shows great potential for wLEDs

Abstract

Complete inorganic quantum dots (QDs) CdSe/CdS:Eu³⁺ with full transmittance were proposed as red color converters for white light emitting diodes (wLEDs) using a facile one-step melt quenching method. TEM, XPS, and XRD were used to verify the successful nucleation of CdSe/CdS:Eu³⁺ QDs in silicate glass. The results indicated that the incorporation of Eu contributed to the nucleation of CdSe/CdS QDs in silicate glass, where the nucleation time of the CdSe/CdS:Eu³⁺ QDs rapidly decreased in 1 h compared with other inorganic QDs that took more than 15 h. CdSe/CdS:Eu³⁺ inorganic QDs exhibited bright and long-term stable red luminescence under both UV and blue light excitation; up to 53.5% quantum yield and 8.05 ms fluorescence lifetime were obtained by adjusting the Eu³⁺ concentration. Based on the luminescence performance and absorption spectra, a possible luminescence mechanism was proposed. Moreover, the application potential of the CdSe/CdS:Eu³⁺ QDs in wLEDs was studied by coupling the CdSe/CdS:Eu³⁺ QDs and commercial Intematix G2762 green phosphor on a InGaN blue LED chip. Warm white light (5217 K) with 89.5 CRI and 91.1 lm W⁻¹ luminous efficacy could be achieved. Additionally, 91% of the NTSC color gamut was obtained, demonstrating the great potential of the CdSe/CdS:Eu³⁺ inorganic QDs as a color converter for wLEDs.