Effect of CdSe/CdS/ZnS quantum dots on the efficiency of LED devices

Purpose of research. To determine the influence of red colloidal quantum dots with the CdSe/CdS/ZnS structure on the luminous efficiency and color rendering index of LED devices.Methods. Microscopic, fluorescent and micro-X-ray studies of a silicone composite with red colloidal quantum dots CdSe/CdS/ZnS and phosphor powder of yttrium-aluminum garnet in white LEDs with a single InGaN chip as a 453.7 nm excitation source were carried out. Goniophotometric measurements of the spatial distribution of luminous intensity together with a spectrocolorimeter made it possible to determine the luminous efficiency and color rendering index of white LEDs.Results. The powder mixture of yttrium aluminum garnet particles obtained in this work with red colloidal quantum dots with a CdSe/CdS/ZnS structure stabilized with trioctylphosphine and trioctylphosphine oxide applied to their surface in the form of an island film and with wavelengths of luminescence maxima in the range from 590 to 630 nm under industrial production conditions made it possible to manufacture more than 100 white SMD LEDs with an improvement in luminous efficiency by 11%. For cold and neutral white light with chromaticity coordinates from x = 0.332 and y = 0.318 to x = 0.404 and y = 0.401 in the CIE 1931 color space, the color rendering index Ra of white LEDs with quantum dots exceeded 90 with red color index R9 values from 63 to 81.Conclusion. This paper shows the efficiency of using red quantum dots based on II-VI semiconductors for white LEDs with a quantum yield of at least 50% at a controlled concentration corresponding to the yttrium-aluminum garnet powder weight, due to the absence of a luminescence shift to the IR region, which is characteristic of the CaAlSiN3 nitride phosphor.