Highly bright yellow-green-emitting CuInS2 colloidal quantum dots with core/shell/shell architecture for white light-emitting diodes

Sang Hyun Park, Ara Hong, Jong Hoon Kim, Heesun Yang, Kwangyeol Lee, Ho Seong Jang

Research output: Contribution to journalArticlepeer-review

84 Citations (Scopus)

Abstract

In this study, we report bright yellow-green-emitting CuInS2 (CIS)-based quantum dots (QDs) and two-band white light-emitting diodes (LEDs) using them. To achieve high quantum efficiency (QE) of yellow-green-emitting CIS QDs, core/shell/shell strategy was introduced to high quality CIS cores (QE = 31.7%) synthesized by using metal-oleate precursors and 1-dodecanethiol. The CIS/ZnS/ZnS QDs showed a high QE of 80.0% and a peak wavelength of 559 nm under the excitation of 450 nm, which is well matched with dominant wavelength of blue LEDs. The formation of core/shell/shell structure was confirmed by X-ray diffraction, transmission electron microscopy, and inductively coupled plasma-optical emission spectroscopy analyses. Intense and broad yellow-green emission band of the CIS/ZnS/ZnS is beneficial for bright two-band white light. When the CIS/ZnS/ZnS was coated on the blue LEDs, the fabricated white LED showed bright natural white light (luminous efficacy (ηL) = 80.3 lm·W-1, color rendering index (Ra) = 73, correlated color temperature (Tc) = 6140 K). The QD-white LED package showed a high light conversion efficiency of 72.6%. In addition, the CIS/ZnS/ZnS-converted white LED showed relatively stable white light against the variation of forward bias currents of 20-150 mA [color coordinates (x, y) = (0.3320-0.3207, 0.2997-0.2867), Ra = 70-72, Tc = 5497-6375 K].

Original languageEnglish
Pages (from-to)6764-6771
Number of pages8
JournalACS Applied Materials and Interfaces
Volume7
Issue number12
DOIs
Publication statusPublished - 2015 Apr 1

Keywords

  • core/shell/shell
  • luminescence
  • quantum dots
  • white LEDs

ASJC Scopus subject areas

  • Materials Science(all)

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