title: Emission-tunable CuInS2/ZnS quantum dots: structure, optical properties, and application in white light-emitting diodes with high color rendering index.
abstract: Synthesis and application of CuInS2/ZnS core/shell quantum dots (QDs) with varying [Cu]/[In] ratios were conducted using a stepwise solvothermal route. CuInS2 (CIS) core QDs with varying [Cu]/[In] ratios exhibited deep-red emissions result from donor-acceptor pair recombination. The absorption and emission band gap of the CuInS2 QDs increased with the decrease in Cu content. The emission bands of the CuInS2/ZnS were tuned from 550 to 616 nm by controlling the [Cu]/[In] ratio after coating ZnS layer. The CIS QDs model was developed to elucidate the synthesized crystal structure and photoluminescence of the QDs with various [Cu]/[In] ratios. Temperature-dependent photoluminescence spectra of the CIS/ZnS QDs were also investigated. The temperature dependency of the photoluminescence energy and intensity for various CIS/ZnS QDs were studied from 25 to 200 °C. Efficient white light-emitting diodes with high color rendering index values (Ra = 90) were fabricated using CIS/ZnS QDs as color converters in combination with green light-emitting Ba2SiO4:Eu(2+) phosphors and blue light-emitting diodes.
authors.affiliation: Department of Chemistry, National Taiwan University , Taipei 106, Taiwan.
authors.forename: Po-Hsiang
authors.initials: PH
authors.lastname: Chuang
authors.forename: Chun Che
authors.initials: CC
authors.lastname: Lin
authors.forename: Ru-Shi
authors.initials: RS
authors.lastname: Liu
keywords: CuInS2; color rendering index; donor−acceptor pair; light-emitting diodes; quantum dots; temperature-dependent photoluminescence