title: Employing heavy metal-free colloidal quantum dots in solution-processed white light-emitting diodes.
abstract: We report in this communication the design and fabrication of solution-processed white light-emitting diodes (LEDs) containing a bilayer of heavy metal-free colloidal quantum dots (QDs) and polymer in the device active region. White electroluminescence was obtained in the LEDs by mixing the red emission of ZnCuInS/ZnS core/shell QDs and the blue-green emission of poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine). A high color rendering index of 92 was achieved as compared to a 5310 K blackbody reference by virtue of broadband emission of the QDs. The Commission Internationale de l'Eclairage chromaticity coordinates of the white LED output exhibit a distinctive bias dependence. Finally, aging of the white LEDs was studied, revealing the difference between the photochemical stabilities of the QDs and polymer molecules and the consequent effect on the color evolution of the LEDs.
authors.affiliation: Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Chuang
authors.initials: C
authors.lastname: Xie
authors.forename: Huaipeng
authors.initials: H
authors.lastname: Su
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.forename: Shawn
authors.initials: S
authors.lastname: Pickering
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Wang
authors.forename: William W
authors.initials: WW
authors.lastname: Yu
authors.forename: Jingkang
authors.initials: J
authors.lastname: Wang
authors.forename: Yiding
authors.initials: Y
authors.lastname: Wang
authors.forename: Jong-in
authors.initials: JI
authors.lastname: Hahm
authors.forename: Nicholas
authors.initials: N
authors.lastname: Dellas
authors.forename: Suzanne E
authors.initials: SE
authors.lastname: Mohney
authors.forename: Jian
authors.initials: J
authors.lastname: Xu
mesh_terms: D003102:Colloids / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008029:Lighting / Q000295:instrumentation*; D019216:Metals, Heavy / Q000737:chemistry; D036103:Nanotechnology / Q000295:instrumentation*; D045663:Quantum Dots; D012666:Semiconductors
chemical_list: D003102:Colloids; D019216:Metals, Heavy