title: Quantum-dot-based white lighting planar source through downconversion by blue electroluminescence.
abstract: We report the unprecedented fabrication of a planar white lighting quantum dot light-emitting diode (QD-LED) through integrating a CdZnS QD-based blue electroluminescence (EL) device with a free-standing polymethyl methacrylate (PMMA) composite film embedded with orange-emitting Cu-In-S (CIS) green-greenish yellow-emitting Cu-In-Ga-S (CIGS) QDs. The hybrid device successfully generates bicolored white emission that comprises blue EL and downconverted QD photoluminescence. The hybrid QD-LEDs loaded with the composite film embedded with one type of QDs exhibit a limited white spectral coverage, consequently producing low values (<65) in color rendering index (CRI). Thus, the QD-PMMA film consisting of a blend of green CIGS and orange CIS QD downconverters is applied for obtaining a higher-CRI white light through the spectral extension, resulting in a much improved CRI of 75-77. Various EL performances of the hybrid planar white device versus the reference blue QD-LED are also characterized in details.
authors.forename: Ki-Heon
authors.initials: KH
authors.lastname: Lee
authors.forename: Jong-Hoon
authors.initials: JH
authors.lastname: Kim
authors.forename: Ho Seong
authors.initials: HS
authors.lastname: Jang
authors.forename: Young Rag
authors.initials: YR
authors.lastname: Do
authors.forename: Heesun
authors.initials: H
authors.lastname: Yang