title: Matching Solid-State to Solution-Phase Photoluminescence for Near-Unity Down-Conversion Efficiency Using Giant Quantum Dots.
abstract: Efficient, stable, and narrowband red-emitting fluorophores are needed as down-conversion materials for next-generation solid-state lighting that is both efficient and of high color quality. Semiconductor quantum dots (QDs) are nearly ideal color-shifting phosphors, but solution-phase efficiencies have not traditionally extended to the solid-state, with losses from both intrinsic and environmental effects. Here, we assess the impacts of temperature and flux on QD phosphor performance. By controlling QD core/shell structure, we realize near-unity down-conversion efficiency and enhanced operational stability. Furthermore, we show that a simple modification of the phosphor-coated light-emitting diode device-incorporation of a thin spacer layer-can afford reduced thermal or photon-flux quenching at high driving currents (>200 mA).
authors.forename: Christina J
authors.initials: CJ
authors.lastname: Hanson
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Buck
authors.forename: Krishna
authors.initials: K
authors.lastname: Acharya
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Torres
authors.forename: Janardan
authors.initials: J
authors.lastname: Kundu
authors.forename: Xuedan
authors.initials: X
authors.lastname: Ma
authors.forename: Sarah
authors.initials: S
authors.lastname: Bouquin
authors.forename: Christopher E
authors.initials: CE
authors.lastname: Hamilton
authors.forename: Han
authors.initials: H
authors.lastname: Htoon
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Hollingsworth
keywords: down-conversion materials; giant quantum dots; high power light-emitting diodes; solid-state lighting