title: Ultra-high photoluminescent quantum yield of β-NaYF4: 10% Er3+ via broadband excitation of upconversion for photovoltaic devices.
abstract: The upconversion photoluminescent quantum yield (PLQY) of erbium-doped hexagonal sodium yttrium fluoride (β-NaYF(4): 10% Er(3+) was measured under broadband excitation with full width half maxima ranging from 12 to 80 nm. A novel method was developed to increase the bandwidth of excitation, while remaining independent of power via normalization to the air mass 1.5 direct solar spectrum. The measurements reveal that by broadening the excitation spectrum a higher PLQY can be achieved at lower solar concentrations. The highest PLQY of 16.2 ± 0.5% was achieved at 2270 ± 100 mW mm(-2) and is the highest ever measured.
authors.affiliation: Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, Scotland.
authors.forename: Sean K W
authors.initials: SK
authors.lastname: MacDougall
authors.forename: Aruna
authors.initials: A
authors.lastname: Ivaturi
authors.forename: Jose
authors.initials: J
authors.lastname: Marques-Hueso
authors.forename: Karl W
authors.initials: KW
authors.lastname: Krämer
authors.forename: Bryce S
authors.initials: BS
authors.lastname: Richards