Synthesis and efficient near-infrared quantum cutting of Pr3+/Yb3+ co-doped LiYF4 single crystals

Yttrium lithium fluoride single crystals doped with trivalent lanthanide ions Pr3+ and Yb3+ are prepared by an improved Bridgman method. X-ray diffraction, photoluminescence excitation, and emission spectra and decay curves are measured to investigate the structural and luminescent properties of the crystals. An efficient near-infrared quantum cutting downconversion from the crystals was observed. The downconversion involves the emission of two near-infrared photons for each blue photon absorbed at 480 nm via cross relaxation energy transfer from Pr3+ to Yb3+. Decay curve fitting using a modified Inokuti-Hirayama expression indicates dipole-dipole energy transfer from Pr3+ to Yb3+, which is consistent with the expected cross-relaxation scheme. The maximum quantum cutting efficiency approaches up to 168.4% in LiYF4: 0.28 mol. % Pr3+ and 6.02 mol. Yb3+, and this is equivalent to 68.4% energy transfer efficiency. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4757925]