Time and temperature dependence of the emissions from the quantum-cutting phosphor LiGdF4:Eu3+

The Gd-Eu couple is well known for efficient conversion of absorbed high-energy photons into two visible photons (quantum cutting). For this couple, a model describing the quantum-cutting mechanism has been proposed by Wegh et al. [J. Lumin. 82 (1999) 93]. This model is mainly supported by emission spectra, while the kinetics of the energy-transfer processes involved in quantum cutting have hardly been investigated. The present paper reports time and temperature dependent studies of the spectroscopic properties of LiGdF4:Eu3+ 0.5%. The experimentally observed decay curves at room temperature of the Eu3+ D-5(0), D-5(1) and Gd3+ P-6(7/2) emission can be explained by a parameter model based on the kinetics of the mechanism. The temperature-dependent study shows a change in the energy-transfer kinetics that is consistent with the absence of quantum cutting at low temperatures (T < 50 K). (c) 2005 Elsevier B.V. All rights reserved.