Concentration dependence of energy transfer Ce3+→Er3+ in YAG host

Abstract

In the doubly doped YAG:Ce,Er single crystal we show the effect of the nonradiative energy transfer from the donor (Ce3+) to the acceptor (Er3+) in terms of the Förster-Dexter model. Such an energy transfer process is enabled by the overlap of the donor and acceptor emission and absorption spectra, respectively, and makes the donor to de-excite faster. This phenomenon can be used to tailor the luminescence decay of a phosphor in order to increase the rate at which it converts incoming radiation, if the decrease of its quantum efficiency can be tolerated. Quantitative comparison of experimental data obtained at the sample set with large concentration interval of Er3+ acceptor (up to the concentration Y2.835Al5O12: Ce0.006Er0.159) with the mentioned theoretical model allows the determination of the microscopic parameters of the energy transfer process, such as the critical concentration of the Er3+ ions. The Er concentration higher than 1% has proven to shorten the 1/e decay time from 62 ns below 30 ns. The concentration dependence of the absorption lines of the Er3+ is also discussed.