Bi3+–Ce3+ energy transfer and luminescent properties of LuAG:Bi,Ce and YAG:Bi,Ce single crystalline films

The absorption, cathodoluminescence, excitation spectra of photoluminescence (PL) and PL decay kinetics were studied at 300 K for the double Bi3+–Ce3+-doped and separately Bi3+- and Ce3+-doped Y3Al5O12 (YAG) and Lu3Al5O12 (LuAG) single crystalline film phosphors grown by liquid phase epitaxy method. Emission bands in the UV range arising from the intrinsic radiative transitions of Bi3+-based centers, and emission bands in the visible range related to the luminescence of excitons localized around Bi-based centers, were identified in both Bi–Ce and Bi-doped YAG and LuAG SCF. Energy transfers from the host lattice to Bi3+ and Ce3+ ions and from Bi3+ to Ce3+ ions were investigated. Competition between Bi3+ and Ce3+ ions in the energy transfer from the YAG and LuAG hosts was evidenced. A strong decrease of intensity of the Ce3+ luminescence both in YAG:Ce and LuAG:Ce SCF phosphors, grown from a Bi2O3 flux, is observed due to the quenching influence of Bi3+ flux related impurity. Due to overlap of the visible emission band of Bi3+ centers with the absorption band of Ce3+ ions peaking at around 450–460 nm, an effective energy transfer from Bi3+ ions to Ce3+ ions takes place, resulting in the appearance of a slower component in the Ce3+ luminescence decay kinetics.