Combinatorial optimization of the atomic compositions for green-emitting YBO3:Ce3+,Tb3+ and red-emitting YBO3:Ce3+,Tb3+,Eu3+ phosphors using a microplate reader

Microplate readers are versatile devices that can rapidly measure the photoluminescence intensities of multiple samples, and are widely used in biological chemistry. In this work, using a commercial microplate reader, we attempted to optimize the atomic compositions of green-emitting phosphor Y1−x−yCexTbyBO3 and red-emitting phosphor Y1−x−y−zCexTbyEuzBO3. We filled 48 individual wells of an alumina microplate with aqueous solutions of nitrates of Y3+, Ce3+, Tb3+, and Eu3+ with different compositions, and then added an aqueous solution of boric acid to each well. After drying, the microplate was heated at 550 °C for 2 h in air, and then at 1100 °C for 3 h in a reducing atmosphere. Y1−x−yCexTbyBO3 absorbed near ultraviolet light through 4f → 5d transitions of Ce3+ and emitted green fluorescence corresponding to 4f → 4f transitions of Tb3+ through Ce3+ → Tb3+ energy transfer. Moreover, Y1−x−y−zCexTbyEuzBO3 emitted red fluorescence corresponding to 4f → 4f transitions of Eu3+ through Ce3+ → Tb3+ → Eu3+ energy transfer under near-ultraviolet light. Measurement of the photoluminescence intensity of each well by a microplate reader revealed that the optimized green and red phosphors were Y0.835Ce0.025Tb0.14BO3 and Y0.535Ce0.005Tb0.45Eu0.01BO3, respectively.