Phase-selective pyrolysis and Pr³⁺ luminescence in a YF₃-Y₂O₃ system from a single-source precursor

Pr³⁺-doped YF₃ (orthorhombic), YO_0.80F_1.40 (orthorhombic), YOF (rhombohedral), and Y₂O₃ (cubic) films were synthesized on quartz-glass substrates through pyrolysis of a single-source trifluoroacetate precursor at temperatures between 400° and 900°C in air. Phase-selective deposition was achieved by controlling heating temperature and time. YF₃, which formed first from the precursor, was transformed to YO_0.80F_1.40, YOF, and Y₂O₃. Photoluminescent properties of Pr³⁺-doped films were examined using ultraviolet excitation. An intense green photoluminescence was observed in the YOF: Pr³⁺ film, which was deposited at 700°C, through an efficient charge transfer (O^2-Pr³⁺) excitation.