Understanding the luminescence in Yb 3+ co-doped Sialon: Eu 2+ /Eu 3+ transparent phosphor ceramic plate

The transparent Sialon phosphor ceramic plates were fabricated with varying amounts of Yb 2 O 3 and Eu 2 O 3 . The hot press sintering technique was used to sinter the compact powders. The fabricated samples with the highest Yb 2 O 3 concentration (10 wt%) and lowest Eu 2 O 3 concentration (1 wt%) show a dominant α-Sialon phase, whereas the highest Eu 2 O 3 (8 wt%) and lowest Yb 2 O 3 (3 wt%) containing sample shows composite α/β-Sialon phases as confirmed by the XRD analysis. The light transmittance was measured for 0.1 mm thick samples. The maximum light transmission of 60% was observed at 800 nm wavelength for the highest Yb 2 O 3 added Sialon ceramics. Also, the higher Yb 2 O 3 and lower Eu 2 O 3 containing samples show a sharp orange luminescence at 590 nm, attributed to the parity allowed magnetic dipole induced 5 D 0 → 7 F 1 transition of the Eu 3+ . These samples also produced upconversion luminescence as irradiated by 980 nm wavelength. The sample with the highest Eu 2 O 3 addition exhibits broad greenish-yellow down-conversion emission with a sharp emission at 590 nm for composite α/β-Sialon phases. The recorded broad emission ranges from green to red, offering a wide spectrum of visible light for lighting applications.