Mechanical, photoluminescent properties and energy transfer mechanism of highly transparent (Y0.99-xGdxSm0.01)2O3 ceramics for scintillator applications

In this study, highly (Y0.99-xGdxSm0.01)2O3 transparent ceramics with varying Gd3+ content (x = 0-0.1) was successfully fabricated by vacuum sintering. The effect of the Gd3+ content on the structural, mechanical and optical properties of the Y2O3 ceramics were systematically investigated. The prepared transparent ceramics have high optical quality with an in-line transmittance of 75.16%- 81.44% at 610 nm (4G5/2 -> 6H9/2 transitions of Sm3+). Mechanical properties, including Vickers hardness (HV), are also evidently enhanced by solid solution strengthening. Photoluminescence properties of ceramics including excitation spectra, emission spectra and fluorescence lifetimes are systematically investigated. Notably, the photoluminescence properties of the cera-mics, including excitation spectra, emission spectra and fluorescence lifetimes, confirm the existence of energy transfer (ET) from Gd3+ to Sm3+ ions and provide a qualitative understanding of the ET process. The efficiency of ET between Gd3+ and Sm3+ emission centers was found to increase with higher Gd3+ concentration. This work may provide guidance on the design, preparation and application of Gd-doped transparent ceramic scintillators.