Tunable Luminescent Properties and Multifunctional Imaging Applications of (Gd_1–xR_x)₂O₂S:Tb³⁺ (R = Y, La) Phosphor and Screen

Gd 2 O 2 S:Tb 3+ phosphor screens are widely used in image intensifiers, computed tomography, and neutron imaging. To improve the luminescent properties and thermal stability, (Gd 1– x R x ) 2 O 2 S: y Tb 3+ (R = Y, La) ( x = 0, 0.05, 0.15, 0.25, and 0.35; y = 0.02, 0.04, 0.06, 0.08, and 0.10) phosphors were successfully prepared by the carbothermal reduction method. The luminescent spectra showed that the optimum concentrations of Tb 3+ ions were 6 and 4 mol % when excited by 292 nm UV light and cathode ray, respectively. The emission wavelengths mainly peaked at 489 and 544 nm. It was found that the introduction of Y 3+ ions could improve the luminescent intensity, and the luminescent intensity of (Gd 1– x Y x ) 2 O 2 S:0.06Tb 3+ was the highest at x = 0.25, while La 3+ ions played the opposite role. Then, the thermal stability also improved, and the emission intensities of Gd 2 O 2 S:0.06Tb 3+, (Gd 0.75 Y 0.25 ) 2 O 2 S:0.06Tb 3+, and (Gd 0.75 La 0.25 ) 2 O 2 S:0.06Tb 3+ phosphors at 423 K decreased to 66.22%, 68.23%, and 76.10% of the emission intensities at 303 K, respectively. Finally, the (Gd 0.75 Y 0.25 ) 2 O 2 S:0.06Tb 3+ phosphor screen was successfully prepared by the gravity deposition method and could be well imaged under UV light and cathode ray excitation with a CMOS camera. In summary, this study demonstrates that (Gd 1– x R x ) 2 O 2 S:Tb 3+ (R = Y, La) is a phosphor with excellent luminescent and thermal stability properties and has great potential for application in the field of low-level-light night vision, nondestructive testing, and medical imaging.