X-ray excited luminescence in scintillators plays a crucial role in applications ranging from medical diagnostics to industrial quality inspection and scientific research. This study explores the potential of Bi³⁺-doped Gd₂O₃ phosphors as next-generation scintillators, leveraging their broad-spectrum emission characteristics to achieve higher light yields. We synthesized Gd₂O₃:Bi³⁺ phosphors in two crystalline phases─cubic and monoclinic─using a high-temperature solid-phase method. These phosphors demonstrate varied applications, from backlighting displays to X-ray imaging of opaque and biological samples. Under UV light excitation, each phase exhibits distinct luminescence properties due to different Bi³⁺ occupancy environments. The monoclinic phase, excited at λ_ex = 370 nm, showed stronger luminescence and a broader emission peak (fwhm = 70 nm) with a higher photoluminescence quantum yield (67.94%), compared to the cubic phase, which under optimal conditions (λ_ex = 377 nm) exhibited narrower peaks (fwhm = 40 nm) and a lower yield (44.41%). Notably, under X-ray excitation, the cubic phase outperformed with a higher light yield (48,900 photons/MeV) and lower detection limits (380 nGy·s^–1 at λ_em = 430 nm and 285 nGy·s^–1 at λ_em = 520 nm). Both phosphors were also embedded in PMMA to create thin films for X-ray imaging, achieving high-resolution outputs (14 lp·mm^–1).

中文翻译：

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Bi3+ 掺杂 Gd2O3 荧光粉在紫外和 X 射线激发下的发光性能


闪烁体中的 X 射线激发发光在从医疗诊断到工业质量检测和科学研究的应用中起着至关重要的作用。本研究探讨了 Bi³⁺ 掺杂 Gd₂O₃ 荧光粉作为下一代闪烁体的潜力，利用其广谱发射特性实现更高的光产量。我们使用高温固相法合成了 Gd₂O₃：Bi³⁺ 荧光粉在立方和单斜晶相两种晶相中。这些荧光粉展示了各种应用，从背光显示器到不透明和生物样品的 X 射线成像。在紫外光激发下，由于不同的 Bi³⁺ 占用环境，每个相都表现出不同的发光特性。在 λ_ex = 370 nm 处激发的单斜相显示出更强的发光和更宽的发射峰 （fwhm = 70 nm），与立方相相比，在最佳条件下 （λ_ex = 377 nm） 表现出更窄的峰 （fwhm = 40 nm） 和较低的产率 （44.41%）。值得注意的是，在 X 射线激发下，立方相以更高的光产率（48,900 个光子/MeV）和较低的检测限（λ_em = 430 nm 处为 380 nGy·s^–1，λ _em = 520 nm 处为 285 nGy·s^–1）表现出色。两种荧光粉也嵌入 PMMA 中，以形成用于 X 射线成像的薄膜，实现高分辨率输出 （14 lp·mm^–1）。