高压下Er³⁺掺杂Cs₃Cu₂Cl₅微晶材料多发光中心演化

Evolution of Multiple Luminescent Centers in Er³⁺-Doped Cs₃Cu₂Cl₅ Microcrystals under High Pressure

摘要: 压致发光材料能够利用外界压力实现颜色的可调控变化，在应力传感、信息存储以及极端环境探测等领域具有重要应用价值。无铅铜基卤化物Cs₃Cu₂Cl₅由于具有强自陷激子(self-trapped exciton, STE)发光、低毒性以及较高晶格柔性，被认为是构建新型压力响应发光材料的重要候选体系。然而，在高压环境下，铜基卤化物材料中基质自陷激子态、缺陷相关态以及稀土离子引入后形成的多发光中心如何随压力发生演化，目前仍缺乏系统研究。本文以铒离子(Er³⁺)掺杂的Cs₃Cu₂Cl₅微晶材料为研究对象，利用金刚石对顶砧高压实验技术，结合原位光致发光测试，系统研究了0~16 GPa压力范围内材料发光行为的演化规律。结果表明，该体系主要包含基质STE宽带发射、Er³⁺离子⁴G_11/2→⁴I_15/2特征窄带发射以及压力诱导缺陷相关发射三类发光中心。随着压力增加，STE发射经历峰位移动和强度变化，并表现出明显阶段性演化；Er³⁺特征4f-4f跃迁在整个压力范围内保持较高稳定性，而缺陷相关发光中心随压力逐渐增强。研究结果表明，压力能够通过调节局域晶格环境和载流子复合路径影响不同发光中心之间的相对贡献。本文为理解稀土掺杂铜基卤化物中的高压发光行为以及开发稳定型压力响应发光材料提供参考。

Abstract: Pressure-stimulated luminescent materials enable tunable emission color under external pressure, exhibiting promising application prospects in stress sensing, information storage, and extreme-environment detection. Lead-free copper-based halide Cs₃Cu₂Cl₅ features intense self-trapped exciton (STE) emission, low toxicity, and superior lattice flexibility, rendering it a promising candidate for constructing novel pressure-responsive luminescent materials. Nevertheless, the pressure-dependent evolution of multiple luminescent centers—including matrix STE states, defect-related states, and rare-earth ion centers—in copper-based halides remains poorly understood. In this work, erbium ion Er³⁺-doped Cs₃Cu₂Cl₅ microcrystals are selected as the research subject. Combining diamond anvil cell (DAC) high-pressure technology with in-situ photoluminescence measurements, we systematically investigate the evolution of luminescence behaviors within the pressure range of 0~16 GPa. The results reveal that the system possesses three types of luminescent centers: broad-band STE emission from the host matrix, narrow-band characteristic emission originating from the ⁴G_11/2→⁴I_15/2 transition of Er³⁺, and pressure-induced defect-related emission. As pressure increases, the STE emission undergoes peak shift and intensity variation with distinct stage-dependent evolution. In contrast, the 4f-4f transition of Er³⁺ maintains excellent stability across the entire pressure range, while the defect-related luminescence gradually intensifies upon compression. These findings demonstrate that pressure modulates the relative contributions of diverse luminescent centers by altering local lattice environments and carrier recombination pathways. This study provides insights into the high-pressure luminescence mechanism of rare-earth-doped copper-based halides and offers guidelines for developing robust pressure-responsive luminescent materials.