All-inorganic metal halide perovskites possess significant potentiality in lighting, bioimaging, and optical anti-counterfeiting due to their exceptional and unique properties. However, the exploration of efficient, robustly stable, and long-persistent luminescent blue light-emitting materials poses huge challenges, especially in understanding their electronic structure and photophysical processes. In this work, high-purity Pb2+-doped CsCdCl3 crystals were synthesized using a straightforward hydrothermal method. Parts of Pb2+ ions replaced partial Cd2+ sites in the face-sharing octahedra and formed atomically confined excitons around the Pb(II) octahedra. This exciton could emit blue light (423 nm) at room temperature with an enhanced radiation transition probability at a nearly 90% quantum yield. The incorporation of Pb2+ and confined exciton formation not only shifted the emission color region from weak orange to strong blue but also exhibited intrinsic afterglow behavior as CsCdCl3 perovskite. The Raman spectra and TL spectra indicated their polaronic states corresponding to the A1g 244 cm−1 phonon mode coupling to electron, which dominated their afterglow processes in undoped and doped CsCdCl3. These findings could not only facilitate the understanding of atomically confined excitons around dopant ions as dominant emission centers to tune emission color in halide semiconductors, unveiling the nature of afterglow phenomena in this halide material, but could also find unique applications in optical devices.

中文翻译：

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Pb（II） 掺杂镉基金属卤化物中原子限制激子的增强余辉蓝光发射


全无机金属卤化物钙钛矿由于其特殊和独特的性能，在照明、生物成像和光学防伪方面具有巨大的潜力。然而，探索高效、稳健稳定和持久发光的蓝光发光材料带来了巨大的挑战，尤其是在理解它们的电子结构和光物理过程方面。在这项工作中，使用简单的水热法合成了高纯度 Pb2+ 掺杂的 CsCdCl3 晶体。部分 Pb2+ 离子取代了面共享八面体中的部分 Cd2+ 位点，并在 Pb（II） 八面体周围形成原子限制激子。该激子可以在室温下发射蓝光 （423 nm），在接近 90% 的量子产率下具有增强的辐射跃迁概率。Pb2+ 和局限激子形成的掺入不仅使发射颜色区域从弱橙色转变为强蓝色，而且还表现出与 CsCdCl3 钙钛矿一样的内禀余辉行为。拉曼光谱和 TL 光谱表明它们的极化态对应于 A1g 244 cm−1 声子模式与电子的耦合，这在未掺杂和掺杂 CsCdCl3 中的余辉过程中占主导地位。这些发现不仅可以促进理解掺杂离子周围的原子限制激子作为调节卤化物半导体发射颜色的主要发射中心，揭示这种卤化物材料中余辉现象的性质，而且还可以在光学器件中找到独特的应用。