异价阳离子替代实现的金属卤化物CsCdCl3的明亮宽带绿色发光

全无机金属卤化物灵活多变的结构及优异的发光性能使其在固态光电子领域显示出重要的应用前景。本研究采用异价阳离子取代策略，用三价锑离子部分取代CsCdCl₃中的二价镉离子，促进自陷激子的产生，使CsCdCl₃∶Sb³⁺产生了明亮的宽带绿色发光，中心波长为530 nm。机理研究结果表明，CsCdCl₃∶Sb³⁺中相邻SbCl₆八面体被孤立，形成了低维电子构型，促进了Sb³⁺局域化，实现了量子效率最高为95.5%的高效发光。此外，尽管CsCdCl₃和RbCdCl₃均属于ACdCl₃(A为碱金属家族),但它们的晶体结构明显不同。RbCdCl₃属于正交晶系，空间群为Pnma;CsCdCl₃属于六方晶系，空间群为P6₃/mmc。CsCdCl₃的结构对称性大于RbCdCl₃,其...

Bright Broadband Green Photoluminescence of CsCdCl3 Metal Halides Achieved by Heterovalent Cation Substitution

All-inorganic metal halides have shown significant applications in solid-state optoelectronics because of their flexible structures and impressive fluorescence emissions. In this study, a heterovalent cation substitution strategy was used to partially replace the divalent cadmium ions in CsCdCl₃ with trivalent antimony ions to promote the production of self-trapped excitons, resulting in a bright broadband green photoluminescence of CsCdCl₃∶Sb³⁺ with a central wavelength of 530 nm. Mechanism researches results show that the adjacent SbCl₆ octahedra in CsCdCl₃∶Sb³⁺ are isolated, forming a low-dimensional electronic configuration that promotes Sb³⁺ localization and achieves efficient photoluminescence with a quantum efficiency of up to 95.5%. Furthermore, although both CsCdCl₃ and RbCdCl₃ belong to ACdCl₃ (A is an alkali metal family), they have distinctly different crystal structures. RbCdCl₃ crystallizes in the orthorhombic crystal system with space group of Pnma; while CsCdCl₃ crystallizes in the hexagonal phase crystal system with space group of P6₃/mmc. The structural symmetry of CsCdCl₃ is higher than that of RbCdCl₃, indicating that its crystal structure is less distorted away from the cubic phase than that of RbCdCl₃, resulting in a smaller Stokes shift and corresponding blue shift of the emission spectrum in CsCdCl₃∶Sb³⁺ than in RbCdCl₃∶Sb³⁺. This work not only provides a method for designing new photoluminescence materials by heterovalent cation substitution but also paves an avenue for modulating the luminescent properties of metal halides through crystal structure symmetry.