Doping and alloying are valuable tools for modifying and enhancing the properties and performance of lead halide perovskites. However, the effects of heterovalent doping with Sb³⁺ and Bi³⁺ cations are still a matter of current investigation. Due to the different charge of the dopants compared to the constituting Pb²⁺ ions, a simultaneous creation of defects is unavoidable and the influence of these defects and the actual metal substitution become entangled. Herein, we present the first 14–15 iodido metalates, (BED)₄PbE₂I₁₆ (BED=N‐benzylethylenediammonium; E=Sb (1), Bi (2)), which are model compounds for doped lead iodide perovskites and display surprisingly low band gaps of 2.01 (1) and 1.88 eV (2). Quantum chemical investigations show that this stems from a good electronic match between the PbI₆ and EI₆ units of the compounds. Our results provide a model system for doped perovskites, but also represent the first examples of a promising new class of metal halide materials.

中文翻译：

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14-15族混合金属盐作为掺杂的卤化铅钙钛矿的模型化合物

掺杂和合金化是用于改进和增强卤化铅钙钛矿的性能和性能的有价值的工具。然而，用Sb ³⁺和Bi ³⁺阳离子进行异价掺杂的影响仍是当前研究的问题。由于与构成的Pb ²⁺离子相比，掺杂剂的电荷不同，因此不可避免地会同时产生缺陷，并且这些缺陷的影响和实际的金属取代会纠缠在一起。在这里，我们介绍了前14–15个碘化金属盐（BED）₄ PbE ₂ I ₁₆（BED = N-苄基乙烯二铵； E = Sb（1），Bi（2）），它们是掺杂的碘化铅钙钛矿的模型化合物，并显示出令人惊讶的低带隙，分别为2.01（1）和1.88 eV（2）。量子化学研究表明，这源于化合物的PbI ₆和EI ₆单元之间的良好电子匹配。我们的结果提供了掺杂钙钛矿的模型系统，但也代表了有前途的新型金属卤化物材料的第一个实例。