Doping engineering has emerged as one of the most powerful approaches to impart new optical and electronic properties to halide perovskite nanocrystals (NCs). However, the impact of dopants on the structure of perovskite NCs remains poorly understood. Here, we report on the finding of doping-induced structural phase transitions occurring in all-inorganic perovskite NCs. Using Ni²⁺-doped CsPbCl₃ NCs as a model system, we show that Ni²⁺ doping causes the coexistence of dual subdomains of cubic and orthorhombic phases and inhibits the phase transition from cubic to orthorhombic in NCs with negligible atomic vacancies as the temperature decreases. Car–Parrinello molecular dynamics simulations reveal that the doping-induced structural phase transition results from the dopant-enabled release of lattice strain and a temperature-insensitive local structural change in the doped region of NCs. Since size mismatch between dopants and replaced ions widely exists in doped functional materials, our finding may not be limited to halide perovskite NCs, but could have implications even for other classes of doped NCs and bulk materials.

中文翻译：

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掺杂在全无机卤化物钙钛矿纳米晶体中诱导结构相变。

掺杂工程已经成为赋予卤化物钙钛矿纳米晶体（NCs）新的光学和电子特性的最强大方法之一。但是，对于钙钛矿型NC的掺杂剂的影响仍然知之甚少。在这里，我们报告在全无机钙钛矿NCs中发生的掺杂诱导的结构相变的发现。使用掺杂Ni ^2+的CsPbCl ₃ NC作为模型系统，我们表明Ni ²⁺掺杂导致立方相和正交相的两个子域共存，并抑制了随着温度降低原子空位可忽略的NC中立方相到正交相的相变。Car-Parrinello分子动力学模拟表明，掺杂诱导的结构相变是由掺杂剂使能的晶格应变释放和NCs掺杂区域中对温度不敏感的局部结构变化引起的。由于掺杂功能材料中掺杂剂和取代离子之间的尺寸不匹配，因此我们的发现可能不仅限于卤化钙钛矿型NC，甚至对于其他类别的掺杂NC和块状材料也可能具有影响。