Yarur Villanueva Francisco, Quezada Novoa Victor, Rusch Pascal, Toso Stefano, Terban Maxwell W, Ivanov Yurii P, Chu Joaquin Carlos, Kirshenbaum Maxine J, Nikbin Ehsan, Gendron Romero Maria J, Prato Mirko, Divitini Giorgio, Howe Jane Y, Wilson Mark W B, Manna Liberato
Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy.
Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada.
J Am Chem Soc. 2025 Aug 13;147(32):29413-29422. doi: 10.1021/jacs.5c09495. Epub 2025 Jul 30.
We resolve a phase identification controversy in the Ag-Sn-S material system by unraveling the polymorphic structure of nanocrystals within the argyrodite material family. Argyrodites are a class of superionic materials used in their bulk form for applications in solid-state batteries and thermoelectrics, where their advantageous properties relate to their polymorphism. However, despite their well-studied bulk applications, the limited exploration at the nanoscale has left considerable potential for the discovery of emerging properties due to size effects. Further, phase identification presents a prominent challenge to the study of polymorphs in superionic conductors and related materials. In this work, we synthesize canfieldite-like (AgSnS) nanocrystals to understand their formation and structural behavior at the nanoscale. We observe the emergence of emissive, metastable, cluster-like species. Then, high-resolution transmission electron microscopy reveals indistinguishable polymorphs of canfieldite due to identical heavy-atom frameworks. However, using synchrotron X-ray total scattering for pair distribution function analysis, we uncover structural distortions, showing a pseudo-orthorhombic configuration that likely gives rise to the red emission. Further, we investigate the optical properties and structure of AgSnS nanocrystals upon the addition of Zn, the cation of interest in the canfieldite vs pirquitasite (AgZnSnS) phase identification controversy. We show that Zn is incorporated in the canfieldite-like structure through the replacement of Ag, boosting the emission. Our results solve a standing phase identification challenge and uncover fundamental insights for the synthesis and structure of canfieldite nanocrystals, laying the ground for the exploration of other argyrodite materials with emerging properties at the nanoscale.
我们通过揭示硫银锗矿材料家族中纳米晶体的多晶结构，解决了Ag-Sn-S材料体系中的相识别争议。硫银锗矿是一类超离子材料，其块状形式用于固态电池和热电学应用，其有利特性与它们的多晶性有关。然而，尽管它们的块状应用已得到充分研究，但在纳米尺度上的有限探索使得由于尺寸效应而发现新特性仍有很大潜力。此外，相识别对超离子导体及相关材料中的多晶型物研究提出了重大挑战。在这项工作中，我们合成了类黄锡矿（AgSnS）纳米晶体，以了解它们在纳米尺度上的形成和结构行为。我们观察到发光的、亚稳态的、簇状物种的出现。然后，高分辨率透射电子显微镜显示，由于相同的重原子框架，黄锡矿的多晶型无法区分。然而，使用同步加速器X射线全散射进行对分布函数分析，我们发现了结构畸变，显示出可能导致红色发射的假正交配置。此外，我们研究了添加锌（黄锡矿与皮尔奎他矿（AgZnSnS）相识别争议中的目标阳离子）后AgSnS纳米晶体的光学性质和结构。我们表明，锌通过取代银掺入类黄锡矿结构中，增强了发射。我们的结果解决了一个长期存在的相识别挑战，并揭示了黄锡矿纳米晶体合成和结构的基本见解，为探索其他具有纳米尺度新特性的硫银锗矿材料奠定了基础。
