Mahale Pratibha, Lee Byeongdu, Cheng Hiu Yan, Segad Mo, Mallouk Thomas E
Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
Advanced Photon Source, Argonne National Laboratory, Argonne, Lemont, Illinois 60439, United States.
ACS Appl Mater Interfaces. 2022 Feb 23;14(7):9398-9407. doi: 10.1021/acsami.1c19193. Epub 2022 Feb 8.
Colloidal crystals made from sub-100 nm silica nanoparticles have provided a versatile platform for the template-assisted synthesis of three-dimensionally interconnected semiconducting, metallic, and magnetic replicas. However, the detailed structure of these materials has not yet been characterized. In this study, we investigated the structures of colloidal crystalline films and germanium replicas by scanning electron microscopy and small angle X-ray scattering. The structures of colloidal crystals made by evaporative assembly depends on the size of l-arginine-capped silica nanoparticles. Particles smaller than ∼31 nm diameter assemble into non-close-packed arrangements (bcc) whereas particles larger than 31 nm assemble into random close-packed structures with disordered hexagonal phase. Polycrystalline films of these materials retain their structures and long-range order upon infiltration at high temperature and pressure, and the structure is preserved in Ge replicas. The shear force during deposition and dispersity of silica nanoparticles contributes to the size-based variation in the structure and to the size of crystal domains in the colloidal crystal films.
由直径小于100纳米的二氧化硅纳米颗粒制成的胶体晶体为三维互连的半导体、金属和磁性复制品的模板辅助合成提供了一个通用平台。然而，这些材料的详细结构尚未得到表征。在本研究中，我们通过扫描电子显微镜和小角X射线散射研究了胶体晶体薄膜和锗复制品的结构。通过蒸发组装制成的胶体晶体的结构取决于L-精氨酸封端的二氧化硅纳米颗粒的大小。直径小于约31纳米的颗粒组装成非密排结构（体心立方），而直径大于31纳米的颗粒组装成具有无序六方相的随机密排结构。这些材料的多晶薄膜在高温高压渗透时保留其结构和长程有序，并且该结构在锗复制品中得以保留。二氧化硅纳米颗粒沉积过程中的剪切力和分散性导致了结构中基于尺寸的变化以及胶体晶体薄膜中晶畴的尺寸。
