Colloidal particles with a spherical shape and diameters in the range of 0.01-1 μm have been a subject of extensive research, with applications in areas such as photonics, electronics, catalysis, drug delivery, and medicine. For most of these applications, it is of critical importance to achieve monodispersity for the size while expanding the diversity in terms of structure and composition. The uniformity in size allows one to establish rigorous correlations between this parameter and the physicochemical properties of the colloidal particles while ensuring experimental repeatability and measurement accuracy. On the other hand, the diversity in structure and composition offers additional handles for tailoring the properties. By switching from the conventional plain, solid structure to a core-shell, hollow, porous, or Janus structure, it offers immediate advantages and creates new opportunities, especially in the context of self-assembly, encapsulation, and controlled release. As for composition, monodispersed colloidal spheres were traditionally limited to amorphous materials such as polystyrene and silica. For metals and semiconducting materials, which are more valuable to applications in photonics, electronics, and catalysis, they tend to crystallize and thus grow anisotropically into nonspherical shapes, especially when their sizes pass 0.1 μm. Taken together, it is no wonder why chemical synthesis of monodispersed colloidal spheres has been a constant theme of research in areas such as colloidal science, materials chemistry, materials science, and soft matter. In this Account, we summarize our efforts over the past two decades in developing solution-phase methods for the facile synthesis of colloidal spheres that are uniform in size, together with a broad range of compositions (including metals and semiconductors) and structures (e.g., solid, core-shell, hollow, porous, and Janus, among others). We start with the synthesis of monodispersed colloidal spheres made of semiconductors, metals with low melting points, and precious metals. Through chemical reactions, these colloidal spheres can be transformed into core-shell or hollow structures with new compositions and properties. Next, we discuss the synthesis of colloidal spheres with a Janus structure while taking a pseudospherical shape. Specifically, metal-polymer hybrid particles composed of one metal nanoparticle partially embedded in the surface of a polymer sphere can be produced through precipitation polymerization in the presence of metal seed. With these Janus particles serving as templates, other types of Janus structures such as hollow spheres with a single hole in the surface can be obtained via site-selected deposition. Alternatively, such hollow spheres can be fabricated through a physical transformation process that involves swelling of polymer spheres, followed by freeze-drying. All these synthesis and transformation processes are solution-based, offering flexibility and potential for large-scale production. At the end, we highlight some of the applications enabled by these colloidal spheres, including fabrication of photonic devices, encapsulation, and controlled release for nanomedicine.

中文翻译：

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单分散胶体球的合成，转化和利用。

具有球形形状和直径在0.01-1μm范围内的胶体颗粒已经是广泛研究的主题，其在诸如光子学，电子学，催化，药物递送和药物等领域中得到应用。对于大多数这些应用，至关重要的是要实现尺寸的单分散性，同时在结构和组成方面扩大多样性。尺寸的均匀性使人们可以在该参数与胶体颗粒的理化性质之间建立严格的相关性，同时确保实验的可重复性和测量精度。另一方面，结构和组成的多样性为定制属性提供了额外的处理方式。通过从常规的普通实心结构转换为核-壳，空心，多孔或Janus结构，它提供了直接的优势并创造了新的机会，尤其是在自组装，封装和受控释放的情况下。至于组成，单分散的胶体球传统上限于无定形材料，例如聚苯乙烯和二氧化硅。对于在光子学，电子学和催化领域的应用更有价值的金属和半导体材料，它们往往会结晶并因此各向异性地生长为非球形，特别是当它们的尺寸超过0.1μm时。综上所述，难怪为什么单分散胶体球的化学合成一直是胶体科学，材料化学，材料科学和软物质等领域研究的恒定主题。在这个帐户中，我们总结了过去二十年来我们在溶液相方法开发方面的努力，这些方法用于容易地合成尺寸均匀的胶体球，以及范围广泛的成分（包括金属和半导体）和结构（例如固体，核-壳，空心，多孔和Janus等）。我们从合成半导体，低熔点金属和贵金属制成的单分散胶体球开始。通过化学反应，这些胶体球可以转变为具有新组成和性能的核-壳或中空结构。接下来，我们讨论具有Janus结构同时呈假球形的胶体球的合成。具体来说，由部分嵌入聚合物球体表面的一种金属纳米颗粒组成的金属-聚合物杂化颗粒可以通过在金属种子存在下的沉淀聚合来制备。使用这些Janus颗粒作为模板，可以通过位置选择沉积获得其他类型的Janus结构，例如在表面具有单个孔的空心球。或者，可以通过涉及聚合物球的溶胀然后冷冻干燥的物理转化过程来制造这种空心球。所有这些合成和转化过程均基于解决方案，为大规模生产提供了灵活性和潜力。最后，我们重点介绍了这些胶体球支持的一些应用，包括光子器件的制造，封装，