Nanotechnology & Integrated Bio-Engineering Centre, Ulster University, BT37 0QB, UK.
School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane QLD 4000, Australia.
Nanoscale. 2016 Oct 6;8(39):17141-17149. doi: 10.1039/c6nr03702j.
Highly size-controllable synthesis of free-standing perfectly crystalline silicon carbide nanocrystals has been achieved for the first time through a plasma-based bottom-up process. This low-cost, scalable, ligand-free atmospheric pressure technique allows fabrication of ultra-small (down to 1.5 nm) nanocrystals with very low level of surface contamination, leading to fundamental insights into optical properties of the nanocrystals. This is also confirmed by their exceptional photoluminescence emission yield enhanced by more than 5 times by reducing the nanocrystals sizes in the range of 1-5 nm, which is attributed to quantum confinement in ultra-small nanocrystals. This method is potentially scalable and readily extendable to a wide range of other classes of materials. Moreover, this ligand-free process can produce colloidal nanocrystals by direct deposition into liquid, onto biological materials or onto the substrate of choice to form nanocrystal films. Our simple but efficient approach based on non-equilibrium plasma environment is a response to the need of most efficient bottom-up processes in nanosynthesis and nanotechnology.
通过等离子体为基础的自下而上的工艺，首次实现了对独立的、完美结晶的碳化硅纳米晶体的高尺寸可控合成。这种低成本、可扩展、无配体的常压技术可以制造出超小（小至 1.5nm）纳米晶体，且表面污染程度极低，从而对纳米晶体的光学性质有了更深入的了解。通过将纳米晶体的尺寸缩小到 1-5nm 范围内，其非凡的光致发光发射效率提高了 5 倍以上，这也证实了这一点，这归因于超小纳米晶体中的量子限制。这种方法具有潜在的可扩展性，并且可以很容易地扩展到其他广泛的材料类别。此外，这种无配体的工艺可以通过直接将胶体纳米晶体沉积到液体中、生物材料上或选择的衬底上，形成纳米晶体薄膜。我们基于非平衡等离子体环境的简单但有效的方法是对纳米合成和纳米技术中最有效自下而上工艺的需求的回应。
