Photoelectronic applications for fluorescent carbon dots derived from hydrothermal synthesis

碳纳米材料在新一代器件中的广泛应用引起了人们越来越大的兴趣，最近在生物传感、光催化和光伏领域中特别感兴趣的是碳点(CD)。这种粒子可以用各种合成方法来产生，作为一类材料，它具有特殊的光电特性，这些特性是高度可调的，并依赖于各种环境因素。这为它们的优化和新的应用提供了很大的空间。水热碳化(HTC)是一种产生碳点的合成方法，它还具有可持续、方便和可调整的优点。该方法使用相对较低的温度和反应时间来获得较高的产率，适用的前体种类繁多，包括废生物质。不能低估反应过程的复杂性，对碳点的形成机理知之甚少，特别是因为它们被认为随着前体、溶剂和其他参数的不同而变化。由于颗粒的多分散性和形态异质性，这种方法在文献中也被忽略了，但该方法可能是对多种技术的非常有前景和可扩展的改进。彻底了解光电子学和形成机理对于调整和优化碳点的不同应用至关重要，建议进行更详细的研究。通过尺寸和形态控制来控制光催化和光伏应用中的HOMO和LUMO水平，将使它们能够被用作这些应用的高量子产率敏化剂。此外，这些器件还可以量身定做，以敏化具有各种带隙的各种不同基板，并允许少数载流子通过界面注入到这些器件。这包括设计和优化串联异质结电池的潜在能力，其中碳点的大小是层与层之间的主要变化因素，从而提高单位面积的效率。碳点还可以应用于太阳能电池，作为各种衬底中有源层的一种场效应钝化形式，因为它们具有可调的负电荷，此外还具有光收集而不是表面遮蔽的特性。使用有毒金属制成的量子点的替代品是Gratzel电池结构中的另一种可能性，除了新的设置。总体而言，在碳点的应用领域有很大的空间来探索最令人兴奋的可能性。了解这些粒子的基本形成机制及其独特的光电性质对于方便地操纵这些粒子是至关重要的。对这些性质控制的研究以及更多的基础性研究，如单粒子荧光和原位水热合成电子显微镜，将有助于阐明这一点。此外，包括光催化剂和光伏电池在内的光电子学领域的新应用是可取的，也是可以实现的，以开发结合高性能和可持续发展的下一代这些器件。

The use of carbon nanomaterials is of growing interest in next generation devices for a wide variety of applications, and one of particular recent interest in the ields of biosensing, photocatalysis and photovoltaics is the carbon dot (CD). This particle can be created in a wide variety of synthesis methods and as a class of material possess exceptional optoelectronic properties that are highly tunable and dependent on a variety of environmental factors. This gives them a large scope for optimisation and novel applications.One such synthesis method that produces carbon dots is hydrothermal carbonisation (HTC), which has the added beneits of being sustainable, facile and adjustable. The method uses relatively low temperatures and reaction times for significant yields, with a wide variety of precursors applicable including waste biomass. The complexity of the reaction processes is not to be underestimated and the formation mechanism of carbon dots is poorly understood, especially as these are thought to vary with the precursor, solvent and other parameters. Due to the significant polydispersity and morphological heterogeneity of the particle this method has also been neglected in the literature, but the process could be a very promising and scalable improvement to multiple technologies.A thorough understanding of the optoelectronic and formation mechanisms is crucial to the tuning and optimisation of carbon dots towards diferent applications and is proposed to be studied in more detail. The resulting control of the HOMO and LUMO levels for photocatalytic and photovoltaic applications through size and morphology control will allow them to be used as high quantum yield sensitisers for these applications. Further, these allow them to be tailormade to sensitise a variety of different substrates with a variety of band gaps and allow minority carrier injection across the interface into these devices. This includes the potential ability to design and optimise tandem heterojunction cellswhere the size of the carbon dot is the major varying factor between layers, increasing efficiency per unit area. Carbon dots can also be applied to solar cells as a form of ield efect passivation for active layers in a variety of substrates due to their tunable negative charge in addition to light collection, rather than surface shadowing, properties. Uses as replacements for quantum dots made from toxic metals is another possibility in Gratzel cell structures, in addition to novel setups.Overall, there is significant room to explore the most exciting possibilities in the applications sphere for carbon dots. Understanding the fundamental mechanism of formation and of their unique optoelectronic properties is essential to thefacile manipulation of these particles. Investigations into the control of these properties as well as more fundamental studies, such as single particle fluorescence and in-situ hydrothermal synthesis TEM, will help to elucidate this. Additionally, novel applications in optoelectronics including photocatalysts and photovoltaic cells are desirable and achievable to develop the next generation of these devices that combine high performance with sustainability.