Photoelectronic applications for fluorescent carbon dots derived from hydrothermal synthesis

碳纳米材料的使用在用于各种各样的应用的下一代器件中越来越受关注，并且最近在生物传感、生物传感和光生物学领域中特别感兴趣的一个是碳点（CD）。这种粒子可以用各种各样的合成方法产生，并且作为一类具有特殊光电特性的材料，这些特性高度可调并取决于各种环境因素。水热碳化法（HTC）是生产碳量子点的一种合成方法，它具有可持续、简便和可调节的额外优点。该方法使用相对较低的温度和反应时间以获得显着的产率，其中包括废物生物质在内的各种前体适用。反应过程的复杂性不可低估，并且对碳量子点的形成机制知之甚少，特别是因为这些被认为随前体，溶剂和其他参数而变化。由于碳量子点具有显著的多分散性和形态异质性，这种方法在文献中也被忽视，但该方法可能是一种非常有前途的和可扩展的多技术改进。对光电和形成机制的深入理解对于碳量子点的调整和优化至关重要，并建议进行更详细的研究。通过尺寸和形态控制用于光催化和光伏应用的HOMO和LUMO能级的所得控制将允许它们用作这些应用的高量子产率敏化剂。此外，这些允许它们被定制以使具有各种带隙的各种不同衬底敏感化，并允许少数载流子穿过界面注入到这些器件中。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间的主要变化因素，从而提高单位面积的效率。碳量子点还可以作为用于各种衬底中的活性层的场效应钝化的形式应用于太阳能电池，这是由于除了光收集特性之外，碳量子点还具有可调的负电荷，而不是表面遮蔽特性。除了新颖的设置之外，Gratzel电池结构还可以替代有毒金属制成的量子点。总体而言，碳量子点在应用领域还有很大的空间来探索最令人兴奋的可能性。理解形成的基本机制及其独特的光电性质对于这些粒子的简单操纵至关重要。对这些性质的控制以及更基础的研究，如单颗粒荧光和原位水热合成TEM的调查，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中的新应用是理想的，并且可以实现，以开发将高性能与可持续性相结合的下一代这些器件。

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.