Advances in Shell and Core Engineering of Carbonized Polymer Dots for Enhanced Applications

Abstract

ConspectusCarbon dots (CDs), as a novel type of fluorescent nanocarbon material, attract widespread attention in nanomedicine, optoelectronic devices, and energy conversion/storage due to their excellent optical properties, low toxicity, and high stability. They can be classified as graphene quantum dots, carbon quantum dots, and carbonized polymer dots (CPDs). Among these, CPDs exhibit tunable structures and components that allow fine-tuning of their optoelectronic properties, making them one of the most popular types of CDs in recent years. However, the structural complexity of CPDs stimulates deep exploration of the relationship between their unique structure and luminescent performance. As an organic-inorganic hybrid system, the diversity of self-limited quantum state carbon cores and polymer-hybrid shell layers makes understanding the underlying mechanisms and structure-property relationships in CPDs a very challenging task. In this context, elucidating the structural composition of CPDs and the factors that affect their optical properties is vital if the enormous potential of CPDs is to be realized. Achieving controllable structures with predefined optical properties via the adoption of specific functionalization strategies is the prized goal of current researchers in the field.In this Account, we describe the efforts made by our group in the synthesis, mechanism analysis, structural regulation, and functional applications of CPDs, with particular emphasis on the design of CPDs core-shell structures with tailored optoelectronic properties for applications in the fields of optoelectronics and energy. Specifically, through the rational selection of precursors, optimization of reaction conditions, and postmodification strategies for CPDs, we have demonstrated that it is possible to regulate both the carbon core and polymer shell layers, thereby achieving full-spectrum emission, high quantum yield, persistent luminescence, thermally activated delayed fluorescence, and laser action in CPDs. Furthermore, we have established structure-performance relationship in CPDs and proposed a universal strategy for synergistic interactions between hybrid carbon-based cores and surface micronanostructures. In addition, we unveiled a novel luminescence mechanism in cross-linked CPDs, specifically "cross-linking synergistically inducing quantum-state luminescence", which addresses the challenge of efficient circularly polarized luminescence in the liquid and solid phases of CPDs. Subsequently, strong cross-linking, dual-rigidity, and ordering preparation methods were introduced, thereby pioneering tunable laser emission from blue to near-infrared wavelengths. Additionally, we developed a new strategy of "confined composite nanocrystals of CPDs", leading to various high-performance hydrogen evolution catalysts for water electrolysis. The CPDs developed by this strategy not only possessed excellent optical properties but also enabled high efficiencies in field of energy conversion, thus maximizing the utilization of CPDs. Finally, we discuss important new trends in CPD research and development. Overall, this Account summarizes the latest advancements in CPDs in recent years, providing case-studies that enable deep understanding of structure-property-performance relationships and regulation strategies in CPDs, guiding the future expansion and application of CPDs.