Carbon dots have been considered as a solution to the challenges that semiconductor quantum dots have encountered because they are more biocompatible and can be synthesized from abundant and nontoxic materials such as biomass. This review will highlight the advantages of these biomass-based carbon dots in terms of synthesis, properties, and applications in the biomedical field. Furthermore, future applications especially in the biomedical field of biomass-based carbon dots as well as the challenges of semiconductor quantum dots such as biocompatibility, photobleaching, environmental challenges, toxicity, and poor solubility will be discussed in detail. Biomass-derived quantum dots, a subsection of carbon dots that are the most desirable for future research, will be focused upon including from synthesis to applications. Finally, the future development of biomass derived quantum dots in the biomedical field will be discussed and evaluated to unlock the potential for their applications.

Biomass-Based Carbon Dots: Current Development and Future Perspectives.

Preparation of nitrogen-doped carbon quantum dots from chelating agent and used as fluorescent probes for accurate detection of ClO- and Cr(Ⅵ).

The fluorescent carbon quantum dots (CQDs) represent an emerging subset of carbonaceous nanomaterials, recently becoming a powerful tool for biosensing, bioimaging, and drug and gene delivery. In general, carbon dots are defined as zero-dimensional (0D), spherical-like nanoparticles with <10 nm in size. Their unique chemical, optical, and electronic properties make CQDs versatile materials for a wide spectrum of applications, mainly for the sensing and biomedical purposes. Due to their good biocompatibility, water solubility, and relatively facile modification, these novel materials have attracted tremendous interest in recent years, which is especially important for nanotechnology and nanoscience expertise. The preparation of the biomass-derived CQDs has attracted growing interest recently due to their low-cost, renewable, and green biomass resources, presenting also the variability of possible modification for the enhancement of CQDs’ properties. This review is primarily focused on the recent developments in carbon dots and their application in the sensing of different chemical species within the last five years. Furthermore, special emphasis has been made regarding the green approaches for obtaining CQDs and nanomaterial characterization toward better understanding the mechanisms of photoluminescent behavior and sensing performance. In addition, some of the challenges and future outlooks in CQDs research have been briefly outlined.

An Overview of the Recent Developments in Carbon Quantum Dots—Promising Nanomaterials for Metal Ion Detection and (Bio)Molecule Sensing

Waste-to-wealth: Functional biomass carbon dots based on bee pollen waste and application

Extensive burning of fossil fuels to fulfill the intensifying demands of energy has led to raising the concentration of carbon dioxide in atmosphere, which is a major component responsible for global warming. Imitating the natural photosynthesis, photoreduction of CO2 seems to be one of the most promising solutions to this critical problem. Among the different photocatalysts, ZnO had been thoroughly examined for CO2 reduction owing to its low cost and eco-friendliness. Combining ZnO with carbon-based nanomaterials is being progressively investigated to improve the photocatalytic efficiency. This article is organized to explore the latest advancements in ZnO/carbon nanocomposites for photocatalytic CO2 reduction systems. The article begins with the fundamentals of photocatalysis, and the basic mechanism of CO2 reduction over semiconductor materials is also reviewed. Then, it surveys literature and underlines the recent developments of ZnO/carbon-based hybrid nanomaterials, covering activated carbon, graphene-based materials, carbon nanotubes, carbon dots and recently developed morphologies. More specifically, synthesis routes and mechanisms of CO2 reduction enhancement are thoroughly discussed. Finally, a summary along with some new valuable recommendations are also presented. 

Da-Shu Chen

Papers

Hydrothermal synthesis of N-doped carbon quantum dots and their application in ion-detection and cell-imaging