Anhydride-Terminated Solid-State Carbon Dots with Bright Orange Emission Induced by Weak Excitonic Electronic Coupling

White Fluorescent Carbon Dots for Specific Fe3+ Detection and Imaging Applications

In recent years, carbon dots (CDs) with fluorescence imaging function have been widely used in biomedicine, electronic manufacturing and environmental monitoring. However, monochromatic fluorescence is often limited by the application environment and loses its effectiveness. Here, we carefully designed white fluorescent CDs (WF-CDs) by solvothermal method, which is used for fluorescence imaging applications under different environmental conditions. WF-CDs based on nitrogen doping can produce obvious emission peaks at 640 nm, 490 nm and 400 nm, respectively, corresponding to red, green and blue (RGB) bands in the three primary colors. The full wavelength emission was realized by changing the solvent types and pH values to adjust the emission peak intensity. WF-CDs can accurately detect Fe3+ concentration according to fluorescence extinction degree (fluorescence elimination rate reaches 95.34 %). Furthermore, WF-CDs has practical applications in cell-level fluorescence imaging, near-infrared fluorescence imaging and ultraviolet anti-counterfeiting, and has broad application prospects in the fields of nano-medicine and industrial manufacturing.

A comprehensive dataset of photonic features on spectral converters for energy harvesting

Building integrated photovoltaics is a promising strategy for solar technology, in which luminescent solar concentrators (LSCs) stand out. Challenges include the development of materials for sunlight harvesting and conversion, which is an iterative optimization process with several steps: synthesis, processing, and structural and optical characterizations before considering the energy generation figures of merit that requires a prototype fabrication. Thus, simulation models provide a valuable, cost-effective, and time-efficient alternative to experimental implementations, enabling researchers to gain valuable insights for informed decisions. We conducted a literature review on LSCs over the past 47 years from the Web of ScienceTM Core Collection, including published research conducted by our research group, to gather the optical features and identify the material classes that contribute to the performance. The dataset can be further expanded systematically offering a valuable resource for decision-making tools for device design without extensive experimental measurements.

Fluorescent Fiber-Shaped Aqueous Zinc-Ion Batteries for Bifunctional Multicolor-Emission/Energy-Storage Textiles

Wearable smart textiles are natural carriers to enable imperceptible and highly permeable sensing and response to environmental conditions via the system integration of multiple functional fibers. However, the existing massive interfaces between different functional fibers significantly increase the complexity and reduce the wearability of the textile system. Thus, it is significant yet challenging to achieve all-in-one multifunctional fibers for realizing miniaturized and lightweight smart textiles with high reliability. Herein, as bifunctional electrolyte additives, fluorescent carbon dots with abundant zincophilic functional groups are introduced into electrolytes to develop fluorescent fiber-shaped aqueous zinc-ion batteries (FFAZIBs). Originating from effective dendrite suppression of Zn anodes and multiple active sites of freestanding Prussian blue cathodes, high energy density (0.17 Wh·cm-3) and long-term cyclability (78.9% capacity retention after 1500 cycles) are achieved for FFAZIBs. More importantly, the one-dimensional structure ensures the same luminance in all directions of FFAZIBs, enabling the form of multicolor display-in-battery textiles.

Synthetic strategies, properties and sensing application of multicolor carbon dots: recent advances and future challenges

Recently, carbon dots (CDs) as newly developed carbon-based nanomaterials due to advantages such as excellent photostability and easy surface functionalization have generated wide application prospects in fields such as biological imaging and chemical sensing. The multicolor emission carbon dots (M-CDs) were acquired through the selection of different carbon source precursors, change of synthesis conditions and synthesis environment. Therefore, the aim of this review is to summarize the latest research progress in polychromatic CDs from the perspectives of synthesis strategies, luminescent mechanisms, luminescent properties and applications. This review focuses on how to prepare MCDs by changing raw materials and synthesis conditions such as reaction temperature, synthesis time, synthesis pH, and synthesis solvent. This review also presents the optical properties of MCDs, concentration effects, solvent effects, pH effects, elemental doping, and surface passivation on them, as well as their creative applications in the field of sensing applications. It is anticipated that this review will serve as a guide for the development of multifunctional M-CDs and inspire future research on controllable design and preparation of M-CDs.

Heating-free synthesis of red emissive carbon dots through separated processes of polymerization and carbonization

Polymerization and carbonization are believed as two basic processes for the bottom-up synthesis of carbon dots (CDs). Since these two processes usually occur simultaneously due to the high reaction temperature and fast reaction rate, it is still a challenge to separate and control these two processes. In the present work, we reported a new room temperature method, which achieved the separated and controlled polymerization and carbonization processes. The polymerization process is realized by dissolving o-phenylenediamine (OPD) in ethanol at room temperature, and finally obtained polymer dots (PDs) without any lattice with a sphere size of 29.6 nm. The carbonization process begins in a manual way by adding concentrated sulfuric acid. After carbonization, CDs (noted as CPDs in this work) with a size of 3.6 nm and a clear lattice can be obtained. Importantly, the separated polymerization and carbonization make us possible to adjust the composition or interactions of intermediate products during the synthesis process. As a prototype, we added acetic acid (AA) additives into OPD precursors during the polymerization stage. Due to the crosslink enhanced emission (CEE) effect via hydrogen bonds which are produced by the amide groups from AA reaction products with H in the -NH₃⁺ or aromatic ring, the resulted CPDs show improved PLQY from an initial 6.87% (without AA) to 16.47%. The current work realized the separated and controllable polymerization and carbonization processes, opening up the door for tuning the composition and interactions of intermediate products before carbonization.

Orange-Emissive Carbon Dots with High Photostability for Mitochondrial Dynamics Tracking in Living Cells

Mitochondria play significant roles in maintaining a stable internal environment for cell metabolism. Hence, real-time monitoring of the dynamics of mitochondria is essential for further understanding mitochondria-related diseases. Fluorescent probes provide powerful tools for visualizing dynamic processes. However, most mitochondria-targeted probes are derived from organic molecules with poor photostability, making long-term dynamic monitoring challenging. Herein, we design a novel mitochondria-targeted probe based on carbon dots with high performance for long-term tracking. Considering that the targeting ability of CDs is related to surface functional groups, which are generally determined by the reaction precursors, we successfully constructed mitochondria-targeted O-CDs with emission at 565 nm through solvothermal treatment of m-diethylaminophenol. The O-CDs are bright with a high quantum yield of 12.61%, high mitochondria-targeting ability, and good stability. The O-CDs possess a high quantum yield (12.61%), specific mitochondria-targeting ability, and outstanding optical stability. Owing to the abundant hydroxyl and ammonium cations on the surface, O-CDs showed obvious accumulation in mitochondria with a high colocalization coefficient of up to 0.90 and remained steady even after fixation. Besides, O-CDs showed outstanding compatibility and photostability under various interruptions or long-time irradiation. Therefore, O-CDs are preferable for the long-term tracking of dynamic mitochondrial behavior in live cells. We first observed the mitochondrial fission and fusion behaviors in HeLa cells, and then, the size, morphology, and distribution of mitochondria in physiological or pathological conditions were clearly recorded. More importantly, we observed different dynamics interactions between mitochondria and lipid droplets during the apoptosis and mitophagy processes. This study provides a potential tool for exploring interactions between mitochondria and other organelles, further promoting the research on mitochondria-related diseases.

Post-synthetic regulation of the fluorescence of CDs: insights into the fluorescence mechanism

Exploring the origin of emission is fundamental in the field of carbon dots (CDs). Due to the lack of suitable in situ probing techniques, it is necessary to explore effective alternative methods that can accurately reflect the relationship between the emission and the composition of the functional groups of CDs. Herein, we propose a new method of post-synthetic treatment of CDs by photo-oxidation to investigate the origin of emission for CDs. After the addition of a photo-oxidant into pre-prepared CDs under UV irradiation, the fluorescence of CDs can be regulated from the original orange emission to the final green emission due to the damage of original functional groups and the formation of new functional groups on CDs during the post-treatment process. The abundant dynamic information about the functional groups and emissions of CDs during the visible and ready-to-monitor post-treatment process makes it possible to quantitatively analyze the origin of the emission of CDs. Our results suggest that the emission sub-peaks at 560 nm and 600 nm relate to the CD surface-state-associated -NH₃⁺ groups, while the emission sub-peak at 537 nm or 494 nm is associated with the CD surface-state-associated -OH groups or the CD surface-state-associated carbonyl groups (CO). Under UV irradiation, the CD surface-state-associated -NH₃⁺ groups can be continuously converted into the CD surface-state-associated -OH groups and the CD surface-state-associated carbonyl groups (CO), leading to the changed emission color of CDs.