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Abstract An efficient and economic approach for sustainable production of hierarchically interconnected porous carbons are designed and fabricated through the pyrolysis of Rhus typhina fruits and followed by KOH activation to create micropores or mesopores on the nano-sheet wall of macropores. The related N-doped carbon consists of a plenty of micropores and owns high specific surface area (up to 2675 m2 g−1), resulting in high performances for supercapacitors, such as ultrahigh specific capacitance (568 F g−1 at 1 A g−1), remarkable rate capability (310 F g−1 at 20 A g−1, 282 F g−1 at even 30 A g−1 current density) and good long-term stability (capacitance retention of 99% after 10000 cycles at 30 A g−1) in 1 mol L−1 H 2 SO 4. Moreover, the carbon derived from Rhus typhina fruits demonstrates 474 F g−1 at 1 A g−1, 281 F g−1 at 30 A g−1, and capacitance retention of 92% after 10000 cycles at 30 A g−1 in 6 mol L−1 KOH electrolyte. This novel and sustainable biomass-derived carbon material holds a bright future for fabricating high energy supercapacitors. Graphical abstract Image 1 Highlights • RTFs based carbon exhibits ultrahigh capacitance of 568 F g−1 at 1.0 A g−1. • Graphene like sheets built a hierarchical interconnected porous microstructure. • Functional groups induce Faraday reactions, and generate pseudocapacitance. • Biomass wastes provide sustainable and cheap raw materials for supercapacitors. [ABSTRACT FROM AUTHOR]

A series of polymer dots/graphene sheets composites with high densities are prepared and tested for supercapacitors. Polymer dots (PDs) are synthesized by one-step method at room temperature. They can effectively increase surface areas of the composites (almost 10 times), and the functional groups from PDs produce high pseudocapacitance, so that the samples exhibit high specific capacitances (e. g., 364.2 F cm −3 at 1 A g −1 ) and high cycling stability (e. g., more than 95% of the initial capacity retention over 10 000 cycles at different current densities). The optimal sample is employed to fabricate a symmetric supercapacitor, which exhibits an energy density up to 8 Wh L −1 and a power density up to 11 800 W L −1 , respectively. [ABSTRACT FROM AUTHOR]

As a promising luminescent nanomaterial, carbon dots (CDs) have received tremendous attention for their great potential in biomedical applications, owing to their distinctive merits of ease in preparation, superior optical properties, good biocompatibility, and adjustable modification in structure and functionalities. However, most of the reported CDs exhibit insufficient excitation and emission in red/near-infrared (R/NIR) regions, which significantly limits their practical applications in biomedical assays and therapy. In the latest years, extensive studies have been performed to produce CDs with intensified R/NIR excitation and emission by designed reactions and precise separations. This review article summarizes state-of-the-art progress towards design and manufacture of CDs with long-wavelength or multicolor emissions, involving their synthetic routes, precursors, and luminescence mechanisms. Meanwhile, the applicable availability of CDs in bioimaging, sensing, drug delivery/release, and photothermal/photodynamic therapy, is systematically overlooked. The current challenges concerning feasible controls over optical properties of CDs and their new opportunities in biomedical fields are discussed. The synthesis, optical properties, and biomedical applications of carbon dots with red or near-infrared emissions are summarized. Image 1 [ABSTRACT FROM AUTHOR]