The use of solar energy to produce molecular hydrogen and oxygen (H2 and O2) from overall water splitting is a promising means of renewable energy storage. In the past 40 years, various inorganic and organic systems have been developed as photocatalysts for water splitting driven by visible light. These photocatalysts, however, still suffer from low quantum efficiency and/or poor stability. We report the design and fabrication of a metal-free carbon nanodot-carbon nitride (C3N4) nanocomposite and demonstrate its impressive performance for photocatalytic solar water splitting. We measured quantum efficiencies of 16% for wavelength λ = 420 ± 20 nanometers, 6.29% for λ = 580 ± 15 nanometers, and 4.42% for λ = 600 ± 10 nanometers, and determined an overall solar energy conversion efficiency of 2.0%. The catalyst comprises low-cost, Earth-abundant, environmentally friendly materials and shows excellent stability.

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Self-healing is the way by which nature repairs damage and prolongs the life of bio entities. A variety of practical applications require self-healing materials in general and self-healing polymers in particular. Different (complex) methods provide the rebonding of broken bonds, suppressing crack, or local damage propagation. Here, a simple, versatile, and cost-effective methodology is reported for initiating healing in bulk polymers and self-healing and anticorrosion properties in polymer coatings: introduction of carbon dots (CDs), 5 nm sized carbon nanocrystallites, into the polymer matrix forming a composite. The CDs are blended into polymethacrylate, polyurethane, and other common polymers. The healing/self-healing process is initiated by interfacial bonding (covalent, hydrogen, and van der Waals bonding) between the CDs and the polymer matrix and can be optimized by modifying the functional groups which terminate the CDs. The healing properties of the bulk polymer-CD composites are evaluated by comparing the tensile strength of pristine (bulk and coatings) composites to those of fractured composites that are healed and by following the self-healing of scratches intentionally introduced to polymer-CD composite coatings. The composite coatings not only possess self-healing properties but also have superior anticorrosion properties compared to those of the pure polymer coatings.

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In-doped ZnO nanowires were successfully fabricated by thermal evaporation of a powder mixture of Zn, In2O3, and graphite. Field emission of individual In-doped and pure ZnO nanowire was observed in situ by a transmission electron microscopy. The results show that In-doped ZnO nanowires showed an enhanced field emission properties. First-principle density functional calculations were performed to calculate the electronic structure of the In-doped and pure ZnO in order to explain the observed field emission properties. A two-band field emission mechanics was proposed to explain the enhanced field emission from n-type doping.

Heteroatom (N, P, and B)-codoped nanocarbons (NPBC) with nanoporous morphology are fabricated via a facile one-step pyrolysis method and exhibit good electrocatalytic activity, durability, and selectivity for the oxygen reduction reaction (ORR) in alkaline media. The ORR activity of NPBC is better than single- (nitrogen-doped carbon (NC)) or dual-doped (nitrogen and phosphorus codoped carbon (NPC) or nitrogen and boron codoped carbon (NBC)) catalysts in terms of onset potential and current density. This synthetic approach is efficient and suitable for large-scale fabrication of metal-free carbon-based catalysts.

advantages of simple device structure, light weight, and low fabrication cost by solution-processing. [1][2][3][4][5][6][7][8][9][10][11] Despite the great achievement in fullerene PSCs, fullerene acceptors still suffer from several drawbacks, including high-cost purification, poor morphological stability, and weak absorption in visible wavelength range. To solve these problems, considerable research efforts have been dedicated to nonfullerene acceptors, especially smallmolecular acceptors (SMAs). [12][13][14][15][16][17][18][19][20] Recently, emerging SMAs have been demonstrated as alternatives to fullerene acceptors because the excellent photovoltaic performance with power conversion efficiency (PCE) has reached 12-14% recently. [18][19][20][21] To achieve more efficient SMA PSCs, it is essential to design donor polymers that can match with SMAs through favorable morphology as the device performance of PSCs is strongly dependent on the blend morphology. Therefore, morphology controlling has become one of research key points and still faces a great challenge. Some practical physical strategies have been developed such as ternary blend, additives, thermal annealing, etc., to finely tune blend morphology and form miscible donor/acceptor mixture. [22,23] In the meantime, exploitation of chemical tools as an alternative strategy to control blend morphology is showing its advantages in finely molecular-scaled controlling. [24] One of the most commonly used chemical strategies for tuning morphology is through the fluorination or alkylthiolation of the polymeric side chains to tune the solubility, aggregation properties, and thus the good miscibility with acceptors. [25] In comparison with the high cost and complex synthetic route of fluorinated modification on polymer side chains, low cost of alkylthiolation is obviously synthetic superior to the former. However, in recent literatures it is found that, on the one hand, the alkylthiolation of polymer side chains can improve polymeric crystallinity and mobility and lead to a high photovoltaic performance; [26,27] on the other hand, the strengthened crystallinity after the alkylthiolation for high crystalline polymer may form dense and isolated polymer domains, which causes serious phase separation and destroys the miscibility at donor/acceptor interfaces. [24,28,29] As the thermodynamic miscibility between donor and acceptor mainly drives the phase separation degree, therefore, Morphology and miscibility control are still a great challenge in polymer solar cells. Despite physical tools being applied, chemical strategies are still limited and complex. To finely tune blend miscibility to obtain optimized morphology, chemical steric engineering is proposed to systemically investigate its effects on optical and electronic properties, especially on a balance between crystallinity and miscibility. By changing the alkylthiol side chain orientation different steric effects are realized in three different polymers. Surprisingly, the photovoltaic device of the polymer PTBB-m with...