This Letter describes the synthesis and photophysical characterization of a Ru(II) assembly consisting of metal polypyridyl complexes linked together by a polyfluorene scaffold. Unlike many scaffolds incorporating saturated linkages, the conjugated polymer in this system acts as a functional light-harvesting component. Conformational disorder breaks the conjugation in the polymer backbone, resulting in a chain composed of many chromophore units, whose relative energies depend on the segment lengths. Photoexcitation of the polyfluorene by a femtosecond laser pulse results in the excitation of polyfluorene, which then undergoes direct energy transfer to the pendant Ru(II) complexes, producing Ru(II)* excited states within 500 fs after photoexcitation. Femtosecond transient absorption data show the presence of electron transfer from PF* to Ru(II) to form charge-separated (CS) products within 1-2 ps. The decay of the oxidized and reduced products, PF(+•) and Ru(I), through back electron transfer are followed using picosecond transient absorption methods.
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January 2025
School of Materials and Physics & Center of Mineral Resource Waste Recycling, China University of Mining and Technology, Xuzhou, Jiangsu, 221116, China.
Designing spent graphite anodes from lithium-ion batteries (LIBs) for applications beyond regenerated batteries offers significant potential for promoting the recycling of spent LIBs. The battery-grade graphite, characterized by a highly graphitized structure, demonstrates excellent conductive loss capabilities, making it suitable for microwave absorption. During the Li-ion intercalation and deintercalation processes in battery operation, the surface layer of spent graphite (SG) becomes activated, forming oxygen-rich functional groups that enhance the polarization loss mechanism.
View Article and Find Full Text PDFAcc Chem Res
January 2025
Department of Chemistry, University of California, Berkeley, California 94720, United States.
ConspectusThe electronic properties of atomically thin van der Waals (vdW) materials can be precisely manipulated by vertically stacking them with a controlled offset (for example, a rotational offset─i.e., twist─between the layers, or a small difference in lattice constant) to generate moiré superlattices.
View Article and Find Full Text PDFSmall
January 2025
School of Materials and Chemical Engineering, Xuzhou University of Technology, Xuzhou, 221018, P. R. China.
Constructing a built-in electric field (BIEF) within heterostructures has emerged as a compelling strategy for advancing electrocatalytic oxygen evolution reaction (OER) performance. Herein, the p-n type nanosheet array heterojunction NiP-NCDs-Co(OH)-NF are successfully prepared. The variation in interaction affinity between nitrogen within N-doped carbon dots (NCDs) and Ni/Co induces charge redistribution between Co and Ni in the NiP-NCDs-Co(OH)-NF-3 heterostructure, thereby enhancing the intensity of the BIEF, facilitating electron transfer, and markedly improving OER activity.
View Article and Find Full Text PDFDalton Trans
January 2025
School of Materials Science and Engineering, China University of Petroleum, Qingdao, 266580, PR China.
Non-precious transition metal-based electrocatalysts with high activities are promising candidates for substituting Pt- or Ru-based electrocatalysts in hydrogen evolution. In this study, we propose core-shell engineering to combine the amorphous NiCoP and crystalline CoP (a-NiCoP/CoP@NF), which requires an ultra-low overpotential of only 26 mV to achieve the benchmark current density of 10 mA cm. Furthermore, it achieves an industrial-level hydrogen evolution current density of 500 mA cm with excellent stability.
View Article and Find Full Text PDFJ Org Chem
January 2025
Department of Materials Science and Engineering, Institute of Science Tokyo, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552, Japan.
A series of 1,1,4,4-tetracyanobuta-1,3-diene (TCBD) derivatives with various heterocyclic moieties, including pyridine, carbazole, indole, and benzothiadiazole, was newly synthesized through a [2 + 2] cycloaddition-retroelectrocyclization reaction. Symmetric electron-rich 1,3-butadiynes with end-capped heterocyclic substituents were reacted with tetracyanoethylene (TCNE), yielding the target TCBD products in 60-80% yields under ambient or mild heating conditions. The thermal stability and optical and electrochemical properties of both 1,3-butadiyne precursors and the corresponding TCBD derivatives were investigated by using thermogravimetric analysis (TGA), UV-vis spectroscopy, and cyclic voltammetry (CV).
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