Inorganic nanowires with ultrathin diameters below the magic size (i.e., less than 2 nm) and even one unit cell size, have attracted much research attention in the past few years owing to their unique chemical and physical properties. [1][2][3][4][5][6][7][8][9] As an important semiconductor material, tungsten oxide (WO 3Àx ) nanowires and nanorods have attracted considerable attention because of their wide applications in gas sensors, electrochromic windows, optical devices, and photocatalysts. [10][11][12][13] In particular, monoclinic W 18 O 49 is of great interest owing to its unusual defect structure and promising properties in the nanometer regime. [14,15] Early on, Park and co-workers reported the synthesis of W 18 O 49 nanorods with a diameter of 4 nm by decomposing [W(CO) 6 ] in Me 3 NO 2 ·2 H 2 O and oleylamine.[16] Subsequently, Niederberger and co-workers synthesized hybrid W 18 O 49 / organic nanowires with a very thin diameter of 1.3 nm by a bioligand-assisted method.[17] Recently, Tremel and coworkers prepared W 18 O 49 nanorods with a diameter of 2 nm by decomposing tungsten ethoxide in a mixture of oleic acid and trioctyl amine.[18] Although good control over nanocrystal dimensions can be realized in these methods, removal of the surfactants or organic residues from the nanowire surface requires multiple washing steps. For fundamental investigations on the ultrathin oxide nanowire itself, as well as for technological applications (such as sensing and catalysis), the presence of residues on the nanowire surface from the synthesis may be a significant drawback.Herein, we report the preparation of ultrathin W 18 O 49 nanowires that are efficient in the photochemical reduction of carbon dioxide by visible light. The ultrathin W 18 O 49 nanowires were prepared by a very simple one-pot solution-phase method (see the experimental section in the Supporting Information). In a typical procedure, WCl 6 was dissolved in ethanol, and the clear yellow solution was transferred to a teflon-lined stainless-steel autoclave and heated at 180 8C for 24 h. A blue flocculent precipitate was collected, washed, dried in air, and obtained in a yield of approximately 100 %. The product is insoluble in water and in acid (HCl, pH 0), and has a high specific surface area.W 18 O 49 is a monoclinic structure type (P2 m) with lattice parameters of a = 18.318, b = 3.782, and c = 14.028 . Monoclinic W 18 O 49 has a distorted ReO 3 structure in which cornersharing distorted and tilt WO 6 octahedra are connected in the a-, b-, and c-direction, thereby forming a three-dimensional structure (inset in Figure 1 a). The X-ray diffraction (XRD) pattern of our sample demonstrates that the sample consists of monoclinic-phase W 18 O 49 (Figure 1 a). The narrow (010) and (020) peaks strongly suggest that the possible crystal growth direction of the sample is [010], since the close-packed planes of the monoclinic W 18 O 49 crystal are {010}, which will be further demonstrated by the direct observation of the highresolution transmission electr...

Metal/semiconductor hybrid materials of various sizes and morphologies have many applications in areas such as catalysis and sensing. Various organic agents are necessary to stabilize metal nanoparticles during synthesis, which leads to a layer of organic compounds present at the interfaces between the metal particles and the semiconductor supports. Generally, high-temperature oxidative treatment is used to remove the organics, which can extensively change the size and morphology of the particles, in turn altering their activity. Here we report a facile method for direct growth of noble-metal particles on WO(3) through an in situ redox reaction between weakly reductive WO(2.72) and oxidative metal salts in aqueous solution. This synthetic strategy has the advantages that it takes place in one step and requires no foreign reducing agents, stabilizing agents, or pretreatment of the precursors, making it a practical method for the controlled synthesis of metal/semiconductor hybrid nanomaterials. This synthetic method may open up a new way to develop metal-nanoparticle-loaded semiconductor composites.

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We report two new poly-small-molecule acceptors, PYN-BDT and PYN-BDTF, which serve, by virtue of their π-extended naphthalene rings, as broad optical cross-section macromolecular absorbers (extending to ∼900 nm; ΔE opticalgap = 1.38 eV) in all-polymer solar cells (APSCs). APSCs fabricated by blending PYN-BDT or PYN-BDTF with PM6 exhibit power conversion efficiencies (PCEs) of 7.24 and 9.08%, respectively, while blends with PBDB-T exhibits far higher PCEs of 12.06 and 13.22%, respectively; the latter cell achieves J sc = 22.28 mA cm–2, among the highest known for an APSC. The results of blend morphology, GIWAXS, charge transport, exciton and carrier dynamics, PL quenching efficiency, and impedance-based analysis indicate that the PBDB-TT:PYN-BDTF blends and their APSCs outperform the corresponding PM6:PYN-BDTF devices due to significantly suppressed bimolecular recombination. These results demonstrate that π-conjugative extension of individual polymer acceptor blocks represents an efficient strategy to broaden APSC optical cross sections, decrease bimolecular recombination, and achieve high-performance cells with enhanced J sc metrics.