Search

Developinghigh surface area nanostructured electrodes with rapidcharge transport is essential for artificial photosynthesis, solarcells, photocatalysis, and energy storage devices. Substantial researchefforts have been recently focused on building one-dimensional (1D)nanoblocks with fast charge transport into three-dimensional (3D)hierarchical architectures. However, except for the enlargement insurface area, there is little experimental evidence of fast electrontransport in these 3D nanostructure-based solar cells. In this communication,we report single-crystal-like 3D TiO2branched nanowirearrays consisting of 1D branch epitaxially grown from the primarytrunk. These 3D branched nanoarrays not only demonstrate 71% enlargementin large surface area (compared with 1D nanowire arrays) but alsoexhibit fast charge transport property (comparable to that in 1D singlecrystal nanoarrays), leading to 52% improvement in solar conversionefficiency. The orientated 3D assembly strategy reported here canbe extended to assemble other metal oxides with one or multiple componentsand thus represents a critical avenue toward high-performance optoelectronics. [ABSTRACT FROM AUTHOR]

In this work, well-soluble tris(pentafluorophenyl)borane (BCF) is introduced for the first time into 2,2',7,7'-tetrakis(N,N'-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD) as a p-dopant. The conductivity of spiro-OMeTAD films is dramatically enhanced. When the BCF-doped spiro-OMeTAD film is used as a hole-transport layer (HTL) in perovskite solar cells (PSCs), nearly double increase in power conversion efficiency (PCE) is obtained compared to that of the PSCs based on a pristine spiro-OMeTAD HTL. By the introduction of lithium bis(trifluoromethanesulfonyl)imide and 4-tert-butylpyridine into the BCF-doped spiro-OMeTAD film, the conductivity of spiro-OMeTAD film can be further enhanced, and an optimum PCE of 14.65% is obtained. In addition, the average efficiency of the device and the reproducibility of BCF-based PSCs are better than those of FK209-based PSCs. The working mechanism of the BCF doping effect on spiro-OMeTAD is studied in detail. The strong electron-accepting ability, excellent solubility in common organic solvents, and the low cost make BCF a very attractive p-type dopant for spiro-OMeTAD.

Crystallographic orientation and microstructure of metal oxide nanomaterials have great impact on their properties and applications. Here, we report [101̅0] oriented ZnO nanowire (NW) arrays with a multichannel mesostructure. The NW has a preferential growth of low energy (101̅0) crystal plane and exhibits 2-3 orders of magnitude faster electron transport rate than that in nanoparticle (NP) films. Furthermore, the surface area of the as-prepared NW arrays is about 5 times larger than that of conventional NW arrays with similar thickness. These lead to the highest power conversion efficiency of ZnO NW array-based sensitized solar cells. We anticipate that the unique crystallographic orientation and mesostructure will endow ZnO NW arrays new properties and expand their application fields.

Bi(2)WO(6)/ZnWO(4) composite photocatalysts have been successfully synthesized by a facile hydrothermal process. The catalysts were characterized by powder X-ray diffraction (XRD), transmission electron microcopy (TEM), and UV-vis diffuse reflectance spectrum (DRS). The results show that Bi(2)WO(6) nanoparticles grow on the primary ZnWO(4) nanorods. The Bi(2)WO(6)/ZnWO(4) composites have better UV light photocatalytic activities compared to single ZnWO(4) nanorods. Furthermore, the photoinduced charge transfer properties of Bi(2)WO(6)/ZnWO(4) composites were investigated by means of transient photovoltage (TPV) technique in detail. The interconnected interface of Bi(2)WO(6)/ZnWO(4) composites led to the low recombination ratios of photoinduced electron-hole pairs and enhanced photocatalytic activities.