ZnO nanowire co-growth on SiO2 and C by carbothermal reduction and vapour advection

Heteroleptic Ruthenium(II) Complexes with 2,2'-Bipyridines Having Carbonitriles as Anchoring Groups for ZnO Surfaces: Syntheses, Physicochemical Properties, and Applications in Organic Solar Cells

Heteroleptic ruthenium (II) complexes were used for sensitizing ZnO surfaces in organic solar cells (OSCs) as mediators with photoactive layers. The complexes [Ru(4,4'-X₂-bpy)(Mebpy-CN)₂]²⁺ (with X = -CH₃, -OCH₃ and -N(CH₃)₂; bpy = 2,2'-bipyridine; Mebpy-CN = 4-methyl-2,2'-bipyridine-4'-carbonitrile) were synthesized and studied by analytical and spectroscopical techniques. Spectroscopic, photophysical, and electrochemical properties were tuned by changing the electron-donating ability of the -X substituents at the 4,4'-positions of the bpy ring and rationalized by quantum mechanical calculations. These complexes were attached through nitrile groups to ZnO as interfacial layer in an OSC device with a PBDB-T:ITIC photoactive layer. This modified inorganic electron transport layer generates enhancement in photoconversion of the solar cells, reaching up to a 23% increase with respect to the unsensitized OSCs. The introduction of these dyes suppresses some degradative reactions of the nonfullerene acceptor due to the photocatalytic activity of zinc oxide, which was maintained stable for about 11 months. Improving OSC efficiencies and stabilities can thus be achieved by a judicious combination of new inorganic and organic materials.

Novel Heteroleptic Ruthenium(II) Complexes with 2,2'- Bipyridines Containing a Series of Electron-Donor and Electron-Acceptor Substituents in 4,4'-Positions: Syntheses, Characterization, and Application as Sensitizers for ZnO Nanowire-Based Solar Cells

A novel series of complexes of the formula [Ru(4,4'-X₂-bpy)₂(Mebpy-CN)](PF₆)₂ (X = -CH₃, -OCH₃, -N(CH₃)₂; Mebpy-CN = 4-methyl-2,2'-bipyridine-4'-carbonitrile) have been synthesized and characterized by spectroscopic, electrochemical, and photophysical techniques. Inclusion of the electron-withdrawing substituent -CN at one bpy ligand and different electron-donor groups -X at the 4,4'-positions of the other two bpy ligands produce a fine tuning of physicochemical properties. Redox potentials, electronic absorption maxima, and emission maxima correlate well with Hammett's σ_p parameters of X. Quantum mechanical calculations are consistent with experimental data. All the complexes can be anchored through the nitrile moiety of Mebpy-CN over ZnO nanowires in dye-sensitized solar cells that exhibit an improvement of light to electrical energy conversion efficiency as the electronic asymmetry increases in the series.

Review on nanomaterials synthesized by vapor transport method: growth and their related applications

Nanostructures with different dimensions, including bulk crystals, thin films, nanowires, nanobelts and nanorods, have received considerable attention due to their novel functionalities and outstanding applications in various areas.

High-efficiency second harmonic generation from a single hybrid ZnO nanowire/Au plasmonic nano-oligomer

We introduce a plasmonic-semiconductor hybrid nanosystem, consisting of a ZnO nanowire coupled to a gold pentamer oligomer by crossing the hot-spot. It is demonstrated that the hybrid system exhibits a second harmonic (SH) conversion efficiency of ∼3 × 10(-5)%, which is among the highest values for a nanoscale object at optical frequencies reported so far. The SH intensity was found to be ∼1700 times larger than that from the same nanowire excited outside the hot-spot. Placing high nonlinear susceptibility materials precisely in plasmonic confined-field regions to enhance SH generation opens new perspectives for highly efficient light frequency up-conversion on the nanoscale.

Growth of large-scale vertically aligned GaN nanowires and their heterostructures with high uniformity on SiO(x) by catalyst-free molecular beam epitaxy

The catalyst-free molecular beam epitaxial growth of GaN nanowires and their heterostructures on a SiOx template is studied in detail. It was found that by optimizing the growth temperature, highly uniform and vertically aligned GaN nanowires and InGaN/GaN heterostructures with excellent optical properties can be obtained on a SiOx template in a large-scale. This work provides an entirely new avenue for GaN nanowire based optoelectronic devices.