Solution-Grown Zinc Oxide Nanowires

Abstract

We review two strategies for growing ZnO nanowires from zinc salts in aqueous and organic solvents. Wire arrays with diameters in the nanoscale regime can be grown in an aqueous solution of zinc nitrate and hexamethylenetetramine. With the addition of poly(ethylenimine), the lengths of the wires have been increased to 25 mum with aspect ratios over 125. Additionally, these arrays were made vertical by nucleating the wires from oriented ZnO nanocrystals. ZnO nanowire bundles have been produced by decomposing zinc acetate in trioctylamine. By the addition of a metal salt to the solution, the ZnO wires can be doped with a range of transition metals. Specifically, ZnO nanowires were homogeneously doped with cobalt and showed a marked deviation from paramagnetic behavior. We conclude by highlighting the use of these solution-grown nanowire arrays in dye-sensitized solar cells. The nanowire cells showed an improvement in the charge collection efficiency over traditional nanoparticle cells.

Electron Transport in Dye-Sensitized Solar Cells Based on ZnO Nanotubes: Evidence for Highly Efficient Charge Collection and Exceptionally Rapid Dynamics

“…[7][8][9] It is not surprising then, that several novel photoanode architectures with the prospect of rapid charge collection have recently been explored. 4,[10][11][12][13] Access to these architectures has been facilitated by several attractive fabrication strategies, among them (a) surfactant-controlled crystallization, 10,14 (b) controlled film corrosion, 15 and (c) templated atomic-layer deposition (ALD). 11,[16][17][18][19][20][21][22][23][24] Pseudo 1-D nanostructures, particularly with single or polycrystalline domains, are especially interesting since electrons traveling through the nanoparticle semiconductors are believed to move under diffusive control.…”

Nanorod solar cell with an ultrathin a-Si:H absorber layer

“…Zinc oxide ͑ZnO͒ nanorod arrays were used as the backbones because they can be easily prepared on various cheap substrates such as glass or even flexible plastic by solution-deposition at a temperature below 100°C. [25][26][27][28][29] Furthermore, for the solution-deposition of ZnO nanorods, there is no substrate size limitation and no need for expensive and sophisticated lithographic techniques. We employ hydrogenated amorphous silicon ͑a-Si:H͒ as the absorber material rather than CdSe/CdTe, 3,7 In 2 S 3 , 9,10 CuInS 2 , 11,12 InP, and GaP, 24 since silicon is a nontoxic thin film photovoltaic material that is abundantly available.…”

TEMPLATE ASSISTED ELECTRODEPOSITION OF HIGHLY ORIENTED ZnO NANOWIRE ARRAYS AND THEIR INTEGRATION IN DYE SENSITIZED SOLAR CELLS

“…These nanostructures provide new strategies for designing next generation energy conversion devices [9][10][11][12][13] . Efforts to synthesize nanostructures with well-defined geometrical shapes have further expanded the possibility of developing new strategies for light energy conversion [14][15][16][17][18][19][20][21][22][23][24] .…”