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Nanotechnology for energy materials: Electrodes like leaf veins

Date:
October 4, 2016
Source:
Helmholtz-Zentrum Berlin für Materialien und Energie
Summary:
Scientists have recently demonstrated for these applications that networks of metallic mesh possessing fractal-like nano-features surpass other metallic networks in utility.
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SEM -- model of a metallic nano-network with periodic arrangement ( left) and visual representation of a fractal pattern (right).
Credit: HZB/M. Giersig

An international team headed by HZB scientist Prof. Michael Giersig has recently demonstrated for these applications that networks of metallic mesh possessing fractal-like nano-features surpass other metallic networks in utility. These findings have now been published in the most recent edition of the journal Nature Communications.

Their new development is based on what is termed quasi-fractal nano-features. These structures have similarities to the hierarchical networks of veins in leaves. Giersig's team was able to show that metallic networks with these features optimise performance of electrodes for several applications. They combine minimized surface coverage with ultra-low total resistance while maintaining uniform current density. In addition, it was demonstrated that these networks, inspired by nature, can surpass the performance of conventional indium tin oxide (ITO) layers.

In experiments on artificially constructed electrode networks of different topologies, the scientists established that non-periodic hierarchical organisation exhibited lower resistance as well as excellent optical transmittance in comparison to periodic organisation. This led to elevated output power for photovoltaic components.

"On the basis of our studies, we were able to develop an economical transparent metal electrode," says Giersig, continuing "We obtain this by integrating two silver networks. One silver network is applied with a broad mesh spacing between the micron-diameter main conductors that serve as the "highway" for electrons transporting electrical current over macroscopic distances." Next to it, additional randomly distributed nano-wire networks serve as local conductors to cover the surface between the large mesh elements. "These smaller networks act as regional roadways beside the highways to randomise the directions and strengths of the local currents, and also create refraction effects to improve transparency above that of classical shadow-limited performance," according to Giersig. "Solar cells based upon these electrodes show exceptional a high efficiencies."


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Materials provided by Helmholtz-Zentrum Berlin für Materialien und Energie. Note: Content may be edited for style and length.


Journal Reference:

  1. Bing Han, Qiang Peng, Ruopeng Li, Qikun Rong, Yang Ding, Eser Metin Akinoglu, Xueyuan Wu, Xin Wang, Xubing Lu, Qianming Wang, Guofu Zhou, Jun-Ming Liu, Zhifeng Ren, Michael Giersig, Andrzej Herczynski, Krzysztof Kempa, Jinwei Gao. Optimization of hierarchical structure and nanoscale-enabled plasmonic refraction for window electrodes in photovoltaics. Nature Communications, 2016; 7: 12825 DOI: 10.1038/ncomms12825

Cite This Page:

Helmholtz-Zentrum Berlin für Materialien und Energie. "Nanotechnology for energy materials: Electrodes like leaf veins." ScienceDaily. ScienceDaily, 4 October 2016. <www.sciencedaily.com/releases/2016/10/161004104748.htm>.
Helmholtz-Zentrum Berlin für Materialien und Energie. (2016, October 4). Nanotechnology for energy materials: Electrodes like leaf veins. ScienceDaily. Retrieved May 28, 2017 from www.sciencedaily.com/releases/2016/10/161004104748.htm
Helmholtz-Zentrum Berlin für Materialien und Energie. "Nanotechnology for energy materials: Electrodes like leaf veins." ScienceDaily. www.sciencedaily.com/releases/2016/10/161004104748.htm (accessed May 28, 2017).

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