New Options for transparent contact electrodes

Scanning Electron Microscopy of Nanowires  of Silver. <br />They have diameters around 0,1 micrometer  and lenghts <br /> between 5  and 10 micrometern.

Scanning Electron Microscopy of Nanowires of Silver.
They have diameters around 0,1 micrometer and lenghts
between 5 and 10 micrometern. © ACS Nano 3: 1767-1774

Found in flat screens, solar modules, or in new organic light-emitting diode (LED) displays, transparent electrodes have become ubiquitous. Typically, they consist of metal oxides like In2O3, SnO2, ZnO and TiO2 .

But since raw materials like indium are becoming more and more costly, researchers have begun to look elsewhere for alternatives. A new review article by HZB scientist Dr. Klaus Ellmer, published in the renowned scientific journal Nature Photonics, is hoping to shed light on the different advantages and disadvantages of established and new materials for use in these kinds of contact electrodes.

Metallic (Ag or Cu) or carbon based nanostructures exhibit many interesting properties that could potentially be exploited pending further research.Even graphene, a modified form of carbon, could turn out to be a suitable transparent electrode, since it is both transparent and highly conductive. These properties depend, to a large extent, on the material's composition:graphene, which consists of a single layer of carbon atoms arranged into a hexagonal "honeycomb" grid, is two-dimensional, and, within these dimensions, electrons can freely move about.

According to Ellmer, "these new kinds of materials could be combined with more conventional solutions or find their way into entirely new areas of application." For this to become a reality, researchers have yet to come up with solutions to nanostructure problems like short circuits and continue to illuminate the relevant transport mechanisms. It would also be interesting to determine whether these two-dimensional "electron gases" also form in materials other than graphene. Success ultimately depends on whether or not the new materials prove stable in the long run in their practical application and whether or not they can be produced relatively inexpensively.

Ellmer is sole author of an extensive review article published in Nature photonics online on 30. November 2012, doi: 10.1038/nphoton.2012.282


You might also be interested in

  • Best Innovator Award 2023 for Artem Musiienko
    News
    22.03.2024
    Best Innovator Award 2023 for Artem Musiienko
    Dr. Artem Musiienko has been awarded a special prize for his groundbreaking new method for characterising semiconductors. At the recent annual conference of the Marie Curie Alumni Association (MCAA) in Milan, Italy, he received the MCAA Award for the best innovation. Since 2023, Musiienko has been carrying out his research project with a postdoctoral fellowship from the Marie Sklodowska Curie Actions in Antonio Abate's department, Novel Materials and Interfaces for Photovoltaic Solar Cells (SE-AMIP).
  • The future of BESSY
    News
    07.03.2024
    The future of BESSY
    At the end of February 2024, a team at HZB published an article in Synchrotron Radiation News (SRN). They describe the next development goals for the light source as well as the BESSY II+ upgrade programme and the successor source BESSY III.

  • Sodium-ion batteries: How doping works
    Science Highlight
    20.02.2024
    Sodium-ion batteries: How doping works
    Sodium-ion batteries still have a number of weaknesses that could be remedied by optimising the battery materials. One possibility is to dope the cathode material with foreign elements. A team from HZB and Humboldt-Universität zu Berlin has now investigated the effects of doping with Scandium and Magnesium. The scientists collected data at the X-ray sources BESSY II, PETRA III, and SOLARIS to get a complete picture and uncovered two competing mechanisms that determine the stability of the cathodes.