New Options for transparent contact electrodes
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
- AI agents deliver results – but do they reason scientifically?A research team co-led by Kevin Maik Jablonka from the Helmholtz Institute for Polymers in Energy Applications Jena (HIPOLE Jena) and N. M. Anoop Krishnan from the Indian Institute of Technology Delhi has developed Corral, a new benchmark for AI agents in science. The preprint “AI scientists produce results without reasoning scientifically” has been published on arXiv (https://doi.org/10.48550/arXiv.2604.18805). The analysis shows that current systems can execute scientific workflows and deliver results; however, they often do not follow the basic principles of scientific testing and reasoning.
- Materials chemistry shapes the future of catalysisThe synthesis of materials can serve as a tool for developing smart, adaptive electrocatalysts. This rapidly evolving field of research involves in-situ analytics, data-driven discoveries and autonomous robotics. These new approaches could accelerate the discovery of long-lasting and efficient catalysts for future energy conversion and the decarbonisation of the chemical industry. A recent article by Dr Prashanth Menezes and his team in the renowned journal Angewandte Chemie provides an overview of this research.
- BESSY II: How intrinsic oxygen shortens the lifespan of solid-state batteriesAlthough solid-state batteries (SSBs) demonstrate high performance and are intrinsically safe, their capacity currently declines rapidly. A team from the TU Wien, Humboldt-University Berlin and HZB has now analysed a TiS₂|Li₃YCl₆ solid-state half-cell in operando at BESSY II using a special sample environment that allows for non-destructive investigation under real operating conditions. Data obtained by combination of soft and hard X-ray photoelectron spectroscopy (XPS and HAXPES) revealed a new degradation mechanism that had not previously been identified in solid-state batteries. They have gained some surprising insights, particularly regarding the harmful role played by intrinsic oxygen. This study provides valuable information for improving design and handling of such batteries.