AMBER Researchers Breakthrough in Optimising Nanowire Networks for Emerging Technologies

15 August 2019

Research presents a predictive model which can enable a material-by-design approach for nanowire networks

Researchers at AMBER, the SFI Research Centre for Advanced Materials and BioEngineering Research hosted at Trinity College Dublin, in collaboration with University of Calgary, have developed the first fully predictive model of both the electrical and optical performances of any metal nanowire network. The model, which has been experimentally verified, will enable researchers to quickly benchmark the performance of their materials facilitating a much sought after material-by-design approach. This important breakthrough pushes forward the potential for metallic nanowire networks to meet the needs of next-generation device technologies that require flexible transparent conductors – such as touch screen, display, lighting and solar cells.

The research presents a model which opens new avenues to develop materials for applications requiring transparent conductive (TC) properties beyond the current market leading material ITO (indium tin oxide). ITO, which is found in most touch screen devices, has drawbacks in terms of flexibility, being brittle, coupled with the scarcity of indium and the high cost of the ITO film deposition. In addition to smart phones and other touch screens, transparent conductors are used in modern photovoltaics, light-emitting devices and thin-film heaters. Nanowire networks are well suited as replacements for ITO in a wide variety of current and emerging flexible TC applications. Silver nanowire networks (Ag NWNs), for example, offer a promising alternative as it matches the electro-optical performance of ITO, and can also fulfil the demands for the emerging flexible electronics market, next-generation flexible solar cells, touch screens, displays, thin-film heaters, wearables and anti-static coatings that require flexible electro-optical components.

The development of a predictive model for NWNs is an important step towards a materials-by-design approach for TC applications. The results of this work show that simulation of NWNs can be used as a tool in benchmarking the effectiveness of post-deposition processing methods to be evaluated, potentially improving the efficacies of post-processing methods, and offers a strategic approach to exploring the potential applications of NWN materials guiding the synthesis of systems for specific needs.

The research, published in Scientific Reports*, was a collaboration between Professors John Boland and Mauro Ferreira, AMBER researchers in Trinity’s Schools of Chemistry and Physics, Dr Hugh Manning (lead author) and Dr Claudia Gomes da Rocha at University of Calgary, Canada. This research builds upon previously published work in ACS Nano Nanoscale and Physical Chemistry Chemical Physics.

Lead author of the paper, Dr. Hugh Manning, AMBER and Trinity’s School of Chemistry, said, “There is enormous interest in the development of high performing transparent conductors for a wide variety of applications. Nanowire networks are amongst the leading competitors to the currently used material ITO (indium tin oxide), and also meet the growing industry needs for mechanical flexibility. The key bottleneck in mainstreaming nanowire technologies lies in the need for high optical transparency in balance with low sheet resistance – or essentially maintaining the highly conductive and transparent nature of current transparent conductors, such as ITO, which is found in smart phones for example. The model we have developed can help researchers optimise nanowire networks for various applications by assessing the effectiveness of processing steps taken to improve network performance. Different technologies such as touch screens, lighting, or solar cells require different levels of performance, through material selection and carefully chosen processing steps you can tune the electrical performance of the nanowires to suit the application; this model can help guide that fine tuning.

Prof John Boland, AMBER and Trinity’s School of Chemistry, said, “Nanowire networks offer promising architectures for next generation flexible, transparent devices due to their electrical and optical properties. The model our team has developed has the potential to reduce the lag time from bench to finalised device for specific applications utilising nanowire networks. We envisage the next phase of our research is to expand the model to work with different type of metal nanowires, providing opportunities to further refine the model and its effectiveness, and enhance our understanding of these networks

This publication has emanated from research supported by Science Foundation Ireland (SFI) AMBER Centre under Grant Number SFI/12/RC/2278 and PI grant 16/IA/4462 and the European Research Council under Advanced Grant 321160.