UCLA researchers in the Department of Materials Science and Engineering have developed a novel transparent and flexible electrode material for optoelectronic device applications.
The current gold standard material used for transparent conductive electrodes in industry is indium tin oxide (ITO), but there is great interest in replacing it. Not only is ITO expensive, but also health issues have arisen due to indium-based powders and thin films are brittle, limiting their use in flexible optoelectronics. A leading candidate to replace ITO is silver nanowires (AgNWs) as they have the desirable electrical, mechanical, and optical properties and are solution processable. However, these films have a rough surface and poor thermal stability at industry relevant temperature conditions. Some progress has been made by either using thermally stable polymers to improve the surface smoothness or zinc oxide (ZnO) to enhance the thermal stability of the AgNWs, but to date both developments in one electrode material have not been successfully realized.
Professor Qibing Pei and his research team have invented a novel ZnO/AgNW/polymer composite electrode that has comparable performance to ITO. This new composite electrode shows high long-term thermal stability, up to 300 ˚C for at least six hours, with little change in the sheet resistance and optical clarity. Not only does this material have a smooth surface, but also is flexible, conductive, transparent, and resistant to atmospheric corrosion. Efficacy of this new AgNW composite electrode was demonstrated by solution-processing a white polymer light emitting diode (LED) that showed similar performance to ITO and outperformed previous AgNW-based electrodes.
Prototype white polymer LED devices have been fabricated and extensively tested with this unique composite electrode material.
|United States Of America||Published Application||20180277787||09/27/2018||2015-256|
Transparent conductive electrode, silver nanowires, zinc oxide, polymer, composite electrode, flexible, solution processable, thermal stability, optoelectronic devices, white polymer light emitting diode, display technologies, touch sensors