Highly Robust Indium-Free Transparent Conductive Electrodes Based on Composites of Silver Nanowires and Conductive Metal Oxides

A hybrid approach for the realization of In-free transparent conductive layers based on a composite of a mesh of silver nanowires (NWs) and a conductive metal-oxide is demonstrated. As metal-oxide room-temperature-processed sol-gel SnOx or Al:ZnO prepared by low-temperature (100 degrees C) atomic layer deposition is used, respectively. In this concept, the metal-oxide is intended to fuse the wires together and also to glue them to the substrate. As a result, a low sheet resistance down to 5.2 sq(-1) is achieved with a concomitant average transmission of 87%. The adhesion of the NWs to the substrate is significantly improved and the resulting composites withstand adhesion tests without loss in conductivity. Owing to the low processing temperatures, this concept allows highly robust, highly conductive, and transparent coatings even on top of temperature sensitive objects, for example, polymer foils, organic devices. These Indium- and PEDOT:PSS-free hybrid layers are successfully implemented as transparent top-electrodes in efficient all-solution-processed semitransparent organic solar cells. It is obvious that this approach is not limited to organic solar cells but will generally be applicable in devices which require transparent electrodes.