Sprayed Hybrid Cellulose Nanofibril-Silver Nanowire Transparent Electrodes for Organic Electronic Applications

In times of climatechange and resource scarcity, researchers areaiming to find sustainable alternatives to synthetic polymers forthe fabrication of biodegradable, eco-friendly, and, at the same time,high-performance materials. Nanocomposites have the ability to combineseveral favorable properties of different materials in a single device.Here, we evaluate the suitability of two kinds of inks containingsilver nanowires for the fast, facile, and industrial-relevant fabricationof two different types of cellulose-based silver nanowire electrodesvia layer-by-layer spray deposition only. The Type I electrode hasa layered structure, which is composed of a network of silver nanowiressprayed on top of a cellulose nanofibrils layer, while the Type IIelectrode consists of a homogeneous mixture of silver nanowires andcellulose nanofibrils. A correlation between the surface structure,conductivity, and transparency of both types of electrodes is established.We use the Haacke figure of merit for transparent electrode materialsto demonstrate the favorable influence of cellulose nanofibrils inthe spray ink by identifying Type II as the electrode with the lowestsheet resistance (minimum 5 & PLUSMN; 0.04 & omega;/sq), while at thesame time having a lower surface roughness and shorter fabricationtime than Type I. Finally, we prove the mechanical stability of theType II electrode by bending tests and its long-time stability underambient conditions. The results demonstrate that the mixed spray inkof silver nanowires and cellulose nanofibrils is perfectly suitablefor the fast fabrication of highly conductive organic nanoelectronicson an industrial scale.