Bio-inspired networks for optoelectronic applications

Abstract

Modern optoelectronics needs development of new materials characterized not only by high optical transparency and electrical conductivity, but also by mechanical strength, and flexibility. Recent advances employ grids of metallic micro-and nanowires, but the overall performance of the resulting material composites remains unsatisfactory. In this work, we propose a new strategy: application of natural scaffoldings perfected by evolution. In this context, we study two bio-inspired networks for two specific optoelectronic applications. The first network, intended for solar cells, light sources and similar devices, has a quasi-fractal structure and is derived directly from a chemically extracted leaf venation system. The second network is intended for touch screens and flexible displays, and is obtained by metalizing a spider's silk web. We demonstrate that each of these networks attain an exceptional optoelectonic and mechanical performance for its intended purpose, providing a promising direction in the development of more efficient optoelectronic devices.

Bio‐Inspired Chemical Fabrication of Stretchable Transparent Electrodes

“…It should be noted that very recently, Han et al reported the fabrication of fl exible transparent electrodes by thermal evaporation of Ag on natural structures such as veins and spider webs. [ 29 ] But they found that their electrodes were not stretchable due to the signifi cant increase in resistance at large strains. In this paper, we report for the fi rst time that our chemical fabrication approach can effectively modify natural veins into highperformance STEs.…”

Thermal transport in two- and three-dimensional nanowire networks

“…This effect is much more pronounced in 3D networks due to increased porosity, surface to volume ratio and the enhanced backscattering at 3D nodes compared to 2D nodes. We propose a model to estimate the thermal resistance related to the 2D and 3D interconnections in order to provide an analytic description of thermal conductivity of such nanowire networks; the latter is in good agreement with Molecular Dynamic results.New innovating and hightly sophisticated architectured nanostructures are now feasible with the rapid evolution of the elaboration methods [1][2][3][4]. Among them 2D and 3D networks of nanowires are a new class of nanostructured materials with interesting mechanical, optical, electronic and thermal properties.…”

Electrical limit of silver nanowire electrodes: Direct measurement of the nanowire junction resistance

“…Therefore, highly conductive nanowire networks improving substantially upon the state-of-the-art cannot just be realized by reducing R J : A possible enhancement would only be achievable by an improved nanowire geometry, meaning a higher aspect ratio (length vs. diameter) as already suggested by De et al 14 Another way would be the search for new concepts, such as recently reported on bio-inspired networks. 15 For comparison, we have also investigated the case of a non-annealed nanowire network. These networks can have substantially higher junction resistance while exhibiting a nanowire resistance of around 5 X=lm (obtained from direct measurement) which is nearly identical to the resistance value in annealed nanowire electrodes.…”