Debunking misconceptions about cross-aligned nanowire network electrodes

A network of metallic nanowires (NWs) is a suitable alternative to thin-film oxides for the production of flexible transparent electrodes. Currently available assembly strategies allow for the deposition of NWs in a highly ordered state, with cross-aligned arrangements achieved by stacking layers of NWs with perpendicular preferential orientations. Experimental investigations indicate that the optoelectrical performance of electrodes with a cross-aligned arrangement is superior to that of those with a random arrangement, but the underlying reasons remain unclear. We therefore conduct an extensive set of numerical simulations to compare the performance of networks with cross-aligned and random arrangements in terms of percolative behavior, electrical conductivity, and electrical homogeneity across a wide range of NW densities. Despite the common misconception that the percolation threshold of cross-aligned arrangements is lower than that of random arrangements, we demonstrate that this is not the case. Moreover, our findings indicate that topology alone does not account for the advantages observed in cross-aligned arrangements. We further demonstrate that junction resistance Rj is the key parameter influencing electrical conductivity and homogeneity, estimating that Rj is approximately 20% lower in real cross-aligned arrangements compared to random arrangements. NW assembly strategies also facilitate a spatially homogeneous distribution of NWs, which is rarely observed in real random arrangements, further enhancing the performance of cross-aligned arrangements.