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

Abstract

We measure basic network parameters of silvernanowire (AgNW) networks commonly used as transparent conductingelectrodes in organic optoelectronic devices. By means of four point probing with nanoprobes, the wire-to-wire junction resistance and the resistance of single nanowires are measured. The resistanceRNW of a single nanowire shows a value of RNW=(4.96±0.18) Ω/μm. The junction resistanceRJ differs for annealed and non-annealed NW networks, exhibiting values of RJ=(25.2±1.9) Ω (annealed) and RJ=(529±239) Ω (non-annealed), respectively. Our simulation achieves a good agreement between the measured network parameters and the sheet resistanceRS of the entire network. Extrapolating RJ to zero, our study show that we are close to the electrical limit of the conductivity of our AgNW system: We obtain a possible RS reduction by only ≈20% (common RS≈10 Ω/sq). Therefore, we expect further performance improvements in AgNW systems mainly by increasing NW length or by utilizing novel network geometries.