The effect of particle morphology on unipolar diffusion charging of silver nanowires

Abstract

We investigated the effect of particle morphology on unipolar charging of nanowires. The average diameters of silver nanowires were 32, 48, and 68 nm. Particle electrical capacitance is an important parameter that determines the mean charge per particle in a continuum regime. We predicted that a nanowire has larger electrical capacitance than a sphere, and for a nanowire, the electrical capacitance increases as its diameter decreases. The mean charge per nanowire particle was calculated with the electrical capacitance obtained from theoretical analysis as a function of electrical mobility diameter. The mean charge per particle was measured for polystyrene latex particles with an electrical mobility diameter of 100-300 nm, and silver nanowires with an electrical mobility diameter of 200-400 nm. For a given electrical mobility diameter, the mean charge per particle of a nanowire in theoretical analysis and experiments was larger than that of a sphere, and it increased as the diameter of the nanowire decreased. Our results indicate that the mean charge per particle of a nanowire is dependent on particle morphology such as the diameter and the length.