Correlating Chemical Structure and Charge Transport in Reduced Graphene Oxide for Transparent Conductor and Interconnect Applications

Graphene oxide is solution-process able and widely tunable semiconductor which has potential applications as transparent electrode materials in organic solar cells as well as chemical sensors and interconnects. It is also amenable to micro-patterning with laser-induced heating. Density of defects and water permeation are among the major factors affecting the degree of conduction in reduced graphene oxide. The wide tunability of conduction is related to the nature and density of defects. In this work, we correlate micro structural parameters of reduced graphene oxide with parameters obtained from our transport studies. The quantitative estimation of defect density from IR and Raman spectroscopy is, however, non-trivial. Here, we outline a procedure for carefully extracting the defect density for graphene oxide films subject to varied degrees of thermal reduction. This density of defect scatterers is then correlated with transport length scales extracted from frequency and temperature dependent charge transport studies. Furthermore, the effect of uniaxial strain on the dc and frequency-dependent ac transport in graphene oxide films is studied towards their potential application as hole-transporting layer for flexible solar cells.