Graphene electrode diagnostic with IR imaging of Joule heat emission

Abstract

Conductive graphene electrode of large area is required for some applications like for example photovoltaics or touch screens. Such large area graphene membrane needs specific test methods to assess defects which may obstacle its performance. In this work the infrared imaging of Joule heated graphene was proposed to estimate its uniformity and mechanical continuity. Thermal signatures of the typical mechanical defects like scratches and local resistivity inhomogeneity were identified. Distribution of the heat emission around such defects were simulated using finite elements method and then experimentally verified by recording of thermal landscape around the corresponding real graphene defects. Proposed method gives micrometric resolution and ability to inspection of large area electrodes depending on applied optics. Presented results give suggestions how graphene imperfections generate observed hot points related to graphene layer defects.