Visual measurement of the microscopic temperature of porous graphene based on cholesteric liquid crystal microcapsules

Measuring the microscopic temperature of graphene is challenging. We used cholesteric liquid crystal microcapsules (CLCMs) as temperature sensors to detect the local temperature of three-dimensional porous graphene through quantitative visualization. Based on a CLCM (～20 μm in size), we determined the temperature variation in a small area with an accuracy of 0.1°C. By analyzing the color changes between two CLCMs, we demonstrated the temperature changes dynamically in a region with a diameter of approximately 110 μm. Furthermore, by comparing the color evolution among the three CLCMs, we visualized the anisotropic thermal properties in the micro-zone. This convenient and low-cost temperature measurement method is expected to further improve graphene-based devices.