High-Precision and Reliable Thermal Conductivity Measurement for Graphene Films Based on an Improved Steady-State Electric Heating Method

The graphene film with high thermal conductivity has garnered considerable attention in recent years as an ideal material for dissipating heat in high-power electronic devices. Thermal conductivity is a crucial parameter for evaluating its fundamental performance. High-precision measurement holds significant importance for understanding its basic properties, fabrication optimization, and industrial applications. However, it is difficult to simultaneously achieve efficient, accurate, and reliable measurements with existing commercial thermal conductivity testing methods. The development of a convenient, high-precision, and reliable measurement approach remains a great challenge. Here, we introduce a thermal conductivity testing methodology with superior accuracy and excellent efficiency based on an improved steady-state electric heating method, refined through the optimization of heat transfer principles, experimental operation, and data analysis, supported by finite element simulation. The accuracy of measurements is affected by four factors: heat loss calibration, sample size, device design, and data treatment. The experimental results show that the heat loss caused by heat radiation and heat convection affects the temperature distribution and the measurements of the sample, which should be strictly controlled by sample size and temperature rise. Reasonable screening and preprocessing of data are also necessary to improve measurement accuracy. Through the comparative analysis of the temperature distribution and thermal conductivity measurements of samples under different conditions, we propose feasible operational guidance and a standardized testing protocol to minimize measurement error. The measurement error is less than 3.0%, and uncertainty is reduced to 0.5%. Simulation results confirm that the response time of this method is down to milliseconds, correlating well with the experiment, which can effectively improve test efficiency. Considering the combined merits of high accuracy, repeatability, and fast response, the improved steady-state electric heating method offers useful guidance for the accurate evaluation of the thermal conductivity of materials and crucial technical support for research and application in thermal management.