Study On Joule Thermal Effect And Infrared Radiation Characteristics Of Cm-scale Graphene Films

Graphene,as a typical two-dimensional material,has great potential for basic scientific research and multiple electronic and optoelectronic applications due to its excellent properties.In the past few years,graphene has also attracted widespread attentions for thermal applications.With its extremely high carrier mobility,excellent thermal conductivity and high-temperature stability,graphene has unique advantages over traditional materials and has important applications in thermal devices.Most of previous studies on graphene joule heating and thermal radiation characteristics have been conducted at the microscopic and mesoscopic scale,but there are huge application needs for macroscale graphene joule heating films in the fields of biomedical,wearable devices,defogging and infrared stealth.In this thesis,we study the joule heating and infrared radiation properties of graphene at centimeter scale mainly by experiments,along with theoretical analysis and numerical simulations,which lays an important foundation for the development and application of large-scale graphene joule heating films.The main work of the thesis is as follows:1、We theoretically analyzed the Joule heating and thermal diffusion in graphene and numerically studied the Joule heating properties.We obtained the temperature distribution of graphene under different parameters with numerical simulations.We theoretically analyzed the influence of substrate type,number of graphene layers and graphene area on the joule heating characteristics according to the steady-state thermal distribution.We found that the PET-based graphene joule thermal film has the greatest heating characteristic under the same conditions in the silicon sheet（single plane300nm Si O₂ on single plane）,Ca F₂,quartz and PET;In the case of few-layer graphene,the graphene thermal radiation efficiency is proportional to the number of layers;The increase of layers along the distance of the graphene carrier transport direction weakens its joule thermal properties.2、We abricated s series of centimeter-scale graphene joule heating films with various structural parameters and measured their performance.Graphene films on silicon sheet（300nm Si O₂ on single plane）,Ca F₂,quartz and PET all be heated form room temperature to 100℃at a certain driving voltage.When the driving voltage is DC=25V,the temperature of 6-8 graphene joule heating films with a heating region area of 1.5cm×2cm can be raised from room temperature to 100℃at a time of about 20s.The measurements show the influence of the substrate material,the number of graphene layers,the graphene area and the coating layer on the thermal characteristics of the graphene joule heating properties,with agreement with the simulation results.3、We designed the array structure of graphene Joule thermal films and completed the preparation of a 5×5 array with a single unit heating area of 1cm×1cm.We implemented a rolling display of the graphene array with the letter"N","U","D","T"in an infrared temperature camera using external control.