A procedure to measure the emissivity of ultra-thin graphene based film in long wavelength infrared (LWIR) spectrum region

In the present paper, an experimental procedure to measure the emissivity of ultra-thin graphene based films (G-paper) is presented, with the aim to determine the effect of measuring temperature and graphene concentration on the G-papers emissivity. To this end, two methods were adopted, both according to the ASTM E1933 Standard: Contact Thermometer Method (CTM) and Noncontact Thermometer Method (NTM). The latter was modified in order to take in account the specimens characteristics. In both the cases an IR camera, with a spectral range of 7.5-14 mu m, was adopted. The experimental tests were performed by heating 50 mu m thick G-papers, with different graphene contents (in the range 70-100%). The tests were carried out in the temperature range of 80-200 degrees C. During the NTM tests, a conductive paint was adopted as reference materials for the temperature measuring. Before the tests, the paint calibration curve was obtained. Statistical methodologies, Design Of Experiment and ANalysis Of VAriance, were adopted in order to identify the factors affecting the emissivity. Results show that the measuring temperature and the test methods do not affect the emissivity. The latter decreases at the graphene content increase and vary in the range of 0.38-0.51, minimum and maximum values measured for a graphene content of 100% and 70% respectively.