Effect ofreduction degree of graphene oxide films on temperature sensing and electro heating properties
Due to outstanding advantages such as lightweight,good toughness,low cost and simple forming process,reduced graphene oxide(rGO)films have attracted considerable attention in temperature sensing and electro heating fields.In this study,the difference in the microstructure,bond types,mechanical and electrical properties of rGO films reduced at different temperatures are analysed to explore the influence of reduction de-gree on temperature sensing and heating performance of rGO films.The results indicate that oxygen-containing functional groups including C-O and C=O in graphene oxide(GO)films decrease dramatically at 200 ℃,and the main bonding type of carbon atoms transfers from C-C to C=C.When the reduction temperature rises to 600 ℃,rGO films still retain some oxygen-containing functional groups with a C/O ratio of 7.18,while the composition of rGO films reduced at 800 ℃ approaches to graphene.With the increase of reduction degree,elec-trical resistivity of rGO films shows a significant decrease.However,the outgassing of oxygen atoms disrupts the interlayer dense structure,leading to gradual reduction in tensile strength.At the reduction temperature of 600 ℃,the resistance-temperature curve exhibits excellent linear relationship with a temperature coefficient of resistance(TCR)value of-1.60×10-3/℃ at room temperature.Under 24 V DC driving voltage,rGO films reduced at 600 ℃ and 800 ℃ reach 242 ℃ and 367 ℃,respectively.However,due to the loose and cracked in-terlayer structure,there happens a noticeable fluctuation in the heating temperature curve of rGO films reduced at 800 ℃.Therefore,rGO films reduced at 600 ℃ are proven to be more suitable for heating and temperature sensing.
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