A flexible dual-functional film based on laser-reduced graphene oxide: Simultaneous electrothermal heating and temperature sensing

This paper prepared a flexible dual-functional electronic film fabricated by laser reduction, which could simultaneously achieve efficient electrical heating function and high sensitivity temperature sensing performance. Graphene oxide (GO) film was deposited on a glass substrate and selectively reduced using a 785 nm near-infrared laser to prepare laser-reduced graphene oxide (LrGO) with a multi-channel conductive structure. This paper systematically investigated the effects of laser power, scanning rate, spacing and frequency on the reduction degree, microstructure and electrical properties of LrGO, and determined the optimal process parameters. The LrGO film encapsulated with polydimethylsiloxane (PDMS) has excellent waterproof performance and mechanical stability. Experimental results showed that LrGO/PDMS film exhibited excellent negative temperature coefficient (NTC) characteristics in temperature sensing, with a resistance temperature coefficient (TCR) of up to −0.421%/°C, and had a good linearity (R 2 > 0.99) and a fast response time (3.3 s). The LrGO/PDMS film can rapidly heat up to 81.3 °C under a 25 V load voltage, and the power density showed a highly linear correlation with the equilibrium temperature. This dual-functional film has an important application value in intelligent wearables, medical monitoring and flexible electronic skin fields.