Laser-Induced Graphene-based Flexible Substrate with Photothermal Conversion and Photoresponse Performance on Polyimide Film

laser on a polyimide (PI) film in one step, and the GFS surface covered with carbon nanoparticles (GFSC) with a resistance of 25 Ω was further induced by femtosecond (fs) laser reprocessing. Benefiting from the laser-induced porous graphene structure, the absorptivity of GFS is up to 90% in the wavelength range of 200-2000 nm. The formation of carbon nanoparticles on the GFSC surface further improves the absorptivity to 97.5% in a wide spectral range. Under white light irradiation of 1 sun, the surface temperature of GFS reaches 65.7 °C and that of GFSC is up to 70.8 °C within 2 min. Under the irradiation of a light-emitting diode (LED) with a central wavelength of 365 nm, the highest photoresponsivity of GFS and GFSC was 8.8 and 1.3 mA/W, respectively. The response time and recovery time of GFS are 8 and 7.3 s, and those of GFSC are 8.3 and 6.7 s, respectively. Importantly, GFSC has a more stable photoresponse performance due to the better electron capture and transfer capability of carbon nanoparticles. It is believed that GFS and GFSC have great application potential in flexible photodetectors and sensors.