High-performance Photosensor Based on a Nanocomposite of porous graphene and metal nanoparticles

Photodetectors are critical components widely used in optical sensing and industry, with various applications ranging from autonomous vehicles to consumer electronics. Compared to conventional materials like silicon, laser-induced graphene (LIG) serves as an ideal material for photosensors due to its high broadband light absorption and mechanical durability. However, the effective photoresponse, the current generated per unit of light power, of porous graphene can be significantly enhanced through the addition of metal nanoparticles. We utilize the plasmonic effects of palladium nanoparticles (PdNPs), which concentrate light into intense local fields that increase electron-hole pair generation in the LIG, to boost photoresponsivity. PdNPs can be incorporated into LIG in various ways, including laser doping, physical vapor deposition, and electroless deposition. In this study, we directly compare the effectiveness of two methods: conventional solution processing and deposition during laser fabrication. We expect photosensors with PdNPs added during laser fabrication to have significantly higher photoresponses than those created with conventional solution processing methods. To create the solution-processed photosensor, we irradiate fluorinated polyimide with a CO2 laser to make LIG, then apply a solution of 20nm PdNPs to the graphene. This approach is compared with an alternative technique where PdNPs are incorporated during the laser fabrication of LIG, creating a nanocomposite of graphene and palladium nanoparticles. Due to palladium’s affinity for hydrogen, this platform also demonstrates potential in functioning as a hydrogen detector with further development.