Construction and photothermal properties of Ag–Pt nanoparticles modified hierarchical porous carbon film with ultra-wide infrared spectrum absorption

The rapid development and popularization of infrared detectors have expressed higher and urgent requirements for the light harvesting and photothermal conversion capability of infrared sensitive films. Herein, a hierarchical porous carbon (HPC) derived from polymer carbonization was employed as the porous framework, and then was modified with Pt and Ag particles to construct an efficient photothermal conversion film with ultra-wide infrared spectrum absorption. The light-trapping effect of special porous microstructure, introduction of enormous defects, and intrinsic strong absorption of carbon materials enables the HPC film to holds an absorbance of 72.74 % over the range of 2–20 μm, which could be further improved by about 1.3 times to 94.75 % after Pt and Ag particles (AgPt@HPC) were introduced onto the framework because of the additional plasmon effect and the establishment of complex electric field coupling mechanisms. Moreover, photothermal conversion efficiency of AgPt@HPC film also witnesses a great improvement by about 1.8 times compared with HPC film, and the boosted charge transfer between Ag, Pt and C was confirmed to provides a significant contribution to photothermal conversion. The proposed ultra-wide infrared sensitive film is not only designed for infrared detectors, but also has the potential to provide reference for the development of functionalized photothermal nanomaterials.