Large broadband visible to infrared plasmonic absorption from Ag nanoparticles with a fractal structure embedded in a Teflon AF^® matrix

An unusual almost flat broadband plasmonic absorption, ranging from $400nm$ to well beyond $2500nm$⁠, was observed in a $150nm$ thin film of Ag nanoparticles embedded in a Teflon AF^® matrix. The nanocomposites were synthesized by a simple single-step vapor-phase codeposition method. The Ag nanoparticles of various sizes and shapes, and thus various resonance frequencies, form a fractal percolating network. The broadband absorption, attributed to plasmon excitations within the nanoparticles, could be useful for multicolor applications in the visible and infrared wavelengths region.