Local nanotailoring of polymeric photophysics by Au nanoparticles implantation

We studied the excitation dynamics and the photoluminescence spectra in polymeric matrix implanted with metallic nanoparticles. A supersonic beam of gold nanoparticles (sizes 2-7 nm) was generated by using a Pulsed Microplasma Cluster Source (PMCS). The nanoparticles were implanted in a thin polyfluorene film (thickness around 100 nm) spin coated on a PMMA (poly methyl methacrilate) substrate. We performed photoluminescence and pump-probe measurements using a Ti:Sapphire amplified laser system, the excitation pump pulse was centered at 400 nm with a 150 fs time duration. The experimental results show a suppression of the amplified spontaneous emission from the polyfluorene (PFO) film due to the presence of the implanted nanoparticles. The transient transmission spectra revealed the presence of a photoinduced absorption band due to the nanoparticles which overlaps with the stimulated emission band from the PFO, hindering the possibility of having amplified spontaneous emission. These results demonstrate the possibility of a local nanotailoring of the polymeric photophysics.