Tuning the Optical Characteristics of Poly(p-phenylenevinylene) by in Situ Au Nanoparticle Generation

A composite of 1,4-dihexyloxy-poly(p-phenylenevinylene) (DHPPV) and gold nanoparticles (AuNPs) was prepared by an efficient and simple in situ method. The formation of DHPPV-AuNP composites was confirmed through high-resolution transmission electron microscopy (TEM); UV/vis absorption spectra showed a large blue shift in the polymer absorption peak, which was greater than 60 nm in solution, accompanied by a remarkable change in the intensity, whereas the photoluminescence (PL) spectra in the solution showed only a marginal decrease in intensity in the presence of AuNPs. Solid-state UV/vis spectra of DHPPV-AuNP also showed a decrease in the intensity of the shoulder peak in the region of 400-450 nm. Interesting features were observed in the solid-state PL spectra, where the efficient energy transfer from AuNP to DHPPV results in the complete disappearance of the 585 nm peak with a dominant peak appearing at 635 nm. TEM analysis confirmed that AuNPs were embedded in the DHPPV matrix systematically, thus presenting a simple tool to assemble hybrid nanowires comprising pi-conjugated organic/polymeric systems and inorganic nanoparticles with likely applications in nanosized optoelectronic devices. The optical properties of DHPPV-AuNP could be further tuned by treating the composite with octadecane thiol or sodium sulfide, resulting in a further blue shift of 65 nm.