Deposition of Ag nanoparticles on carbon microspheres surface: Evaluation of structures, electrochemical and optical properties

A hybrid material of carbon microspheres (CMSs) with Ag decoration (Ag/CMSs) was developed. Poly (3-hexylthiophene):Ag/CMSs composite film was prepared by spin-coating. Scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectrometry, X-ray diffraction, thermogravimetric analysis and cyclic voltammetry were employed to analyze the morphologies, structures, thermal properties and energy levels of Ag/CMSs. The optical property of the composite films was characterized by ultraviolet-visible spectrophotometry and fluorescent spectrometry. The results indicate that silver nanoparticles (Ag NPs, d = 10-20 nm) are distributed on the surface of CMSs. LUMO and HOMO energy levels of Ag/CMSs are -3.97 and -5.52 eV, below the vacuum energy level, respectively, indicating that it is feasible to use Ag/CMSs as an electron acceptor. Ag NPs are blended into the active layer to trigger localized surface plasmon resonance, and consequently enhance light harvesting. The coupling of surface plasmons and excitons increased the probability of exciton dissociation.