To improve functionalization of MoSI cluster polymers we have studied the effects of adsorption doping on the electrical transport, bundling, and optical absorption spectra. Doping results both in enhanced conductivity and aggregated bundles in dispersion. The different electronic properties of different bundle diameters can be ascribed to self-doping during the synthesis. Furthermore, doping shifts the characteristic absorption peaks and transfers oscillator strength to lower energies. Femtosecond optical spectroscopy shows that the spectral signature of adsorption and self-doping indeed originates from the population of electronic levels that are empty or absent in the undoped sample. The large spectral shifts and long lifetimes of photoinduced charges suggest efficient localization.
Keywords: Adsorption doping; femtosecond spectroscopy; molybdenum chalcohalides; optical spectroscopy; semiconducting nanowires.