Local spectroscopy of individual hexaphenyl nanofibers

Long, isolated nanofibers made of light-emitting p-hexaphenyl molecules are grown in the focus of an argon ion laser and are investigated via local luminescence spectroscopy. The luminescence is excited in 20 mum wide sections of the nanofibers. As one approaches the end of the nanofiber, the line width narrows by a factor of 2 and a fwhm of less than 10 nm is observed. The spectral narrowing is correlated to a decreasing cross-profile along the nanofibers, which is measured by atomic force microscopy.