Terrylenediimide: A promising chromophore for single-molecule spectroscopy at low temperatures

The method of fluorescence excitation spectroscopy of single molecules isolated in frequency space at liquid helium temperature was used to examine Terrylenediimide (TDI). The chromophore shows sharp zero-phonon lines and high fluorescence count rates which could be demonstrated by saturation studies. Additionally fluorescence spectra of single TDI molecules in the solid host matrix hexadecane will be discussed. As the structure of TDI allows further attachment to other molecules, TDI is a promising chromophore for e.g., fluorescence labeling.