Raman study of 2,7-bis(biphenyl-4-yl-)2',7'-ditertbutyl-9,9'-spirobifluorene adsorbed on oxide surfaces

Abstract

We present a systematic non-resonant Raman study of the vibrational properties of the spirobifluorene derivative 2,7-bis(biphenyl-4-yl)-2’,7’-di-tertbutyl-9,9’-spirobifluorene (SP6) on three different substrates: ZnO(000-1), ZnMgO(000-1), and Al₂O₃(11-20). This investigation of few monolayer coverages is facilitated by the high scattering cross section of this molecule. The vibrational response of SP6 is unaffected by the choice of substrate, showing that the vibrational properties of the molecules remain unchanged by adsorption. Furthermore, we can directly compare the experimental spectra to our density functional theory calculations of the Raman cross sections of SP6 in the gas phase