Vibrational spectra and thin solid films of a bi(propylperylenediimide)

Abstract

The synthesis, the fabrication of thin solid films and the optical spectra of a member of a new series of bis-perylene materials—the bi(propylperylenediimide),N′,N′″-dipropyl-N,N″-bi[perylene-3,4:9,10-bis(dicarboximide)] (Pr2)—are reported. The objective of the present research effort is to provide the fundamental spectroscopic characterization of the ground electronic state and the methods for the fabrication of submicron thin solid films of these new materials which are being tested for performing elementary electrical functions of electronic devices. Pr2 is a high molecular weight perylene dye and the molecular organization formed in vacuum evaporated nanometric films is one of the key elements determining the electrical and optical properties of thin solid films. The spectroscopic techniques used in the study of fundamental vibrational modes were transmission and reflection–absorption infrared spectroscopy (RAIRS). The inelastic scattering was investigated using out-of-resonance excitation (FT-Raman), resonance Raman scattering (RRS) and surface-enhanced resonance Raman scattering (SERRS) on silver island films. The vibrational assignment of characteristic wavenumbers was assisted with semi-empirical quantum mechanical calculations.