Accession Number : ADA330241

Title :   Low Energy Photophysics of Phenylene-Based Strapped Copolymers

Descriptive Note : Technical rept.

Corporate Author : OHIO STATE UNIV COLUMBUS DEPT OF PHYSICS

Personal Author(s) : Epstein, A. J. ; Piskun, N. V. ; Lebedenko, I. V. ; Jessen, S. W. ; Gustafson, T. L.

PDF Url : ADA330241

Report Date : 20 SEP 1997

Pagination or Media Count : 10

Abstract : We present the absorption and emission properties of the phenylene-based copolymers, poly (pyridyl vinylene-phenylene vinylene) (PPyVPV), poly (thienylene p-phenylene) (PTpP) and poly (dithienylene p-phenylene) (PDTpP), which incorporate 'Straps' to bridge the 2 and 5 positions of the phenyl rings. The absorption and luminescence properties of the PPyvPV polymers are morphology dependent. The absorption's maxima are at -3.0 eV, with the films having absorption edges that tail into the IR. The photoluminscence (PL) spectra are red shifted for films compared to solutions and powders, with the presence of smaller red shifted photoluminescence for the PPyVPV polymers with straps. A low-lying absorption maximum occurs at 2.7 eV for both solution and film forms of PTpP. The (PL) spectra also are similar with features at 2.1 eV and 2.3 eV assigned to the 0-1 and 0-0 vibronic transitions, respectively. Solution and film photoluminescence excitation (PLE) profiles qualitatively follow the absorption spectra. Two low energy absorption maxima are seen for PDTpP at 2.8 eV and 3.2 eV with a single feature observed at 2.3 eV for the PL. The PLE spectra in PDTpP also follow the corresponding absorption features in both solution and film samples. The resolved PL studies (ps to ns) show that there is smaller spectral shift for the films of polymers with straps, showing the importance of reduced aggregation. Steady state photoinduced absorption studies (ms) indicate the roles of both polarons and triplet excitons in these systems.

Descriptors :   *PHOTOLUMINESCENCE, FILMS, COPOLYMERS, STRAPS, ABSORPTION SPECTRA, PYRIDINES, EXCITONS, POLYPHENYLENES.

Subject Categories : Laminates and Composite Materials
      Atomic and Molecular Physics and Spectroscopy
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE