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

Report Date:

1997-09-20

Pagination or Media Count:

10.0

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 absorptions 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.

Subject Categories:

  • Laminates and Composite Materials
  • Atomic and Molecular Physics and Spectroscopy
  • Optics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE