Accession Number : ADA330166

Title :   Absorption and Luminescence of Pyridine-Based Polymers

Descriptive Note : Technical rept.

Corporate Author : OHIO STATE UNIV COLUMBUS DEPT OF PHYSICS

Personal Author(s) : Jessen, S. W. ; Blatchford, J. W. ; Lin, L. B. ; Gustafson, T. L. ; Partee, J.

PDF Url : ADA330166

Report Date : 20 SEP 1997

Pagination or Media Count : 8

Abstract : We summarize the low energy photophysics of the pyridine-based polymers poly (p-pyridine) (PPy), poly (p-pyridyl vinylene) (PPyV) and copolymers made up of PPyV and poly (p-phenylene vinylene) (PPyVPV). The absorption and luminescence properties are morphology dependent. The primary photoexcitations within these polymers are singlet excitons which may emit from individual chains following a random walk to lower energy segments, depending upon the excitation energy. Films display redshifted absorption and emission properties with a decrease in photoluminescence efficiency which can be attributed to aggregate formation in comparison to powder and solution forms. Photoinduced absorption (PA) studies show direct conversion of singlet to triplet excitons on the ps time scale. Polaron signatures and the transition between triplet exciton states are seen in powder forms using ms PA techniques. Film forms display only a polaron signature at millisecond times indicating that morphology plays a key role in the long-time photophysics for these systems. Photoluminescene detected magnetic resonance studies also have signatures due to both polaron and triplet excitons. The size of the triplet exciton is limited to a single ring suggesting that the triplet exciton may be trapped by extrinsic effects.

Descriptors :   *POLYMERS, *ABSORPTION, *LUMINESCENCE, *PYRIDINES, CONVERSION, EMISSION, REPRINTS, PHOTOCHEMICAL REACTIONS, POWDERS, EXCITATION, PHOTOLUMINESCENCE, FILMS, COPOLYMERS, TRAPPING(CHARGED PARTICLES), DISPLAY SYSTEMS, AGGREGATES(MATERIALS), LOW ENERGY, RINGS, LIGHT EMITTING DIODES, EXCITONS.

Subject Categories : Organic Chemistry
      Polymer Chemistry
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE