Localized triplet excitations and the effect of photo-oxidation in ladder-type poly(p-phenylene) and oligo(p-phenylene)
- Institut fuer Festkoerperphysik, Technische Universitaet Graz, A-8010 Graz, (Austria)
- Ames Laboratory-United States Department of Energy and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States)
- Max-Planck-Institut fuer Polymerforschung, Mainz, (Germany)
- Department of Physics, Virginia Tech, Blacksburg, Virginia 24060 (United States)
The photophysics of methyl-bridged poly(para-phenylene)-type ladder polymer (m-LPPP) and oligomer films and solutions is described and discussed. The spin sensitive properties, such as the formation and properties of polaron pairs and triplet excitons (TE's) were studied using X-band photoluminescence (PL) detected magnetic resonance (PLDMR). The PLDMR results and quantum chemical calculations show unambiguously that the TE wave-function extent is much smaller than that of the singlet exciton (SE). The weaker vibronic structure of the triplet photoinduced absorption (PA) band of m-LPPP relative to the singlet absorption is assigned to the small energy difference between the geometry of the lowest lying and excited triplet states. This is an additional indication of the strong localization of the triplet wave-function as compared to that of the SE. Finally, the influence of photo-oxidation on the PLDMR and PA is analyzed and discussed in relation to the photoconductivity of the materials. (c) 2000 The American Physical Society.
- OSTI ID:
- 20216112
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 61, Issue 16; Other Information: PBD: 15 Apr 2000; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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