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Title: Polarons and triplet polaronic excitons in poly(paraphenylenevinylene) (PPV) and substituted PPV: An optically detected magnetic resonance study

Journal Article · · Physical Review, B: Condensed Matter; (United States)
; ;  [1];  [2]
  1. Ames Laboratory, Iowa State University, Ames, Iowa 50011 (United States) Physics Department, Iowa State University, Ames, Iowa 50011 (United States)
  2. Institute of Polymers and Organic Solids, University of California, Santa Barbara, California 93106 (United States) Physics Department, University of California, Santa Barbara, California 93106 (United States)

The {ital X}-band optically detected magnetic resonance (ODMR) of poly(paraphenylenevinylene) (PPV) and its dihexoxy derivative films and solutions is described and discussed. As in poly(3-alkylthiophenes) (P3AT), the photoluminescence (PL) -enhancing features include a narrow resonance at {ital g}{congruent}2.0023, a broad triplet powder pattern around {ital g}{similar to}2, and the {Delta}{ital m}{sub {ital S}}=2 transition of this triplet at {ital g}{congruent}4.07. The symmetric narrow resonance, attributed to intrachain distant'' polaron recombination, indicates that charge-conjugation symmetry violation is weaker in PPV than in P3AT. As in P3AT, its spectral dependence is similar to the PL spectrum, suggesting that the polaron levels are close to the band edges. Although the spectral dependence of the half-field resonance is similar, that may result from singlets generated by triplet-triplet collisions. A broad decrease in the ODMR intensity at {ital g}{similar to}2, probably due to a PL-quenching resonance resulting from geminate singlet decay, is also observed at low temperatures.

DOE Contract Number:
W-7405-ENG-82
OSTI ID:
6048290
Journal Information:
Physical Review, B: Condensed Matter; (United States), Vol. 44:19; ISSN 0163-1829
Country of Publication:
United States
Language:
English