Charge-transfer range for photoexcitations in conjugated polymer/fullerene bilayers and blends

Journal Article · Fri Aug 01 00:00:00 EDT 1997 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.56.4573· OSTI ID:538542

Vacar, D ^[1]; Maniloff, E S; McBranch, D W ^[2]; Heeger, A J ^[1]

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1. Institute for Polymers and Organic Solids, University of California, Santa Barbara, California 93106 (United States)
2. Chemical Science and Technology Division, Mail Stop J585, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

Time-resolved photoinduced absorption was measured on bilayers of poly-[2-methoxy,5-(2{sup {prime}}-ethylhexoxy)-1,4-phenylenevinylene] (MEH-PPV) and fullerene (C{sub 60}), and on MEH-PPV/C{sub 60} composite films of various concentrations. We find that even in the picosecond regime, charge transfer from the conjugated polymer to C{sub 60} slows down the decay dynamics relative to the decay in the pure samples. The fact that charge transfer occurs in the picosecond time scale in bilayer structure (thickness{approx}200 {Angstrom}) implies that diffusion of localized excitations to the interface is not the dominant mechanism; the charge-transfer range is a significant fraction of the film thickness. From an analysis of the excited-state decay curves, we estimate the charge-transfer range to be 80 {Angstrom} and interpret that range as resulting from quantum delocalization of the photoexcitations. {copyright} {ital 1997} {ital The American Physical Society}

• OSTI ID: 538542
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 8 Vol. 56; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ABSORPTION SPECTRA
BINDING ENERGY
CHARGE EXCHANGE
EXCITED STATES
FULLERENES
INTERFACES
LAYERS
ORGANIC POLYMERS
PHOTOLUMINESCENCE
THICKNESS
THIN FILMS