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Long range energy transfer in conjugated polymer sequential bilayers.

L A Cury1, K N Bourdakos, DeChang Dai

  • 1Departamento de Física, Instituto de Ciências Exatas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil. cury@fisica.ufmg.br

The Journal of Chemical Physics
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PubMed
Summary

Energy transfer in polymer blends and bilayers of poly(9,9-dioctyl-fluorene-2,7-diyl) (PFO) and poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH PPV) was studied. Blends showed exciplex formation, unlike bilayers, which exhibited efficient, long-range energy transfer via surface interactions.

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Area of Science:

  • Organic electronics
  • Photophysics of conjugated polymers

Background:

  • Polymer blends and bilayers are crucial for organic electronic devices.
  • Understanding energy transfer mechanisms is key to optimizing device performance.

Purpose of the Study:

  • To investigate and compare energy transfer in PFO/MEH PPV blend and bilayer films.
  • To elucidate the role of film morphology and interactions on energy transfer dynamics.

Main Methods:

  • Steady-state and time-resolved photoluminescence spectroscopy.
  • Temperature-dependent photoluminescence measurements.

Main Results:

  • Efficient energy transfer from PFO (donor) to MEH PPV (acceptor) observed in both systems.
  • Blends exhibited exciplex formation, leading to a distinct long decay component in acceptor emission.
  • Bilayers showed no exciplex formation; energy transfer was efficient and long-range, attributed to surface-surface interactions.
  • Exciton migration contributed minimally to energy transfer in bilayers.

Conclusions:

  • Energy transfer mechanisms differ significantly between PFO/MEH PPV blends and bilayers.
  • Exciplex formation in blends influences emission characteristics.
  • Long-range energy transfer in bilayers suggests unique interfacial interactions, exceeding the Förster radius.