Effects of Structure on Charge Generation in Confined Chromophores Derived from PPV

  • Tina Tan, Bio21 Institute, School of Chemistry, The University of Melbourne, Australia
  • Jonathan White, Bio21 Institute, School of Chemistry, The University of Melbourne, Australia
  • Kenneth Ghiggino, Bio21 Institute, School of Chemistry, The University of Melbourne, Australia
  • James Durrant, Department of Chemistry, Imperial College London, United Kingdom
  • Tracey Clarke, Department of Chemistry, Imperial College London, United Kingdom
  • David James, Department of Chemistry, Imperial College London, United Kingdom

    • A series of PPV derivatives with confined conjugation length were prepared by conventional Horner-Emmons chemistry. These materials were fabricated into thin films in a 1:1 ratio of polymer: PCBM and investigated using transient absorption spectroscopy. Initial steady-state quenching experiments indicated the fluorescence of the polymer was quantitatively quenched by PCBM, with the absence of the emission peak at ~750nm, corresponding to the excited state of PCBM, indicating efficient electron transfer from the polymers to PCBM.

    Transient absorption spectroscopy revealed no significant difference in the decay dynamics between the various confined length conjugated polymers, with the decay dynamics being similar to that of Alt-Co-MEH PPV and MDMO-PPV. This suggests that the intermolecular forces are more important in defining the trap distribution rather then the intramolecular forces. However, the charge generation yield is significantly reduced as the chromophore is confined, implying that geminate recombination occurs more readily in the PT’s.