Exciton regeneration at polymeric semiconductor heterojunctions.
Control of the band-edge offsets at heterojunctions between organic semiconductors allows efficient operation of either photovoltaic or light-emitting diodes. We investigate systems where the exciton is marginally stable against charge separation and show via E-field-dependent time-resolved photolum...
Main Authors: | , , , , |
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Format: | Journal article |
Language: | English |
Published: |
2004
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Summary: | Control of the band-edge offsets at heterojunctions between organic semiconductors allows efficient operation of either photovoltaic or light-emitting diodes. We investigate systems where the exciton is marginally stable against charge separation and show via E-field-dependent time-resolved photoluminescence spectroscopy that excitons that have undergone charge separation at a heterojunction can be efficiently regenerated. This is because the charge transfer produces a geminate electron-hole pair (separation 2.2-3.1 nm) which may collapse into an exciplex and then endothermically (E(A)=100-200 meV) back transfer towards the exciton. |
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