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Title: Understanding S-shaped current-voltage characteristics of organic solar cells: Direct measurement of potential distributions by scanning Kelvin probe

We present a comparison of the potential distribution along the cross section of bilayer poly(3-hexylthiophene)/1-(3-methoxycarbonyl)propyl-1-phenyl[6,6]C61 (P3HT/PCBM) solar cells, which show normal and anomalous, S-shaped current-voltage (IV) characteristics. We expose the cross sections of the devices with a focussed ion beam and measure them with scanning Kelvin probe microscopy. We find that in the case of S-shaped IV-characteristics, there is a huge potential drop at the PCBM/Al top contact, which does not occur in solar cells with normal IV-characteristics. This behavior confirms the assumption that S-shaped curves are caused by hindered charge transport at interfaces.
Authors:
;  [1] ;  [2] ;  [2] ;  [1] ;  [2] ; ;  [1] ;  [2]
  1. InnovationLab GmbH, 69115 Heidelberg (Germany)
  2. (Germany)
Publication Date:
OSTI Identifier:
22253816
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 103; Journal Issue: 24; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CHARGE TRANSPORT; CURRENTS; DISTRIBUTION; ELECTRIC CONDUCTIVITY; ELECTRIC POTENTIAL; INTERFACES; ION BEAMS; LAYERS; ORGANIC SOLAR CELLS; POTENTIALS; PROBES