Get access

Thiophene-based copolymers synthesized by electropolymerization for application as hole transport layer in organic solar cells

Authors

  • Despina Triantou,

    Corresponding author
    1. Laboratory Unit “Advanced and Composite Materials,” School of Chemical Engineering, National Technical University of Athens, 157 73 Athens, Greece
    • Laboratory Unit “Advanced and Composite Materials,” School of Chemical Engineering, National Technical University of Athens, 157 73 Athens, Greece
    Search for more papers by this author
  • Spyridon Soulis,

    1. Laboratory Unit “Advanced and Composite Materials,” School of Chemical Engineering, National Technical University of Athens, 157 73 Athens, Greece
    Search for more papers by this author
  • Sofia Koureli,

    1. Laboratory Unit “Advanced and Composite Materials,” School of Chemical Engineering, National Technical University of Athens, 157 73 Athens, Greece
    Search for more papers by this author
  • Antonietta De Sio,

    1. Energy and Semiconductor Research Laboratory, Institute of Physics, Carl von Ossietzky University of Oldenburg, 26111 Oldenburg, Germany
    Search for more papers by this author
  • Elizabeth von Hauff

    1. Institute of Physics, Albert-Ludwigs University of Freiburg, 79104 Freiburg, Germany
    Search for more papers by this author

Abstract

Electrically conducting thiophene-based copolymers were synthesized by electropolymerization. The potential range used has a strong influence on the film structure and properties. The extent of oxidation of the copolymers was determined from the ratio of the oxidation to reduction charge, Qox/Qred. The use of wide potential range leads to reduced films, whereas the narrow range leads to partially oxidized films. The copolymers exhibit a characteristic band in UV–vis spectra at ∼ 410 nm, which shifts to higher wavelengths for the more doped material. The electrical conductivity of the copolymers was correlated to their morphology and their structure. The copolymer with higher conductivity is partially reduced, has compact morphology and higher ratio of quinoid to benzenoid rings. The energy gap of the copolymers is reversely proportional to their electrical conductivity. The optical and electrical properties of the copolymers make them very well suited for use as hole transport layers (HTL) in organic opto-electronic devices. We prepared polymer : fullerene solar cells with copolymer HTLs. The solar cell performance was tested with very encouraging initial results. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Ancillary