Monitoring degradation mechanisms in PTB7:PC71BM photovoltaic cells by means of impedance spectroscopy Articles uri icon

authors

  • ARREDONDO CONCHILLO, BELEN
  • Martín-López, María B.
  • ROMERO, BEATRIZ
  • VERGAZ BENITO, RICARDO
  • ROMERO GÓMEZ, PABLO
  • Martorell, J.

publication date

  • enero 2016

start page

  • 422

end page

  • 428

volume

  • 144

international standard serial number (ISSN)

  • 0927-0248

electronic international standard serial number (EISSN)

  • 1879-3398

abstract

  • We have used impedance spectroscopy technique to monitor degradation mechanisms in organic solar cells based on a blend of PTB7:PC71BM. We have measured the impedance of the cell on a periodical basis for almost four months, and experimental data have been modeled using three different circuits. The evolution of the circuital parameters gives information about the device dynamical mechanisms. We have observed at high voltages a low frequency feature that is more pronounced along days of measurement. This low frequency arc has been associated to charge accumulation that is related to a worsening of charge extraction through the contacts. The simultaneous increase of recombination and low frequency resistances at high voltages (around V-oc) results in a decrease of the fill factor and therefore of the efficiency. (C) 2015 Elsevier B.V. All rights reserved.

keywords

  • organic solar cells; impedance spectroscopy; monitoring degradation; contact selectivity; polymer; stability; layer; standard; lifetime; oxide; thin