Thermal annealing affects vertical morphology, doping and defect density in BHJ OPV devices

Alexandre M. Nardes, Craig L. Perkins, Peter A. Graf, Jian V. Li, Sean E. Shaheen, David P. Ostrowski, Andrew Watte, Dana C. Olson, Nikos Kopidakis

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contribution

1 Citation (Scopus)

Abstract

We demonstrate that a post-annealing step results in enhanced open-circuit voltage (Voc) and fill factor (FF) and lower reverse saturation current (Js) that consequently increases the power conversion efficiency (PCE) of organic bulk-heterojunction (BHJ) devices by about 40 % as a result of better contact formation, as typically assumed. Although true, we show that additional device properties are affected as well. We found that annealing induces vertical phase segregation and consequently the enrichment of donor and acceptor materials at the correct electrical contact. In addition, a de-doping process and a decrease in defect density also take place and are the major causes for device improvement after post-annealing the OPV devices. Implications for OPV basic research and manufacturing are discussed.

Original languageEnglish
Title of host publication2014 IEEE 40th Photovoltaic Specialist Conference, PVSC 2014
Place of PublicationPiscataway, NJ
PublisherInstitute of Electrical and Electronics Engineers (IEEE)
Pages2575-2580
Number of pages6
ISBN (Electronic)9781479943982
DOIs
Publication statusPublished - 15 Oct 2014
Externally publishedYes
Event40th IEEE Photovoltaic Specialist Conference, PVSC 2014 - Denver, United States
Duration: 8 Jun 201413 Jun 2014

Other

Other40th IEEE Photovoltaic Specialist Conference, PVSC 2014
CountryUnited States
CityDenver
Period8/06/1413/06/14

Keywords

  • capacitance
  • defects
  • organic semiconductors
  • photovoltaic cells

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    Nardes, A. M., Perkins, C. L., Graf, P. A., Li, J. V., Shaheen, S. E., Ostrowski, D. P., ... Kopidakis, N. (2014). Thermal annealing affects vertical morphology, doping and defect density in BHJ OPV devices. In 2014 IEEE 40th Photovoltaic Specialist Conference, PVSC 2014 (pp. 2575-2580). [6925457] Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE). https://doi.org/10.1109/PVSC.2014.6925457