Elucidating the factors that determine the open circuit voltage in discrete heterojunction organic photovoltaic cells

Virendra Chauhan, Ross Hatton, Paul Sullivan, Tim Jones, Sangwan Cho, Louis Piper, Alex Demasi, Kevin Smith

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23 Citations (Scopus)


The operation of discrete heterojunction organic photovoltaic (OPV) cells employing chloro-aluminium phthalocyanine (ClAlPc) as the electron donor and C60 as the electron acceptor is reported and the characteristics are correlated with the energy level structure of the devices determined using X-ray photoelectron spectroscopy. The results give new insight into the origin of the open circuit voltage (Voc) in discrete heterojunction OPVs. The measured Voc in this system is found to be determined by: (i) the frontier orbital energy offsets between the donor and acceptor materials, accounting for the likely formation of an abrupt vacuum level shift at the heterojunction interface and (ii) the degree of alignment between the hole-extracting electrode Fermi level and the highest occupied molecular orbital energy of the electron donor material. The generality of the findings is demonstrated by rationalising the Voc in OPVs employing the archetypal electron donor, copper phthalocyanine.

Original languageEnglish
Pages (from-to)1173-1178
Number of pages6
JournalJournal of Materials Chemistry
Issue number6
Publication statusPublished - 2010 Mar 24


All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Chemistry

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