Elucidating the Factors that Determine the Open Circuit Voltage in Discrete Heterojunction Organic Photovoltaic Cells

Journal Article · Fri Jan 01 04:00:00 EST 2010 · Journal of Materials Chemistry

DOI:https://doi.org/10.1039/b919723k· OSTI ID:1020063

Chauhan, V; Hatton, R; Sullivan, P; Jones, T; Cho, S; Piper, L; DeMasi, A; Smith, K

The operation of discrete heterojunction organic photovoltaic (OPV) cells employing chloro-aluminium phthalocyanine (ClAlPc) as the electron donor and C{sub 60} 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 (V{sub oc}) in discrete heterojunction OPVs. The measured V{sub oc} 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 V{sub oc} in OPVs employing the archetypal electron donor, copper phthalocyanine.

• Research Organization: Brookhaven National Laboratory (BNL) National Synchrotron Light Source
• Sponsoring Organization: DOE - OFFICE OF SCIENCE
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1020063
• Report Number(s): BNL--95911-2011-JA
• Journal Information: Journal of Materials Chemistry, Journal Name: Journal of Materials Chemistry Journal Issue: 6 Vol. 20; ISSN JMACEP; ISSN 0959-9428
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
ALIGNMENT
BINDING ENERGY
COPPER
ELECTRIC POTENTIAL
ELECTRODES
ELECTRONS
ENERGY LEVELS
FERMI LEVEL
HETEROJUNCTIONS
ORIGIN
PHOTOVOLTAIC CELLS
PHTHALOCYANINES
VALENCE
X-RAY PHOTOELECTRON SPECTROSCOPY
national synchrotron light source