Alkyl Surface Treatments of Planar Zinc Oxide in Hybrid Organic/Inorganic Solar Cells

Journal Article · Thu Apr 26 00:00:00 EDT 2012 · Journal of Physical Chemistry. C

DOI:https://doi.org/10.1021/jp211692m· OSTI ID:1048585

Allen, C G; Baker, D J; Brenner, T M; Weigand, C C; Albin, J M; Steirer, K X; Olson, D C; Ladam, C; Ginley, D S; Collins, R T; Furtak, T E

Hybrid organic/inorganic solar cells have not lived up to their potential because of poor interface properties. Interfacial molecular layers provide a way of adjusting these devices to improve their performance. We have studied a prototypical system involving poly(3-hexylthiophene) (P3HT) on planar zinc oxide (ZnO) films that have been modified with two types of molecules having identical 18-carbon alkyl chain termination and different surface attachments: octadecanethiol (ODT) and octadecyltriethoxysilane (OTES). We examined the functionalized surfaces using water contact angle measurements, Kelvin probe measurements, infrared absorbance spectroscopy, and atomic force microscopy. These have shown that OTES forms disordered incomplete monolayers, while ODT is prone to develop multilayered islands. Both treatments enhance polymer ordering. However, inverted solar cell devices fabricated with these treated interfaces performed very differently. ODT improves the short circuit current (J{sub SC}), open circuit voltage (V{sub OC}), and power conversion efficiency ({eta}), while these parameters all decrease in devices constructed from OTES-treated ZnO. The differences in V{sub OC} are related to modifications of the surface dipole associated with deposition of the two types of alkyl molecules, while changes in J{sub SC} are attributed to a balance between charge transfer blocking caused by the saturated hydrocarbon and the improved hole mobility in the polymer.

• Research Organization: National Renewable Energy Lab. (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
• DOE Contract Number: AC36-08GO28308
• OSTI ID: 1048585
• Report Number(s): NREL/JA-5200-55502; TRN: US201216%%1018
• Journal Information: Journal of Physical Chemistry. C, Vol. 116, Issue 16; ISSN 1932-7447
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ATOMIC FORCE MICROSCOPY
DEPOSITION
DIPOLES
EFFICIENCY
ELECTRIC POTENTIAL
ELECTRICAL FAULTS
HOLE MOBILITY
HYDROCARBONS
ISLANDS
MODIFICATIONS
PERFORMANCE
POLYMERS
PROBES
SOLAR CELLS
SPECTROSCOPY
SURFACE TREATMENTS
WATER
ZINC OXIDES
solar energy
solar cells
organic photovoltaic devices