Sputtered Nickel Oxide Thin Film for Efficient Hole Transport Layer in Polymer-Fullerene Bulk-Heterojunction Organic Solar Cell

Journal Article · Thu Mar 01 00:00:00 EST 2012 · Thin Solid Films

DOI:https://doi.org/10.1016/j.tsf.2011.10.059· OSTI ID:1049613

Widjonarko, N. Edwin; Ratcliff, E. L.; Perkins, Craig L.; Sigdel, Ajaya K.; Zakutayev, Andriy; Ndione, Paul F.; Gillaspie, Dane T.; Ginley, David S.; Olson, Dana C.; Berry, Joseph J.

Bulk-heterojunction (BHJ) organic photovoltaics (OPV) are very promising thin film renewable energy conversion technologies due to low production cost by high-throughput roll-to-roll manufacturing, an expansive list of compatible materials, and flexible device fabrication. An important aspect of OPV device efficiency is good contact engineering. The use of oxide thin films for this application offers increased design flexibility and improved chemical stability. Here we present our investigation of radio frequency magnetron sputtered nickel oxide (NiO{sub x}) deposited from oxide targets as an efficient, easily scalable hole transport layer (HTL) with variable work-function, ranging from 4.8 to 5.8 eV. Differences in HTL work-function were not found to result in statistically significant changes in open circuit voltage (V{sub oc}) for poly(3-hexylthiophene):[6,6]-phenyl-C{sub 61}-butyric acid methyl ester (P3HT:PCBM) BHJ device. Ultraviolet photoemission spectroscopy (UPS) characterization of the NiO{sub x} film and its interface with the polymer shows Fermi level alignment of the polymer with the NiO{sub x} film. UPS of the blend also demonstrates Fermi level alignment of the organic active layer with the HTL, consistent with the lack of correlation between V{sub oc} and HTL work-function. Instead, trends in j{sub sc}, V{sub oc}, and thus overall device performance are related to the surface treatment of the HTL prior to active layer deposition through changes in active layer thickness.

• 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: 1049613
• Report Number(s): NREL/JA-5200-55528; THSFAP; TRN: US201218%%91
• Journal Information: Thin Solid Films, Vol. 520, Issue 10; ISSN 0040-6090
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
ALIGNMENT
DEPOSITION
EFFICIENCY
ELECTRIC POTENTIAL
ENERGY CONVERSION
ESTERS
FABRICATION
FERMI LEVEL
FLEXIBILITY
MAGNETRONS
MANUFACTURING
NICKEL OXIDES
ORGANIC SOLAR CELLS
OXIDES
PHOTOEMISSION
POLYMERS
SPECTROSCOPY
STABILITY
SURFACE TREATMENTS
TARGETS
THICKNESS
THIN FILMS
nickel oxide
organic solar cells
hole transport layer
selective interlayer
work-function
organic-oxide interface