Efficient inverted polymer solar cells

Authors

G. Li, University of California, Los Angeles
C.-W. Chu, University of California, Los Angeles
V. Shrotriya, University of California at Los Angeles
Jinsong Huang, University of Nebraska-LincolnFollow
Y. Yang, University of California at Los Angeles

Document Type

Article

Date of this Version

2006

Citation

APPLIED PHYSICS LETTERS 88, 253503 (2006)

Comments

© 2006 American Institute of Physics.

Abstract

We investigate the effect of interfacial buffer layers—vanadium oxide (V₂O₅) and cesium carbonate (Cs₂CO₃)—on the performance of polymer solar cells based on regioregular poly-(3-hexylthiophene) and [6,6]-phenyl C₆₀ butyric acid methyl ester blend. The polarity of solar cells can be controlled by the relative positions of these two interfacial layers. Efficient inverted polymer solar cells were fabricated with the structure of indium tin oxide (ITO)/Cs₂CO₃/polymer blend/vanadium oxide (V₂O₅)/aluminum (Al). Short-circuit current of 8.42 mA/cm2, open-circuit voltage of 0.56 V, and power conversion efficiency of 2.25% under a AM1.5G 130 mW/cm² condition were achieved. The interfacial layers were also used to fabricate polymer solar cells using ITO and a thin gold (Au) layer as the transparent electrodes. The thickness of V₂O₅ layer (10 nm) makes it an effective protective layer for the active layer so that ITO can be used for both the electrodes, enabling highly efficient transparent polymer solar cells (i.e., polymer solar cells with transparent electrodes). Application of this structure for multiple-stacking polymer solar cells is also discussed.