On the use of cyanine dyes as low-bandgap materials in bulk heterojunction photovoltaic devices

作者:Castro Fernando A; Faes Antonin; Geiger Thomas; Graeff Carlos F O; Nagel Matthias; Nueesch Frank; Hany Roland*
来源:Synthetic Metals, 2006, 156(14-15): 973-978.
DOI:10.1016/j.synthmet.2006.06.010

摘要

Cyanine dyes with absorption edges of almost 1000nm were used in combination with MEH-PPV for the fabrication of organic solar cells. For blended thin films, a pronounced phase separation between the two components occurred and resulted in photocurrents with different signs for bilayer and bulk heterojunction devices. Absorption spectra and selective dissolution experiments were used to illustrate the process of vertical phase segregation, with the preferential wetting of the polar anode by the cyanines while maintaining percolating carrier pathways between the electrodes. For a cyanine with long alkyl side chains, the compatibility with the polymer matrix was increased and the development of the effective inverted bilayer configuration was not observed. The generally low oxidative photocurrents were explained with unfavourable shifts of the highest occupied molecular orbital (HOMO) dye energy levels in the solid state.

  • 出版日期2006-7-1