Efficient Tandem Polymer Solar Cells Fabricated by All-Solution Processing

✍ Scribed by Kim, J. Y.; Lee, K.; Coates, N. E.; Moses, D.; Nguyen, T.-Q.; Dante, M.; Heeger, A. J.

• Book ID: 111874410
• Publisher: American Association for the Advancement of Science
• Year: 2007
• Tongue: English
• Weight: 455 KB
• Volume: 317
• Category: Article
• ISSN: 0036-8075
• DOI: 10.1126/science.1141711

✦ Synopsis

Tandem solar cells, in which two solar cells with different absorption characteristics are linked to use a wider range of the solar spectrum, were fabricated with each layer processed from solution with the use of bulk heterojunction materials comprising semiconducting polymers and fullerene derivatives. A transparent titanium oxide (TiO
~x~
) layer separates and connects the front cell and the back cell. The TiO
~x~
layer serves as an electron transport and collecting layer for the first cell and as a stable foundation that enables the fabrication of the second cell to complete the tandem cell architecture. We use an inverted structure with the low band-gap polymer-fullerene composite as the charge-separating layer in the front cell and the high band-gap polymer composite as that in the back cell. Power-conversion efficiencies of more than 6% were achieved at illuminations of 200 milliwatts per square centimeter.