Details

Autor(en) / Beteiligte

• Congreve, Daniel N.
• Lee, Jiye
• Thompson, Nicholas J.
• Hontz, Eric
• Yost, Shane R.
• Reusswig, Philip D.
• Bahlke, Matthias E.
• Reineke, Sebastian
• Van Voorhis, Troy
• Baldo, Marc A.

Titel

External Quantum Efficiency Above 100% in a Singlet-Exciton-Fission–Based Organic Photovoltaic Cell

Ist Teil von

• Science (American Association for the Advancement of Science), 2013-04, Vol.340 (6130), p.334-337

Ort / Verlag

United States: American Association for the Advancement of Science

Erscheinungsjahr

2013

Quelle

American Association for the Advancement of Science

Beschreibungen/Notizen

• Singlet exciton fission transforms a molecular singlet excited state into two triplet states, each with half the energy of the original singlet. In solar cells, it could potentially double the photocurrent from high-energy photons. We demonstrate organic solar cells that exploit singlet exciton fission in pentacene to generate more than one electron per incident photon in a portion of the visible spectrum. Using a fullerene acceptor, a poly(3-hexylthiophene) exciton confinement layer, and a conventional optical trapping scheme, we show a peak external quantum efficiency of (109 ± 1)% at wavelength λ = 670 nanometers for a 15-nanometer-thick pentacene film. The corresponding internal quantum efficiency is (160 ± 10)%. Analysis of the magnetic field effect on photocurrent suggests that the triplet yield approaches 200% for pentacene films thicker than 5 nanometers.