15 April 1997 High-sensitivity photodetectors made with charge-transfer polymer blends
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Blending organic semiconductors with different electron affinities results in an interpenetrating bi-continuous network of internal donor/acceptor (D/A) heterojunctions. These nano-scale D/A junctions show efficient charge separation and charge transfer. The interpenetrating bi- continuous networks of the donor and the acceptor phases also allow the separated carriers to be collected effectively at the anode and cathode contacts. Typical materials used for the donor phase are conjugated polymers (MEH-PPV). Typical materials used for the acceptor phase are conjugated polymer CN-PPV or fullerene molecules. These photosensitive materials are soluble to common organic solvents, and are processable at room temperature. Photodiodes and photovoltaic cells are fabricated with high quantum efficiencies. The carrier collection efficiency and energy conversion efficiency of MEH-PPV:C60 photovoltaic cells are approximately 29 percent electrons/photon and approximately 3 percent under illumination of 20 mW/cm2 at 430 nm, two orders of magnitude higher than that in devices with MEH-PPV alone. The photosensitivity and the quantum yields increase to 0.26 A/W and approximately 75 percent electrons/photon at reverse bias of -2V, even higher than those in UV-enhanced Si photodiodes at the same wavelength. Large size photodetectors and image sensors have been fabricated with these materials.
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Gang Yu, Gang Yu, Jun Gao, Jun Gao, Cuiying Yang, Cuiying Yang, Alan J. Heeger, Alan J. Heeger, } "High-sensitivity photodetectors made with charge-transfer polymer blends", Proc. SPIE 2999, Photodetectors: Materials and Devices II, (15 April 1997); doi: 10.1117/12.271201; https://doi.org/10.1117/12.271201


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