Berlin 2008 – scientific programme

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SYSA: Symposium Tayloring Organic Interfaces: Molecular Structures and Applications

SYSA 5: Poster Session SYSA

SYSA 5.36: Poster

Tuesday, February 26, 2008, 14:30–20:00, Poster A

External Quantum Efficiency of p-i-n Solar Cells incorporating Oligothiophene:Fullerene Heterojunctions — •Holger Seifert¹, Rico Schueppel¹, Eduard Brier², Egon Reinold², Peter Baeuerle², Moritz K. Riede¹, and Karl Leo¹ — ¹Institut für Angewandte Photophysik, Technische Universität Dresden — ²Institut für Organische Chemie II und Neue Materialien, Universität Ulm

We investigate organic p-i-n solar cells with an oligothiophene derivative as donor and Fullerene C₆₀ as acceptor materials. This donor-acceptor heterojunction leads to solar cells with an open circuit voltage as high as 1.0V and a reasonable power conversion efficiency of up to 3.4% [1].

Measuring current-voltage characteristics under monochromatic illumination of low intensity (non-standard reporting conditions), we find a wavelength dependent fill factor of these photovoltaic devices.

Furthermore, we determine the external quantum efficiency (EQE) from the photoresponse of these devices using a modulated monochromatic illumination on top of a white light bias as well as an external voltage bias. The EQE spectrum can be attributed to the spectrally different absorption of donor and acceptor. We discuss the dependence of the EQE spectrum from the applied external voltage with respect to the charge generation mechanism.

[1] K. Schulze et al., Adv. Mater. 18, 2872 (2006).