Regensburg 2013 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 92: Poster Session: Structure and transport in organic photovoltaics; Photovoltaics; Impurities/Amorphous semiconductors; New materials

HL 92.12: Poster

Thursday, March 14, 2013, 16:00–20:00, Poster A

Temperature-dependent quantum efficiency measurements on Cu(In,Ga)Se₂ thin film solar cells — •Thorsten Sonnet, Janet Neerken, Dirk Otteken, Jürgen Parisi, Ingo Riedel, and Maria Hammer — Energy and Semiconductor Research Laboratory, Department of Physics, University of Oldenburg, 26111 Oldenburg, Germany

Solar cells based on Cu(In,Ga)Se₂ absorber layers demonstrate high power conversion efficiencies around 20%. However, solar cells obtained from industrial production exhibit lower efficiencies. In order to understand the physical mechanisms, the characterization of internal and external losses of the solar cell is important. While the temperature dependence of the open circuit voltage of the cells is an established tool to characterize recombination processes, the fact of a temperature dependent photocurrent is often overlooked. In order to characterize the collection efficiency, temperature-dependent internal quantum efficiency (IQE(T)) measurements were performed. The spectral response of the sample is measured within a temperature range from 100 K to 300 K. A reference cell and reflectance measurements of the sample at room temperature are used to calculate the internal quantum efficiency. From these measurements the temperature-dependent carrier diffusion length and thus the minority carrier lifetime can be extracted.