Physics Seminar

Tuesday, 16 April 2013 at 16h00
(coffee at 15h45)

Campus Limpertsberg
Room BS004

Talk by Prof. Uwe Rau

IEK5-Photovoltaik, Forschungszentrum Jülich

Photons in and electrons out/ electrons in and photons out
Electroluminescence and photovoltaic action of solar cells and modules

Electroluminescence (EL) is the complementary physical action to the normal operating mode of a solar cell
or module. Therefore, photovoltaic energy conversion and electroluminescent light emission are interlinked
by the principle of detailed balance, resulting in reciprocity relations and superposition principles. Such
relations are powerful tools for the evaluation of experimental data. Based on these relations, spatially and/or
spectrally resolved EL is widely used as a tool for the quantitative characterization of solar cells and modules.
However, the validity of these relations relies on the extrapolation of equilibrium rate constants towards nonequilibrium
situations. Therefore, the validity of the relations must be tested for every type of photovoltaic
material and device. The lecture will investigate under which circumstances basic principles like the
reciprocity between EL emission and photovoltaic quantum efficiency or the linear superposition of EL and
photoluminescence are strictly valid. The fundamental aspects of electro- and photoluminescence of different
photovoltaic materials at various temperatures will be discussed and examples for EL investigations will be
given covering a wide range of length scales from the square meter size of a solar module down to the
microscopic aspect of radiative transitions in a photovoltaic material.

Next Physics Seminars
• Tuesday, 23 April 2013 Prof. Hartmut Loewen
Limpertsberg, 16h00 What active particle can do together
• Tuesday, 30 April 2013 Prof. Gregory C. Rutledge
Limpertsberg, 16h00

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