Journal Article

FZJ-2021-00092

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Luminescence Analysis of Charge-Carrier Separation and Internal Series-Resistance Losses in Cu ( In , Ga ) Se 2 Solar Cells

Rau, U. (Corresponding author)FZJ* ; Huhn, V. ; Pieters, B.FZJ*

2020
American Physical Society College Park, Md. [u.a.]

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Please use a persistent id in citations: http://hdl.handle.net/2128/26698  doi:10.1103/PhysRevApplied.14.014046

Abstract: Cu(In,Ga)Se2 solar cells are investigated by luminescence measurements. We construct the current vs. internal voltage characteristics of these devices from the luminescence intensity at different voltage and light bias conditions. A comparison of these characteristics to electrically measured current vs. voltage curves unveils an internal resistance loss that is strongly dependent on voltage bias and illumination. Especially, we find significant residual luminescence for the device under short circuit conditions. Numerical device simulations reveal that this effect is caused by a drop of the electron Quasi-Fermi-level within the space charge region of the absorber material. We use a modified equivalent circuit model to describe the observed behavior in terms of simple equations. We show that such a voltage dependent series resistance leads to a violation of a linear network theorem which under standard circumstances provides a useful method for the determination of the photocurrent collection efficiency. An analysis of resistive and recombination losses in the devices demonstrates that the internal voltage dependent series resistance causes an efficiency loss of about 1.3 % (absolute) for a device with an efficiency 13.4 %. Finally, we show that the observed behavior is general feature of charge carrier separation in solar cells with finite charge carrier mobility and that the intensity of the residual sort circuit luminescence provides valuable information on the efficiency of this process.

Keyword(s): Energy (1st) ; Materials Science (2nd)

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Contributing Institute(s):

1. Photovoltaik (IEK-5)

Research Program(s):

1. 121 - Solar cells of the next generation (POF3-121) (POF3-121)

Appears in the scientific report 2020

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Essential Science Indicators ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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