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arXiv · 1406.2326

Suns-V$_\textrm{OC}$ characteristics of high performance kesterite solar cells

Oki Gunawan·Tayfun Gokmen·David B. Mitzi
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Abstract

Low open circuit voltage ($V_{OC}$) has been recognized as the number one problem in the current generation of Cu$_{2}$ZnSn(Se,S)$_{4}$ (CZTSSe) solar cells. We report high light intensity and low temperature Suns-$V_{OC}$ measurement in high performance CZTSSe devices. The Suns-$V_{OC}$ curves exhibit bending at high light intensity, which points to several prospective $V_{OC}$ limiting mechanisms that could impact the $V_{OC}$, even at 1 sun for lower performing samples. These V$_{OC}$ limiting mechanisms include low bulk conductivity (because of low hole density or low mobility), bulk or interface defects including tail states, and a non-ohmic back contact for low carrier density CZTSSe. The non-ohmic back contact problem can be detected by Suns-$V_{OC}$ measurements with different monochromatic illumination. These limiting factors may also contribute to an artificially lower $J_{SC}$-$V_{OC}$ diode ideality factor.

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Oki Gunawan, Tayfun Gokmen, David B. Mitzi. 2014-06-09. Suns-V$_\textrm{OC}$ characteristics of high performance kesterite solar cells. https://doi.org/10.1063/1.4893315

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