Overall Distribution of Rubidium in Highly Efficient Cu(In,Ga)Se2 Solar Cells

Schoeppe P, Schoenherr S, Jackson P, Wuerz R, Wisniewski W, Ritzer M, Zapf M, Johannes A, Schnohr CS, Ronning C (2018)

Publication Type: Journal article

Publication year: 2018

Journal

ACS Applied Materials and Interfaces American Chemical Society

Book Volume: 10

Pages Range: 40592-40598

Journal Issue: 47

DOI: 10.1021/acsami.8b16040

Abstract

Thin-film solar cells based on Cu(In,Ga)Se2 (CIGS) absorbers have achieved conversion efficiencies close to 23%. Such a high performance could be reached by incorporating heavy alkali elements into the CIGS absorber using an alkali fluoride post-deposition treatment (PDT). In order to improve the understanding of the effect of the PDT, we investigated a highly efficient CIGS solar cell whose absorber was subjected to a RbF-PDT. By applying synchrotron-based X-ray fluorescence analysis in combination with scanning transmission electron microscopy and electron backscatter diffraction to a cross-sectional lamella of the whole device, we were able to correlate the local composition of the absorber with its microstructure. The incorporated Rb accumulates at grain boundaries, with a random misorientation of the adjacent grains, at the p-n junction, and at the interface between the absorber and the MoSe2 layer. The accumulation of Rb at the grain boundaries is accompanied by a reduced Cu concentration and slightly increased In and Se concentrations. Additionally, variations in the local composition of the absorber at the p-n junction indicate the formation of a secondary phase, which exhibits a laterally inhomogeneous distribution. The improved solar cell performance due to RbF-PDT can thus be expected to originate from a favorable modification of the back contact interface, the random grain boundaries, the p-n junction, or a combination of these effects.

Involved external institutions

Friedrich-Schiller-Universität Jena DE Germany (DE) Zentrum für Sonnenenergie- und Wasserstoff-Forschung (ZSW) DE Germany (DE) European Synchrotron Radiation Facility (ESRF) FR France (FR)

How to cite

APA:

Schoeppe, P., Schoenherr, S., Jackson, P., Wuerz, R., Wisniewski, W., Ritzer, M.,... Ronning, C. (2018). Overall Distribution of Rubidium in Highly Efficient Cu(In,Ga)Se2 Solar Cells. ACS Applied Materials and Interfaces, 10(47), 40592-40598. https://doi.org/10.1021/acsami.8b16040

MLA:

Schoeppe, Philipp, et al. "Overall Distribution of Rubidium in Highly Efficient Cu(In,Ga)Se2 Solar Cells." ACS Applied Materials and Interfaces 10.47 (2018): 40592-40598.

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