On the Germanium Incorporation in Cu2ZnSnSe4 Kesterite Solar Cells Boosting Their Efficiency

Ritzer M, Schoenherr S, Schoeppe P, Wisniewski W, Giraldo S, Gurieva G, Johannes A, Plass CT, Ritter K, Martinez-Criado G, Schorr S, Saucedo E, Ronning C, Schnohr CS (2020)

Publication Type: Journal article

Publication year: 2020

Journal

ACS Applied Energy Materials American Chemical Society

Book Volume: 3

Pages Range: 558-564

Journal Issue: 1

DOI: 10.1021/acsaem.9b01784

Abstract

The presence of Ge during the synthesis of thin film kesterite Cu2ZnSnSe4 (CZTSe) solar cell absorbers boosts their power conversion efficiency, especially due to an improved open circuit voltage. The mechanism underlying this beneficial effect of Ge is still under debate. We gained deep insights into the role of Ge by applying advanced synchrotron nanoprobe-based X-ray fluorescence spectroscopy and X-ray absorption near-edge structure spectroscopy to cross-sectional lamellas taken from high efficiency devices. We observe that Ge remains in the CZTSe absorber layer after the synthesis process with a specific heterogeneous distribution. Different grains contain different Ge concentrations. Moreover, Ge depletion exists at random grain boundaries but not at symmetric ς3-boundaries, leading to different band alignments. The incorporated Ge occupies Sn lattice sites in the CZTSe crystal structure; however, the concentration is only 0.1 to 0.5 at %. Also Ge aggregates in nanoscale inclusions, which we could identify to be GeO2 that likely lessen the beneficial effect of Ge on the photovoltaic performance.

Involved external institutions

Friedrich-Schiller-Universität Jena DE Germany (DE) Trenčianska univerzita Alexandra Dubčeka v Trenčíne SK Slovakia (SK) Catalonia Institute for Energy Research / Institut de Recerca en Energia de Catalunya (IREC) ES Spain (ES) Helmholtz-Zentrum Berlin für Materialien und Energie (HZB) DE Germany (DE) European Synchrotron Radiation Facility (ESRF) FR France (FR) Spanish National Research Council / Consejo Superior de Investigaciones Científicas (CSIC) ES Spain (ES)

How to cite

APA:

Ritzer, M., Schoenherr, S., Schoeppe, P., Wisniewski, W., Giraldo, S., Gurieva, G.,... Schnohr, C.S. (2020). On the Germanium Incorporation in Cu2ZnSnSe4 Kesterite Solar Cells Boosting Their Efficiency. ACS Applied Energy Materials, 3(1), 558-564. https://doi.org/10.1021/acsaem.9b01784

MLA:

Ritzer, Maurizio, et al. "On the Germanium Incorporation in Cu2ZnSnSe4 Kesterite Solar Cells Boosting Their Efficiency." ACS Applied Energy Materials 3.1 (2020): 558-564.

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