Study on formation and characterization of CZTSSe-based absorber layer from a green solution based approach

• Published in: Solar energy materials and solar cells 2019-09, Vol.200, p.109959, Article 109959
• Main Authors: Kogler, Willi, Schnabel, Thomas, Ahlswede, Erik, Powalla, Michael
• Format: Article
• Language: English
• Subjects: Absorbers (materials); Ammonium; Carbon; Carbon-rich intermediate layer; CZTSSe; Fabrication; High temperature; Kesterite; Localization; Photovoltaic cells; Solar cells; Solution processing
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2019.109959

In this work, investigations on the localization and impairment of carbon residuals on device performance were performed. A green, ammonium thioglycolate (ATGL)-based solution process was used to fabricate the Cu2ZnSn(S,Se)4 (CZTSSe) absorber material. The resulting absorber triple layer structure was characterized in detail combining various characterizations methods to localize the carbon residuals from the utilized ink. Major differences were found between the upper and lower large-grained layer and the intermediate fine-grained layer. Furthermore, a formation mechanism for the absorber layer stack was derived from stopping the high temperature fabrication process and analyzing the respective samples. Investigations of the impact of the fine-grained intermediate layer on the solar cell parameters revealed that it does not contribute to the device performance. •Carbon residuals accumulate in the absorber in the form of an intermediate layer.•Formation mechanism of the absorber layer stack is derived from experimental data.•The intermediate layer does not contribute to the device performance.