Atomic Scale Structure of (Ag,Cu)2ZnSnSe4 and Cu2Zn(Sn,Ge)Se4 Kesterite Thin Films

Frontiers in Energy Research

Rakesh Agrawal¹  Charles J. Hages²  Edmund Welter³  Claudia S. Schnohr⁴  Konrad Ritter⁴  Stefanie Eckner⁴  Galina Gurieva⁵  Susan Schorr⁶  Maurizio Ritzer⁷  Cora Preiß⁷ 

[1] Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, United States;Department of Chemical Engineering, University of Florida, Gainesville, FL, United States;Deutsches Elektronen-Synchrotron DESY−A Research Centre of the Helmholtz Association, Hamburg, Germany;Felix-Bloch-Institut für Festkörperphysik, Universität Leipzig, Leipzig, Germany;Institut für Festkörperphysik, Friedrich-Schiller-Universität, Jena, Germany;Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany;Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany;Institut für Geologische Wissenschaften, Freie Universität Berlin, Berlin, Germany;Institut für Festkörperphysik, Friedrich-Schiller-Universität, Jena, Germany;

关键词: kesterite;    CZTGSe;    ACZTSe;    thin films;    alloys;    EXAFS;    local atomic structure;   

DOI  :  10.3389/fenrg.2021.656006

来源: Frontiers

【 摘 要 】

Kesterite based materials are being researched and developed as affordable, efficient, and mechanically flexible absorber materials for thin film photovoltaics. Both (Ag,Cu)2ZnSnSe4 and Cu2Zn(Sn,Ge)Se4 based devices have shown great potential in overcoming some of the remaining challenges for further increasing the conversion efficiency of kesterite based solar cells. This study therefore investigates the long range crystallographic structure and the local atomic scale structure of technologically relevant thin films by means of grazing incidence X-ray diffraction and low temperature X-ray absorption spectroscopy. As expected, the unit cell dimensions change about an order of magnitude more than the element specific average bond lengths. In case of Cu2Zn(Sn,Ge)Se4, the thin film absorbers show a very similar behavior as Cu2Zn(Sn,Ge)Se4 powder samples previously studied. Small amounts of residual S in the thin films were taken into account in the analysis and the results imply a preferential formation of Sn-S bonds instead of Ge-S bonds. In (Ag,Cu)2ZnSnSe4, the dependence of the Ag-Se and Cu-Se bond lengths on Ag/(Ag+Cu) might indicate an energetic advantage in the formation of certain local configurations.

【 授权许可】

CC BY