Crystal Structure of Cu2Zn(GexSi1−x)Se4 Solid Solution: The Kesterite to Wurtz–Kesterite Structural Phase Transition
April 12, 2026
For Cu2Zn(GexSi1−x)Se4 series: Ge-rich mixed crystals Ge/(Ge+Si)=0.59-1.0 crystallize in the tetragonal kesterite type structure
(left figure), Si-rich mixed crystals with Ge/(Ge+Si)=0-0.37 adopt the monoclinic wurtz-kesterite type structure
(right figure) and bad gap energies (center figure).
Scientific Achievement
We used neutron powder diffraction (NPD) to analyze how cations shift from special positions (in the kesterite-type structure) to more general positions (in the wurtz–kesterite type structure).
Significance and Impact
Reducing structural disorder in Cu2Zn(GexSi1−x)Se4 increases band gap energies, thus making these materials candidates for top absorber layers for tandem solar cells.
Research Details
- NPD enables us to differentiate the isoelectronic cations Cu+, Zn2+ and Ge4+ in the crystal structure analysis.
- Raman spectra of Cu2Zn(GexSi1−x)Se4 were measured to deepen the understanding of the phase formation.
“Crystal structure of Cu2Zn(GexSi1−x)Se4 solid solution: the kesterite to wurtz–kesterite structural phase transition,” J. Mater. Chem. A, 14, 1770 (2026).
https://doi.org/10.1039/d5ta06163f
