Multi-nuclear ( 119 Sn and 65 Cu) NMR and Raman spectroscopy to probe secondary phases in Cu 2 ZnSnS 4

Raman spectroscopy is combined with X-ray diffraction and nuclear magnetic resonance (NMR) to probe several phases in the Cu-Zn-Sn-S system, including Cu 2 ZnSnS 4 , Cu 4 Sn 7 S 16 and Cu 2 SnS 3 powders. 119 Sn and 65 Cu spectra reveal at least one other Cu-containing phase present in all samples. Most of these phases were not easily observed in x-ray diffraction or the Raman spectra. Also, contrary to previous work, the Cu in these CZTS powders was shown to exist in three unique lattice sites. Thus, NMR spectroscopy is potentially useful as a complimentary technique to traditional characterization methods due to its ability to probe secondary phases that might otherwise be undetectable.