The local atomic structure in non-stoichiometric Cu2ZnSnS4 (CZTS) thin films was investigated using X-ray absorption fine structure spectroscopy (XAFS). From the XAFS spectra we infer the presence of disorder in the Cu-Zn plane suggesting that this characteristic might be intrinsic of non-stoichiometric CZTS. This disorder increases with the Cu/(Zn+Sn) ratio. Structural parameters derived from fits to the data show a contraction in the Cu-S bond length and an expansion in the Sn-S bond length, compared to distances obtained from diffraction, for all samples. X-ray absorption near edge spectroscopy (XANES) indicates presence of secondary phases not observed by X-ray diffraction. In Cu-poor samples, ZnS and SnS were identified as secondary phases. The amount of those phases correlates with the Cu deficit and were quantified by a linear combination fit of the XANES of standard materials. This work provides direct evidence of intrinsic disorder in CZTS, which must be considered to generate a realistic atomic structural model, in addition to lattice relaxations and secondary phases.

Solubility, migration, and bioavailability of plutonium is lacunar because experimental evidences are missing. We report here on X‐ray Absorption Spectroscopy of plutonium in natural seawater. The observed valence state is +IV and its speciation corresponds to PuO2 type colloids. Furthermore, aging of the solution shows a gradient of ordering from hydroxide colloidal species to more crystalline PuO2 colloids.

The local atomic structure of multilayer films of graphene oxide, cadmium sulfide, and cadmium sulfide−selenide was analyzed by Xray absorption fine structure spectroscopy. The films were prepared by sequential electrophoretic deposition and successive ion layer adsorption and reaction onto F-doped SnO 2 substrates. The obtained films were characterized by scanning electron microscopy, energy dispersive spectroscopy, Raman spectroscopy, UV−vis spectroscopy, and step-potential photocurrent response. From the transmittance data analysis, a direct band gap ranging from 2.13 to 2.3 eV was deduced. From photocurrent measurements, we conclude that films of CdS and CdSSe have photovoltaic properties suitable for utilization as an active layer in multilayer thin film hybrid solar cells. X-ray absorption near-edge structure spectra show a difference in amplitude between CdS/GO and CdSSe/GO samples, ascribed to a change in the local electronic structure around S. Extended X-ray absorption fine structure spectra show a direct C−S bond between the CdS/CdSSe nanoparticles and the graphene oxide layer. Band diagrams for the CdS/GO and CdSSe/GO electrolyte interfaces are proposed.

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