Cu2SnS3 (CTS) thin films were produced by the co-evaporation of Cu, Sn, and cracked sulfur, followed by annealing. The as-deposited films were then annealed at 570 °C for 5 min in the presence of 100 mg of sulfur lumps in a rapid thermal processing furnace filled with N2 gas at atmospheric pressure. Solar cells were then fabricated using the CTS films as absorber layers, and their efficiency was evaluated for different Cu/Sn compositional ratios. The largest grain size was found for films with a slightly Sn-rich composition. The highest performance was obtained for solar cells containing a CTS thin film with a Cu/Sn ratio of about 1.9. A cell with a Cu/Sn ratio of 1.87 exhibited an open-circuit voltage of 258 mV, a short-circuit current density of 35.6 mA/cm2, a fill factor of 0.467, and a power conversion efficiency of 4.29%.

We report on the sulfurization of metal-alloyed precursors in Cu 2 SnS 3 (CTS)-based thin-film solar cells. CTS thin films were prepared through the sulfurization of Cu-Sn alloy precursors at sulfurization temperatures of 500-580 °C for 2 h in a N 2 atmosphere with sulfur vapor. The Cu/Sn composition ratios of the sulfurized films were determined by X-ray fluorescence analysis to be in the range of 1.77-1.89. The photovoltaic properties of CTS-based solar cells improved with increasing sulfurization temperature owing to the higher external quantum efficiency at long wavelengths. The solar cell comprising a CTS thin film with a sulfurization temperature of 580 °C exhibited the optimum performance among the cells examined: an open-circuit voltage of 244 mV, a short-circuit current density of 29 mA/cm 2 , a fill factor of 0.385, and a conversion efficiency of 2.7% were obtained.

Cu2SnS3 is a promising compound for use as an absorber layer in thin film solar cells because it is made up of low‐cost and abundant elements, and has a high optical absorption coefficient. However, the band gap energy of monoclinic Cu2SnS3 is less than the value required for absorber layers in single‐junction solar cells. On the other hand, the band gap energy of Cu2SiS3 was reported to be approximately 2.5 eV, which is sufficiently large for this purpose. Therefore, in the present study, an attempt was made to synthesize Cu2Six Sn1‐xS3, which is a solid solution between Cu2SnS3 and Cu2SiS3. In X‐ray diffraction patterns from the synthesized compounds, the diffraction peaks were found to shift to higher 2θ values with increasing x, indicating a decrease in the lattice constants. In addition, the estimated band gap energy increased from 0.85 to 2.56 eV with increasing x. Cu2Six Sn1‐xS3 is therefore a potential candidate for use as the absorber layer in thin film solar cells because its band gap energy can be adjusted simply by varying its composition. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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We report a successful growth of the ZnMgHf F-type icosahedral quasicrystal in the form of faceted single grains. By varying the heat treatment parameters we were able to obtain single crystals with a quality suitable for a single crystal X-ray diffraction which was conducted in a synchrotron facility. Ab initio structure solution by a charge flipping algorithm manifests the existence of two types of Bergman clusters. Clusters are differentiated by the preferential occupation of the high-symmetry positions by hafnium in a rhombic triacontahedron, being the outer shell of the atomic cluster. This paper is part of a Thematic Issue on The Crystallographic Aspects of Metallic Alloys.