Cu2ZnSnS4 is an ideal candidate absorber material for thin film solar cells with an optimal band-gap for a single junction photovoltaic device of 1.4–1.5 eV, high absorption coefficient (>104 cm-1), and abundant elemental components. In this paper, Cu2ZnSnS4 nanocrystallines have been successfully synthesized by a hydrothermal method using CuCl, ZnCl2, SnCl4·5H2O and (NH2)2CS as reaction reagents for the first time. The as-grown product was characterized by X-ray powder diffraction, transmission electron microscopy, high-resolution transmission electron microscopy and selected-area electron diffraction. The results confirm that the product was polycrystalline Cu2ZnSnS4 nanoparticles with the diameter of 5–7 nm. The effect of the reaction temperature and time on the formation of the Cu2ZnSnS4 nanocrystallines was discussed. The band-gap of Cu2ZnSnS4 nanocrystallines was estimated to be 1.70 eV via ultraviolet–visible (UV–vis) absorption spectrum of Cu2ZnSnS4 nanocrystallines. Raman spectrum of Cu2ZnSnS4 nanocrystallines had about 8 cm-1 red-shift in comparison with that of the responding bulk counterpart.

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In this paper, pulsed infrared thermography is applied to the study of a mold casting Chinese bronze lei 罍 dated to the late Shang dynasty (c.a.1250–1050 BC), currently housed in the Capital Normal University Museum. Many spacers and a defective area of this ancient bronze are partly covered with repair material. By analyzing thermographic images using a one-layer thermal diffusion model, it is found that the spacers were specifically made for this bronze. The thickness of the repairing material in the defective area is measured using thermal quadrupole modelling in multi-layer materials. This is the first application of this method to the field of cultural heritage conservation. These results provide a deeper understanding of the manufacturing process of ancient Chinese bronzes from the viewpoint of archaeological research. They also help assess the repair status from the conservation viewpoint.