Fabrication of hollow-sphere films of wurtzite CuInS2 on copper substrate

As important semiconductors, I–III–VI2 compounds have attracted wide attention, among which the wurtzite structured CuInS2 has been the research focus due to its metastable phase. In this paper, the wurtzite CuInS2 hollow-sphere films have been successfully prepared on copper substrate in a self-designed solvothermal detached system. The films of Cu(OH)2 one-dimensional nanostructure arrays and thioacetamide were used as the precursors and triethylene glycol was used as the solvent. Experiments showed that the amount of indium trichloride played a determinative role in the final morphology of the products. Meanwhile, the one-dimensional nanostructure arrays and the detached solvothermal system have great influences on the crystal shape as well. Based on the experimental results, a possible formation mechanism for the CuInS2 hollow spheres was also proposed. The UV–Vis absorption spectrum showed a broad absorption over the entire visible light and extending into the near-infrared region and presented the band gap of 1.53 eV for the as-prepared wurtzite CuInS2, which indicates the potential applications in solar cells. - Highlights: • A self-designed detached system along with solvothermal treatment was developed. • Wurtzite CuInS2 hollow-sphere films were successfully fabricated on Cu substrate. • The detached system and InCl3 usage were crucial for the hollow spheres. • The broadband absorption and 1.53 eV band-gap indicates its potentials in PV