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Chalcopyrite copper indium sulfide (CuInS 2 , CIS) has a bandgap that is optimal for a solar energy conversion material. In this paper, we used a polymer-type ion release source to control the precursor concentration of the hydrothermal system to grow CIS nanowires. The analytical results indicate that the reaction process is based on the formation of CuS binary compound, which is then followed by indium intercalation, which induces the formation of the CIS chalcopyrite crystal structure. The products were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The CIS nanowires were 100–300 nm in diameter and 2–5 µm in length. [ABSTRACT FROM AUTHOR]

To improve the performance of the thin hematite photoanode for photoelectrochemical water oxidation, in this work, an nN(+) α-Fe2O3 (hematite)-TiO2 heterojunction photoanode is constructed on fluorine-doped tin oxide substrate to establish a built-in field in the space charge region for facilitating the charge separation in the hematite layer. Charge distribution in the hematite-TiO2 heterostructure is investigated using Kelvin probe force microscopy, which confirms the improvement of charge separation in hematite layer by the formation of energy-matched nN(+) α-Fe2O3-TiO2 heterojunction. Compared to the hematite photoanode, an eightfold enhancement of the photocurrent density at 1.23 V versus reversible hydrogen electrode is measured in the hematite-TiO2 heterojunction photoanode. By using hydrogen peroxide as a hole scavenger, it demonstrates that both charge separation and charge injection efficiencies in the hematite-TiO2 heterojunction photoanode are superior to those in the hematite photoanode. It results from the significant suppressions of the charge recombinations occurring within the hematite layer as well as at the interface of photoelectrode and electrolyte by the formation of the nN(+) α-Fe2O3-TiO2 heterojunction.