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Silver sulfide (Ag 2 S) attached to ZnO nanorods film has been successfully prepared by a two-step hydrothermal process. The prepared photoelectrodes were characterized by Field Emission Scanning Eletron Microscopy (FESEM), Energy Dispersive Spectroscopy (EDS), X-ray diffractometry (XRD), UV-vis spectrophotometry (UV–vis) and photoelectrochemical measurements (PEC). The results revealed that Ag 2 S deposited onto the surface of ZnO nanorods was under the influence of growth temperature. The absorption in the visible region and efficient transfer of photoelectron between Ag 2 S/ZnO/ITO photoelectrode and the redox species in the electrolyte were significantly enhanced under the illumination intensity of 100 mW cm−2. The band gap values of the five different growth temperatures ranging from 50 °C to 90 °C were found to decrease from 2.93 eV to 1.57 eV. Besides, the photoelectrochemical measurements verified that Ag 2 S/ZnO nanocomposite grown at 60 °C exhibited the highest photocurrent density of 3.97 mA/cm2 at 1.0 V. The findings suggested that Ag 2 S/ZnO nanocomposite is an efficient alternative for photoelectrode applications. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A nanocomposite nanostructured Ag 2 S sensitized ZnO NRAs synthesised via hydrothermal method. • Photoelectrochemical analysis verified that the Ag 2 S/ZnO NRAs under heat treatment gave better photocurrent response. • Nanocomposite structure shows substantial improvement in charge collection efficiency. Abstract Low temperature hydrothermal method was used to produce a large surface area ZnO NRs on conductive glass. The same method was used to fabricate a photoelectrode of Ag 2 S quantum dots onto the nanorod arrays. Ag 2 S QDs/ZnO NRAs heterostructure was employed as photoanode in a standard 3-electrodes photoelectrochemical cell. A significant enhancement in the photoelectrochemical performance was observed for the Ag 2 S QDs/ZnO upon heat treatment 400 °C which displayed an impressive photoconversion efficiency of 4.08% by achieving ∼10-times higher compared to bare ZnO NRAs. This enhancement was attributed to the improved morphological structure, crystallinity and optical properties of the synthesised heterostructures. [ABSTRACT FROM AUTHOR]

Ternary nanostructured Ag 2 S/CdS/ZnO thin film was prepared by using a simple low-cost hydrothermal method. The hexagonal phase of ZnO nanorods and CdS shells combined with monoclinic Ag 2 S quantum dots resulted in improved optical and photoelectrochemical properties. CdS shell with high absorption property efficiently compliment the energy levels of ZnO and improved the ability of light absorption. Furthermore, narrow band gap Ag 2 S also played a vital part in the light harvesting. The photoelectrochemical performance of the ternary nanostructured Ag 2 S/CdS/ZnO NRs was investigated in a mixture of Na 2 S and Na 2 SO 3 aqueous solutions under visible light illumination. The Ag 2 S/CdS/ZnO NRs were found to be more efficient than ZnO NRs, CdS/ZnO NRs, and Ag 2 S/ZnO NRs as this particular sample gave a maximum photocurrent of 5.69 mA cm −2 , which is around 2 and 1.5 times greater than CdS/ZnO NRs and Ag 2 S/ZnO NRs, respectively. Besides that, it was found that this ternary film possessed 15 times higher photocurrent density than plain ZnO NRs. This is attributed to the larger amount of visible light absorbed by the ternary nanostructured composite. [ABSTRACT FROM AUTHOR]

High density and vertically aligned zinc oxide nanorod arrays (ZnO NRs) have been prepared directly on indium-doped tin oxide (ITO) substrates via two-steps preparation: sol-gel spin coating and hydrothermal process. The nanostructured ZnO was characterized for its morphology, crystalline structure and optical properties by using field emission scanning electron microscopy (FESEM), X-ray diffractometry, and ultraviolet-visible spectroscopy respectively. In addition, the photoeletrochemical (PEC) properties were investigated through photocurrent measurements. The ZnO NRs/ITO had wurtzite-structured (hexagonal) ZnO and preferred growth along (0001) direction. When the growth time was 4 h, ZnO NRs/ITO showed impressive photoresponse. The PEC analysis verified that the ZnO NRs gave better photocurrent response and photoconversion efficiency with approximately 42 times greater than seed layer. [ABSTRACT FROM AUTHOR]