Search

Trithiocyanuric acid trisodium salt hydrate (Na3TMT) has been proved an excellent heavy metal chelating agent and widely applied for heavy metal ions elimination in industrial wastewater. In this work, the chelating products of Bismuth(III) ion with this effective agent were prepared by solid state and liquid phase reactions, and proved as a new kind of n-type semiconductor. For full utilization of resource, the green and low-cost massive Bismuth chelate with good crystallinity, distinctive morphology, appropriate band structure and high stability was applied for photoelectrochemical application and photocatalytic organic pollutants degradation upon visible light. Results indicated that OH radicals were the main reactive specie in the photodegradation process. The combination of heavy metals and organic contaminants removal was achieved by a waste-to-wealth route.

Indium oxide (IO) has been demonstrated as an efficient and stable electron transporting layer for planar heterojunction perovskite solar cells, but dispersive pinholes in the sol-gel derived IO film limit its hole blocking capacity and corresponding device performance. In this study, we introduce an ultrathin TiOx interlayer between Indium Tin Oxide (ITO) substrate and IO film via a low temperature TiCl4 treatment method. By optimizing the process time, we obtain the optimal perovskite solar cells with a 30 min TiCl4 treatment process, showing an impressive power conversion efficiency of 16.38%. In addition, the average device efficiency is improved from 13.7% to 15.1%, which is mainly attributed to the greatly improved fill factor. By means of investigating film roughness, pinhole effect and open circuit voltage decay, we find that the low-temperature processed TiOx interlayer efficiently enhance the hole blocking capacity of the electron transporting layer, and consequently boost the device performance.

A new ternary system consisting of ZnO nanorod/reduced graphene oxide (RGO)/CuInS2 quantum dots has been successfully prepared for photocatalytic application under visible light irradiation. Through the hybridization with the light harvesting material of CuInS2, as well as the conductivity medium RGO, the ternary composite achieves a greatly enhanced light absorption and charge transfer than that of the pristine ZnO. The photocatalytic performance of ZnO-RGO-CuInS2 is substantially elevated with an optimized content of 10% CuInS2 incorporated. The composite material of ZnO-RGO-10% CuInS2 can nearly completely degrade Rhodamine B (RhB) solution in 120 min, whereas bare ZnO itself can only degrade 20% RhB. The excellent photocatalytic performance of ZnO-RGO-CuInS2 demonstrates its promising in the photocatalytic or other extended applications. This work demonstrates a facile way to prepare integrative photosensitizer by taking advantage from the co-catalysts for more efficient and stable semiconductor based composite photocatalyst.

A mesoporous NiO x (m-NiO x ) film which is deposited from a precursor using solution-derived Ni(OH) 2 nanosheets as the starting material is employed as the hole transport layer to fabricate the perovskite solar cell. A simple annealing process at 500 °C in air decomposes the Ni(OH) 2 nanosheets into NiO x nanoparticles, removes organic components, and produces nanopores in the film, leading to the formation of m-NiO x films at once. Results indicate that the annealing time has a great effect on the morphology and crystallinity of the resulting m-NiO x films, and prolonging the annealing time leads to smaller NiO x nanoparticles, bigger pores and higher crystallinity, which contribute to a better device performance. After a careful optimization, the highest power conversion efficiency of 11.97% is achieved on the device based on the m-NiO x film annealed at 500 °C for 3 h. This work provides a new method to prepare efficient m-NiO x films for high performance perovskite solar cells.

TiO 2 nanohexagon arrays (TNHAs) were grown by anodization of Ti foil in an electrolyte containing NH 4 F, and then the TNHAs were transferred onto FTO glass by using a drop of sol containing Ti(OBu) 4 for fabricating a front-side illumination cell. In order to improve the power conversion efficiency (PCE) of the as-fabricated dye-sensitized solar cells (DSSCs), ZnO was introduced into the TNHAs by a facile immersing method. The as-obtained ZnO/TiO 2 nanohexagon heterojunction was used as the photoanode for DSSCs, which is expected to have a low recombination rate and high absorption of light. Results indicated that the DSSCs based on the ZnO/TNHAs exhibit an enhanced current density and high PCE of 6.85% under 100 mW cm −2 illumination. Furthermore, electrochemical impedance spectroscopy showed that the ZnO/TNHAs heterojunction-based DSSCs have optimized electron properties, including longer electron lifetime, lower resistance to electron transport, and smaller probability for electron recombination as compared to the DSSCs fabricated from pure TNHAs as photoanode.

Anatase TiO2 nanohexagon arrays were grown by using an anodization process of Ti foil in fluoride containing electrolytes. Photoanode based on the as-grown anatase TiO2 nanohexagon arrays for DSSCs showed a power photoconversion efficiency of 4.01% and incident photon-to-current conversion efficiency of 68%, which are significantly higher than those of the device based on anatase TiO2 nanotube arrays. This improvement in power conversion efficiency should be attributed to the fact that the nanotubes with hexagonal structure have higher surface area to allow the uploading of more dye molecules for light harvesting. Also, the spacing introduced inside the hexagon might allow the dye molecules to cover the interior of the walls. In addition, it is believed that the photoconversion efficiency can be further increased by optimizing the hexagonal structure through the electrochemical conditions.

Ag nanoparticle/ZnO nanorods (Ag NP/ZnO NRs) nanocomposites with a core/shell structure were prepared by a seed-mediated method, which contains a polyol synthesis of Ag NPs and an overgrowth process of ZnO NRs on the surface of Ag NPs. Compared with the previously reported Ag/ZnO nanocomposites which were mostly constructed by a ZnO core and a Ag shell, the nanocomposites reported in this article showed a novel structure that contained a Ag NP core and ZnO NRs shell, resulting a hedgehog-like morphology. Electron microscope images reveal that the volume content ratio of Ag NPs colloids and the ZnO precursory solution is crucial for the morphology of the resulted samples and a well-constructed Ag NP/ZnO NRs core/shell nanocomposite can be easily obtained when their volume content ratio is set at a proper value. X-ray diffraction analysis shows a good crystalline property of both Ag NPs and ZnO NRs. The relationship between the growing temperature and the morphology of the resulted samples was investigated and a possible growing mechanism of the Ag NP/ZnO NRs nanocomposites was also proposed and discussed. Furthermore, photocatalytic activities of the resulting samples with different morphologies were also studied.

Colloidal zinc sulfide (ZnS) quantum dots are synthesized by a solvothermal route from Zn(Ac) 2 ·2H 2 O, sulfur powder and oleylamine at 120–240 °C. Microstructural, morphological, and optical properties of the as-synthesized ZnS quantum dots are characterized by X-ray diffraction analysis, transmission electron microscopy, UV–vis absorption spectroscopy, and photoluminescence spectroscopy. Results indicate that the obtained ZnS quantum dots distribute uniformly, the particle size is in the range between 1.7 nm and 3.1 nm, and the band gap decreases from 4.16 eV to 3.90 eV with an increase of the particle size. The size-dependent photoluminescence exhibits a strongly broadened peak accompanied by a pronounced blue-shift. It is also found that the size of the ZnS nanocrystals can be effectively controlled by adjusting synthesis temperature. It is shown that the present method is also applicable to synthesize other binary II–VI semiconductor materials, such as ZnSe quantum dots.