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A Z-scheme BiVO 4 /NiCo 2 O 4 (BVO/NCO) heterojunction structure was constructed by modifying optimal ultrathin nickel–cobalt (NiCo 2 O 4) spinel nanosheets on BiVO 4 as an efficient photocatalyst toward water oxidation, which deliver an excellent photocatalytic O 2 evolution performance of 1640.9 μmol∙g−1∙h−1 by reducing the energy barriers and enhancing the separation and transfer of photogenerated carriers. [Display omitted] The sluggish water oxidation process is a severe obstacle for solar-driven water splitting. Therefore, it is imperative to develop a suitable photocatalyst with reduced energy barrier for strong oxidation. In this study, a Z-scheme BiVO 4 /NiCo 2 O 4 (BVO/NCO) heterojunction system was designed by decorating ultrathin nickel–cobalt (NiCo 2 O 4) spinel nanosheets on BiVO 4 as an efficient photocatalyst for water oxidation. The unique structure of the system significantly reduced the energy barrier and improved the oxidation ability of BiVO 4 to efficiently enhance the separation and transfer of the photogenerated carriers. Thus, the photocatalyst delivered an excellent O 2 evolution performance of 1640.9 μmol∙g−1∙h−1 and showed 124% improved efficiency as compared to pristine BiVO 4 and a quantum efficiency of 5.39% at 400 nm for O 2 evolution. Additionally, the theoretical calculations revealed that the formation of *OOH was the rate-determining step for water oxidation. The decoration with NiCo 2 O 4 significantly reduced the energy barrier between *O and *OOH, which eventually improved the photocatalytic performance of BVO/NCO. The results hold great promise for the potential application of spinel-based materials in efficient photocatalytic O 2 evolution and offer fundamental insights into the design of efficient water oxidation heterojunctions. [ABSTRACT FROM AUTHOR]

Solar cells devices based on inorganic/polymer heterojunction can be a possible solution to harvest solar energy and convert to electric energy with high efficiency through a cost-effective fabrication. The solution-process method can be easily used to produce large area devices. Moreover, due to the intrinsic different charge separation, diffusion or recombination in various semiconductors, the interfaces between each component may strongly influence the inorganic/polymer heterojunction performance. Here we prepared a n-type Ag 3 CuS 2 (Eg = 1.25 eV) nanostructured film through a room-temperature element reaction process, which was confirmed as direct bandgap semiconductor through density function theory simulation. This Ag 3 CuS 2 film was spin-coated with an organic semiconducting poly(3-hexythiophene) (P3HT) or polythieno[3,4-b]-thiophene-co-benzodithiophene (PTB7) film, which formed an inorganic/polymer heterojunction. After constructing it to a solar cell device, the power conversion efficiencies of 0.79% and 0.31% were achieved with simulated solar illumination on Ag 3 CuS 2 /P3HT and Ag 3 CuS 2 /PTB7, respectively. A possible mechanism was discussed and we showed the charge separation at interface of inorganic and polymer semiconductors played an important role. [ABSTRACT FROM AUTHOR]

The development of new chemical methods to prepare large area perovskite thin film solar cells is desirable for potential future industrial applications. In this paper, a novel fabrication of perovskite CH 3 NH 3 PbI 3 thin films based on direct metal surface elemental reaction (DMSER) method in an ambient atmosphere is discussed. The as-prepared CH 3 NH 3 PbI 3 thin films are highly pure and crystalline. Consequent Transient photovoltaic (TPV) tests were conducted and show that these thin films have a long minority carrier lifetime as good as the perovskite thin films obtained via common two-step method from the literature. Although there have been many studies that have developed perovskite solar cells (PSCs) during the past five years, the current study is the first report using elemental Pb as a precursor to fabricate perovskite solar cells, which were found to be relatively stable upon storage without encapsulation in glove box for more than 200 days. This Pb-initiated in-situ reaction allows for the fabrication of large area and uniform perovskite thin films. For example, in our preliminary studies, we have fabricated large area solar cell device samples (1.10 ± 0.05 cm 2 ) and have evaluated their photovoltaic performance under standard conditions (AM 1.5, 100 mW cm −2 ). [ABSTRACT FROM AUTHOR]

• CdS under-layer reduces the recombination at Ag 2 S/FTO interface. • Photoinduced charge carrier dynamics of FTO/CdS/Ag 2 S has been studied. • CdS under-layer raise 52% PCE of Ag 2 S solar cell. [Display omitted] The recombination of photoinduced charge carriers is detrimental to the photovoltaic performance of solar cells. In this work, we used CdS as an under-layer to reduce the recombination of photoinduced charge carriers at the Ag 2 S/FTO (F-doped SnO 2) interface. The CdS under-layer was deposited onto an FTO substrate using a facile chemical bath deposition (CBD) method. By controlling the thickness of the CdS film between Ag 2 S and FTO, the recombination of photoinduced charge carriers was successfully suppressed. The effect of the CdS under-layer on the charge carrier recombination was carefully evaluated by transient surface photovoltage (TSPV) measurements, electrochemical impedance spectroscopy (EIS) and a photoelectrochemical method. The power conversion efficiency (PCE) of solar cell devices with a 40 nm CdS under-layer is 1.16%, which is ~52% enhancement compared to those of FTO/Ag 2 S-based solar cell devices. Our work may provide a useful strategy to suppress photoinduced charge carrier recombination at the electrode and absorber semiconductor interface. [ABSTRACT FROM AUTHOR]

A well-ordered highly crystalline g-C 3 N 4 nanorods (CNR) is rationally tailored by molten salt-assisted anti-defect engineering for efficient artificial photosynthesis of H 2 O 2. [Display omitted] • Highly crystalline and well-ordered g-C 3 N 4 nanorods are tailored. • Molten salt-assisted preparation of highly crystalline organic polymeric materials. • Anti-defect engineering promotes charge separation and transfer. • The H 2 O 2 generation rate reaches 1.58 mmol g-1h−1 only using air as oxygen source. • Molten salt-assisted anti-defect engineering to improve photocatalytic activity. Graphite carbon nitride (g-C 3 N 4) is widely recognized as one of the most popular catalysts for photocatalytic hydrogen peroxide (H 2 O 2) production. However, it is often overlooked that general g-C 3 N 4 materials contain numerous dangling bonds and defects, which serve as recombination centers for photogenerated carriers and significantly hinder their catalytic activity. Herein, we present a novel approach to address this issue by rationally tailoring well-ordered g-C 3 N 4 nanorods (CNR) through molten salt-assisted anti-defect engineering. The resulting highly crystalline CNR demonstrates high efficiency in the artificial photosynthesis of H 2 O 2. Experimental results indicate that enhancing the crystallinity of g-C 3 N 4 while reducing the defect concentration effectively promotes charge separation and transport. As a result, it exhibits a remarkable H 2 O 2 generation rate of 1.58 mmol g-1h−1 using air as the oxygen source, accompanied by an apparent quantum yield of 18.00 % (λ = 400 nm). The excellent photocatalytic performance of CNR surpasses that of all previously reported pristine g-C 3 N 4 materials. This work sheds light on the effectiveness of molten salt-assisted anti-defect engineering in improving catalyst activity, with potential applications in solar cells, sensor devices and other catalytic systems. [ABSTRACT FROM AUTHOR]

Although hybrid solar cells take advantages of both inorganic and organic semiconductors for high performance, there have not been comparably photoelectric conversion efficiencies as expected from this kind of solar cells till now. The photoelectric response behavior of inorganic/organic hybrid solar cells has been explained on the theory of inorganic solar cells, but the distinctive wavelength dependent photoelectric character of organic semiconductors has not been well considered. In this work, Ag 2 S/organic bulk heterojunction solar cell devices were designed and fabricated in-situ on indium tin oxide (ITO) based on the direct metal surface elemental reaction (DMSER) method, to understand the corresponding photoinduced charge carrier dynamics under different wavelength light. The commonly used small molecule Spiro-OMeTAD and polymeric PTB7-Th were selected as the organic components of the fabricated solar cells. In Ag 2 S/Spiro-OMeTAD, Ag 2 S donated the charge carriers and controlled the photoinduced charge carrier dynamics of the devices at both 355 nm and 532 nm lights. Under 532 nm light, the PTB7-Th acted as hole transport materials (HTM) rather than charge carrier donor. These results indicated that hybrid thin films without wavelength dependent charge carrier dynamics is preferred for high performance solar cells. [ABSTRACT FROM AUTHOR]

Without sacrifice of photovoltaic performances, low-platinum alloy counter electrodes (CEs) are promising in bringing down the fabrication cost of dye-sensitized solar cells (DSSCs). We present here the realization of ZnO nanostructure assisted hollow platinum-nickel (PtNi) alloy microstructure CEs with a simple hydrothermal methods and maximization of electrocatalytic behaviors by tuning Zn precursors. The maximal power conversion efficiency is up to 8.74% for the liquid-junction dye-sensitized solar cells with alloyed PtNi 0.41 electrode, yielding a 37.6% cell efficiency enhancement in comparison with pristine solar cell from planar Pt electrode. Moreover, the dissolution-resistant and charge-transfer abilities toward I − /I 3 − redox electrolyte have also been markedly enhanced due to competitive dissolution reactions and alloying effects. [ABSTRACT FROM AUTHOR]

A fantastic 2D/1D hierarchical layered ZnIn 2 S 4 /TiO 2 hetero-structure is reported as an efficient catalyst for in- situ H 2 O 2 production via 2-electrons oxygen reduction (ORR) process and be activated to high concentration hydroxyl radical (•OH) for water purification under visible light irradiation. [Display omitted] • Solar-driven H 2 O 2 synthesis to purify water via cascade reaction. • A fantastic 2D/1D hierarchical layered heterojunction of ZnIn 2 S 4 /TiO 2. • ZnIn 2 S 4 effectively promote the activation of in- situ generated H 2 O 2. • The superior H 2 O 2 production rate arrives 1530.59 μmol h−1 g−1. Hydrogen peroxide (H 2 O 2) is a significant green oxidant for environment and new energy, especially for Fenton-like system. Onsite production and sustainable consumption of H 2 O 2 are the two critical challenges. Here, a fantastic 2D/1D hierarchical layered ZnIn 2 S 4 /TiO 2 heterojunction is reported as an efficient catalyst for in- situ H 2 O 2 production via 2-electrons oxygen reduction (ORR) process and be rapidly activated to high concentration hydroxyl radical (•OH) for water purification under visible light irradiation. The high-quality catalyst enables superior H 2 O 2 production rate of 1530.59 μmol h−1 g−1 with an external quantum efficiency of 10.39% illuminated at 400 nm, is much higher than that of reported photocatalysts. The bimetallic sulfide ZnIn 2 S 4 can effectively promote the activation of H 2 O 2 due to the unsaturation of sulfur atoms, so that the wastewater containing tetracycline (50 ppm) can be degraded by 90% only within 60 min by ZnIn 2 S 4 /TiO 2 via this cascade reaction. This work provides a novel strategy and ZnIn 2 S 4 -based catalyst for photocatalytic Fenton-like reaction. [ABSTRACT FROM AUTHOR]