Bandgap modulation and phase boundary region of multiferroic Gd, Co co-doped BiFeO3 thin film

Ferroelectric polarization is a crucial factor to induce photovoltaic effect in ferroelectric materials. Here, a novel modulation of bandgap by Gd and Co co-doped BFO is found for a polycrystalline Bi0.9Gd0.1Fe0.85Co0.15O3 thin film prepared by the sol–gel process. The ferroelectric properties, magnetic properties, and bandgap of the BFO films were altered by doping Gd and Co. This work has led to a greater understanding of bismuth ferrate, and it proposes the Bi0.9Gd0.1Fe0.85Co0.15O3 thin film for the possibility of better preparation of high conversion efficiency ferroelectric photovoltaic devices

Fabrication and tribological properties of carbon fiber and copper fiber reinforced carbon-based composite by hot pressing

To attain new pantograph skateboard with high strength-toughness and simple fabrication process, copper fiber and carbon fiber reinforced carbon-based composite (Cuf/Cf/C composite) was fabricated by hot pressing technology, micro-structure, mechanical and tribological performances were investigated and compared with the results of carbon skateboard. Cuf/Cf/C composite is superior to carbon skateboard in terms of compactness, hardness, electrical conductivity, mechanical strength and wear resistance. During sliding friction tests with electric current, mechanical acting wear and arc erosion have a stimulating circulation on the worn surface, and adding carbon fiber slows down the deteriorated wear cycle and improves wear resistance. High carbon crystallinity degree of the tribolayer presents low molecular acting friction force, and adjusting crystallite structure is essential to improve friction performance

Thickness dependence of magnetoelectric response for composites of Pb(Zr0.52Ti0.48)O3 films on CoFe2O4 ceramic substrates

Using chemical solution spin-coating we grew Pb(Zr0.52Ti0.48)O3 films of different thicknesses on highly dense CoFe2O4 ceramics. X-ray diffraction revealed no other phases except Pb(Zr0.52Ti0.48)O3 and CoFe2O4. In many of these samples we observed typical ferroelectric hysteresis loops, butterfly-shaped piezoelectric strains, and the magnetic-field-dependent magnetostriction. These behaviors caused appreciable magnetoelectric responses based on magnetic-mechanical-electric coupling. Our results indicated that the thickness of the Pb(Zr0.52Ti0.48)O3 film was important in obtaining strong magnetoelectric coupling

Modulating light absorption and multiferroic properties of BiFeO3-based ferroelectric films by the introduction of ZnO layer

Pure bismuth ferrite (BiFeO _3 , BFO) and ZnO thin films, as well as BFO/ZnO and ZnO/BFO composite thin films were successfully deposited by a sol-gel process on Pt/Ti/SiO _2 /Si and FTO/glass substrates, respectively. The chemical composition, surface morphology, optical properties, and multiferroicity were systematically investigated. X-ray diffraction and electron microscopy measurements were used to determine the crystalline phase and to analyze the surface morphology. Evidently, the absorption edges of both BFO/ZnO and ZnO/BFO films show a redshift, broadening the absorption range. The leakage current density decreases with the introduction of ZnO, and the ferroelectricity was significantly improved of the bilayers. Thereinto, BFO/ZnO and ZnO/BFO show the highest saturate polarization (2 P _s ) of 46.7 μ c cm ^−2 and the maximum remanent polarization (2 P _r ) of 18.5 μ c cm ^−2 , respectively. Meanwhile, the magnetization measurement revealed that both BFO/ZnO and ZnO/BFO exhibiting an enhanced magnetization, especially, BFO/ZnO displays the highest saturation magnetization (2 M _s , 68.87 emu cm ^−3 ) and remanent magnetization (2 M _r , 4.87 emu cm ^−3 )

Achieving Solar‐Thermal‐Electro Integration Evaporator Nine‐Grid Array with Asymmetric Strategy for Simultaneous Harvesting Clean Water and Electricity

Abstract Water evaporation is a ubiquitous and spontaneous phase transition process. The utilization of solar‐driven interface water evaporation that simultaneously obtains clean water and power generation can effectively alleviate people's concerns about fresh water and energy shortages. However, it remains a great challenge to efficiently integrate the required functions into the same device to reduce the complexity of the system and alleviate its dependence on solar energy to achieve full‐time operation. In this work, a multifunctional device based on reduced graphene oxide (RGO)/Mn3O4/Al2O3 composite nanomaterials is realized by an asymmetric strategy for effective solar‐thermal‐electro integration that can induce power generation by water evaporation in the presence/absence of light. Under one sun irradiation, the solar‐driven evaporation rate and output voltage are 1.74 kg m−2 h−1 and 0.778 V, respectively. More strikingly, the nine‐grid evaporation/power generation array integrated with multiple devices in series has the advantages of small volume, large evaporation area, and high power generation, and can light up light‐emitting diodes (LEDs), providing the possibility for large‐scale production and application. Based on the high photothermal conversion efficiency and power production capacity of the RGO/Mn3O4/Al2O3 composite evaporation/generator, it will be a promising energy conversion device for future sustainable energy development and applications

Anodic Behavior of Hafnium in Anhydrous Electrodissolution-Coupled Hafnium Alkoxide Synthesis

The electrodissolution-coupled hafnium alkoxide (Hf(OR)4, R is alkyl) synthesis (EHS) system, which has significant environmental and economic advantages over conventional thermal methods, serves as a promising system for green and efficient Hf(OR)4 electro-synthesis. The EHS system is operated based on the simultaneous heterogeneous reactions of hafnium dissolution and ethanol dehydrogenation, as well as the spontaneous solution-based reaction of Hf4+ and OR−. Employing green ethanol and Hf as feedstocks, the anodic hafnium corrosion/dissolution electrochemical behavior of the Et4NCl or Et4NHSO4 based anhydrous system was investigated through electrochemical measurements combined with SEM observations. The results demonstrated that the Et4NCl-based anhydrous ethanol system exhibited an efficient mechanism of passive film pitting corrosion breakdown and metal hafnium dissolution, while the Et4NHSO4-based anhydrous ethanol system reflected the weak corrosion mechanism of the anodic hafnium under the passive film. The polarization resistance of the Et4NCl system was dramatically lower than that of the Et4NHSO4 system, which indicated that the Et4NCl system had superior anodic hafnium corrosion performance compared to the Et4NHSO4 system. Overall, the investigation of the electrochemical behaviors of anodic hafnium corrosion/dissolution provides theoretical guidance for the efficient operation of EHS electrolysis