固体氧化物燃料电池铁素体不锈钢连接体的导电/保护涂层

铁素体不锈钢因具有诸多优点而成为中温固体氧化物燃料电池(SOFC)连接体部件的标准材料。根据SOFC的运行环境,综述了连接体在电池堆中所起的作用、性能要求和材料种类。针对用作SOFC铁素体不锈钢连接体的活性元素氧化物型、稀土钙钛矿型、尖晶石型和MAlCrYO型4类导电/保护涂层材料,重点论述了其作用机理、主要制备技术及研究进展。     

TiO2 Electron Transport Bilayer for Highly Efficient Planar Perovskite Solar Cell

In planar perovskite solar cells, it is vital to engineer the extraction and recombination of electron–hole pairs at the electron transport layer/perovskite interface for obtaining high performance. This study reports a novel titanium oxide (TiO₂) bilayer with different Fermi energy levels by combing atomic layer deposition and spin‐coating technique. Energy band alignments of TiO₂ bilayer can be modulated by controlling the deposition order of layers. The TiO₂ bilayer based perovskite solar cells are highly efficient in carrier extraction, recombination suppression, and defect passivation, and thus demonstrate champion efficiencies up to 16.5%, presenting almost 50% enhancement compared to the TiO₂ single layer based counterparts. The results suggest that the bilayer with type II band alignment as electron transport layers provides an efficient approach for constructing high‐performance planar perovskite solar cells.     

Perovskite oxide nanowires: synthesis, property and structural characterization

Perovskite oxide materials display a wide spectrum of functional properties, including switchable polarization, piezoelectricity, pyroelectricity, and non-linear dielectric behavior. These properties are indispensable for application in electronic devices such as non-volatile memories, sensors, microactuators, infrared detectors, microwave phase filters, and so on. Recent advances in science and technology of perovskite oxide materials have resulted in the feature sizes of perovskite oxides-based electronic devices entering into nanoscale dimensions. At nanoscale perovskite oxide materials exhibit a pronounced size effect manifesting itself in a significant deviation of the properties of low-dimensional structures from the bulk and film counterparts. In the last decade low-dimensional perovskite nanosized oxides have been received much attention because of their superior physical and chemical properties. Among them, perovskite oxide nanowires are especially attractive for nanoscience studies and nanotechnology applications. Compared to other low-dimensional perovskite oxide systems, perovskite oxide nanowires are not only used as the building blocks of future nanodevices, but also they offer fundamental scientific opportunities for investigating the intrinsic size effects of physical properties. In the recent years, much progress has been made both in synthesis and physical property testing of perovskite oxide nanowires, which have a profound impact on the nanoelectronics. In this work, an overview of the state of art in perovskite oxide nanowires is presented, which covers their synthesis, property, and structural characterization. In the first part, the recent literatures for fabricating perovskite oxide nanowires with promising features, are critically reviewed. The second part deals with the recent advances on the physical property testing of perovskite oxide nanowires. The third part summarizes the recent progress on microstructural characterizations of perovskite oxide nanowires, to improve their crystalline quality, morphology and uniformity. Finally, this review concludes with some perspectives and outlook on the future developments of perovskite oxide nanowires.     

Oxide-ion conducting ceramics for solid oxide fuel cells

Realization of a solid oxide fuel cell (SOFC) operating at 700°C on a hydrocarbon fuel or gaseous H₂ is an outstanding technical target. For the past 25 years, efforts to achieve this goal have been based on yttria-stabilized zirconia as the electrolyte, a NiO + electrolyte composite as the anode, a porous La_0.85Sr_0.15MnO₃ (LSM) metallic perovskite as the cathode, and a La_1–x Sr _x CrO₃ ceramic as the interconnect material. This paper reviews progress in our laboratory on an alternate approach that would use a Sr- and Mg- doped LaGaO₃ perovskite as the electrolyte, a Sm-doped ceria (SDC) as the anode or as a buffer layer with a NiO + SDC composite as the anode, a mixed oxide-ion/electronic conductor (MIEC) as the cathode, and a stainless steel as the metallic interconnect.     

Self‐Powered,Flexible, and Solution‐Processable Perovskite Photodetector Based on Low‐Cost Carbon Cloth

Flexible perovskite photodetectors are usually constructed on indium‐tin‐oxide‐coated polymer substrates, which are expensive, fragile, and not resistant to high temperature. Herein, for the first time, a high‐performance flexible perovskite photodetector is fabricated based on low‐cost carbon cloth via a facile solution processable strategy. In this device, perovskite microcrystal and Spiro‐OMeTAD (hole transporting material) blended film act as active materials for light detection, and carbon cloth serves as both a flexible substrate and a conductive electrode. The as‐fabricated photodetector shows a broad spectrum response from ultraviolet to near‐infrared light, high responsivity, fast response speed, long‐term stability, and self‐powered capability. Flexible devices show negligible degradation after several tens of bending cycles and at the extremely bending angle of 180°. This work promises a new technique to construct flexible, high‐performance photodetectors with low cost and self‐powered capability.     

钙钛矿太阳能电池的研究进展

钙钛矿太阳能电池由纳米晶致密层、钙钛矿型光活性层CH₃NH₃PbX₃ (X= Cl、Br、I)、空穴传输层及对电极组成。其中光活性层吸光材料的种类及其成膜技术、空穴传输层材料类型及结构设计是影响钙钛矿太阳能电池光电性能的重要因素。本文结合钙钛矿太阳能电池近年来的最新研究进展, 对影响器件光电性能的关键因素: 光吸收层、空穴传输层、工艺参数以及结构设计等进行综述, 同时展望了钙钛矿太阳能电池未来的发展趋势。     

Novel dual-phase symmetrical electrode materials for protonic ceramic fuel cells

Protonic ceramic fuel cells (PCFCs) can use hydrogen and hydrocarbon fuels to generate electricity with good performance and anti-cooking resistance. Herein, a novel dual-phase perovskite oxide BaCe_0.5Fe_0.4Ni_0.1O_3-δ (BCFN) with BaCe_0.5Fe_0.5O_3-δ (BCF) as one reference was synthesized, characterized and then evaluated as the symmetrical electrodes for PCFCs. Both BCF and BCFN can be self-assembled into an orthorhombic cerium-rich oxide phase and a cubic iron-rich oxide phase after calcined at 1000 °C and show good redox stability. BCFN shows much better electrical conductivity and lower area specific resistance than BCF. Applying BCF and BCFN as symmetrical electrodes for PCFCs with the BaZr_0.1Ce_0.7Y_0.2O_3-δ (BZCY) electrolyte supporting, the cell performance with BCFN symmetrical electrode is almost twice (141 mW·cm² at 700 °C) than those with BCF symmetrical electrode, and the electrode polarization resistances are also reduced from 0.7 to 0.5 Ω·cm² using humidified H₂. The preliminary experimental results can demonstrate that dual-phase perovskite oxides with nanoparticle in situ precipitation are very promising symmetrical electrodes for protonic ceramic fuel cells.

     

Highly Efficient and Stable Perovskite Solar Cells via Modification of Energy Levels at the Perovskite/Carbon Electrode Interface

Perovskite solar cells (PSCs) have attracted great attention in the past few years due to their rapid increase in efficiency and low‐cost fabrication. However, instability against thermal stress and humidity is a big issue hindering their commercialization and practical applications. Here, by combining thermally stable formamidinium–cesium‐based perovskite and a moisture‐resistant carbon electrode, successful fabrication of stable PSCs is reported, which maintain on average 77% of the initial value after being aged for 192 h under conditions of 85 °C and 85% relative humidity (the “double 85” aging condition) without encapsulation. However, the mismatch of energy levels at the interface between the perovskite and the carbon electrode limits charge collection and leads to poor device performance. To address this issue, a thin‐layer of poly(ethylene oxide) (PEO) is introduced to achieve improved interfacial energy level alignment, which is verified by ultraviolet photoemission spectroscopy measurements. Indeed as a result, power conversion efficiency increases from 12.2% to 14.9% after suitable energy level modification by intentionally introducing a thin layer of PEO at the perovskite/carbon interface.     

Laser-Generated Supranano Liquid Metal as Efficient Electron Mediator in Hybrid Perovskite Solar Cells

Creating colloids of liquid metal with tailored dimensions has been of technical significance in nano-electronics while a challenge remains for generating supranano (<10 nm) liquid metal to unravel the mystery of their unconventional functionalities. Present study pioneers the technology of pulsed laser irradiation in liquid from a solid target to liquid, and yields liquid ternary nano-alloys that are laborious to obtain via wet-chemistry synthesis. Herein, the significant role of the supranano liquid metal on mediating the electrons at the grain boundaries of perovskite films, which are of significance to influence the carriers recombination and hysteresis in perovskite solar cells, is revealed. Such embedding of supranano liquid metal in perovskite films leads to a cesium-based ternary perovskite solar cell with stabilized power output of 21.32% at maximum power point tracing. This study can pave a new way of synthesizing multinary supranano alloys for advanced optoelectronic applications.     

Position-controlled functional oxide lateral heterostructures consisting of artificially aligned (Fe,Zn)(3)O(4) nanodots and BiFeO(3) matrix

We demonstrate an advanced fabrication method for perfectly position-controlled ferromagnetic semiconductor (Fe,Zn)(3)O(4) nanodot arrays down to several hundred nanometers in size surrounded by a ferroelectric BiFeO(3) matrix. By performing position-selective crystal growth of perovskite BiFeO(3) on the position-controlled epitaxial spinel (Fe,Zn)(3)O(4) nanodot-seeding template, which is prepared using a hollow molybdenum mask lift-off nanoimprint lithography process on a perovskite La-doped SrTiO(3)(001) substrate, we produce functional oxide three-dimensional lateral heterojunctions. The position-selectivity can be explained based on standard surface diffusion theory with a critical nucleation point. Establishing this fabrication process could lead to innovative nanointegration techniques for spintronic oxide materials.     

Integration of copper multilevel interconnects with oxide and polymer interlevel dielectrics

Copper interconnect structures are being evaluated for 0.25 μm minimum feature size technology and below. This work focuses on fabrication of one- and two-level test structures with copper metallization and both oxide and polymer interlevel dielectrics to demonstrate the compatibility of unit processes being developed for future copper-based interconnects. Emphasis is placed on dual Damascene patterning and material and process compatibility with such patterning and the required barriers and passivation techniques required with copper. Future directions of this work are described in this invited review paper.     

Preparation,formulation and deposition of mica flake supported cobalt oxide for nanostructured lithium ion battery anodes

We describe the fabrication and morphological and electrochemical characterisation of lithium ion battery anodes whereby the active material is supported on flake-like microparticles. Using various physical analytical techniques we verify that nanostructured cobalt (II, III) oxide can be directly grown onto commercial titanium dioxide-coated mica flakes by a liquid phase oxidation route. We then investigate the formulation and deposition of this material along with carbon black in order to form electrodes. Here we consider two binder/solvent systems, one widely used based on polyvinylidene fluoride in N-methy-2-pyrrolidone, and one more recently identified based on sodium alginate in water. We show that the latter system is preferable for the formation of anodes using the cobalt oxide coated flake-like particles as it leads to a more homogeneous distribution of active and conductive material in the electrode. Using cyclic voltammetry and electrochemical impedance spectroscopy we show that this feature improves the access to active material and facilitates efficient charge transfer in the electrode while maintaining electrode integrity. Moreover, an electrode based on the alginate binder exhibited a high reversible specific capacity of 650 mAh/g along with 84.8% capacity retention after 70 cycles. Overall our study indicates the promise of including shape anisotropic particles such as microflakes in battery electrodes.     

Chemical stability of MgO/CaO/Cr2O3–Al2O3–B2O3–phosphate glasses in solid oxide fuel cell environment

The thermal properties, glass forming tendency and glass stability in solid oxide fuel cell (SOFC) relevant atmospheres have been determined for four different refractory MgO/CaO/Cr2O3–Al2O3–B2O3 phosphate based glasses. Also, the bonding ability and interaction as a function of temperature between the glasses and La0.8Ca0.22CrO3 interconnect material have been studied. The microstructural characterization and elemental analysis of reaction couples reveal that the bonding ability and interface interaction is closely related to the CaO content and the relative glass forming tendency. The reactions at 1000°C between the glass and the solid interconnect material for the high CaO or MgO containing compositions occur by a liquid phase or a vapour phase mechanism, respectively. The reaction at 1200°C in both cases occurs by a liquid phase mechanism. © 1998 Chapman & Hall     

Insights into the Influence of Work Functions of Cathodes on Efficiencies of Perovskite Solar Cells

Though various efforts on modification of electrodes are still undertaken to improve the efficiency of perovskite solar cells, attributing to the large scope of these methods, it is of significance to unveil the working principle systematically. Herein, inverted perovskite solar cells based on indium tin oxide (ITO)/poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/CH₃NH₃PbI₃/phenyl‐C61‐butyric acid methyl ester (PC₆₁ BM)/buffer metal/Al are constructed. Through the choice of different buffer metals to tune work function of the cathode, the contact nature of the active layer with the cathode could be manipulated well. In comparison with the device using Au/Al as the electrode that shows an unfavorable band bending for conducting the excited electrons to the cathode, the one with Ca/Al presents a dramatically improved efficiency over 17.1%, ascribed to the favorable band bending at the interface of the cathode with the active layer. Details for tuning the band bending and the corresponding charge transfer mechanism are given in a systematic manner. Thus, a general guideline for constructing perovskite photovoltaic devices efficiently is provided.     

Paintable Carbon‐Based Perovskite Solar Cells with Engineered Perovskite/Carbon Interface Using Carbon Nanotubes Dripping Method

Paintable carbon electrode‐based perovskite solar cells (PSCs) are of particular interest due to their material and fabrication process costs, as well as their moisture stability. However, printing the carbon paste on the perovskite layer limits the quality of the interface between the perovskite layer and carbon electrode. Herein, an attempt to enhance the performance of the paintable carbon‐based PSCs is made using a modified solvent dripping method that involves dripping of the carbon nanotubes (CNTs), which is dispersed in chlorobenzene solution. This method allows CNTs to penetrate into both the perovskite film and carbon electrode, facilitating fast hole transport between the two layers. Furthermore, this method is results in increased open circuit voltage (V_oc) and fill factor (FF), providing better contact at the perovskite/carbon interfaces. The best devices made with CNT dripping show 13.57% power conversion efficiency and hysteresis‐free performance.     

Synthesis of Ru/multiwalled carbon nanotubes by microemulsion for electrochemical supercapacitor

An efficient way to decorate multiwalled carbon nanotubes with Ru had been developed. In this method, Ru nanoparticles were prepared by water-in-oil reverse microemulsion, and the produced Ru anchored on MWCNTs. Transmission electron microscopy (TEM) result showed that RuO₂ nanoparticles had the uniform size distribution after electrochemical oxidation. Energy dispersive X-rays (EDX) spectra elucidated the presence of ruthenium oxide in the as-prepared composites after electrochemical oxidation. Cyclic voltammetry result demonstrated that a specific capacitance of deposited ruthenium oxide electrode was significantly greater than that of the pristine MWCNTs electrode in the same medium.     

Structural evolution of La-Cr-O thin films: Part I. Microstructure and phase development

The structural evolution of La-Cr-O thin films and the formation mechanisms of the LaCrO₃ perovskite phase have been studied. X-ray amorphous La-Cr-O protective coatings were deposited by magnetron sputtering on metallic interconnect materials. During the annealing of the material in air a two-step phase transition from La-Cr-O to a monoclinic LaCrO₄ monazite and further to an orthorhombic LaCrO₃ perovskite phase was observed. The formation of a fine nanoporous structure is a result of the significant increase in density of the final LaCrO₃ perovskite in comparison with monazite LaCrO₄ phase. While the porous structure was not sought after for this application, these distinctive nanostructures may have numerous applications in catalysis, separation membranes or for other SOFC components.     

Cesium lead halide perovskite triangular nanorods as high-gain medium and effective cavities for multiphoton-pumped lasing

High-performance multiphoton-pumped lasers based on cesium lead halide perovskite nanostructures are promising for nonlinear optics and practical frequency upconversion devices in integrated photonics.However,the performance of such lasers is highly dependent on the quality of the material and cavity,which makes their fabrication challenging.Herein,we demonstrate that cesium lead halide perovskite triangular nanorods fabricated via vapor methods can serve as gain media and effective cavities for multiphoton-pumped lasers.We observed blue-shifts of the lasing modes in the excitation fluence-dependent lasing spectra at increased excitation powers,which fits well with the dynamics of Burstein-Moss shifts caused by the band filling effect.Moreover,efficient multiphoton lasing in CsPbBr3 nanorods can be realized in a wide excitation wavelength range (700-1,400 nm).The dynamics of multiphoton lasing were investigated by time-resolved photoluminescence spectroscopy,which indicated that an electron-hole plasma is responsible for the multiphoton-pumped lasing.This work could lead to new opportunities and applications for cesium lead halide perovskite nanostructures in frequency upconversion lasing devices and optical interconnect systems.     

Pseudohalide‐Induced 2D (CH3NH3)2PbI2(SCN)2 Perovskite for Ternary Resistive Memory with High Performance

Recently, organic–inorganic hybrid perovskites (OIHP) are studied in memory devices, but ternary resistive memory with three states based on OIHP is not achieved yet. In this work, ternary resistive memory based on hybrid perovskite is achieved with a high device yield (75%), much higher than most organic ternary resistive memories. The pseudohalide‐induced 2D (CH₃NH₃)₂PbI₂(SCN)₂ perovskite thin film is prepared by using a one‐step solution method and fabricated into Al/perovskite film/indium–tin oxide (glass substrate as well as flexible polyethylene terephthalate substrate) random resistive access memory (RRAM) devices. The three states have a conductivity ratio of 1:10³:10⁷, long retention over 10 000 s, and good endurance properties. The electrode area variation, impedance test, and current–voltage plotting show that the two resistance switches are attributable to the charge trap filling due to the effect of unscreened defect in 2D nanosheets and the formation of conductive filaments, respectively. This work paves way for stable perovskite multilevel RRAMs in ambient atmosphere.     

LaCrO3基陶瓷材料在SOFC中的研究进展

综述了LaCrO3材料在固体氧化物燃料电池(SOFC)中作为陶瓷连接材料、合金连接体的涂层材料以及新型阳极材料的国内外最新研究进展.介绍了LaCrO3作为陶瓷连接材料的使用要求,在热膨胀性能、烧结性能、电性能和化学稳定性能等方面的研究情况,并介绍了磁控溅射、等离子喷涂、溶胶-凝胶(Sol-gel)工艺等几种LaCrO3涂层材料制备方法以及LaCrO3作为新型阳极材料的催化性能、导电性能和热膨胀性能等方面的研究进展,对其发展前景进行了展望.