Hierarchically Structured Porous Materials for Energy Conversion and Storage

Materials with hierarchical porosity and structures have been heavily involved in newly developed energy storage and conversion systems. Because of meticulous design and ingenious hierarchical structuration of porosities through the mimicking of natural systems, hierarchically structured porous materials can provide large surface areas for reaction, interfacial transport, or dispersion of active sites at different length scales of pores and shorten diffusion paths or reduce diffusion effect. By the incorporation of macroporosity in materials, light harvesting can be enhanced, showing the importance of macrochannels in light related systems such as photocatalysis and photovoltaics. A state‐of‐the‐art review of the applications of hierarchically structured porous materials in energy conversion and storage is presented. Their involvement in energy conversion such as in photosynthesis, photocatalytic H₂ production, photocatalysis, or in dye sensitized solar cells (DSSCs) and fuel cells (FCs) is discussed. Energy storage technologies such as Li‐ions batteries, supercapacitors, hydrogen storage, and solar thermal storage developed based on hierarchically porous materials are then discussed. The links between the hierarchically porous structures and their performances in energy conversion and storage presented can promote the design of the novel structures with advanced properties.     

半导体材料的化学功能—光催化技术与环境保护

半导体材料的光催化效应可将光能转化为化学，在环保化工和太阳能利用方面有巨大应用潜力。文章介绍光催化技术的基本原理，实施方法以及在环保领域内的应用前景。对光催化技术实用化过程中的几个重要问题进行了讨论。     

Surface Plasmonic‐Assisted Photocatalysis and Optoelectronic Devices with Noble Metal Nanocrystals: Design,Synthesis, and Applications

The surface plasmon resonance (SPR) of noble metals is known to improve the efficiency of various processes and devices. The photocatalytic process is the production of fuels and storage of solar photons in chemical bonds without imposing harmful threats to the environment. Photovoltaics are other devices utilizing solar energy for electrical energy. Similarly, other optoelectronic devices like photodetectors absorb photons and convert it into charges via electron–hole dissociation processes. In contrast, light‐emitting optoelectronic devices work based on the phenomenon of charge recombination to produce light. All these devices, however, have efficiency limitations, which impede the application of novel functional materials in these devices. A more direct approach is the utilization of noble metals and their complexes, which significantly enhance the efficiencies of these devices by SPR. This article highlights recent works and applications of noble metals by SPR‐enhanced photocatalysis for hydrogen evolution from water, CO₂ conversion into useful compounds, and oxidation of hazardous pollutants. In addition, the plasmon‐enhancement of optoelectronic devices is summarized. Several possible mechanisms that have been previously reported in the literature are discussed in this work, with particular emphasis on different features of these mechanisms involving devices that are not highlighted and therefore need more attention.     

Thin‐Layered Photocatalysts

Semiconductor photocatalysis, a green and sustainable technology, is of great significance for solving environmental pollution and energy shortages. However, the common problems of inefficient light harvesting, rapid recombination of electron–hole pairs, and low surface reactive reaction sites for photocatalysts urgently need to be solved. In this regard, thin‐layered photocatalysts are considered to be one of the most promising candidates for addressing these issues, due to their unique surface and electronic properties. In this review, the various strategies for constructing thin‐layered photocatalysts are summarized, and emphasis is given to approaches for optimizing the photocatalytic performance of the thin‐layered materials, which can be classified into surface engineering and junction construction. In addition, the photocatalytic applications of thin‐layered materials, i.e., water splitting, CO₂ reduction, nitrogen fixation, and molecule oxygen activation, are summarized. Finally, based on current achievements in thin‐layered photocatalysts, their future development and challenges are discussed.     

Perylene diimide self-assembly: From electronic structural modulation to photocatalytic applications

As an emerging organic semiconductor, perylene diimide (PDI) self-assembly has attracted tremendous attention in the aspects of solar cells, sensors, fluorescence probes and n-transistors, etc. In term of photocatalysis, various photocatalysts based on PDI self-assembly exhibit some unique properties, such as intrinsic Π-Π stacking structure, fast internal charge transfer, band-like electronic structure, flexible structural modifiability, well-defined morphological adjustability and excellent light absorption. This paper mainly presents recent progress on PDI self-assembly regarding how to regulate the electronic structure of PDI self-assembly. In addition, the photocatalytic applications of PDI self-assembly and its complexes were reviewed, such as environmental remedy, energy productions, organic synthesis and photodynamic/photothermal therapy, further highlighting related photocatalytic mechanisms. Finally, the review contents and some perspectives on photocatalytic research of PDI self-assembly were summarized, and some key scientific problems were put forward to direct related photocatalytic research in future.     

The application of perovskite materials in solar water splitting

Solar water splitting is a promising strategy for sustainable production of renewable hydrogen, and solving the crisis of energy and environment in the world. However, large-scale application of this method is hampered by the efficiency and the expense of the solar water splitting systems. Searching for non-toxic, low-cost, efficient and stable photocatalysts is an important way for solar water splitting. Due to the simplicity of structure and the flexibility of composition, perovskite based photocatalysts have recently attracted widespread attention for application in solar water splitting. In this review, the recent developments of perovskite based photocatalysts for water splitting are summarized. An introduction including the structures and properties of perovskite materials, and the fundamentals of solar water splitting is first provided. Then, it specifically focuses on the strategies for designing and modulating perovskite materials to improve their photocatalytic performance for solar water splitting. The current challenges and perspectives of perovskite materials in solar water splitting are also reviewed. The aim of this review is to summarize recent findings and developments of perovskite based photocatalysts and provide some useful guidance for the future research on the design and development of highly efficient perovskite based photocatalysts and the relevant systems for water splitting.     

Nanostructured thin films based on TiO2 and/or SiC for use in photoelectrochemical cells: A review of the material characteristics,synthesis and recent applications

In solar energy harvesting research, there is growing interest in the study of photoelectrochemical (PEC) properties of the following classes of semiconductor materials: metal oxides and silicon-based compounds. The motivation is that such materials are being successfully used as photoelectrode in PEC cells. Special attention has been given to the wide band gap materials. This review discusses, from the material science perspective, the recent literature relating to two wide band gap semiconductor materials: one metal oxide, titanium dioxide (TiO₂), and one silicon-based compound, silicon carbide (SiC). Emphasis is placed on TiO₂ and SiC thin films for PEC applications. Materials characteristics, synthesis methods and recent photocatalytic applications are presented. Finally, the interesting effect of the efficiency increase of PEC devices developed from a hetero-junction of TiO₂ and SiC is discussed.     

Development and Evolution of the System Structure for Highly Efficient Solar Steam Generation from Zero to Three Dimensions

Direct solar steam generation (DSSG) offers a promising, sustainable, and environmentally friendly solution to the energy and water crisis. In the past decades, DSSG has gained tremendous attention due to its potential applications for clean water production, desalination, wastewater treatment, and electric energy harvesting. Even though the solar–thermal conversion efficiency has approached 100% under 1 sun illumination (1 kW m^?2) using various photothermal materials and systems, the optimization of the materials and system structure remains unclear because of the lack of evaluation methods in unity for the output efficiency. In this review, a few key concerns about different dimensional materials and systems that determine the characteristics of DSSG are explored. Quantitative analysis, including calculations and methods for the solar–thermal conversion efficiency, evaporation rate, and energy loss, is employed to evaluate the materials and systems from the point of view of ultimate utilization. This article focuses on the relationship between the system dimension and energy efficiency and notes opportunities for future system design and commercialization of DSSG.     

Vacancy Engineering in Semiconductor Photocatalysts: Implications in Hydrogen Evolution and Nitrogen Fixation Applications

It is a well-known fact that the pronounced photogenerated charge recombination and poor light absorption are the main bottlenecks of photocatalysis applications. The conventional approaches to address these problems involve bandgap engineering and suppression of charge recombination after light irradiation, which results in an enhancement in the photocatalytic performance of the materials. However, the most essential aspect of surface modification to engineer active sites on the catalyst surface is generally not given much importance. Contrary to this, defect engineering is another approach by which the optical, charge separation, and surface properties of the photocatalytic materials can be tuned. In this review article, the effect of the introduction of vacancies on the photocatalytic properties of selected semiconductor materials, viz., metal oxides, perovskite oxides, metal sulfides, oxyhalides, and nitrides is comprehensively summarized. The engineering of vacancies in these materials not only improves their optical and charge transfer properties but also affects the surface properties, which are helpful in the adsorption of the reactants on catalyst surface. Herein, photocatalytic hydrogen evolution and nitrogen fixation applications of vacancy engineered materials are discussed in detail along with the current trends, scalability requirements, and rigorous experimental protocols.     

Porous Single‐Crystal‐Based Inorganic Semiconductor Photocatalysts for Energy Production and Environmental Remediation: Preparation,Modification, and Applications

Semiconductor photocatalytic and photovoltaic performance depends on crystallinity and surface area to a large extent. One strategy that has recently emergyed to improve semiconductor photoresponse efficiency is their synthesis as porous single crystals (PSCs), therefore providing simultaneously high crystallinity, minimization of grain boundaries, and large specific surface area. Other factors, such as high density of active sites, and enhanced light absorption, also contribute to increased PSC photoresponse with respect to analogous bulk or amorphous materials. This review initially presents the concept and main properties of PSCs. Then, the synthetic routes and the applications as photocatalysts and as photovoltaic devices, mainly in sunlight applications, are summarized. The synthetic procedures have been classified according to the mechanism of pore generation. Applications cover photocatalysis for environmental remediation, solar fuels production, selective photooxidation of organic compounds, and photovoltaic devices. Finally, a summary and views on future developments are provided. The purpose of this review is to show how the use of PSCs is a powerful general methodology applicable beyond metal oxides and can ultimately lead to sufficient photoresponse efficiency, bringing these processes close to commercial application.     

Improving the Stability of Halide Perovskites for Photo-, Electro-, Photoelectro-Chemical Applications

Owing to their remarkable and adjustable optoelectronic properties, halide perovskites (HPs) have been regarded as a class of promising materials for various optoelectronic applications based on different energy conversion reactions, including photovoltaic cell, photocatalysis, electrocatalysis, and photoelectrochemical (PEC) systems. However, the low stability of HPs upon exposure to ambient conditions (e.g., water, heat, light, electricity) greatly hinders the practical applications of HPs. In the past few years, significant efforts have been devoted to enhancing the eventual stability of the perovskite-based optoelectronic systems, mainly focusing on delivering improvements in the stabilities of halide perovskite materials and the relevant operation conditions of optoelectronic systems, which deserve in-depth and systematic summaries. In this comprehensive review, the in-depth environment-induced decomposition mechanisms of typical HPs are elucidated. Simultaneously, the strategies for addressing the instability issues of halide perovskite materials are critically reviewed, including dimension control, compositional engineering, ligand passivation, and encapsulation engineering. Furthermore, the photoelectric applications based on the modified HPs and operation conditions are discussed systematically. In the last part of this review, future perspectives and outlooks toward the stability of HPs and their photoelectric applications are envisaged respectively.     

Surface Defect Engineering in Colored TiO2 Hollow Spheres Toward Efficient Photocatalysis

Nanostructured TiO₂ is one of the best materials for photocatalysis, thanks to its high surface area and surface reactivity, but its large energy bandgap (3.2 eV) hinders the use of the entire solar spectrum. Here, it is proposed that defect-engineered nanostructured TiO₂ photocatalysts are obtained by hydrogenation strategy to extend its light absorption up to the near-infrared region. It is demonstrated that hydrogenated or colored TiO₂ hollow spheres (THS) composed of hierarchically assembled nanoparticles result in much broader exploitation of the solar spectrum (up to 1200 nm) and the engineered surface enhances the photogeneration of charges for photocatalytic processes. In turn, when applied for photodegradation of a targeted drug (Ciprofloxacin) this results in 82% degradation after 6 h under simulated sunlight. Valence band analysis by photoelectron spectroscopy revealed the presence of oxygen vacancies, whose surface density increases with the hydrogenation rate. Thus, a tight correlation between degree of hydrogenation and photocatalytic activity is directly established. Further insight comes from electron paramagnetic resonance, which evidences bulk Ti³⁺ centers only in hydrogenated THS. The results are anticipated to disclose a new path toward highly efficient photocatalytic titania in a series of applications targeting water remediation and solar fuel production.     

Outlook for photovoltaic developments in Taiwan

This paper describes the various aspects of photovoltaic developments in Taiwan, which include applications of space and terrestrial solar cells, solar cell production and research on advanced thin-film solar cell materials. The advanced materials are hydrogenated polycrystalline silicon films deposited at low substrate temperatures and ternary chalcopyrite films with the potential for intrinsically stable and ultra-high-efficiency solar cells having a conversion efficiency in the vicinity of AMI 35%. © 1998 John Wiley & Sons, Ltd.     

聚苯胺光学吸收及应用

从结构和性能的角度对聚苯胺不同形态因电子或极子跃迁引起的在可见近红外区的吸收特性进行了总结。重点讨论了本征态盐的分子链构像结构对光学吸收的影响，报道了作者在降苯胺用于透明导电材料和节能方面的一些设想和研究结果。     

Progress in crystalline multijunction and thin-film photovoltaics

Photovoltaics are important in terrestrial applications such as remote power and renewable energy but are the primary source of electrical power for space systems. For space applications, priorities are high conversion efficiency and resistance to radiation-induced degradation. The emphasis is on III-V multijunction solar cells and comparatively lower efficiency but flexible, lightweight thin-film solar cells. Triple-junction III-V solar cells have reached conversion efficiencies of 30% at air mass zero (AM0). New lattice mismatch techniques and nitride materials hold promise for further efficiency increases. Thin-film solar cells generally have less than 15% efficiency but greater radiation resistance, lower cost, and lower mass.     

Positioning MXenes in the Photocatalysis Landscape: Competitiveness,Challenges, and Future Perspectives

MXenes are becoming a worthy contender for boosting the efficacy of semiconductor photocatalysts because of their rich surface and electronic properties, which is exemplified to be a dynamic yet open‐ended exploration of the materials space. Herein, the promise that MXenes hold for photocatalytic applications is elucidated by presenting the various roles of MXenes in the preparation of composite photocatalysts and enhancing their activity and stability. A specific focus is put on the key issues that should be taken into account when utilizing the specific function of MXenes and the strategies to deliver the great potential of MXenes into better play. The discussion is based on different aspects closely related to the flexible surface and electronic features of MXenes, including their morphology control, stability issue, and electronic structure mutability with the purpose to present an objective and comprehensive scenario of MXenes for photocatalysis. Finally, some noteworthy research directions for the future development of MXenes‐based photocatalytic systems are outlined and prospected. This review is expected to provide a useful scaffold for the rational design and synthesis of efficient and stable MXenes‐based photocatalysts by objectively understanding and taming the functional vitality of MXenes.     

Visible‐Light‐Activated Photocatalytic Films toward Self‐Cleaning Membranes

Membranes are among the most promising means of delivering increased supplies of fit‐for‐purpose water, but membrane fouling remains a critical issue restricting their widespread application. Coupling photocatalysis with membrane separation has been proposed as a potentially effective approach to reduce membrane fouling. However, commonly used materials in photocatalysis limit use of low‐cost sources such as sunlight due to their large bandgaps. There are few examples of in situ photocatalytic self‐cleaning of membranes, with removal from the filtration system and ex situ illumination being more common. In this work, a visible‐light‐activated photocatalytic film prepared by nitrogen doping into the lattice of TiO₂ is deposited on commercial ceramic membranes via atomic layer deposition. The synergy between membrane separation and redox reactions between organic pollutants and reactive oxygen species produced by the visible‐light‐activated layer offers a possibility for stable and sustainable membrane operation under in situ solar irradiation.     

Halide Perovskite Materials for Energy Storage Applications

Halide perovskites, traditionally a solar‐cell material that exhibits superior energy conversion properties, have recently been deployed in energy storage systems such as lithium‐ion batteries and photorechargeable batteries. Here, recent progress in halide perovskite‐based energy storage systems is presented, focusing on halide perovskite lithium‐ion batteries and halide perovskite photorechargeable batteries. Halide‐perovskite‐based supercapacitors and photosupercapacitors are also discussed. The photorechargeable batteries and photorechargeable supercapacitors employ solar energy to photocharge the battery; this saves energy and improves device portability. These lightweight, integrated halide perovskite‐based systems, which are pertinent to electric vehicles and portable electronic devices, are reviewed in detail. Suggestions on future research into the design of halide‐perovskite‐based energy storage materials are also given. This review provides a foundation for the development of integrated lightweight energy conversion and storage materials.     

Surface Defect Engineering in 2D Nanomaterials for Photocatalysis

2D Nanomaterials, with unique structural and electronic features, have shown enormous potential toward photocatalysis fields. However, the photocatalytic behavior of pristine 2D photocatalysts are still unsatisfactory, and far below the requirements of practical applications. In this regard, surface defect engineering can serve as an effective means to tune photoelectric parameters of 2D photocatalysts through tailoring the local surface microstructure, electronic structure, and carrier concentration. In this review, recent progress in the design of surface defects with the classified anion vacancy, cation vacancy, vacancy associates, pits, distortions, and disorder on 2D photocatalysts to boost the photocatalytic performance is summarized. The strategies for controlling defects formation and technique to distinguish various surface defects are presented. The crucial roles of surface defects for photocatalysis performance optimization are proposed and advancement of defective 2D photocatalysts toward versatile applications such as water oxidation, hydrogen production, CO₂ reduction, nitrogen fixation, organic synthesis, and pollutants removal are discussed. Surface defect modulated 2D photocatalysts thus represent a powerful configuration for further development toward photocatalysis.     

最新高效率光伏逆变器拓扑结构及功率器件介绍

效率正成为电力电子装置设计中越来越重要的参数。在某些应用中,效率甚至成为行业发展的驱动力,典型的如太阳能发电行业。因为对于光伏发电行业,效率的提升可以直接带来经济效益。本文详细介绍了最新的能够提供高效率的光伏逆变器拓扑结构和功率器件,包括单相和三相逆变器,功率因数补偿对策,高效电流双向流动逆变器等。