稀土上转换发光在钙钛矿太阳能电池中的应用

目前,钙钛矿太阳能电池最常使用的钙钛矿材料为CH_3NH_3PbI_3,其禁带宽度为1.55eV,导致低于该能量值的太阳光的光子无法被直接地吸收利用。因此,提高器件对太阳光谱的响应范围是提高钙钛矿太阳能电池性能的关键。稀土上转换材料可以将低能量近红外光转换为高能量可见光,所以,稀土上转换发光的应用是提高钙钛矿太阳能电池性能的较为可行的途径。本文概述了稀土上转换发光的基本机制,介绍了钙钛矿太阳能电池的结构和工作原理,综述了该太阳能电池的研究现状及其主要优势,重点阐述了稀土上转换发光在钙钛矿太阳能电池中的应用,最后对该太阳能电池的发展前景进行了展望。     

上转换纳米材料及其在提高太阳能电池光电效率中的应用

上转换纳米材料在提高太阳能电池光电效率方面的应用主要通过提高上转换纳米材料的发光性能来实现。利用上转换纳米材料能将2个或2个以上的低能短波光子转换成高能可见光的特性,可以拓宽太阳能电池对光的响应范围,达到提升光电转换效率的目的。主要介绍了上转换纳米材料,包括其发光机制与基质材料的选择。回顾了在近阶段主要使用的热分解法、水热法等制备方法,分析了其他一些制备方法。着重介绍了上转换纳米材料在晶体硅太阳能电池和染敏太阳能电池中的应用。从提升上转换材料发光性的角度来讨论对太阳能电池的研究,并指出了未来上转换纳米材料在太阳能电池中应用的研究重点是利用异质离子掺杂、表面等离子体耦合与量子点敏化等手段提升上转换效率,而染料耦联上转换纳米材料、上转换纳米材料壳包覆等方法也具有很大发展潜力。     

面向太阳光全光谱应用铒掺杂硫卤玻璃上转换发光特性研究

使用熔融淬冷法制备了Er³⁺掺杂Ge-Ga-S-CsBr硫卤玻璃, 研究了其在1550 nm激光激发下的上转换发光特性, 观察到强的波长中心位于525和545 nm绿色发光及弱的中心波长位于660 nm红色发光, 也观察到了中心波长分别位于810和980 nm的红外上转换发光。基于泵探光功率关系和能级寿命测试研究了发光机理, 发现中间态能级寿命的延长是上转换发光效率增强的根本原因。使用全光谱光源测试了Si太阳能效率, 当使用上转换发光层时, 太阳能电池平均效率从7.28%上升至7.32%。结果显示所探索的稀土掺杂硫卤玻璃有望应用于硅太阳能电池效率增强领域。     

Optimized solvent-thermal preparation of NaYF4 :Yb3+, Er3+ up-conversion nanoparticles for application in solar cells

用溶剂热法合成Yb³⁺、Er³⁺共掺的NaYF₄ 纳米上转换材料, 研究了去离子水、乙醇两种反应溶剂对材料性能的影响. 用X射线衍射光谱、扫描电镜和荧光光谱等测试手段对材料性能进行了对比分析. 结果表明: 以乙醇为溶剂并加入一定比例的EDTA, 所制备的上转换材料能发射较强的、可被太阳电池吸收的可见光.     

Compact diode pumped cw solid-state lasers in the visible spectral region

This paper reviews recent advances in diode pumped cw solid-state lasers in the visible spectral region. Such lasers are based on rare earth doped materials. Visible wavelengths can be generated by frequency conversion of near IR-lasers or by up-conversion pumped rare earth ion lasers.     

Near‐Unity Emitting Copper‐Doped Colloidal Semiconductor Quantum Wells for Luminescent Solar Concentrators

Doping of bulk semiconductors has revealed widespread success in optoelectronic applications. In the past few decades, substantial effort has been engaged for doping at the nanoscale. Recently, doped colloidal quantum dots (CQDs) have been demonstrated to be promising materials for luminescent solar concentrators (LSCs) as they can be engineered for providing highly tunable and Stokes‐shifted emission in the solar spectrum. However, existing doped CQDs that are aimed for full solar spectrum LSCs suffer from moderately low quantum efficiency, intrinsically small absorption cross‐section, and gradually increasing absorption profiles coinciding with the emission spectrum, which together fundamentally limit their effective usage. Here, the authors show the first account of copper doping into atomically flat colloidal quantum wells (CQWs). In addition to Stokes‐shifted and tunable dopant‐induced photoluminescence emission, the copper doping into CQWs enables near‐unity quantum efficiencies (up to ≈97%), accompanied by substantially high absorption cross‐section and inherently step‐like absorption profile, compared to those of the doped CQDs. Based on these exceptional properties, the authors have demonstrated by both experimental analysis and numerical modeling that these newly synthesized doped CQWs are excellent candidates for LSCs. These findings may open new directions for deployment of doped CQWs in LSCs for advanced solar light harvesting technologies.     

CIS太阳电池材料的研究进展

综述了国内外太阳电池及其材料的发展概况.目前应用的光电转换材料主要有硅材料和化合物半导体材料,介绍了用这几类材料制作的太阳电池的特点,重点介绍了其光电转换效率.在薄膜电池材料中重点综述了铜铟硒(CIS)基薄膜太阳电池的研究进展.由于制约太阳电池发展的关键问题是制备成本高和转换效率低,提出了采用化学法制备CIS基薄膜材料及其梯度带隙,该方法将开辟高性能CIS基吸收层薄膜材料及其器件制备的低成本新途径.     

染料敏化太阳能电池中纯铂对电极的研究进展

作为染料敏化太阳能电池的重要组成部分,对电极的催化性能和价格直接关系到电池的光电转换效率和成本。作为对电极的催化材料,导电聚合物、碳材料和无机化合物等材料虽成本低廉,但其催化性能仍不及金属铂。因此,重点综述了近年来染料敏化太阳能电池纯铂对电极的研究状况,并指出了纯铂对电极中有待解决的问题及今后的发展方向,同时还介绍了染料敏化太阳能电池的工作原理和对电极的作用。     

Titanium glycolate-derived TiO2 nanomaterials: Synthesis and applications

Titanium oxide (TiO₂) is one of the most widely studied materials due to its fascinating properties and versatile applications in environmental and energy fields ranging from photocatalysis to solar cells and lithium ion batteries. The significance and variety of these applications have attracted great attention and spurred substantial progress in the synthesis and fundamental understanding of TiO₂-based nanomaterials, nanocomposites, and nanoderivatives. This review summarizes the recent advances in the design and preparation of TiO₂-based nanomaterials, nanocomposites, and nanoderivatives obtained from titanium glycolate precursor. Utilizing different fabrication strategies, titanium glycolate precursor with controllable morphology and size has been successfully produced, and it can be directly transformed into crystalline TiO₂ nanomaterials through diverse post-treatments, including calcination thermal-decomposition, and refluxing, hydrothermal, and microwave treatment-assisted hydrolysis. Furthermore, doped TiO₂, TiO₂-composites, and other derivatives could be simply achieved by adding additional chemicals during transformation. The favorable properties of the resulting TiO₂-based materials are also discussed, which are relevant to energy and environmental applications in the areas of dye-sensitized solar cells, lithium ion batteries, photocatalytic hydrogen evolution, photocatalytic CO₂ reduction, photocatalytic degradation, and adsorption removal of pollutants.     

Multicolor polystyrene nanospheres tagged with up-conversion fluorescent nanocrystals

Compared to conventional down-conversion fluorescent materials, NIR-to-visible up-conversion fluorescent materials which emit visible light upon near-infrared (NIR) excitation are better suited for biodetection/bioimaging due to their advantages such as minimum photo-damage to living organisms, weak background fluorescence, low signal-to-noise ratio and high detection sensitivity. Uniform hexagonal NaYF(4) (β-NaYF(4)) nanocrystals with up-conversion fluorescence were synthesized. Monodisperse polystyrene nanospheres with an average size of 400?nm in diameter, tagged with different color β-NaYF(4) nanocrystals, were prepared using a miniemulsion polymerization method. More than 20 β-NaYF(4) nanocrystals were encapsulated in a single polystyrene nanosphere. The nanospheres emit multicolor NIR-to-visible up-conversion fluorescence upon excitation at a wavelength of 980?nm. The nanospheres could be used for a variety of biological applications which require high-sensitivity detection of biomolecules.     

Infrared Colloidal Quantum Dots for Photovoltaics: Fundamentals and Recent Progress

Colloidal quantum dots (CQDs) are solution‐processed semiconductors of interest in low‐cost photovoltaics. Tuning of the bandgap of CQD films via the quantum size effect enables customization of solar cells’ absorption profile to match the sun's broad visible‐ and infrared‐containing spectrum reaching the earth. Here we review recent progress in the realization of low‐cost, efficient solar cells based on CQDs. We focus in particular on CQD materials and approaches that provide both infrared and visible‐wavelength solar power conversion CQD photovoltaics now exceed 5% solar power conversion efficiency, achieved by the introduction of a new architecture, the depleted‐heterojunction CQD solar cell, that jointly maximizes current, voltage, and fill factor. CQD solar cells have also seen major progress in materials processing for stability, recently achieving extended operating lifetimes in an air ambient. We summarize progress both in device operation and also in gaining new insights into materials properties and processing – including new electrical contact materials and deposition techniques, as well as CQD synthesis, surface treatments, film‐forming technologies – that underpin these rapid advances.     

纳米WO3材料的制备、应用及研究趋势

结合近年来国内外相关文献，综述了纳米WO3材料的研究现状与进展，重点概述了超细WO3粉体和纳米WO3薄膜的各种制备方法及各自优缺点，并介绍了纳米WO3薄膜的稀有金属掺杂研究等；分析了纳米WO3材料的研究意义，介绍了纳米WO3材料在变色及催化等方面的应用。最后分析了纳米WO3材料应用的发展趋势。     

Recent progress in advanced optical materials based on gadolinium aluminate garnet (Gd3Al5O12)

This review article summarizes the recent achievements in stabilization of the metastable lattice of gadolinium aluminate garnet (Gd₃Al₅O₁₂, GAG) and the related developments of advanced optical materials, including down-conversion phosphors, up-conversion phosphors, transparent ceramics, and single crystals. Whenever possible, the materials are compared with their better known YAG and LuAG counterparts to demonstrate the merits of the GAG host. It is shown that novel emission features and significantly improved luminescence can be attained for a number of phosphor systems with the more covalent GAG lattice and the efficient energy transfer from Gd³⁺ to the activator. Ce³⁺ doped GAG-based single crystals and transparent ceramics are also shown to simultaneously possess the advantages of high theoretical density, fast scintillation decay, and high light yields, and hold great potential as scintillators for a wide range of applications. The unresolved issues are also pointed out.     

Superior Sodium Storage in 3D Interconnected Nitrogen and Oxygen Dual‐Doped Carbon Network

Carbonaceous materials have attracted immense interest as anode materials for Na‐ion batteries (NIBs) because of their good chemical, thermal stabilities, as well as high Na‐storage capacity. However, the carbonaceous materials as anodes for NIBs still suffer from the lower rate capability and poor cycle life. An N,O‐dual doped carbon (denoted as NOC) network is designed and synthesized, which is greatly favorable for sodium storage. It exhibits high specific capacity and ultralong cycling stability, delivering a capacity of 545 mAh g^?1 at 100 mA g^?1 after 100 cycles and retaining a capacity of 240 mAh g^?1 at 2 A g^?1 after 2000 cycles. The NOC composite with 3D well‐defined porosity and N,O‐dual doped induces active sites, contributing to the enhanced sodium storage. In addition, the NOC is synthesized through a facile solution process, which can be easily extended to the preparation of many other N,O‐dual doped carbonaceous materials for wide applications in catalysis, energy storage, and solar cells.     

硅酸盐长余辉发光材料的最新研究进展

系统地分析和概括了稀土离子激活硅酸盐体系长余辉发光材料的种类、特性、组成、结构、发光机理和制备技术。并根据长余辉发光材料研究现状，探讨了硅酸盐长余辉发光材料的研究方向与发展前景。     

Perovskite solar cells: must lead be replaced – and can it be done?

Perovskite solar cells have recently drawn significant attention for photovoltaic applications with a certified power conversion efficiency of more than 22%. Unfortunately, the toxicity of the dissolvable lead content in these materials presents a critical concern for future commercial development. This review outlines some criteria for the possible replacement of lead by less toxic elements, and highlights current research progress in the application of low-lead halide perovskites as optically active materials in solar cells. These criteria are discussed with the aim of developing a better understanding of the physio-chemical properties of perovskites and of realizing similar photovoltaic performance in perovskite materials either with or without lead. Some open questions and future development prospects are outlined for further advancing perovskite solar cells toward both low toxicity and high efficiency.     

Deposition of new microcrystalline materials, μc-SiC, μc-GeC by HWCVD and solar cell applications

This paper describes at first the present status of solar cell efficiencies prepared by Hot Wire CVD (HW-CVD), and then preparation techniques of μc-3C(cubic)-SiC developed for innovative solar cell applications by using HW-CVD method are presented. For preparing μc-3C-SiC, monomethylsilane (MMS) and hydrogen were used for reactant gases. The high conductivity of 5 S/cm could be achieved for N doped n-type μc-3C-SiC. For p-type, as-grown Al-doped μc-3C-SiC films showed a relatively high resistivity, but on thermal annealing, the conductivity increased to the level of 1 × 10^− 2 S/cm. Monomethylgermane (MMG) and H₂ were used to prepare μc-GeC thin films. μc-GeC thin films with a carbon composition of about 7-8% showed a clear shift of absorption coefficient spectra by 0.44 eV, when compared to crystalline Ge. The pin solar cell structures in which all p,i,n layers consist of μc-SiC have been prepared for the first time. It was found that μc-3C-SiC and μc-GeC are the promising candidates as the next generation thin-film solar cell materials, but at present, the film quality is strictly limited by the residual impurity concentration of filament material Re.     

Recent progress in advanced optical materials based on gadolinium aluminate garnet (Gd3Al5O12)

Abstract

This review article summarizes the recent achievements in stabilization of the metastable lattice of gadolinium aluminate garnet (Gd₃Al₅O₁₂, GAG) and the related developments of advanced optical materials, including down-conversion phosphors, up-conversion phosphors, transparent ceramics, and single crystals. Whenever possible, the materials are compared with their better known YAG and LuAG counterparts to demonstrate the merits of the GAG host. It is shown that novel emission features and significantly improved luminescence can be attained for a number of phosphor systems with the more covalent GAG lattice and the efficient energy transfer from Gd³⁺ to the activator. Ce³⁺ doped GAG-based single crystals and transparent ceramics are also shown to simultaneously possess the advantages of high theoretical density, fast scintillation decay, and high light yields, and hold great potential as scintillators for a wide range of applications. The unresolved issues are also pointed out.     

TiO2空心球制备及在染料敏化太阳能电池和锂离子电池中应用的研究进展

空心球结构的半导体氧化物具有密度低、比表面积大、机械和热稳定性好等优点。空心球结构对TiO_2纳米材料的电化学性能有着显著的优化作用,TiO_2空心球作为一种重要的半导体氧化物具有良好的物理和化学性质,在多种领域均表现出潜在的应用价值,制备大小和壳层数均可控的半导体TiO_2空心球已引起了研究者的广泛关注。主要综述了在硬模板、软模板和无模板条件下TiO_2空心球的制备方法;同时还介绍了其在染料敏化太阳能电池和锂离子电池方面的最新研究进展;最后,对TiO_2空心球的可控合成前景进行了展望。