非铅金属卤化物类钙钛矿发光材料研究进展

铅基卤化物钙钛矿发光材料因具有荧光量子产率高、发射光谱窄、发射波长可调等优异性能优势而备受关注。但金属铅的毒性和钙钛矿的稳定性是其未来在显示与照明领域实际应用中需要解决的问题。因此,探索与铅基卤化物钙钛矿光电性质相当、但更绿色环保的非铅金属卤化物类钙钛矿发光材料是势在必行的趋势。近年来,非铅金属卤化物类钙钛矿发光材料的研究取得了显著进展。本文总结了非铅金属卤化物类钙钛矿材料的晶体结构、制备方法和发光机理。归纳了影响非铅金属卤化物类钙钛矿光电性能的因素,并列举了在光致和电致发光器件领域的应用。最后,就如何进一步提升非铅金属卤化物钙钛矿发光材料的性能做了总结和展望。     

异质结构在光伏型卤化物钙钛矿光电转换器件中的应用

钙钛矿材料由于具有长的载流子扩散长度、较高的吸收系数和较低的缺陷态密度等优点在太阳电池、光电探测器、发光二极管等光电转换器件领域得到广泛应用.同时,层状二维材料、低维半导体纳米结构、金属纳米结构和绝缘材料等功能材料因它们特殊的化学、电学和物理性质而越来越受到人们的关注.为了拓宽钙钛矿材料在光电转换器件的应用,可将钙钛矿与这些功能材料进行组合,形成异质结构,集成两种材料的优点.钙钛矿/功能材料异质结构可作为界面修饰层、电荷传输层、封装层等应用于卤化物钙钛矿光电转换器件中,用来抑制光生载流子的复合损耗,提升载流子的传输性能,改善器件的稳定性等.本文综述了钙钛矿与层状二维材料、低维半导体纳米结构、金属纳米结构和绝缘材料等形成的异质结构在光伏型光电转换器件中应用的最新研究进展,并对该方向未来的发展做出了展望.     

钙钛矿量子点:机遇与挑战

近年来,卤化物钙钛矿纳米材料因其优异的光电性能引起了国内外学者的广泛关注。本文回顾了钙钛矿量子点从材料到多功能应用发展中的多个"高光"时刻,探讨了其快速发展过程中面临的机遇与挑战,强调了该领域发展存在的瓶颈,希望以此与广大同仁进行交流,共同推进钙钛矿量子点的研究进程。     

铯铅卤化物钙钛矿量子点从玻璃中析出的诱导因素

铯铅卤化物(CsPbX3,X=Cl,Br,I)钙钛矿量子点以其优异的光电性能(如可调的发射光谱、高色纯度和量子效率等)引起了研究者们的广泛关注,但较差的水稳定性、热稳定性和光稳定性等缺点极大地限制了其在光电器件中的应用.目前,提高铯铅卤化物钙钛矿量子点稳定性的一种有效方法是将CsX和PbX2加入惰性玻璃陶瓷基质中,只要...     

高压下正交相CsPbI3钙钛矿纳米棒的带隙调制

全无机卤化物钙钛矿由于其稳定性强,且具有良好的光学性质,是一种很有前途的光电材料。然而,有效地设计其带隙以满足实际应用需求仍是亟待解决的关键问题。通过控制合成的反应时间和温度,对铯铅碘(CsPbI_3)纳米材料进行形貌调控,合成出形貌均一、结晶性良好的棒状CsPbI_3纳米材料。进一步利用金刚石对顶砧,结合原位高压紫外-可见吸收光谱,对CsPbI_3纳米棒在高压下的带隙变化进行研究,发现高压下CsPbI_3纳米棒的带隙减小,带隙的可调控性为纳米材料在光伏电池领域的应用奠定基础。研究结果不仅有助于在原子尺度上建立CsPbI_3纳米棒的结构特性关系,而且为全无机钙钛矿纳米材料的实际应用提供重要线索。     

铯铅卤化物钙钛矿量子点从玻璃中析出的诱导因素EI北大核心CSCD

铯铅卤化物(CsPb X 3,X=Cl,Br,I)钙钛矿量子点以其优异的光电性能(如可调的发射光谱、高色纯度和量子效率等)引起了研究者们的广泛关注,但较差的水稳定性、热稳定性和光稳定性等缺点极大地限制了其在光电器件中的应用。目前,提高铯铅卤化物钙钛矿量子点稳定性的一种有效方法是将Cs X和Pb X 2加入惰性玻璃陶瓷基质中,只要外界提供的能量可以克服成核和晶体生长的能量障碍,玻璃中就会析出铯铅卤化物钙钛矿量子点。本文重点介绍了热处理、激光、应力和水四种铯铅卤化物钙钛矿量子点从玻璃中析出的诱导因素,并分析了每种诱导因素的优缺点,最后提出了每种诱导因素相对适合的玻璃陶瓷和一些建议。     

蓝光钙钛矿发光二极管:机遇与挑战

基于金属卤化物钙钛矿材料制备的发光二极管(LED)发展迅速,短短五年内,近红外、红光和绿光钙钛矿发光器件的外量子效率均超过了20%,在显示与照明领域展示出很好的应用前景.然而,蓝光钙钛矿LED的性能相对较差,制约了钙钛矿LED在全色显示领域的应用.目前,实现钙钛矿蓝光主要有两种方式,一种是基于卤素掺杂的组分工程,另一种是基于量子限域效应的维度调控.本文主要介绍了基于这两种方法的蓝光钙钛矿LED的发展历程,讨论了蓝光钙钛矿LED面临的主要问题,并对如何提升蓝光钙钛矿LED性能进行展望.     

非磁性发光材料的磁场效应:从有机半导体到卤化物钙钛矿

磁场效应(magnetic field effects, MFEs)指的是材料或器件的光电物理特性(包括光致发光、电致发光、注入电流、光电流等)在外加磁场下发生的变化.本文所述的是非磁性发光材料的MFEs,其首先在有机半导体光电器件中被发现.近十几年来, MFEs作为一种新兴的物理现象引起了广泛的研究;同时它也成为一种独特的实验手段,用以探讨有机半导体中电荷的输运、复合以及自旋极化等过程.近期的研究发现, MFEs不仅存在于有机半导体中,而且在拥有强自旋-轨道耦合作用的金属卤化物钙钛矿材料中被观测到,这既拓展了MFEs的研究方向,也为通过研究MFEs来探索金属卤化物钙钛矿器件的物理机制,进而为提升其器件性能提供了契机.本文重点关注有机半导体和卤化物钙钛矿在磁场下的电致发光和光致发光变化,即发光的磁场效应.回顾了到目前为止主流的理论模型和代表性实验现象,对比分析了磁场下有机半导体和卤化物钙钛矿的发光物理行为.以期为有机及钙钛矿磁场效应领域的研究提供一些思路,同时为有机及钙钛矿发光领域的发展贡献些许想法.     

稀土离子掺杂钙钛矿纳米晶的光学性质和应用

近年来,钙钛矿纳米晶由于具有优异的光电性质,在发光、光电转换等领域获得了广泛的研究,已然成为科研界的"明星材料".然而,钙钛矿纳米晶存在一些不足之处(例如稳定性差、光谱仅限于可见光区等),限制了其应用.稀土离子具有丰富的4f能级和特殊的电子构型,因此,将稀土离子掺杂到钙钛矿纳米晶中,能够显著提升材料的光电性质,并改善稳...     

钡作为掺杂元素调控铅基钙钛矿材料的毒性和光电特性

近年来,有机-无机杂化卤化物钙钛矿材料(ABX_3)由于具有优异的光电性质,受到了材料、能源等领域的广泛关注.但是,卤化物钙钛矿存在两个明显阻碍其商业化应用的问题:热稳定性差和含有有毒的铅(Pb)元素.相比于有机-无机杂化卤化物钙钛矿,全无机卤化物钙钛矿通常拥有更好的热稳定性.同时,采用一些无毒的元素部分替代B位的Pb,可以在保持优异光电特性的同时减小材料的毒性.本文结合无序合金结构搜索方法和第一性原理计算,系统研究了Ba掺杂CsPbX_3 (X=Cl, Br, I)钙钛矿体系的热稳定性和光电特性.计算结果显示,只有在高Ba浓度时,可以在室温下形成无序固溶体.由于Ba和Pb的离子半径和电负性等物理化学性质存在显著差异,随着Ba掺杂浓度的增加,带隙和载流子有效质量都呈现上升趋势,且带隙具有很宽的调节范围.因此,我们预测高Ba掺杂浓度的CsPbX_3 (X=Cl, Br, I)钙钛矿体系在短波段(如紫外或近紫外光)发光二极管或辐射探测器等领域具有潜在的应用价值.     

Optical properties of two-dimensional perovskites

The optical properties of two-dimensional (2D) perovskites recently receive numerous research focus thanks to the strong quantum and dielectric confinement effects. In addition to the strong excitonic effect at room temperature, 2D perovskites also have appealing features that their optical properties can be flexibly tuned by alternating organic or inorganic layers. Particularly, 2D chiral perovskites and 2D perovskites based heterostructures are emerging as new platforms to extend their functionalities. To optimize performance of 2D perovskites-based optoelectronic devices, it is critical to understand the fundamentals and explore the strategies to engineer their optical properties. This review begins with an introduction to the excitons and self-trapped excitons of 2D perovskites. Subsequently, inorganic/organic layer effects on optical properties and 2D perovskites based heterostructures are discussed. We also discussed the nonlinear optical properties of 2D perovskite. We are looking forward to that this review can stimulate more efforts to understand and optimize the optical properties of 2D perovskites.     

锡基钙钛矿的研究进展及其在发光二极管中的应用

卤化铅钙钛矿由于具有高吸收系数、高载流子迁移率、高缺陷容忍度和高光致发光效率等优越的光电子性能,近年来引起了人们的广泛关注.然而,可能阻碍其商业应用的关键是铅元素的存在引起的毒性问题.为了解决这一毒性问题,谨慎而有策略地用其他无毒候选元素替代Pb2+是一个很有前途的方向.锡具有和铅相似的结构和性质,是目前最有希望替代铅...     

Research progress of low-dimensional metal halide perovskites for lasing applications

Metal halide perovskites have been regarded as remarkable materials for next-generation light-harvesting and light emission devices. Due to their unique optical properties, such as high absorption coefficient, high optical gain, low trappingstate density, and ease of band gap engineering, perovskites promise to be used in lasing devices. In this article, the recent progresses of microlasers based on reduced-dimensional structures including nanoplatelets, nanowires, and quantum dots are reviewed from both fundamental photophysics and device applications. Furthermore, perovskite-based plasmonic nanolasers and polariton lasers are summarized. Perspectives on perovskite-based small lasers are also discussed. This review can serve as an overview and evaluation of state-of-the-art micro/nanolaser science.     

Potential development of all-inorganic perovskites

A recent review [19] provides detailed information on the synthesis, optical properties, applications and potential development of all-inorganic metal halide nanostructured perovskites.     

Ion migration in metal halide perovskite QLEDs and its inhibition

Benefiting from the excellent properties such as high photoluminescence quantum yield (PLQY), wide gamut range, and narrow emission linewidth, as well as low-temperature processability, metal halide perovskite quantum dots (QDs) have attracted wide attention from researchers. Despite tremendous progress has been made during the past several years, the commercialization of perovskite QDs-based LEDs (PeQLEDs) is still plagued by the instability. The ion migration in halide perovskites is recognized as the key factor causing the performance degradation of PeQLEDs. In this review, the elements species of ion migration, the effects of ion migration on device performance and stability, and effective strategies to hinder/mitigate ion migration in PeQLEDs are successively discussed. Finally, the forward insights on the future research are highlighted.     

Could two-dimensional perovskites fundamentally solve the instability of perovskite photovoltaics

The high efficiency and low production cost enable the halide perovskite solar cells as a promising technology for the next generation photovoltaics. Nevertheless, the relatively poor stability of the organic-inorganic halide perovskites hinders their commercial applications. In the past few years, two-dimensional (2D) perovskite has emerged as a more stable alternative to the three-dimensional (3D) counterparts and attracted intense research interests. Although many attempts and advances have been made, it is still ambiguous that whether the 2D perovskites could bring closure to the stability issue. To answer this essential question, a systematic study of the nature of 2D halide perovskites is necessary. Here, we focus on the stability investigations of 2D perovskites from different perspectives, especially light, heat, ion migration and strain. Several remaining challenges and opening problems are also discussed. With further material and device engineering, we believe that the 2D perovskites would promote perovskite solar cells to a promising future.     

Two‐Dimensional Au Nanocrystals: Shape/Size Controlling Synthesis,Morphologies, and Applications

The fascinating roles of two‐dimensional (2D) nanomaterials in natural super‐strong bio‐composites (i.e. aragonite platelets in nacre and apatite platelets in bone) have aroused great interest in scientific communities to synthesize their artificial counterparts with controllable geometric and physical properties. The quantum 2D confinement of electrons recently revealed in graphene nanosheets further inspires to explore 2D metal nanocrystals with intrinsic anisotropic properties and quantum size effect. Among them, 2D Au nanocrystals stand out not only due to their unique structure‐ and environmental‐dependent properties, but also due to their rapid development in synthesis approaches and emerging applications in electronics, optics, sensing and biomedicines. In this Review the aim is to rationalize numerous newly published studies on 2D Au nanocrystals and to gain insight into their shape/size controlling synthesis, diverse morphologies, properties, and applications, potentially serving a handy guide to achieve on‐demand 2D Au nanocrystals.     

硅基底石墨烯器件的现状及发展趋势

石墨烯是一种由单层碳原子紧密排列而形成的具有蜂窝状结构的二维晶体材料,特殊的结构赋予了其优异的性能,如高载流子迁移率、电导率、热导率、力学强度以及量子反常霍尔效应.由于石墨烯优异的特性,迅速激起了人们对石墨烯研究以及应用的热情.石墨烯沉积或转移到硅片后,其器件构建与集成和传统硅基半导体工艺兼容.基于石墨烯的硅基器件与硅基器件的有机结合,可以大幅度提高半导体器件的综合性能.随着石墨烯制备工艺和转移技术的优化,硅基底石墨烯器件将呈现出潜在的、巨大的实际应用价值.随着器件尺寸的纳米化,器件的发热、能耗等问题成为硅基器件与集成发展面临的瓶颈问题,石墨烯的出现为解决这些问题提供了一种可能的解决方案.本文综述了石墨烯作为场效应晶体管研究的进展,为解决石墨烯带隙为零、影响器件开关比的问题,采用了量子限域法、化学掺杂法、外加电场调节法和引入应力法.在光电器件研究方面,石墨烯可以均匀吸收所有频率的光,其光电性能也受到了广泛的关注,如光电探测器、光电调制器、太阳能电池等.同时,石墨烯作为典型的二维材料,其优越的电学性能以及超高的比表面积,使其作为高灵敏度传感器的研究成为纳米科学研究的前沿和热点领域.     

A molecular dynamics study of the effect of Coulomb Buckingham Potential on equilibrium structural properties of calcium titanate perovskite

The demand on new and highly efficient energy conversion systems and many other advanced applications have suggested perovskites to be important future candidate materials. Though a lot of work has been done to understand and model their structure and properties, further investigation is still needed. Consequently, the development and enhancement of computational methods including molecular dynamics and quantum chemical calculations is one of the main issues regarding the understanding and optimization of perovskites. In this work, Coulomb Buckingham interatomic potential function is investigated to analyze the structure of Calcium Titanate CaTiO₃ through the application of Molecular Dynamics via LAMMPS open source code. The results are compared with the results of other potential functions representations, namely Vashishta-Rahman (VR) and Lennard-Jones (LJ) potentials. The understanding of the effect of potential representation on structural properties would lead to deduction of mechanical and thermal properties and to building a platform for adapting the different types of oxide perovskites, or even nonorganic halide perovskites, to enhance their technological aspects. The VR interaction potential was previously proven to be the most effective for describing the phase changes of perovskites and to match the experimental observations. It was also proven in previous studies that the radial distribution function (RDF) undergoes essential changes when replacing LJ with VR. According to the findings of this study, Buckingham potential is shown to produce much closer results to VR than LJ of the radial distribution function.     

The DarkSHINE experiment: A promising window into the dark world

Science China Physics, Mechanics & Astronomy - Two-dimensional halide perovskites, emerging materials with quantum well structures, demonstrate excellent physical properties, such as easily...