层状类钙钛矿结构有机-无机杂合物的结构设计思想

层状类钙钛矿结构有机-无机杂合物是由有机、无机组元在分子尺度上组装而成的一类新材料,其结构和能带具有可设计可控性,因此应用前景广阔.论述了无机类钙钛矿和类钙钛矿杂合物在结构上低维拆分与组装的设计思想.     

层状类钙钛矿结构有机-无机杂合物的结构与性能

层状类钙钛矿结构有机-无机杂合物是由有机、无机组元在分子尺度上组装而成的一类新材料,其结构和能带具有可设计可控性,因此应用前景广阔.综述了层状类钙钛矿杂合物的结构形成规则和组成、结构变化对能带及其电子学性能的影响.     

自组装制备有机/无机层状复合材料

自然界中形成的生物材料在结构和性能上具有优异的配备性。模仿生物矿化的形成机制,利用自组装原理能够仿生合成出性能优良和具有多级结构特点的有机/无机界面层状复合材料。本文在总结近年来最新研究的成果上,简要介绍了自组装和生物矿化的机理,重点阐述了基于无机相层的自组装和以有机大分子为模板自组装制备有机／无机层状复合材料两种合成连径,并对未来的发展趋势做了展望。     

倒置结构全无机钙钛矿太阳能电池的界面层研究进展

铯基无机钙钛矿(CsPbX3)因其耐热性好、低成本和带隙可调等优点,近年来备受关注,并广泛用于制备新型薄膜太阳能电池。目前,虽然具有倒置结构的无机钙钛矿太阳能电池(PSC)更稳定且有望应用于构筑叠层电池的顶电池,其性能仍落后于正置结构的电池。因此,倒置电池的结构,特别是其界面层亟待进一步优化。近年来,研究者们设计和开发了一系列有机、无机界面层(包括空穴传输层和电子传输层),尝试优化基于无机钙钛矿的倒置电池。本综述针对这一现状,从材料和制备工艺的角度出发,综述了基于有机、无机材料体系的多种界面层的制备和应用进展,总结各类界面层材料的特点,讨论目前界面层的瓶颈问题和潜在的解决方案。     

杂化钙钛矿(HOC2H4NH3)2CuCl4的制备与表征

采用低温溶液法合成了新型层状有序的含有羟基的有机/无机杂化钙钛矿材料(HOC₂H₄NH₃)₂CuCl₄, 采用元素分析、红外光谱、紫外-可见光吸收光谱、X射线衍射和X射线吸收精细结构等手段对其结构与性能进行了表征。结果表明:该材料通过无机框架诱导有机组分有序排列, 形成了规则的层状结构, 有序性高。该杂化钙钛矿材料的分解温度为212℃, 电阻率为2.86×10⁶ Ω·cm, 比不含羟基杂化钙钛矿的电阻率低两个数量级。紫外-可见光吸收光谱显示285 nm左右有一归因于电子从Cl(3p)价带顶跃迁到Cu(4s)导带底而产生的吸收峰。X射线吸收精细结构谱图表明: 二维层状杂化钙钛矿晶体中的Cu²⁺与6个Cl^-形成八面体配位, Cu-Cl键长为0.191 nm, 层间距为1.099 nm。     

有机-无机杂化钙钛矿太阳电池的研究进展

可溶液加工的高效太阳电池及其活性层材料一直是全世界学术界与产业界关注与研究的热点。近年来,由于优异的光吸收特性和载流子传输能力,以及相对简单的制备方法,具有立体三维结构的有机-无机杂化钙钛矿晶体材料在太阳电池中的应用受到越来越多的关注,并在过去的两年内取得了重大的研究进展。有机-无机杂化钙钛矿太阳电池的光电转化效率(PCE)纪录被不断刷新,目前已达19.3%,与无机太阳电池相当。主要从有机-无机杂化钙钛矿材料的结构与性质、有机-无机杂化钙钛矿薄膜材料的制备方法、纳米多孔载体结构和平板结构钙钛矿太阳电池、杂化钙钛矿太阳电池的稳定性4个方面,介绍了有机-无机杂化钙钛矿太阳电池近期的研究进展,并对其发展方向进行了展望。     

复合材料Co2（OH）4-x(C10H17O2)x·zH2O的差热分析与磁特性

将有机手性配体3,7-二甲基-6-辛烯酸(C10H18O2)嫁接到无机层状羟基醋酸钴中,合成出新型的有机-无机杂化材料,并对这些杂化材料通过元素和热重分析,研究了有机配体在无机层间的交换过程,并在此基础上讨论了合成出的这些杂化材料的磁性特性。     

有机-无机纳米复合材料的合成与性质

概述了近年来用聚合物嵌入层状无机物晶体夹层或坑道中,制备有机-无机纳米复合材料的新方法及其性质,讨论了层状无机物晶体的结构特点,并展望了有机-无机纳米复合材料的主要应用领域。     

无机电荷传输层在有机-无机杂化钙钛矿太阳能电池中的应用及研究进展

近年来,基于有机-无机杂化钙钛矿材料为光活性层构建的太阳能电池由于具有直接带隙、吸光系数高、激子束缚能低、激子和载流子扩散距离长,以及成本低、制备工艺简单、光电转换率高、易于实现大面积柔性器件等优点,而成为当今新型光伏技术中一颗耀眼的新星。在钙钛矿太阳能电池中,电荷传输层在提高光电转换效率、稳定性及寿命等方面扮演着非常重要的角色,其中无机电荷传输层因具有载流子迁移率高、稳定性好、制备工艺简单等优势越来越受到人们的关注。本文总结了无机电荷传输层在钙钛矿太阳能电池中的应用,详细介绍了各种无机电子/空穴传输层在钙钛矿太阳能电池中的研究进展,并对其发展趋势进行了展望。     

无机—有机纳米杂化材料的分子设计与构筑的研究

着重介绍用分子设计制备无机—有机纳米杂化材料的新方法及其结构、性能演变规律和功能化的工作。特别介绍关于纳米晶—聚合物杂化材料、纳米二氧化硅—聚合物纳米复合材料及其有机—无机聚合物表面结构与性能关系规律。如通过对纳米无机材料功能化修饰,使其含有与聚合物共聚的官能团,实现了与聚氨酯、硅橡胶、环氧树脂的分子组装,形成了无机—有机的互穿网络式嵌断共聚物,大大提高了聚氨酯、硅橡胶和环氧树脂的力学性能和热稳定性能。该聚氨酯杂化材料的拉伸强度和伸长率比未改性前均提高了2倍以上。通过原位聚合、聚合物刷、从表面接枝技术制备出高性能材料。探讨用催化链转移聚合等聚合方法实现新颖有机—无机纳米杂化材料的制备及其表面构筑。通过无机材料的表面设计和表面处理控制无机/聚合物复合材料的界面结构和行为,得到了多种性能优良的多元多尺度复合材料。提高纳米杂化复合高分子材料的加工性能,探索其特异的光电等特异性能。     

Enhanced Electroluminescence from Organic Light‐Emitting Diodes with an Organic–Inorganic Perovskite Host Layer

The development of host materials with high performance is essential for fabrication of efficient and stable organic light‐emitting diodes (OLEDs). Although host materials used in OLEDs are typically organics, in this study, it is shown that the organic–inorganic perovskite CH₃NH₃PbCl₃ (MAPbCl₃) can be used as a host layer for OLEDs. Vacuum‐evaporated MAPbCl₃ films have a wide band gap of about 3 eV and very high and relatively balanced hole and electron mobilities, which are suitable for the host material. Photoluminescence and electroluminescence take place through energy transfer from MAPbCl₃ to an organic emitter in films. Incorporation of an MAPbCl₃ host layer into OLEDs leads to a reduction of driving voltage and enhancement of external quantum efficiency as compared to devices with a conventional organic host layer. Additionally, OLEDs with an MAPbCl₃ host layer demonstrate very good operational stability under continuous current operation. These results can be extensively applied to organic‐ and perovskite‐based optoelectronics.     

Mix and Match: Organic and Inorganic Ions in the Perovskite Lattice

Materials science evolves to a state where the composition and structure of a crystal can be controlled almost at will. Given that a composition meets basic requirements of stoichiometry, steric demands, and charge neutrality, researchers are now able to investigate a wide range of compounds theoretically and, under various experimental conditions, select the constituting fragments of a crystal. One intriguing playground for such materials design is the perovskite structure. While a game of mixing and matching ions has been played successfully for about 150 years within the limits of inorganic compounds, the recent advances in organic–inorganic hybrid perovskite photovoltaics have triggered the inclusion of organic ions. Organic ions can be incorporated on all sites of the perovskite structure, leading to hybrid (double, triple, etc.) perovskites and inverse (hybrid) perovskites. Examples for each of these cases are known, even with all three sites occupied by organic molecules. While this change from monatomic ions to molecular species is accompanied with increased complexity, it shows that concepts from traditional inorganic perovskites are transferable to the novel hybrid materials. The increased compositional space holds promising new possibilities and applications for the universe of perovskite materials.     

Perovskite Films with Reduced Interfacial Strains via a Molecular-Level Flexible Interlayer for Photovoltaic Application

Interface strains and lattice distortion are inevitable issues during perovskite crystallization. Silane as a coupling agent is a popular connector to enhance the compatibility between inorganic and organic materials in semiconductor devices. Herein, a protonated amine silane coupling agent (PASCA-Br) interlayer between TiO₂ and perovskite layers is adopted to directionally grasp both of them by forming the structural component of a lattice unit. The pillowy alkyl ammonium bromide terminals at the upper side of the interlayer provide well-matched growth sites for the perovskite, leading to mitigated interface strain and ensuing lattice distortion; meanwhile, its superior chemical compatibility presents an ideal effect on healing the under-coordinated Pb atoms and halogen vacancies of bare perovskite crystals. The PASCA-Br interlayer also serves as a mechanical buffer layer, inducing less cracked perovskite film when bending. The developed molecular-level flexible interlayer provides a promising interfacial engineering for perovskite solar cells and their flexible application.     

Improved Performance of Printable Perovskite Solar Cells with Bifunctional Conjugated Organic Molecule

A bifunctional conjugated organic molecule 4‐(aminomethyl) benzoic acid hydroiodide (AB) is designed and employed as an organic cation in organic–inorganic halide perovskite materials. Compared with the monofunctional cation benzylamine hydroiodide (BA) and the nonconjugated bifunctional organic molecule 5‐ammonium valeric acid, devices based on AB‐MAPbI₃ show a good stability and a superior power conversion efficiency of 15.6% with a short‐circuit current of 23.4 mA cm^?2, an open‐circuit voltage of 0.94 V, and a fill factor of 0.71. The bifunctional conjugated cation not only benefits the growth of perovskite crystals in the mesoporous network, but also facilitates the charge transport. This investigation helps explore new approaches to rational design of novel organic cations for perovskite materials.     

Hole transporting materials in inorganic CsPbI3−xBrx solar cells: Fundamentals,criteria and opportunities

Inorganic cesium lead halide (i.e., CsPbI_3−xBr_x) perovskite solar cells have made great breakthroughs in the last years with power conversion efficiency beyond 20%, thermal and photo stability reaching hundreds of hours. Hole transporting materials, as important building blocks in perovskite solar cells, present significant influences on both performance and stability. Understanding the energy loss mechanisms and failure pathways of inorganic perovskite solar cells that are originated from the hole transporting layer and the adjacent interfaces paves the way to enhance the efficiency towards Shockley-Queisser limit and to approach the long-term stability requirement. In this review, we first briefly overview the fundamentals of inorganic perovskites and solar cells, particularly on the criteria for designing and engineering efficient hole transporting materials. Second, we give a comprehensive review of recent advances on inorganic, small molecular and polymeric hole transporting materials. Finally, we discuss the challenges of state-of-the-art inorganic perovskite solar cells in view of the hole transporting materials and conclude this review by providing perspective on development of advanced hole transporting materials towards next-generation efficient and stable inorganic PSCs.     

Multilayered Ruddlesden–Popper perovskite hybrids with alternative organic spacers of 4-XC6H4C2H4NH2 (where X = H,Br, Cl) for solar cell applications

Journal of Materials Science - Two-dimensional (2D) organic–inorganic perovskite hybrid materials with enhanced stability have attracted wide attention in optoelectronic field in recent...     

Bio-nanocomposites by assembling of gelatin and layered perovskite mixed oxides

A new class of bio-nanocomposites based on hybrid gelatin-perovskite hydrogels was prepared by mixing exfoliated perovskite-tetraalkylammonium species in aqueous suspensions with gelatin solutions. Colloidal nanosheets derived from the CsCa2Nb3O10 layered perovskite re-stacked in the gelatin solutions give bio-nanocomposite materials with different content in the inorganic moiety. These films can be easily processed as homogeneous self-supported films. The partial exfoliation of the pristine mixed oxide is produced from alkylammonium exchanged phases, being the tetraalkylammonium ions (tetraethylammonium, TEA+) an efficient intermediate to give the colloid phase constituted by well exfoliated materials useful to generate homogeneous films. The nanosheets are highly oriented in the bio-nanocomposite films in agreement with the XRD patterns and the FTIR dichroism. This orientation could be considered as a characteristic of this type of hybrid materials leading to new potential applications. In this way, we have observed that the assembling of perovskite to gelatin produces a greater increase of the dielectric permittivity than the dielectric loss in the studied samples.     

Organic–Inorganic Hybrid Perovskite with Controlled Dopant Modification and Application in Photovoltaic Device

Organic–inorganic hybrid perovskite as a kind of promising photovoltaic material is booming due to its low‐cost, high defect tolerance, and easy fabrication, which result in the huge potential in industrial production. In the pursuit of high efficiency photovoltaic devices, high‐quality absorbing layer is essential. Therefore, developing organic–inorganic hybrid perovskite thin films with good coverage, improved uniformity, and crystalline in a single pass deposition is of great concern in realizing good performance of perovskite thin‐film solar cell. Here, it is found that the introduction of suitable amounts of LiI plays a dramatically positive role in enlarging the grain size and reducing the grain boundaries of absorbing layer. In addition, the carrier lifetime and built‐in potential of the LiI doped perovskite device are observed to increase. Thus, it leads to about 15% gain in solar cell efficiency comparing to that without the LiI doping. Meanwhile, a hysteresis reduction is observed and 18.16% power conversion efficiency is achieved in LiI doped perovskite device, as well.     

3D Nanoprinting of Perovskites

As competing with the established silicon technology, organic–inorganic metal halide perovskites are continually gaining ground in optoelectronics due to their excellent material properties and low‐cost production. The ability to have control over their shape, as well as composition and crystallinity, is indispensable for practical materialization. Many sophisticated nanofabrication methods have been devised to shape perovskites; however, they are still limited to in‐plane, low‐aspect‐ratio, and simple forms. This is in stark contrast with the demands of modern optoelectronics with freeform circuitry and high integration density. Here, a nanoprecision 3D printing is developed for organic–inorganic metal halide perovskites. The method is based on guiding evaporation‐induced perovskite crystallization in mid‐air using a femtoliter ink meniscus formed on a nanopipette, resulting in freestanding 3D perovskite nanostructures with a preferred crystal orientation. Stretching the ink meniscus with a pulling process enables on‐demand control of the nanostructure's diameter and hollowness, leading to an unprecedented tubular‐solid transition. With varying the pulling direction, a layer‐by‐layer stacking of perovskite nanostructures is successfully demonstrated with programmed shapes and positions, a primary step for additive manufacturing. It is expected that the method has the potential to create freeform perovskite nanostructures for customized optoelectronics.     

Halide Perovskites for Nonlinear Optics

Halide perovskites provide an ideal platform for engineering highly promising semiconductor materials for a wide range of applications in optoelectronic devices, such as photovoltaics, light-emitting diodes, photodetectors, and lasers. More recently, increasing research efforts have been directed toward the nonlinear optical properties of halide perovskites because of their unique chemical and electronic properties, which are of crucial importance for advancing their applications in next-generation photonic devices. Here, the current state of the art in the field of nonlinear optics (NLO) in halide perovskite materials is reviewed. Halide perovskites are categorized into hybrid organic/inorganic and pure inorganic ones, and their second-, third-, and higher-order NLO properties are summarized. The performance of halide perovskite materials in NLO devices such as upconversion lasers and ultrafast laser modulators is analyzed. Several potential perspectives and research directions of these promising materials for nonlinear optics are presented.