脂质体封端CsPbX3(X=Cl,Br,I)纳米晶体的制备及在发光二极管中的应用

以脂质体充当表面封端配体修饰合成后的CsPbX₃纳米晶体.封端CsPbX₃纳米晶能保持原始形状和粒径大小,相对量子产率提升至（100±3）%,发射光谱在411~626 nm范围内可调.将其存储于空气（温度25℃,相对湿度50%）中150 d仍保持立方晶型.以DOPC-CsPbBr₃为颜色转换器可制造显色指数高达91.2的白色发光二极管,应用前景广阔.     

全无机卤化铅钙钛矿的结构、热力学稳定性和电子性质

有机-无机杂化卤化铅钙钛矿因具有独特的电子和光学特性,已经成为光电领域最有前途的材料。但是,有机-无机钙钛矿材料及器件稳定性差,限制了其实际应用。与杂化钙钛矿相比,全无机卤化物钙钛矿CsPbX₃(X=Cl,Br,I)显示出更强的热稳定性。全无机卤化物钙钛矿CsPbX₃具有多个晶型,在不同的温度下呈不同相结构。目前,关于CsPbX₃的结构和物理性质仍存在争议。本文我们针对三个晶相α-,β-和γ-CsPbX₃的结构,热力学稳定性和电子性质进行了全面的理论研究。第一性原理计算表明,从高温α相到低温β相,然后再到γ相的相变伴随着PbX₆八面体的畸变。零温形成能计算表明,γ相最稳定,这与实验中γ相为低温稳定相的结论一致。电子性质计算表明,所有CsPbX₃钙钛矿都表现出直接带隙性质,并且带隙值从α相到β相再到γ相逐渐增加。这是由于相变发生时,Pb-X成键强度逐渐减弱,使价带顶能量降低,进而带隙增加。在所有相中,α相结构中较强的Pb-X相互作用,导致了较强的带边色散,使其具有较小的载流子有效质量。     

磁性Fe3O4纳米晶制备及应用

磁性Fe₃O₄纳米晶由于其独特的磁性能,已在许多领域得到了广泛的应用,并且在不同的应用领域其制备方法也不尽相同。本文综述了近年来磁性Fe₃O₄纳米晶的液相制备方法,如沉淀法、溶剂热法、溶胶-凝胶法、微乳液法、微波超声法等研究进展,对这些制备方法的特点进行了归纳概括,并详细分析了制备工艺中不同影响因素对Fe₃O₄纳米晶结构与性能的影响。同时,对磁性Fe₃O₄纳米晶在磁流体、微波吸收、污水处理、催化、药物载体、生物酶固定、生物传感器等方面的应用及发展趋势进行了评述,以期对Fe₃O₄纳米晶的制备及应用有较全面的认识。     

多色高发光效率CsPbX3(X=Cl,Br,I)钙钛矿量子点的制备及其在发光二极管中的应用

采用室温合成法制备出一系列具有高发光效率和多色发光的CsPbX₃钙钛矿量子点(PQDs),反应全过程快速简便,且通过调节不同的卤素组成(Cl,Br,I)可以实现CsPbX₃ PQD的多色发光。 通过表征证明,CsPbX₃ PQDs呈立方晶型,平均粒径约为10 nm,发射光谱覆盖可见光波长范围为410~630 nm,半峰宽14~38 nm,荧光量子产率10%~90%。 最后将CsPbX₃ PQDs应用于发光二极管(LED)器件的制备中,在恒定电压下工作时,能保持LED器件的发光颜色、强度和颜色坐标不变。     

金属卤化物钙钛矿光电材料和器件

2009年ABX₃钙钛矿晶型的甲胺铅卤CH₃NH₃PbX₃(X=I、Br、Cl)钙钛矿材料首次应用于太阳能电池,但初始报道效率低、稳定性差。2012年后,可溶液法制备的钙钛矿太阳能电池凭借其吸光系数高、激子结合能低等优点,迅速表现出低成本和高效率的突出优势,并在光电器件等交叉领域具有很强的应用潜力。因此,钙钛矿太阳能电池被Science杂志评为2013年度国际十大科技进展,是化学和材料领域特别是光伏领域新兴的变革性技术之一。钙钛矿太阳能电池材料与器件的发展一直面临大面积、高效率、稳定性和环境友好性等挑战,对应的是钙钛矿晶体可控生长、缺陷钝化、器件优化材料稳定性和铅毒性等科学问题。     

二维硫化钼基原子晶体材料的化学气相沉积法制备及其器件

二维过渡族金属硫属化合物因其带隙具有强烈的层数依赖性而在电子器件方面具有广泛的应用前景.其中单层二硫化钼(MoS₂)是该系列材料中最典型的一种直接带隙半导体,它具有优异的光、电、磁、热和力学性能.二维MoS₂有望在光电探测、光伏器件、场效应晶体管、存储器件、谷电子和自旋器件、温差电器件、微纳机电器件和系统等方面得以广泛应用.化学气相沉积(CVD)法已成为制备二维过渡族金属硫属化合物如MoS₂、MoSe₂、WS₂和WSe₂等原子层薄膜的主要手段,尤其科学界利用CVD法对二维MoS₂材料进行了深入的制备探索,通过该方法制备的MoS₂薄膜在电子和光电器件方面已经有广泛研究.本文将从二维MoS₂的基本物性出发,详细介绍CVD法制备MoS₂的各种工艺过程,如热分解硫代硫酸盐法、硫化Mo(MoO_3-x)薄膜制备法、MoO_3-x粉体与硫属前驱体气相合成法和钼箔表面直接硫化法,并介绍了基于MoS₂的二维异质结构筑方法.在制备材料的基础上,详细阐述了二维MoS₂在场效应晶体管、光电探测器、柔性电子器件以及异质结器件方面的应用,并展望了二维材料在半导体器件中的应用前景.     

大尺寸二维卤化物钙钛矿铁电晶体的生长及偏振光电探测性能研究※

低维半导体材料, 尤其是近些年快速发展的二维卤化物钙钛矿材料, 因其固有的结构各向异性、独特的量子限域效应和优异的半导体特性, 在偏振光电探测等领域展现出巨大的应用潜力. 其中, 铁电极化所产生的体光伏效应为实现高灵敏的偏振光电探测提供了一种简单有效的途径. 然而二维卤化物钙钛矿铁电体的大尺寸晶体生长仍然是其在光电器件应用中所面临的一个科学难题. 本工作中, 利用溶液降温法生长出了厘米级尺寸的高质量二维卤化物钙钛矿(iPA)₂EA₂Pb₃I₁₀ (iPA为异戊胺, EA为乙胺)铁电单晶, 其最大晶体尺寸达15 mm×15 mm×3 mm. 实验结果表明二维钙钛矿结构赋予(iPA)₂EA₂Pb₃I₁₀晶体强的光学各向异性、窄的光学带隙(1.80 eV)和极其优异的光电特性(光电响应开关比达到10³). 更重要的是, 基于(iPA)₂EA₂Pb₃I₁₀铁电单晶组装的光电探测器在弱偏振光的照射下表现出极其优异的光电特性, 包括大二色比(2.3)、高响应度(193 mA•W^–1)和探测率(7.0×10¹¹ Jones), 超过大多数基于材料本征光学各向异性的光电探测器件. 这项工作不仅为高度各向异性卤化物钙钛矿铁电体的晶体生长指明了方向, 而且推动了铁电材料在高性能偏振光电探测器等方面的应用.     

SnO2-SnS2复合纳米粒子的制备及光电性质研究

采用离子交换法制备了SnO₂-SnS₂复合纳米粒子.用XRD、TEM和X-EDAS测定了样品的组成、结构、形貌和尺寸,结果表明,样品为SnS₂部分包覆SnO₂的球形复合纳米粒子,其平均粒径为5nm.研究了该复合纳米粒子的紫外-可见漫反射光谱和光电化学性质,观察到SnO₂-SnS₂复合纳米粒子的光吸收比SnO₂的明显向长波区扩展;制成工作电极后的光电流值和光电转换效率(IPCE)都比相应的纯组分纳米粒子电极显著提高.     

混晶TiO2光催化剂的制备及机理研究

本文总结了混晶TiO₂光催化剂的各种制备方法,并将其分为两大类：一类是原位生成混晶,如水热法、溶剂热法、溶胶-凝胶法、微乳液-水热联用方法等;另一类是对两种晶型TiO₂材料进行物理混合或对锐钛矿进行高温煅烧,如溶剂混合-煅烧法、高温煅烧法等。其中,后者操作简单易行、对设备要求不高,但获得的混晶TiO₂易产生硬团聚,严重影响其光催化性能;在实际应用中前者制备的TiO₂材料更具优势。同时,本文还对混晶TiO₂光催化机理的研究历程进行了总结,并对其中存在的争议进行了评述。最后,展望了混晶TiO₂光催化剂在环境和能源领域中的应用。     

PbO-PbI2复合物膜转化的CH3NH3PbI3钙钛矿薄膜及其光电特性

有机-无机卤化物钙钛矿是一类优异的光电材料. 在过去四年内, 基于有机-无机卤化物钙钛矿的光电器件实现了超过15%的光电转换效率. 而有机-无机卤化物钙钛矿材料的可控制备是保证其在光电器件中应用的基础. 本文采用新的沉积方法在玻璃衬底表面制备了一种典型的有机-无机卤化物钙钛矿CH₃NH₃PbI₃薄膜. 其制备过程是: 采用超声辅助的连续离子吸附与反应法在玻璃衬底表面沉积PbO-PbI₂复合物膜, 之后与CH3NH3I蒸汽在110 ℃环境下反应, 将PbO-PbI₂复合物膜转化成CH₃NH₃PbI₃钙钛矿薄膜. 对CH₃NH₃PbI₃薄膜的微观结构, 结晶性及其光电性能等进行了表征. 结果表明, CH₃NH₃PbI₃薄膜呈晶态, 具有典型的钙钛矿晶体结构. 薄膜表面形貌均匀, 晶粒尺寸超过400 nm. 在可见光范围, CH₃NH₃PbI₃薄膜透过率低于10%, 能带宽度为1.58eV. 电学性能研究表明CH₃NH₃PbI₃薄膜表面电阻率高达1000 MΩ. 高表面电阻率表明CH₃NH₃PbI₃薄膜具有一定的介电性能, 其介电常数(ε_r)在100 Hz时达到155. 本研究提出了一种制备高质量CH₃NH₃PbI₃钙钛矿薄膜的新方法, 所得CH₃NH₃PbI₃薄膜可望在光、电及光电器件中得到应用.     

Dibenzocarbazolediimides: Synthesis,Solid Structure,Self‐Assembly Behavior,and Optoelectronic Properties

Both planar and nonplanar polycyclic aromatic hydrocarbons (PAHs) have attracted attention owing to their potential applications in optoelectronic materials. Four twist benzopicenediimides with good optoelectronic properties have been reported previously. Following on from this work, four functionalized dibenzocarbazoles have been synthesized and reported herein. The fluorescence quantum yields of these compounds were high in dichloromethane and moderate in the solid state. They have interesting self‐assembling behavior and tunable packing motifs in single crystals obtained by introducing different functional groups. Their good optoelectronic properties make them potential candidates for organic devices, bioimaging, and biolabeling.     

Metal Doped PVA Films for Opto-Electronics-Optical and Electronic Properties,an Overview

Polyvinyl alcohol is unique among polymers. Apart from its preparation, it is not built up in polymerization reactions from monomers, unlike most vinyl-polymers, and it is biodegradable in the presence of suitably acclimated microorganisms. It is an environmentally friendly material for a wide range of applications, from medical ones, based on its biocompatibility, to integrated optics. This paper reviews, in addition to the preparation and optimization of films of polyvinyl alcohol doped with different metal species, the role of dopants and doping technologies in the involved electronic mechanism. The optical properties were studied by UV-VIS-IR, Mössbauer spectroscopy, and other measurement techniques, with applications such as real-time holography, microlasers, optical sensors or nanophotonics in mind.     

N,N’-二(2-吡啶基)-1,6,7,12-四(4-叔丁基苯氧基)-3,4:9,10-苝酰亚胺的合成、表征及性能研究

优化了N,N’-二(2-吡啶基)-1,6,7,12-四(4-叔丁基苯氧基)-3,4:9,10-苝酰亚胺的合成方法, 得到一种简单有效的在苝酰亚胺的酰胺和bay位置同时取代的方法. 对其结构进行了表征, 研究了其溶液态和薄膜态的光学性质和电化学性质. 并且对其能级结构和电荷分布进行了分子模拟.     

基于过渡金属配合物的阻变存储材料

阻变型电存储依靠外加电场作用下存储介质的导电性高低差异,即电学双稳态或多稳态来实现数据存取,并具有高容量、高柔韧性、低成本、低能耗、可规模化等优点,为下一代高密度存储技术提供新前景. 除了无机氧化物、碳纳米材料、有机小分子和有机聚合物半导体材料之外,近年来,过渡金属配合物在阻变型电存储方面的应用也引起广泛关注. 本文对迄今为止报道的大部分基于过渡金属配合物的阻变存储材料进行了总结和讨论,主要包括第VⅢ族金属[包括Fe（Ⅱ）、Ru（Ⅱ）、Co（Ⅲ）、Rh（Ⅲ）、Ir（Ⅲ）、Pt（Ⅱ）等配合物]、第IB族和ⅡB族金属[Cu（Ⅱ）、Au（Ⅲ）、Zn（Ⅱ）等配合物]和镧系过渡金属配合物[Eu（Ⅲ）及其它],并对各种配合物的存储行为和存储机理进行了探讨. 过渡金属配合物具有清晰可逆的氧化还原过程,通过改变配体的结构和金属的种类可以很方便地调节材料的前线轨道能级和能隙,利于形成电学双稳态或多稳态,达到二进制或多进制存储的目的,具有潜在应用价值.     

Black Current: Structure,Characterization, and Optoelectronic Properties of Ce3Cl3[MoO6]

The admixture of CeO₂, Ce, CeCl₃, and MoO₃ with an excess of LiCl as flux in evacuated silica ampules leads to large black single crystals as well as a black microcrystalline powder of Ce₃Cl₃[MoO₆] after tempering at 850 °C for three days. The title compound crystallizes in the hexagonal space group P6₃/m (a=934.93(4), c=538.86(2) pm) with two formula units per unit cell. The crystal structure consists of rather unusual trigonal-prismatic [MoO₆]⁶⁻ units besides Ce³⁺ ions in a tetra-capped trigonal-prismatic coordination, formed by four Cl⁻ and six O²⁻ ions. The black color is related to an optical band gap of 1.35(2) eV, which was determined by diffuse reflectance spectroscopy and confirmed by theoretical calculations. The low band gap between the 4f¹ state of cerium (HOMO) and the 5d⁰ state of molybdenum (LUMO) gave rise to the idea of electronic excitation between these two states by IR irradiation, creating a drop in the resistivity of the material, which was detected by appropriate measurements.     

Modulating the Optoelectronic Properties of Large,Conjugated, High‐Energy Gap,Quaternary Phosphine Oxide Hosts: Impact of the Triplet‐Excited‐State Location

The purposeful modulation of the optoelectronic properties was realised on the basis of a series of the large, conjugated, phosphine oxide hosts 9,9‐bis‐{4′‐[2‐(diphenylphosphinoyl)phenoxy]biphenyl‐4‐yl}‐9H‐fluorene (DDPESPOF), 9,9‐bis‐{3′‐(diphenylphosphinoyl)‐4′‐[2‐(diphenylphosphinoyl)phenoxy]biphenyl‐4‐yl}‐9H‐fluorene (DDPEPOF), 9‐[4′‐(9‐{4′‐[2‐(diphenylphosphoryl)phenoxy]biphenyl‐4‐yl}‐9H‐fluoren‐9‐yl)biphenyl‐4‐yl]‐9H‐carbazole (DPESPOFPhCz) and 9‐[4′‐(9‐{3′‐(diphenylphosphoryl)‐4′‐[2‐(diphenylphosphoryl)phenoxy]biphenyl‐4‐yl}‐9H‐fluoren‐9‐yl)biphenyl‐4‐yl]‐9H‐carbazole (DPEPOFPhCz). The last two are quaternary with fluorenyls as linking bridges, diphenylphosphine oxide (DPPO) moieties as electron acceptors and diphenylethers and carbazolyls as two different kinds of electron donors. Owing to the fine‐organised molecular structures and the mixed indirect and multi‐insulating linkages, all of these hosts achieve the same first triplet energy levels (T₁) of 2.86 eV for exothermic energy transfer to phosphorescent dopants. The first singlet energy levels (S₁) and the carrier injection/transportation ability of the hosts were accurately modulated, so that DPESPOFPhCz and DPEPOFPhCz revealed extremely similar optoelectronic properties. However, the T₁ state of the former is localised on fluorenyl, whereas the carbazolyl mainly contributes to the T₁ state of the latter. A lower driving voltages and much higher efficiencies of the devices based on DPESPOFPhCz indicated that the chromophore‐localised T₁ state can suppress the quenching effects through realising independent contributions from the different functional groups to the optoelectronic properties and the embedding and protecting effect on the T₁ states by peripheral carrier transporting groups.     

基于3,4-二烷氧基噻吩的D-A-D型有机共轭分子的合成及其光学和电化学性能

基于Wittig反应合成了新型D-A-D型有机半导体材料——双(2-乙烯基-3,4-二烷氧基噻吩)-对-2,5-二苯基-1,3,4-噁二唑[(3,4DAOTV)2-OXD],用核磁共振氢谱(1HNMR)、傅里叶变换红外(FTIR)光谱、高效液相色谱(HPLC)和元素分析法(EA)对化合物的结构进行分析和表征.用紫外-可见(UV-Vis)光谱、荧光(PL)光谱及电化学分析研究其光学和电化学性能.在氯仿溶液中,各化合物的紫外最大吸收波长(λmabasx)在382-383nm之间,光学带能隙在2.92-2.97eV之间,荧光最大发射波长在448-452nm之间,发出明亮的青色光,荧光量子产率可达36.8%-37.6%;在固体薄膜状态下,各化合物于513-516nm处发射出亮蓝绿色光.循环伏安法研究显示:三种大π共轭分子在正、负向区域均表现出明显的氧化、还原现象.其中,5.65-5.70eV的电离势(Ip),与噻吩类有机半导体材料的空穴传输特征相符;电子亲和势(Ia)在2.74-2.88eV之间,与有机电子传输材料的特性相近,这利于电子从阴极的注入和传输.理论计算结果表明,该D-A-D型共轭分子共平面性好和电荷离域程度高,对光电功能材料的分子界面组装、载流子的有效传输和器件量子效率的提高十分有利.     

Designs,Synthesis, Characterization and Direct Electrochemistry of Zinc‐Porphyrin Bearing Pyrene Noncovalent Functionalized Graphene Oxide Sheet

We have designed and synthesis a new compound of zinc‐porphyrin bearing four pyrene groups (ZnP‐t‐P(py)₄) and prepared a new hybrid materials of ZnP‐t‐P(py)₄ with graphene oxide (GO) via non‐covalent interactions. The ZnP‐t‐P(py)₄, along with four pendant pyrene entities ZnP‐t‐P(py)₄, stacking on the (GO) surface due to π‐ π interactions, has been revealed by AFM measurements. FTIR, UV‐vis absorption confirm the non‐covalent functionalization of the GO. Raman spectral measurements revealed the electronic structure of the GO to be intact upon hybrid formation. In this donor‐acceptor nanohybrid, the fluorescence of photoexcited ZnP‐t‐P(py)₄ is effectively quenched by a possible electron‐transfer process. The fluorescence and photoelectrical response measurements also showed that this hybrid may act as an efficient photoelectric conversion material for optoelectronic applications.     

全共轭嵌段共聚物的合成组装与应用

全共轭嵌段共聚物体系将共轭聚合物的光电特性和嵌段聚合物的自组装优势相结合,是近几年发展起来的一类新型自组装光电功能材料,对其自组装机理、自组装结构与光电性能之间关系的研究,有利于共轭聚合物微观纳米结构的构筑以及未来光电器件的开发。本文主要介绍全共轭嵌段共聚物包括共轭聚电解质在内的合成发展过程,综述其在溶液中和薄膜状态下独特的自组装行为,介绍共轭聚合物在光电器件中的应用,并对其今后的研究方向做出展望。     

Dimesitylboryl‐Decorated Azaarene: Synthesis,Enhanced Stability and Optoelectronic Property

The instability of large acenes and analogues usually limits their wide potentials in organic devices. Thus, effectively constructing large acenes or heteroacenes and examining their optoelectronic properties are of great interest. We herein describe the synthesis, optoelectronic behaviors and electroluminescent property of dimesitylboryl‐decorated azaarene 5 and its homologue 7 . The former emits strong green fluorescence in non‐polar solvents but yellow light in polar solvents. The latter emits a blue light in various organic solvents. Moreover, their electrochemical behavior, photostability and electroluminescent property were further studied in a comparative manner, and the experimental findings suggest that the desired heteroarenes are appealing materials for fabricating electroluminescent devices.