金属卤化物钙钛矿纳米晶高效发光二极管的制备与器件性能优化

金属卤化物钙钛矿作为一类新型的离子型直接带隙半导体材料在电致发光二极管(LED)中有着重要应用前景. 但实现其应用的前提在于金属卤化物钙钛矿材料需要保持高的发光效率和好的稳定性. 为了提高金属卤化物钙钛矿作为LED发光层的激子结合效率, 从而提升其发光效率, 设计和合成金属卤化物钙钛矿纳米晶材料是一个有效途径. 目前, 基于纳米晶材料设计的金属卤化物钙钛矿LED在绿光和红光(包括近红外光)范围已经展现了高的发光亮度和外量子效率(EQE), 其中最高EQE已经超过了20%, 但其稳定性仍无法满足器件应用的要求. 此外, 更值得关注且更重要的是, 蓝光钙钛矿LED的发光亮度和EQE目前仍然不高. 如何制备高效、 稳定的金属卤化物钙钛矿纳米晶LED, 特别是蓝光LED, 是一个具有重大应用前景且具有挑战性的课题. 本文重点介绍了金属卤化物钙钛矿纳米发光层的结构设计和合成方法及金属卤化物钙钛矿LED的研究进展, 分析了金属卤化物钙钛矿LED不稳定的原因, 并对金属卤化物钙钛矿LED研究面临的挑战和未来发展方向进行了总结与展望.     

纳米金/碳纳米管复合材料修饰电极催化鲁米诺电致发光体系的研究

制备了纳米金/多壁碳纳米管(MWNT)复合材料修饰电极,并将此电极应用于鲁米诺电化学发光体系.电化学发光实验表明,此复合材料修饰电极同时具备了纳米金和碳纳米管的催化性能.此外通过电极活性表面积测算、电化学交流阻抗实验等方法研究了纳米金和碳纳米管在此体系催化过程中的作用.纳米金/碳纳米管修饰电极具有良好的重现性,可以广泛应用于鲁米诺电化学发光测定体系.     

绿色合成CdSe及制备CdSe-聚氨酯纳米复合发光材料

通过一步法绿色合成了CdSe-聚氨酯(CdSe-PU)纳米复合发光材料.在N2保护下,将单质硒(Se)溶于蓖麻油,以蓖麻油酸作为氧化镉(CdO)的配体,合成硒化镉(CdSe)纳米晶.将聚丙二醇2000和异佛尔酮二异氰酸酯(IPDI)合成的预聚体,加入含CdSe纳米晶的蓖麻油溶液,通过交联作用得到CdSe-PU纳米复合发光材料.采用紫外-可见分光光度计(UV-Vis)、荧光光谱仪(PL)、傅里叶红外光谱仪(FT-IR)、热重分析仪(TGA)、透射电子显微镜(TEM)对CdSe纳米晶和聚氨酯复合材料的结构和性能进行了表征.结果表明:此方法合成的CdSe纳米晶性能良好,能在聚氨酯纳米复合材料中均匀分散且性能稳定,CdSe-PU纳米复合材料耐热性有所提高.     

基于纳米ZnO的白光LED

白光发光二极管被誉为第4代照明光源。ZnO纳米结构因含有大量本征和/或非本征缺陷使其除出现在紫外区域的带边发射外还能产生覆盖400-700 nm可见光范围的深能级发光,从而可用于白光LED。本文系统地介绍了将ZnO纳米结构应用于白光LED的几种器件构造,并评述了各自的性能特点和研究进展。因为直接基于ZnO纳米结构电致发光的白光LED需要施加较高的偏压,所以将ZnO纳米结构与p型半导体复合制成异质结成为了研究的热点。ZnO纳米结构的制备方法和形貌特性会影响白光LED性能,对ZnO纳米结构进行掺杂是提升性能的重要手段。此外,将ZnO纳米材料和聚合物的优点集于一体的ZnO/聚合物异质结构也在白光LED中具有广阔的发展空间。最后,指出了纳米ZnO在白光LED应用中存在的问题和今后的发展方向。     

纳米MCM-41组装DBC-偶氮胂的研究

以纳米MCM-41孔道为模版,组装制备了二溴对氯偶氮胂(DBC-ASA)纳米簇合物。采用化学分析、粉末X-射线衍射、77 K N2吸附-解吸附、红外光谱、固体扩散漫反射光谱及发光光谱表征了制备的(MCM-41)-(DBC-ASA)主-客体纳米复合材料。结果表明,DBC-ASA成功地组装在了主体MCM-41中,并且处于主体分子筛材料的纳米孔道中。(MCM-41)-(DBC-ASA)纳米复合材料具有作为发光材料的应用前景。     

(SBA-15)-ZnS主-客体纳米复合材料的制备与表征

本研究在SBA-15分子筛孔道中制备了纳米ZnS。Zn_{2+首先通过离子交换交换到SBA-15中,通过水热法在SBA-15分子筛孔道中制备了纳米ZnS。(SBA-15)-ZnS复合物由粉末X-线衍射,傅立叶变换红外光谱,低温氮气吸附-解析附技术,固体扩散漫反射光谱以及发光研究进行了表征。粉末X-线衍射研究说明在制备主-客体纳米复合材料中分子筛骨架未被制备过程所破坏,保持完整且结晶度仍很高。傅立叶变换红外光谱表明制备的材料骨架完好。77 K低温氮气吸附-解析附研究表明所制备的复合材料孔体积,孔尺寸以及表面积相对于SBA-15分子筛降低,证明客体ZnS已成功地组装入分子筛孔道中。所制备的纳米复合材料固体扩散漫反射吸收光谱相对于体相ZnS显示出蓝移表明,ZnS已限制在分子筛的孔道中且复合材料中分子筛的孔道对ZnS具有明显的立体限域效应,ZnS成功地组装在SBA-15分子筛的孔道中。发光研究表明,(SBA-15)-ZnS样品出现明显发光现象。主-客体复合材料具有良好的发光性能,有望在发光材料领域中获得应用。}     

LaPO4∶Eu3+—Fe3O4光-磁复合材料的合成与性能研究

采用2步水热法合成了LaPO4∶Eu3+-Fe3O4复合材料.在LaPO4∶Eu3+-Fe3O4复合材料中,LaPO4∶Eu3+为单斜晶相,呈纳米棒状,纳米棒的直径和长度分别为20~100nm和0.2~1μm;Fe3O4为正交晶相、呈20~30nm的颗粒状,Fe3O4粒子紧紧附着在LaPO4∶Eu3+纳米棒的表面;样品的磁性和发光性质研究表明所合成的LaPO4∶Eu3+—Fe3O4复合材料既具有发光性质又具有磁性.     

黄光类水滑石的制备、表面改性及应用

采用共沉淀法合成了荧光类水滑石材料,该材料在470 nm蓝光激发下可发出黄色荧光(557 nm),采用硅烷偶联剂对其进行表面改性,探讨了表面改性对黄光类水滑石的发光性能、结构及热稳定性的影响。将改性黄光类水滑石与GaN基蓝光芯片封装后制得了白光LED。研究结果表明,改性的黄光类水滑石是制作白光LED可供选用的黄色发光材料。本文成功地将低温一步法制备得到的金属有机配合物/无机纳米杂化材料应用于LED,拓展了LED用荧光粉的选用范围。     

黄光类水滑石的制备、表面改性及应用

采用共沉淀法合成了荧光类水滑石材料,该材料在470 nm蓝光激发下可发出黄色荧光(557 nm),采用硅烷偶联剂对其进行表面改性,探讨了表面改性对黄光类水滑石的发光性能、结构及热稳定性的影响。将改性黄光类水滑石与GaN基蓝光芯片封装后制得了白光LED。研究结果表明,改性的黄光类水滑石是制作白光LED可供选用的黄色发光材料。本文成功地将低温一步法制备得到的金属有机配合物/无机纳米杂化材料应用于LED,拓展了LED用荧光粉的选用范围。     

功率型LED封装用高分子材料的研究进展

随着发光二极管(LED)亮度和功率的不断提高,封装材料已成为制约LED进入照明领域的关键技术之一。对于功率型LED封装材料,要求具有高折射率、高透光率、高导热率、耐紫外、耐热老化、低应力、低吸水率等性能特点。目前LED封装用两大主要高分子材料是环氧树脂和有机硅复合材料。对这两种材料的改性主要集中在折射率、耐老化性、导热性、吸水性和力学性能等方面。脂环族环氧树脂及纳米有机硅复合材料作为高功率LED封装材料具有广阔的发展前景。     

有机-无机纳米复合水凝胶*

本文综述了近年来有机-无机纳米复合水凝胶领域的研究进展。针对无机成分的不同种类及复合形式,本文将目前已见报道的有机-无机纳米复合水凝胶划分为三类,分别为层状硅酸盐纳米插层复合水凝胶、粘土交联纳米复合水凝胶和二氧化硅纳米杂化复合水凝胶。阐述了三类纳米复合水凝胶的发展趋势,特别就它们的合成方法进行了详细归纳与总结。在此基础上,介绍了纳米无机成分对复合水凝胶的性能增强机理,并就三者之间的增强差异进行了说明。     

Overview of Polyvinyl Alcohol Nanocomposite Hydrogels for Electro‐Skin,Actuator, Supercapacitor and Fuel Cell

The properties of polyvinyl alcohol (PVA) nanocomposite hydrogels influenced by nanoparticles are reviewed. Various kinds of nanoparticles with excellent mechanical and electrical properties have been introduced into PVA hydrogel to produce stretchable and conductive PVA nanocomposite hydrogel. Understanding the mechanism between the matrix of PVA hydrogel and nanoparticles is therefore critical for the development of PVA nanocomposite hydrogels. This review focuses on the nanoparticles include carbon nanotubes, graphene oxide and metal nanoparticles, and describes the effects of nanoparticles on the mechanical and conductive properties of PVA nanocomposite hydrogels. A new promising area of soft stretchable PVA nanocomposite hydrogel is highlighted for possible applications. Finally, a brief outlook for future research is presented.     

Fabrication and characterization of core/shell structured TiO2/polyaniline nanocomposite

A novel core/shell structured TiO(2)/polyaniline nanocomposite was fabricated by grafting aniline on aminobenzoate monolayer that is chemically adsorbed on the TiO(2) nanocrystal surface. The formation and nanostructure of the nanocomposite were investigated by FT-IR and UV-Vis spectra, TEM, FE-SEM, and TG-DTA analysis. Adsorption of aminobenzoate on the TiO(2) surface is an effective method to obtain the uniform nanocomposite. The thickness of polyaniline layer coating on the TiO(2) nanocrystal surface can be controlled in a range of 2-5 nm by this method. A photoelectrochemical study was carried out on the TiO(2)/polyaniline nanocomposite, and found that polyaniline in the nanocomposite acted as a visible-light sensitizer in a photoelectrochemical reaction. The sensitization effect increased with increasing binding strength between polyaniline and TiO(2). A dye-sensitized solar cell with a short circuit current density of 0.19 mA/cm(2) and an open circuit voltage of 0.35 V was fabricated by using the TiO(2)/polyaniline nanocomposite film as a sensitized electrode.     

Carboxymethylcellulose-coated magnesium-layered hydroxide nanocomposite for controlled release of 3-(4-methoxyphenyl)propionic acid

Carboxymethylcellulose (CMC) acts as a coating material for a magnesium-layered hydroxide-3-(4-methoxyphenyl)propionate (MLH-MPP) nanocomposite via spontaneous self-assembly. The resulting product is called a magnesium-layered hydroxide-3-(4-methoxyphenyl)propionate/carboxymethylcellulose (MLH-MPP/CMC) nanocomposite. The XRD pattern of the MLH-MPP/CMC nanocomposite showed that MPP was maintained in the interlayers of the MLH, thus confirming that CMC is only deposited on the surface of the MLH-MPP nanocomposite. These findings were also supported by FTIR spectra, SEM and TEM. TGA data showed that the thermal stability of the intercalated MPP was significantly enhanced compared to pure MPP and uncoated nanocomposite. The release of MPP from the interlayers of MLH-MPP/CMC nanocomposite showed slower release than did uncoated nanocomposite and followed pseudo–second-order kinetics. Since the herbicide, MPP was released from the synthesised nanocomposite in a sustained manner, thus, it has excellent potential to be used as a controlled-release herbicide formulation.     

聚酰胺6/蒙脱石纳米复合材料的紫外光老化

聚合物 /层状硅酸盐纳米复合材料的研究十分活跃 [1～ 4 ] .聚酰胺 6/蒙脱石 ( PA6/MMT)纳米复合材料与纯聚酰胺 6( PA6)相比 ,模量和强度明显提高 ,耐热性能提高尤为显著 .光氧化行为材料科学领域的重要研究课题 .Admas等 [5]报道在紫外光照射下 ,聚丙烯 /粘土纳米复合材料的氧化速度要比纯聚丙烯的快 .对于 PA6/MMT纳米复合材料的光老化研究尚未见报道 .本文以傅里叶变换红外光谱定量研究手段 ,对比分析了 PA6/MMT纳米复合材料与 PA6的紫外光氧化性能 .1　实验部分　　采用熔体插层技术 ,将 PA6( Honeywell B1 0 0 MP)和有机蒙…     

有机--无机纳米复合材料的制备方法

本文综述了无机--有机纳米复合材料的制备方法,介绍了其结构和性质,并展望了其应用前景.     

Polymer/carbon-based quantum dot nanocomposite: forthcoming materials for technical application

This endeavor presents state-of-the-art overview on polymer/carbon-based quantum dot nanocomposite. Carbon-based quantum dot (graphene quantum dot, carbon nanodot, and polymer dot) are ～10nm. Carbon-based quantum dot own exciting features such as tunable optoelectronic and photoluminescence properties, high stability, chemical inertness, low cytotoxicity, and biocompatibility owing to quantum confinement and edge effects. Main emphasis of article was to see the combined effect of polymer and carbon-based quantum dot in nanocomposite. Five major categories have been reviewed in this article including conjugated polymer/carbon-based quantum dot nanocomposite, epoxy/carbon-based quantum dot nanocomposite, polystyrene/carbon-based quantum dot nanocomposite, poly(dimethyl siloxane)/carbon-based quantum dot nanocomposite, and block copolymer/carbon-based quantum dot nanocomposite. The review also refers to cutting edge application areas of polymer/carbon-based quantum dot nanocomposite. Conducting polymer/carbon quantum dot nanocomposite has been integrated in energy storage devices, detectors, and electronic devices. These materials are also promising candidates for bulk heterojunction solar cells and light-emitting diodes. Another important use is the identification and removal of toxic metals. Functional materials have also been used for fluorescence imaging of live cells. Modification of carbon-based quantum dot and incorporation in appropriate polymer matrices can be adopted as powerful future tool enabling desired tailored applicability of nanocomposite in advance high performance technical applications.     

Fe3O4 nanoparticles decorated smectite nanocomposite: Characterization,photocatalytic and electrocatalytic activities

Magnetite nanoparticles-decorated smectite nanocomposite was prepared by precipitation method and the obtained nanocomposite was used as both nanophotocatalyst for removal of rhodamine B from wastewater under UVA irradiation and electrocatalyst for the electrooxidation of chlorite ion on the carbon paste electrode. The raw smectite, bare magnetite and the synthesized nanocomposite catalyst were comparatively characterized by using XRD, FTIR, SEM, EDX, XPS, VSM, TG/DTG, DTA, DSC, electrophoretic mobility and BET techniques in detail. The XRD, SEM, electrophoretic mobility and VSM results indicated that the magnetite nanoparticles were uniformly distributed on the surface of smectite with a diameter of about 7 nm by electrostatic interactions and the prepared nanocomposite displayed well superparamagnetic behaviour with strong saturation magnetization at room temperature. The XPS, EDX, FTIR and thermal analysis data of synthesized nanocomposite further confirmed that the magnetite nanoparticles were successfully decorated on the smectite without formation of another ferric phase species. Furthermore, the surface area of magnetite smectite nanocomposite is higher than that of raw smectite, which is related to the magnetite nanoparticles decorated onto the smectite. The catalytic activities of all samples were comparatively investigated by using the degradation of aqueous rhodamine B solutions as a model pollutant in the heterogeneous photo-like-Fenton process which is well defined by the pseudo-first-order equation in kinetics. The resultant magnetite-smectite nanocomposite showed excellent magnetic separability and much better photocatalytic activity in a short period compared to the bare magnetite and smectite. The synergetic effect between magnetite and smectite showed high activity not only in photodegradation but also in electrocatalytic applications. Because the developed nanocomposite material exhibited enhanced catalytic activity towards to chlorite ion oxidation it was applied for the voltammetric quantification of chlorite ion in aqueous medium. After the optimization of the measurement parameters, the limit of detection and quantification of the method were calculated as 3.0 and 10.0 μM, respectively.     

采用一锅法制备量子点/琼脂纳米复合凝胶

以天然高分子琼脂为稳定剂,采用简单便捷的一锅法制备Mn掺杂ZnS量子点/琼脂纳米复合凝胶,琼脂不仅作为制备量子点的稳定剂,同时也是纳米复合凝胶的主要成分。对该纳米复合凝胶中量子点的化学结构和尺寸大小进行了表征,并对纳米复合凝胶的荧光性能和凝胶性能进行了研究。实验结果表明,制备得到的纳米复合凝胶均一稳定,在302 nm紫外光下呈现十分明显的橙红色荧光。在该纳米复合凝胶的透射电子显微镜（TEM）表征中可以观察到大小比较均一、粒径为3 nm左右的纳米粒子,光谱分析结果进一步证实纳米复合凝胶中存在Mn掺杂ZnS量子点。该纳米复合凝胶不仅具有良好的荧光性能,还具有温度刺激响应性可逆溶胶-凝胶转变性能,同时具有较高的溶胶转变温度和较好的温度稳定性。利用这些性能特点,可以方便地制备纳米复合凝胶小球。此外,该纳米复合凝胶还可以被潜在应用于金属离子的荧光检测分析领域。     

Polystyrene-silica nanocomposite particles via alcoholic dispersion polymerization using a cationic azo initiator

Submicrometer-sized polystyrene-silica nanocomposite particles have been prepared by alcoholic dispersion polymerization of styrene using commercial alcoholic silica sols of 13 or 22 nm diameter as the sole stabilizing agent. The key to the formation of colloidally stable nanocomposite particles is the selection of a cationic azo initiator (use of nonionic or anionic initiators leads either to the formation of silica-stabilized polystyrene latex particles with very low silica contents or to the precipitation of polystyrene, respectively). Neither surface modification of the silica sol nor the addition of surfactant or polymeric stabilizers is required for successful nanocomposite syntheses. The purified polystyrene-silica nanocomposite particles have relatively narrow particle size distributions, with mean diameters ranging from 331 to 464 nm as judged by disk centrifuge photosedimentometry. Thermogravimetric analyses indicated mean silica contents of 13-26 wt. %, depending on the synthesis conditions. Calcination of the polystyrene-silica nanocomposite particles leads to the formation of hollow silica shells, which indicates a well-defined core-shell morphology for the original nanocomposite particles.