高效溶液法小分子磷光电致发光器件研究

以小分子化合物CDBP[4，4＇-bis（carbazo1．9-yl）-9，9-dimethyl-fluorene]为主体材料，Ir（pppy）3[tris（5-phenyl-10，10-dimethyl-4-aza—tficycloundeca-2，4，6-triene）Iridium（Ⅲ）]为磷光客体材料，采用溶液法和真空蒸镀法相结合的制备工艺，制作了小分子磷光电致发光器件．研究表明，通过器件结构的优化，Ir（pppy）3（重量百分比为2）掺杂的多层绿光电致发光器件效率达22．0cd／A，最大亮度达到26600cd／m^2，这一结果可与当今基于真空蒸镀的小分子或基于溶液法的高分子磷光电致发光器件性能相媲美．本工作为降低有机电致发光器件的成本，扩展溶液法有机电致发光器件制备工艺中材料的选择范围提供了实验依据．     

一种聚芴类磷光主体材料的合成与性能研究

有机电致磷光材料,由于具有100%的内量子效率,在OLED领域中被广泛应用。为了避免磷光材料本身存在的三线态-三线态激子猝灭导致磷光效率的降低,磷光材料应用于有机电致发光器件时,需要用主体材料将其均匀分散以减少发光中心间的相互作用,因此主体材料的选择对磷光器件是十分重要的。而聚合物主体材料由于具有易加工,成本低等优点,且对于实现高性能的蓝光和白色旋涂器件有重要意义,而备受关注。本文设计合成了一种聚芴类主体材料PSiF,聚合物表现出良好的热稳定性(热分解温度Td≥400℃),将其与绿色磷光染料Ir(ppy)3以16 wt%的浓度掺杂,器件的最大的发光效率为0.25cd/A;最大的功率效率为0.14l m/w。     

发光有机器件用新型荧光掺杂材料的合成及表征

对具有代表性的绿色磷光发光掺杂材料Ir(ppy)3[三(2-苯基吡啶)合铱]进行了改性,在其配位体处导入了含有较大空间位阻的芳香族置换基团;设计开发了具有空穴/电子传导部位的EL(有机电致发光)共聚物,并分别对改性后的磷光掺杂材料[如Ir(Bu-ppy)3(三丁基吡啶合铱配合物)、Ir(Cz-ppy)3(三咔唑吡啶合铱配合物)等]与导电高分子掺杂后制成的OLED(有机发光二极管)的性能进行了分析。研究结果表明:上述芳香族置换基团能减轻浓度消光效应,提高原有掺杂材料的发光效率,并且提高了含该掺杂体的高分子材料在有机溶剂中的溶解性;含Bu-ppy配位结构的磷光掺杂材料比含Cz-ppy配位结构的掺杂材料具有更高的器件效率。     

基于联咔唑为骨架的双极主体材料的合成及其在有机电致发光器件中的应用

咔唑类衍生物具有良好的空穴传输性能和较高的三重态能级,在有机电致发光器件中一般用来构建空穴传输材料和主体材料。本文通过在联咔唑的3和6位引入具有电子传输能力的氰基,设计合成了一种以双咔唑二聚体为分子骨架的新型双极性有机电致发光主体材料6,6′-双氰基-9,9′-二苯基-3,3′-联咔唑(BCzDCN),研究了其发光性能、热稳定性和电化学性质。低温磷光发射光谱测试表明BCzDCN的三重态能级高于传统的天蓝色磷光掺杂材料双(4,6-二氟苯基吡啶-N,C2′)吡啶甲酰合铱(FIrpic)。以BCzDCN为主体材料,FIrpic和双(4-苯并噻吩[3,2-C])吡啶-N,C2′)乙酰丙酮合铱(PO-01)分别为蓝色和黄色磷光掺杂材料,制备了蓝色和白色有机磷光发光二极管器件。器件的最大电流效率分别达到34.6cd/A和59.0cd/A。并且在1000cd/m2亮度下的效率滚降仅有4.1%和5.1%。     

纯有机室温磷光材料的研究进展

纯有机室温磷光材料因其斯托克斯位移大、寿命长、毒性小、制备成本低等优势,在防伪、生物成像、有机发光二极管等方面有着广泛的应用前景,近年来受到了人们极大的关注.在磷光体系的构建上,不仅要引入溴、碘重原子或羰基等基团促进系间窜越过程,还要采用主-客体相互作用、聚合、掺杂、卤键、氢键、π-π堆积相互作用等方法为磷光体提供良好...     

有机电致磷光材料的研究进展

有机电致磷光发光材料是一类具有很高发光效率的有机电致发光材料,它的理论内量子效率为100%,是有机荧光电致发光材料的4倍。综述了有机小分子磷光发光材料、有机聚合物磷光发光材料、树枝形磷光发光材料近年来的研究状况及存在的问题,介绍了分子结构对材料和器件性能的影响,并总结了目前已经取得的研究成果。     

高功函数金属Al作阴极的高效率白光聚合物电致发光

我们用聚电解质PFN做电子注入层,制备了高功函数金属Al做阴极的高效率白光聚合物电致发光。以蓝绿光发光中心的聚合物为主体和掺杂红光磷光染料,通过改变红磷光的掺杂浓度调节器件的电致发光光谱,得到白光发射。并研究了电子传输材料对WILLED器件发光光谱的影响。     

三嗪和吡嗪类热致延迟荧光材料的合成及性能

近年来,随着电子信息技术的快速发展与应用,相关新型技术与材料更新与发展的速度不断加快,有机发光二极管是近年来被广泛应用的新型平板显示技术,也是重点研究内容和方向,与以往荧光、磷光材料相比,热致延迟荧光材料具有显著的优势,器件中的量子效率理论可达100%。热延迟荧光材料属于有机小分子,其化学性质相对稳定,通常不需要与金属配位,使得其成本大幅度降低,所以,进一步开发与研究新型热致延迟荧光材料有着重要的意义。三嗪属于电子传输功能基团,其性能非常好,因具备很强的化学与光热稳定性,被广泛应用于有机光电子领域,以三嗪类化合物M1为主体材料,制备了相应的绿色与蓝色磷光期间,并深入探究了其电致发光性质,两者均有高效的性能,数据显示,M1可作为发光材料被广泛应用于有机电致发光器件当中,其主体材料性能也比较突出。     

高效磷光OLED材料的设计、合成与性能

结合我国高效磷光OLED材料设计、合成工作的开展情况来看,有机电致发光器件二十年来得到了长远发展,并且在我国固态照明领域进入了实用化的发展阶段。通过介绍高效磷光OLED材料的发展现状,对高效磷光OLED材料的功能进行了探究,从化学角度以及物理载流子方面对高效磷光OLED材料的主体进行了分析与总结。     

Ti3+在Sol-gel多孔磷光SiO2干凝胶中的发光

采用常规的Sol-gel工艺合成了Ti3+掺杂的多孔磷光SiO2干凝胶,Ti3+离子作为间隙离子存在于SiO2网络中,展示了一种新颖的发光现象,改变了Sol-gel SiO2干凝胶的发射光谱.这种掺杂SiO2干凝胶的激发和发射光谱均由2个带组成,短波长的发光峰在440nm(λex＝380nm),其相对荧光强度约是纯SiO2干凝胶的5倍;长波长的发光峰在600nm(λex＝550nm),其相对荧光强度约是Ti3+掺杂ZnS纳米晶的20倍.由此可以得出:过渡金属离子掺杂的多孔磷光SiO2干凝胶形成了一类新型的发光材料.     

Rare earth (RE) doped phosphors and their emerging applications: A review

The evolution of luminescent materials has witnessed rapid advancement in research and development. Solid inorganic light-emitting materials or phosphors are the optoelectronic material of the 21st century because of their power-efficient potential over various illumination sources, eco-friendliness and resourceful display perspectives. The inorganic phosphors have been extensively explored to meet the demand of low voltage stimulated lighting sources owing to increased global energy consumption. Due to environmental friendliness, advantages long lifetime, lower energy consumption, reliability and high luminous efficiency, modern white light-emitting diodes (WLEDs) have replaced less effective incandescent and mercury-enclosing conventional fluorescent lighting sources. This review highlights the developments in preparation, luminescence and potential perceptions of rare-earth activated phosphors for solid-state lighting technologies. The role of RE ions as an activator as well as a sensitizer in doped materials and possible transitions within their energy levels are reviewed in detail. The paper reviews the substantial influence of host lattices such as aluminate, oxide, phosphate, silicate, sulfide, etc on the optical transitions of doped RE ions. Studies on the advancement into the design of novel phosphors are very crucial as they will provide an opportunity to boom prospects in the course of promising applications. The sustainable energy facilities include clean technologies providing a cheaper lighting source which can produce significant indirect economic benefits via limiting the deforestation and use of scrubbing technology to mitigate air pollution.     

聚乙二醇/硬脂酸复合体系用于卷烟香料缓释的机理研究

以聚乙二醇/硬脂酸复合体系为基质型缓释材料,以陈皮/薄荷复合香精为被缓释香料,深入研究基质材料的组成、相结构、升温相变行为对香料缓释过程的影响,揭示了聚乙二醇/硬脂酸复合体系的常温锁香机理和香料缓释机理。缓释基材中的晶区通过晶格排列和晶区内分子相互作用储存少量香料分子,其余大量香料分子则通过强氢键相互作用附着于疏松的非晶区。常温下热力学稳定,香料分子得以稳定储存。卷烟燃吸的升温过程伴随着基材的熔融和氢键相互作用的解离,同时以分段释放的方式控制香料分子的缓释。香料被加入基材后,两个释放阶段的最大释放速率及释放量均有明显降低,说明基材对于香料的释放存在明显的抑制作用。     

Self-reporting materials: protein-mediated visual indication of damage in a bulk polymer

Damage self-reporting materials are able to indicate the presence of microscopic damaged regions by easy to detect signals, such as fluorescence. Therefore, these smart materials can reduce the risk of catastrophic failure of load-bearing components, e.g., in aerospace and construction applications. We highlight here our proof-of-concept paper and we present some additional data, which shows that proteins can be used as mechanophores in solid polymeric materials. Macroscopic mechanical forces were transferred from the polymer to the embedded proteins. The biomolecules act as molecular strain sensor, giving the material the desired self-reporting property. Poly(ethylene glycol) and poly(acrylamide) (PAAm) networks were doped with small amounts of thermsosome (THS), a protein cage from the family of chaperonins, that encapsulated a pair of fluorescent proteins. THS acts as a scaffold which brings the two fluorescent proteins into distance suitable for fluorescence resonance energy transfer (FRET). Moreover, THS can be distorted by mechanic forces so that the distance between the fluorescent proteins changes, leading to a change in FRET efficiency. Using the brittle PAAm as a model system, we were able to visualize microcracks in the polymers by FRET microscopy and by fluorescence lifetime imaging. THS also stabilizes the encapsulated guest proteins against thermal denaturation, increasing their half-live at 70 degrees C by a factor of 2.3.     

Carbon mesophase-substrate interactions

The formation, growth and coalescence of mesophase materials have been followed by hot stage microscopy and by room temperature examination of polished surfaces for various mesophase-forming materials and in the presence of various substrates. The appearance of mesophase particles should be preceded by polymerization of isotropic material into sheet-like molecules, followed by orientation of the sheet-like molecules into ordered regions. Precipitation, growth and coalescence should require ordering of small molecules in a viscous medium. Our results indicate that dynamic motion in the fluid, rather than the presence of nucleating particles, is the controlling factor, very likely reflecting a small mesophase-isotropic liquid interfacial energy. Where dynamic motion is restricted, as in the interstices of a yarn, mesophase formation and growth are also restricted. Alignment of mesophase material with a substrate is primarily controlled by the motion of the mesophase droplets as they flow across the substrate. In general, substrates are not wetted by mesophase in the presence of isotropic material. Certain surfaces are wetted by the mesophase droplets but alignment appears to be controlled more by flow orientation than by surface energy interaction.     

Energy and Charge Transfer Dynamics in Doped Semiconductor Nanocrystals

Doping semiconductor nanocrystals with transition metal ions introduces new optical, electronic, and magnetic properties to the host semiconductor nanocrystals. The energy transfer and charge transfer between exciton and dopant ions are the key photophysical processes responsible for the unique properties of doped semiconductor nanocrystals, which are distinct from their undoped counterparts. Since the energy transfer and charge transfer processes between exciton and dopant ions compete with the usual relaxation pathways of the exciton, competition among different dynamic processes ultimately determines the photophysical properties of doped nanocrystals. In this review, we discuss the dependence of the dynamics of the energy transfer and charge transfer processes in Mn-doped II-VI semiconductor nanocrystals on the structure of the host nanocrystal, spatial distribution of the dopant ions within the nanocrystal, and charge carrier-trapping molecules near the surface of the nanocrystals.     

MnO_2掺杂Bi（Ⅴ）电极材料的制备与性能

以MnSO4、Bi（NO3）3为原料,在碱性条件下与NaClO反应,制备了掺杂Bi（V）的MnO2电极材料,实验比较了NaClO、Bi（NO3）3、NaOH浓度,反应时间等条件改变对电极材料充放电性能的影响。实验表明,掺杂了Bi（V）的MnO2试样,经恒电流充放电测试其充放电容量可达272 mAh.g-1,远高于未掺杂的MnO2电极材料,且二次放电容量仍可达一次容量的93%。表明在本实验条件下制备的掺杂少量Bi（V）的MnO2电极材料,放电容量明显提高,且循环性能也有一定的改善。     

New NOx sensors based on hematite doped with alkaline and alkaline-earth elements

Alkaline (lithium, potassium, rubidium) and alkaline-earth (magnesium, barium) doped hematite materials were studied for NO₂ sensing application. The synthesized materials were characterized by laser granulometry, X-ray diffraction and scanning electronic microscopy. A temperature of 1300 °C was chosen as the optimal heat treatment in order to obtain the densest material. Humidity dependence of the electrical properties revealed a strong influence in the case of rubidium doped hematite material while the other doped materials were less sensitive.The AC impedance analyses underlined the n-type intrinsic semi-conduction of pure hematite. Alkaline-earth doped hematite materials showed two semi-conducting regions, below and above 500 °C, corresponding to extrinsic and intrinsic n-type semi-conduction, respectively. These electrical analyses associated with SEM observations suggested instability of the ferrites formed in rubidium and potassium doped materials.AC electrical measurements were performed in the 0-500 ppm NO₂ partial pressure range. The alkaline-earth doped hematite materials exhibited the most promising behavior.     

纳米粒子掺杂太阳盐复合材料热物性研究

在聚光式太阳能系统中,熔盐被视为良好的储热材料,具有成本低、使用安全、低饱和蒸汽压等特点。合理改善其热物性可实现太阳能高效利用,掺杂纳米颗粒可提高熔盐的储热及传热性能。在之前工作中,采用高温静态熔融法将纳米氧化铝（Nano alumina,NA2）掺杂于太阳盐（SS,质量分数为60%的硝酸钠与质量分数为40%的硝酸钾的混合物）中,获得了具有较高比热容的纳米流体（NA2-SS,N2S）。在此基础上,采用相同方法将纳米石墨粉（GP）和NA2同时掺杂于SS中（NA2-GP-SS,N2GS）,利用差式扫描量热法和瞬态平面热源法对体系比热和导热进行测试。结果表明,优化样品为N2GS-4,比热容与原样SS相比提升21.79%,导热提升20.69%,在高温状态下具有较好的热稳定性。N2GS-4作为一种硝酸盐基纳米复合蓄热材料在热能存储系统中具有广阔的应用前景。     

Azobenzene photomechanics: prospects and potential applications

The change in shape inducible in some photo-reversible molecules using light can effect powerful changes to a variety of properties of a host material. This class of reversible light-switchable molecules includes molecules that photo-dimerize, such as coumarins and anthracenes; those that allow intra-molecular photo-induced bond formation, such as fulgides, spiro-pyrans, and diarylethenes; and those that exhibit photo-isomerization, such as stilbenes, crowded alkenes, and azobenzenes. The most ubiquitous natural molecule for reversible shape change, however, and perhaps the inspiration for all artificial bio-mimics, is the rhodopsin/retinal protein system that enables vision, and this is the quintessential reversible photo-switch for performance and robustness. Here, the small retinal molecule embedded in a cage of rhodopsin helices isomerizes from a cis geometry to a trans geometry around a C=C double bond with the absorption of just a single photon. The modest shape change of just a few angstroms is quickly amplified and sets off a cascade of larger shape and chemical changes, eventually culminating in an electrical signal to the brain of a vision event, the energy of the input photon amplified many thousands of times in the process. Complicated biochemical pathways then revert the trans isomer back to cis, and set the system back up for another cascade upon subsequent absorption. The reversibility is complete, and many subsequent cycles are possible. The reversion mechanism back to the initial cis state is complex and enzymatic, hence direct application of the retinal/rhodopsin photo-switch to engineering systems is difficult. Perhaps the best artificial mimic of this strong photo-switching effect however in terms of reversibility, speed, and simplicity of incorporation, is azobenzene. Trans and cis states can be switched in microseconds with low-power light, reversibility of 10⁵ and 10⁶ cycles is routine before chemical fatigue, and a wide variety of molecular architectures is available to the synthetic materials chemist, permitting facile anchoring and compatibility, as well as chemical and physical amplification of the simple geometric change. This review article focuses on photo-mechanical effect taking place in various material systems incorporating azobenzene. The photo-mechanical effect can be defined as reversible change in shape by absorption of light, which results in a significant macroscopic mechanical deformation, and reversible mechanical actuation, of the host material. Thus, we exclude simple thermal expansion effects, reversible but non-mechanical photo-switching or photo-chemistry, as well as the wide range of optical and electro-optical switching effects for which good reviews exist elsewhere. Azobenzene-based material systems are also of great interest for light energy harvesting applications across much of the solar spectrum, yet this emerging field is still in an early enough stage of research output as to not yet warrant review, but we hope that some of the ideas put forward here toward promising future directions of research, will help guide the field.     

YAG纳米粉体的制备技术研究进展

近年来YAG纳米粉体因其具有特殊的性能而备受人们的关注。以此为原料采用先进的陶瓷制备工艺可以得到透明的YAG固体激光工作介质 ,其物理化学及光学性能可与单晶相比拟。YAG粉体通过掺杂Ce3 ,Tb3 ,Eu3 等离子还可以作为超短余辉荧光粉 ,在发光材料领域有广泛的应用。本文着重介绍了目前应用较多的几种YAG纳米粉体的制备方法 ,并简要地比较了各种方法的优劣。