高分子空穴传输材料的合成与性能研究

本论文以改善有机／高分子电致发光器件的载流子注入与传输平衡为目的，以具有良好成膜性、热稳定性及氧化还原性的氮硫共扼聚合物为母体，通过在氮上引入不同的侧基来研究所得聚合物的空穴传输性能，发光性能及其在电致发光器件中佩的应用。1．设计与合成出一系列不同链长的烷基取代的氮硫共扼聚合物，所得聚合物具有规整的结构，高的分子量，可溶于常见的有机溶剂且具有良好的成膜性。电化学研究表明，它们具有良好的氧化还原可逆性及稳定性，其HOMO值在5.02一5.16eV之间，与阳极ITO具有较好的匹配，说明它们有着良好的空穴注入性能。通过对“hole-only"器件（ITO/PPSA-R/C u )的研究表明随着烷基侧链的增长，所得聚合物的空穴传输能力逐渐下降。双层器件(TO/PPSA-R/Alq3几佩F/AI）研究结果表明与传统的高分子空穴传输材料聚乙烯咔叫含(PVK)相比，器件的启动电压降低，发光效率明显提高，说明烷基取代氮硫共扼聚合物具有优良的空穴传输性能。2.设计与合成出侧链悬挂有三芳胺类空穴传输小分子的氮硫共辆单体，在强酸体系下聚合后，通过核磁表征发现由于醚键断裂导致部分三芳1}5}小分子脱落，聚合物中三芳胺小分子含量降低。电化学研究表明它们具有良好的氧化还原可逆性，其HOMO值在-5.18eV左右，大于未引入二芳服时的氮硫共扼聚合物。双层器件(ITO/PPSA-TPA/Alq3/LiF/Al)研究结果表明，与未引入三芳l}}C的氮硫共扼聚合物相比，器件的启动电压升高，发光效率降低。3.设计与合成出侧链悬挂有高荧光效率的蓝色发光二苯葱小分子的氮硫单体，并通过其与可合成出高性能的空穴传输材料一的乙基取代的氮硫单体以不同比例共聚获得一系列新型的主链传输空穴而侧链发光的聚合物。它们具有高的热稳定性，良好的溶解性及成膜性，电化学研究表明它们具有良好的氧化还原可逆 性及低的起始氧化电位。通过对其发光性质的研究，我们发现在溶液荧光光谱中短波长的发射归结于二苯葱单体的发射，而长波长的发射则归结于分子内或分子间受激分子的发射；在固体膜的荧光光谱中，主要表现为激基缔合物发光，并随着二苯葱基元含量的减少光致发光亮度增加，且发光蓝移。4.设计与合成出含有N一烷基咔吟或N一芳基咔畔和不同发光中心的小分子发光材料，我们发现含葱环的发光小分子发光颜色向长波移动，含联苯结构的发光小分子的发光颜色则向短波移动。电化学研究表明，11卜畔的存在提高了发光小分子的空穴传输性能。通过将含有电子传输层的发光小分子双层器件与单层器件对比，我们发现双层器件的各项性能远高于单层器件，进一步说明了发光小分子传输性能的改善。

聚芴及其衍生物电致发光材料的合成与表征

本论文以合成聚荀及其衍生物电致发光材料为目的。通过光谱性质、电化学性质的表征及聚合物单层电致发光器件的测试来评价所合成的聚合物的性能。经过研究不同分子结构的共聚合单体及其含量对聚合物光电性能的影响及相关机理，为设计高性能的电致发光聚合物材料探索切实可行的途径。1．设计并合成了在侧链中带有嗯二哇类电子注入和传输基团的聚（9，9-二烷芴）系列聚合物，详细讨论了嗯二哇侧基含量对聚合物的分子量、溶解性、热性能的影响。嗯二哇侧基使聚合物有较大的空间位阻，限制了聚（9，9-二烷芴）的分子间的堆积，破坏了其晶相的形成。由于不同含量的唔二哇的引入，提高了聚合物的LUMO值，降低了电子的注入势垒。聚合物单层电致发光器件的性能数据表明，嗯二哇侧基的引入可以提高器件的效率和亮度，且含嗯二哇侧基的单体含量的最佳范围为27％左右。嗯二哇侧基的加入，导致电致发光出现较强的激基复合物发光，器件的电致发光表现为蓝白色荧光。2．设计和合成了在侧链中带有三苯胺基团的芴类系列聚合物，详细讨论了三苯胺侧基对聚合物的分子量、溶解性、热性能进行的影响。三苯胺侧基使聚合物有较大的位阻，限制了聚合物分子间的堆积，破坏了晶相的形成。三苯胺的引入降低了聚合物的HOMO值，因此空穴的注入势垒较小。聚合物单层电致发光器件的研究结果表明，三苯胺侧基的引入可以提高器件的效率和亮度，且三苯胺侧基的单体的含量的最佳范围为13％左右。加入三苯胺侧基后，聚合物保持了聚药本身的蓝光发光特性，并在一定程度上可以抑制激基复合物的形成。3．设计并合成了一类新的N-苯基取代吩噬嗦与9，9-二烷芴的具有空穴注入和传输功能的共聚物发光材料。N一苯基取代的吩唆嗓使聚合物发光有较大的红移，且光谱变宽。N-苯基取代的吩唆嗦与9，9-二烷芴交替共聚物显示出比三苯胺和咔哇类单体与9，9-二烷芴交替共聚物更低的HOMO值，是一类潜在的空穴注入和传输材料。在共聚含量低于30％时，吩噬啧单体的引入可以提高器件的效率。其电致发光光谱显示出与光致发光光谱相同的变化规律。4．本章基于“蓝光和橙光二原色”协同形成白光的物理思想，采用聚芴为蓝光构造基元，蔡酞亚胺衍生物为橙光构造基元，设计合成了将蔡酞亚胺衍生物共聚到聚荀及其衍生物主链的系列聚合物，实现蓝光和橙光发射基元在单一高分子中共同发光。通过调节蔡酰亚胺衍生物单体的含量，调控蓝光发射与橙光发射的相对强度，实现单一高分子的白光发射。利用能量转移和电荷转移（或电荷捕获）提高了聚合物器件性能，来达到提高白光器件电致发光光谱稳定性的目的。本章制备的白色电荧光聚合物是目前世界上器件结构和制备工艺最简单，效率最高的白光电致发光聚合物材料。

The properties and possible transformation path for C12B24N24

The structure and frequencies of C12B24N24 have been calculated by means of an ab initio method. By comparing the average bond energies with C-60, the calculated results predict that the cage C12B24N24 is a stable molecule. The calculated results indicate that the cage molecule C12B24N24 has a relative large HOMO-LUMO energy gap and a low rigidity The structures and stability of six possible isomers of C2B4N4 are used to suggest a possible transformation path from the pentagon CB2N2 to the C12B24N24 materials. (C) 2001 John Wiley & Sons, Inc.

Preparation and characteristics of nonflammable polyimide materials

The thermal and flame-retardant properties of homo- and copolyimides were evaluated. Those containing sulfone linkages in the backbone were found to be more flame retardant. Both properties were dependent on the composition. A polyimide/silica nanocomposite was obtained through sol-gel processing. The effects of the addition of silica an the dispersion, interfacial adhesion, fire resistance, mechanical properties, and thermal stability of the composites were investigated. SEM analysis showed a good dispersion of silica with a diameter of 50-300 nm in the organic matrices. The addition of silica increased the fire retardancy and mechanical properties of the composites. (C) 2000 John Wiley & Sons, Inc.

Length dependence of electron conduction for oligo(1,4-phenylene ethynylene)s: A conductive probe-atomic force microscopy investigation

The dependence of electron conduction of oligo(1,4-phenylene ethynylene)s (OPEs) on length, terminal group, and main chain structure was examined by conductive probe-atomic force microscopy (CP-AFM) via a metal substrate-molecular wire monolayer-conductive probe junction. The electron transport in the molecular junction was a highest occupied molecule orbital (HOMO)-mediated process following a coherent, non-resonant tunneling mechanism represented by the Simmons equation.

Different electronic structures and spectroscopic properties of cationic [M(ppy)2(N--N)]+ (M = Rh, Ir; N--N = Hcmbpy, H2dcbpy), a DFT study.

We report a comparative quantum-chemical study of the electronic structures and optical properties of a series of cationic complexes [M(ppy)(2)(N--N)](+) (N--N = Hcmbpy = 4-carboxy-4'-methylbpy, M = Rh (Rh1), Ir(Ir2); N--N = H(2)dcbpy = 4,4'-dicarboxy-bpy, M = Rh (Rh3) and Ir (Ir4)). The theoretical calculation reveals that the increased number of -COOH groups on the bpy ligand can decrease the energy levels of LUMO more than HOMO and narrow down the HOMO-LUMO energy gaps, which results in the red-shifted of the lowest-lying absorption and phosphorescent spectra. The lowest-lying singlet absorptions were categorized as d(M,M = Rh or Ir) + pi(ppy) -->pi*(bpy) with MLCT and LLCT characters.

Solution-Processable Carbazole-Based Conjugated Dendritic Hosts for Power-Efficient Blue-Electrophosphorescent Devices

A novel class of hosts suitable for solution processing has been developed based on a conjugated dendritic scaffold. By increasing the dendron generation, the highest occupied molecular orbital (HOMO) energy level can be tuned to facilitate hole injection, while the triplet energy remains at a high level, sufficient to host high-energy-triplet emitters. A power-efficient blue-electrophosphorescent device based on H2 (see figure) is presented.

Colorimetric recognition of the coralyne-poly(dA) interaction using unmodified gold nanoparticle probes, and further detection of coralyne based upon this recognition system

Among the functional nucleic acids studied, adenine-rich nucleic acids have attracted attention due to their critical roles in many biological processes and self-assembly-based nanomaterials, especially deoxyribonucleic acids (abbreviated as poly(dA)). Therefore the ligands binding to poly(dA) might serve as potential therapeutic agents. Coralyne, a kind of planar alkaloid, has been firstly found that it could bind strongly to poly(dA). This work herein reports an approach for visual sensing of the coralyne-poly(dA) interaction. This method was based on the coralyne inducing poly(dA) into the homo-adenine DNA duplex and the difference in electrostatic affinity between single-stranded DNA and double-stranded DNA with gold nanoparticles (GNPs). Furthermore, we applied the recognition process of the interaction between coralyne and poly(dA) into specific coralyne detection with the assistance of certain software (such as Photoshop). A linear response from 0 to 728 nM was obtained for coralyne, and a detection limit of 91 nM was achieved.

Diarylmethylene-bridged 4,4 '-(bis(9-carbazolyl))biphenyl: morphological stable host material for highly efficient electrophosphorescence

novel compound (BCBP) based on the modification of a well-known host material 4,4'-(bis(9-carbazolyl))biphenyl (CBP) through arylmethylene bridge linkage was synthesized, and fully characterized. Its thermal, electrochemical, electronic absorption and photoluminescent properties were studied. A high glass transition temperature (T-g) of 173 degrees C is observed for BCBP due to the introduction of the bridged structure, remarkably contrasting with a low T-g of 62 degrees C for CBP. Furthermore, the bridged structure enhances the conjugation and raises the HOMO energy, thus facilitating hole-injection and leading to a low turn-on voltage in an electroluminescent device. With the device structure of ITO/MoO3/NPB/Ir complex: BCBP/BCP/Alq(3)/LiF/Al, maximum power efficiencies of 41.3 lm/W and 6.3 lm/W for green- and blue-emitting OLED were achieved, respectively.

Copolymerization of ethylene with norbornene catalyzed by cationic rare earth metal fluorenyl functionalized N-heterocyclic carbene complexes

Rare earth metal bis(alkyl) complexes attached by fluorenyl modified N-heterocyclic carbene (NHC) (Flu-NHC)Ln(CH2SiMe3)(2) (Flu-NHC = (C13H8CH2CH2(NCHCCHN)C6H2Me3-2,4,6); Ln = Sc (2a); Y (2b); Ho (2c); Lu (2d)), ((tBu)Flu-NHC)Ln(CH2SiMe3)(2) ((tBu)Flu-NHC = 2,7-(Bu2C13H6CH2CH2)-Bu-t(NCHCCHN)C6H2Me3-2,4,6; Ln = Sc (1a); Lu (1d)) and attached by indenyl modified N-heterocyclic carbene (Ind-NHC)Ln(CH2SiMe3)(2) (Ind-NHC = C9H6CH2CH2(NCHCCHN)C6H2Me3-2,4,6; Ln = Sc (3a); Lu (3d)), under the activation of (AlBu3)-Bu-i and [Ph3C][B(C6F5)(4)], showed varied catalytic activities toward homo- and copolymerization of ethylene and norbornene. Among which the scandium complexes, in spite of ligand type, exhibited medium to high catalytic activity for ethylene polymerization (10(5) g mol(Sc)(-1) h(-1) atm(-1)), but all were almost inert to norbornene polymerization. Remarkably, higher activity was found for the copolymerization of ethylene and norbornene when using Sc based catalytic systems, which reached up to 5 x 10(6) g mol(Sc)(-1) h(-1) atm(-1) with 2a. The composition of the isolated copolymer was varying from random to alternating according to the feed ratio of the two monomers (r(E) = 4.1, r(NB) = 0.013).

Solvent effects on spectrophotometric titrations and vibrational spectroscopy of 5,10,15-triphenyl-20-(4-hydroxyphenyl)porphyrin in aqueoius DMF

The spectrophotometric titration by sodium hydroxide of 5,10,15-triphenyl-20-(4-hydroxyphenyl)porphyrin ((OH)(1)PH2) is studied as a function of solvent composition of DMF-H2O binary solvent mixture ([OH-] = 0.04 M). Combining the structure changes of the porphyrin and the "four orbital" model of Gouterman, many features of the optical spectra of this deprotonated para-hydroxy-substituted tetraphenylporphyrin in different composition of binary solvent mixtures can be rationalized. In highly aqueous solvents, the changes of the titration curves are shown to be mainly due to hydrogen-bonding of the oxygen of the phenoxide anion group by the hydroxylic solvent, Which decreases the energy of the phenoxide anion pi orbital. Thus the phenoxide anion pi orbital cannot cross over the porphyrin Tr orbital being a different HOMO. However, its energy is close to that of the porphyrin pi orbitals. As a result, in the visible region, no charge-transfer band is observed, while in the visible-near region, the Soret peak split into two components. In nonaqueous solvents, the changes are mainly attributed to further deprotonation of pyrrolic-Hs of (OH) 1PH2 by NaOH and coordination with two sodium ions to form the sodium complex of (OH) 1PH2, which turns hyperporphyrin spectra of deprotonated of phenolic-H of (OH)(1)PH2 into three-banded spectra of regular metalloporphyrin.

Photoluminescence and electroluminescence properties of a samarium complex Sm(TTA)(3)phen

The photoluminescence (PL) and electroluminescence (EL) properties of a samarium complex Sm(TTA)(3)phen (TTA = 2-thenoyltri-fluoroacetonate, phen = 1, 10-phenanthroline) were investigated. The results show that Sm(TTA)3phen could be used as promising luminescent and electron transporting material in the electroluminescent devices. The difference between PL and EL spectra was noticed and discussed. Besides, it is noteworthy that the choice of the hole transporting layer (HTL) showed significant effect on the device performance, which was explained by the low-lying highest occupied molecular orbit (HOMO) level of Sm(TTA)3phen and the different hole injection barrier at the HTL/EML (emitting material layer) interface.

Syntheses and ethylene polymerization behavior of supported salicylaldimine-based neutral nickel(II) catalysts

Two novel salicylaldimine-based neutral nickel(II) complexes, [(2,6-iPr(2)C(6)H(3))NCH(2-ArC6H3O)]Ni(PPh3)Ph (6, Ar = 2-(OH)C6H4; 8, Ar = 2-OH-3-(2,6-iPr(2)C(6)H(3)NCH)C6H3), have been synthesized, and their structures have also been confirmed by X-ray crystallography, elemental analysis, and H-1 and C-13 NMR spectra. An important structural feature of the two complexes is the free hydroxyl group, which allows them to react with silica pretreated with trimethylaluminum under immobilization by the formation of a covalent bond between the neutral nickel(II) complex and the pretreated silica. As active single-component catalysts, the two complexes exhibited high catalytic activities up to 1.14 and 1.47 x 10(6) g PE/mol(Ni)center dot h for ethylene polymerization, respectively, and yielded branched polymers. Requiring no cocatalyst, the two supported catalysts also showed relatively high activities up to 4.0 x 10(5) g PE/mol(Ni)center dot h and produced polyethylenes with high weight-average molecular weights of up to 120 kg/mol and a moderate degree of branching (ca. 13-26 branches per 1000 carbon atoms).

Synthesis, structure and luminescence properties of zinc (II) complexes with terpyridine derivatives as ligands

Five zinc (II) complexes (1-5) with 4 '-phenyl-2,2 ':6 ',2 ''-terpyridine (ptpy) derivatives as ligands have been synthesized and fully characterized. The para-position of phenyl in ptpy is substituted by the group (R), i.e. tert-butyl (t-Bu), hexyloxy (OHex), carbazole-9-yl (Cz), naphthalen-1-yl-phenyl-amine-N-yl (NPA) and diphenyl amine-N-yl (DPA), with different electron-donating ability. With increasing donor ability of the R, the emission color of the complexes in film was modulated from violet (392 nm) to reddish orange (604 nm). The photoexcited luminescence exhibits significant solvatochromism because the emission of the complexes involves the intra-ligand charge transfer (ILCT) excited state. The electrochemical investigations show that the complexes with stronger electro-donating substituent have lower oxidation potential and then higher HOMO level. The electroluminescence (EL) properties of these zinc (II) complexes were studied with the device structure of ITO/PEDOT/Zn (II) complex: PBD:PMMA/BCP/AlQ/ LiF/Al. Complexes 3, 4 and 5 exhibit EL wavelength at 552, 600 and 609 nm with maximum current efficiency of 5.28, 2.83 and 2.00 cd/A, respectively.

蓝光萘酰亚胺发光材料的合成与表征

通过在4位引入不同芳香基团,采用Suzuki和Stille偶联反应,设计与合成了一系列新型1,8-萘酰亚胺类荧光染料,并研究了它们的紫外-可见吸收、荧光发射和电化学行为等光物理性质。这些化合物在甲苯中均发射蓝色荧光,最大吸收和荧光发射峰分别在357～378和423～451nm之间,且随着芳香基团供电性增强,吸收和荧光发射波长发生红移。芳香基团的结构对化合物的发光效率影响很大,其中,取代基为甲氧基苯的化合物具有最高的荧光量子效率,可达0.98,而取代基为噻吩的化合物荧光量子效率最低,只有0.17。电化学循环伏安研究表明该类化合物具有较高的电子亲合力,不同芳香基团的引入只影响化合物的被占分子轨道(HOMO)能级,而对化合物的最低空分子轨道(LUMO)能级没有影响,即LUMO能级由1,8-萘酰亚胺单元决定。