Novel blue‐greenish electroluminescent poly(fluorenevinylene‐alt‐dibenzothiophenevinylene)s and their model compounds

Poly(9,9‐dihexylfluorene‐2,7‐vinylene‐alt‐dibenzothiophene‐2,8‐vinylene) (PS) and poly(9,9‐dihexylfluorene‐2,7‐vinylene‐alt‐dibenzothiophene‐5,5‐dioxide‐2,8‐ vinylene) (PSO) as well as corresponding model compounds were synthesized by Heck coupling. Both the polymers and model compounds were readily soluble in common organic solvents such as tetrahydrofuran, dichloromethane, chloroform, and toluene. The polymers showed a decomposition temperature at ～430 °C and a char yield of about 65% at 800 °C in N₂. The glass‐transition temperatures of the polymers were almost identical (75–77 °C) and higher than those of the model compounds (26–45 °C). All samples absorbed around 390 nm, and their optical band gaps were 2.69–2.85 eV. They behaved as blue‐greenish light emitting materials in both solutions and thin films, with photoluminescence emission maxima at 450–483 nm and photoluminescence quantum yields of 0.52–0.72 in solution. Organic light‐emitting diodes with an indium tin oxide/poly(ethylene dioxythiophene):poly(styrene sulfonic acid)/polymer/Mg:Ag/Ag configuration with polymers PS and PSO as emitting layers showed green electroluminescence with maxima at 530 and 540 nm, respectively. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6790–6800, 2006     

Highly substituted poly(2,3‐diphenyl‐1,4‐phenylenevinylene) derivatives having bulky phenyl and fluorenyl pendant groups: Synthesis,characterization, and electro‐optical properties

Two series of poly(2,3‐diphenyl‐1,4‐phenylenevinylene) (DP‐PPV) derivatives containing multiple bulky substituents were synthesized. In the first series, two different groups were incorporated on C‐5,6 positions of the phenylene moiety to increase steric hindrance and to obtain blue‐shifted emissions. In the second series, bulky fluorenyl groups with two hexyl chains on the C‐9 position were introduced on two phenyl pendants to increase the solubility as well as steric hindrance to prevent close packing of the main chain. Polymers with high molecular weights and fine‐tuned electro‐optical properties were obtained by controlling the feed ratio of different monomers during polymerization. The maximum photoluminescent emissions of the thin films are located between 384 and 541 nm. Cyclic voltammetric analysis reveals that the band gaps of these light‐emitting materials are in the range from 2.4 to 3.3 eV. A double‐layer EL device with the configuration of ITO/PEDOT/P4/Ca/Al emitted pure green light with CIE′1931 at (0.24, 0.5). Using copolymer P6 as the emissive layer, the maximum luminescence and current efficiency were both improved when compared with the homopolymer P4. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6738–6749, 2006     

Vinyl copolymers containing pendant 1,4‐distyrylbenzene and 1,3,4‐oxadiazole chromophores: Preparation and optoelectronic properties

We prepared two vinyl copolymers P1 and P2 containing pendant distyrylbenzene and aromatic 1,3,4‐oxadiazole derivatives, respectively, from their precursor poly(styrene‐ran‐4‐vinylbenzyl chloride) (M_w = 11,400, PDI = 1.18), which had been prepared by the controlled radical polymerization (RAFT). Two main chain polymers containing similar isolated distyrylbenzene ( P3) and aromatic 1,3,4‐oxadiazole ( P4 ) chromophores were also synthesized for comparative study. The resulted copolymers ( P1 – P4 ) are soluble in common organic solvents and are basically amorphous materials with 5% weight‐loss temperature higher than 360 °C. The PL spectral results reveal that the architecture of P1 prevents the formation of inter‐ or intramolecular interaction. The HOMO and LUMO levels of P2 , estimated from cyclic voltammetric data, are ?5.96 and ?3.81 eV, respectively, which are much lower than those of P1 (?5.12 and ?3.11 eV). The emission of blend from P1 and P2 are contributed mainly from distyrylbenzene fluorophore (～450 nm) owing to efficient energy transfer. Moreover, the blend exhibits three kinds of redox behavior depending on their weight ratios. The luminance and current efficiency of the EL device lpar;ITO/PEDOT/ MEH ‐ PPV + P2 /Al) are 503 cd/m² and 0.11 cd/A, which can be improved to 1285 cd/m² and 0.44 cd/A, respectively, as the weight ratio of P2 increases from 0 to 20%. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5362–5377, 2006     

Probing the use of small‐angle light scattering for characterizing structure of titanium dioxide/low‐density polyethylene nanocomposites

Small‐angle light scattering (SALS) measurements were used to study the structure of titanium dioxide (TiO₂)/low‐density polyethylene (LDPE) nanocomposites. The results showed that the scattering from LDPE crystalline structures and the scattering from TiO₂ nanoparticles can be resolved and separated. It is shown that the independent effects of crystallization conditions and the presence of nanoparticle aggregates on the spherulitic structure of the LDPE matrix can be determined by analyzing the scattering patterns using the methods proposed. From the SALS results, we conclude that the nanoparticle surface chemistry affects both nucleation of spherulites and their structure particularly under rapid cooling conditions. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1084–1095, 2006     

催化动力学光度法测定痕量铜的研究

本研究了在氨水介质中铜（Ⅱ）催化过氧化氢氧化亮黄的褪色反应及其动力学条件，建立了一种超高灵敏、高选择性的测定环境试样中痕量铜的新方法，可测定０．００４～０．５μｇ／２５ｍＬ范围内的铜（Ⅱ）。     

CTAB胶束微环境中BY增溶位置的探讨

本文用ＵＶ吸收光谱对（ＢＹ＝ＣＴＡＢ）体系胶束化过程中预胶束的形成，以及预胶束向胶束的转变过程进行了分析。采用Ｇｏｕｙ－Ｃｈａｐｍａｎ模型，建立了ＣＴＡＢ胶束微环境中ＢＹ表现解离常数与胶束结构参数之间的定量关系，根据水溶液和各种盐浓度条件下ＣＴＡＢ胶束溶液中酸碱解离常数的测量，分析了ＢＹ在ＣＴＡＢ胶束扩散层中的增溶位置，讨论了ＣＴＡＢ胶束对ＢＹ选择性吸附的特性。     

8-羟基喹啉对甲基苯酚合锌配合物的合成及光致发光和电致发光性能

有机电致发光 ( EL )技术作为一种有着广阔应用前景的显示技术 ,自 1 987年 [1] 以来已获得了空前迅速的发展 .部分发光器件的亮度、效率和寿命已经达到或接近实用化的程度 .许多有机化合物 [2～ 5] ,包括小分子和聚合物 ,已被用于制备有机 LEDs.应用于有机 EL的化合物很多 ,这为优化和筛选优秀的 EL材料提供了基础 .以 8-羟基喹啉铝为代表的有机金属配合物是一类重要的有机 EL材料 ,这类材料荧光效率高、易于提纯且性质比较稳定 .目前应用于有机 EL金属配合物的发光材料大多配位数均为偶数 ,四配位的 8-羟基喹啉锌配合物 ( Znq2 ) [6…