Poly(N‐vinylcarbazole) chemically modified graphene oxide

A new soluble donor‐acceptor type poly(N‐vinylcarbazole)‐covalently functionalized graphene oxide (GO‐PVK) has been synthesized by reaction of DDAT (S‐1‐dodecyl‐S′‐(α,α′‐dimethyl‐α″‐aceticacid)trithiocarbonate)‐PVK with GO‐toluene‐2,4‐diisocynate. The incorporation of sufficient amount of PVK chains makes the modified GO nanosheets readily dispersible in organic solvents. The resulting material exhibits an enhanced solubility of 10 mg/mL in organic solvents. Covalent grafting of PVK onto the edge and surface of GO nanosheets did not change the carbazole absorption in the ultraviolet region, but substantially reduced the absorption intensity of GO in the visible region. The intensity of the emission band of GO‐PVK at 437 nm was a little bit quenched when compared with that of DDAT‐PVK, suggesting intramolecular quenching from PVK to GO. Such intramolecular quenching process may involve energy or electron transfer between the excited singlet states of the PVK moiety and the GO moiety. The HOMO/LUMO values and the energy bandgap of GO‐PVK experimentally estimated by the onset of the redox potentials are ?5.60, ?3.58, and 2.02 eV, respectively. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2642–2649, 2010     

多孔硅/多孔氧化铝与PVK复合光致发光特性

用旋涂法实现了多孔硅、多孔氧化铝与聚乙烯咔唑(PVK)的复合,研究了多孔硅／PVK、多孔氧化铝／PVK复合体系的光致发光性能。PL谱的测试发现,多孔硅／PVK复合体系的PL谱同时具有多孔硅和PVK的发射峰。此外,在485nm的位置出现了一个新峰,讨论了这个峰的来源。而多孔氧化铝与PVK复合后,没有产生新的峰。但多孔氧化铝与PVK复合后,由于多孔氧化铝纳米孔的纳米限制效应使PVK的发光峰出现大幅度蓝移。从多孔硅与多孔氧化铝发光机制的不同出发,讨论了多孔硅、多孔氧化铝与PVK复合后产生不同结果的原因。     

PVK∶DBVP掺杂体系的能量转移及发光性质的研究

研究了不同比例的PVK与齐聚PPV衍生物DBVP掺杂体系的能量转移和发光特性.通过对PVK,DBVP及PVK:DBVP掺杂体系的UV-vis,PL和PLE光谱的研究,分析了PVK与DBVP之间的能量转移过程.利用PVK在体系中类似于溶剂的分散作用,制备了结构为ITO/PEDOT/PVK:DBVP/LiF/Al的电致发光器件,研究了掺杂体系的电致发光性能.结果表明,在掺杂体系的光致发光和电致发光中,PVK的发射被有效地抑制,PVK与DBVP之间发生了非常有效的能量转移,通过调节PVK与DBVP的比例,可以获得蓝色和绿色发光,同时可以改善器件的发光性能,当PVK与DBVP的重量比为1∶2时,器件的绿色发光效率达到1·06cd/A,此时发光亮度为52cd/m2.     

C60与聚乙烯咔唑（PVK）键合物和共混物在紫外激光作用下的碳笼增强融合

用飞行时间质谱测量３０８ｎｍ激光熔蚀Ｃ６０化学修饰的聚乙烯咔唑（Ｃ６０－ＰＶＫ）与Ｃ６０／聚乙烯咔唑共混物（Ｃ６０／ＰＶＫ）的产物分布，分析了正负离子质谱，发现明显的碳笼融合现象。比较分析了融合过程的增强机理，认为Ｃ６０与ＰＶＫ间的化学键合以及电荷转移络合分别在Ｃ６０－ＰＶＫ键合物和Ｃ６０／ＰＶＫ共混物的富勒烯融合过程中起了重要作用。     

掺杂聚合物蓝光发光二极管

报道了用有机染料ＴＰＢ（１，ｌ，４，４－四苯基丁二烯）分散到ＰＶＫ（聚乙烯基咔唑）中的掺杂聚合物作有源层制作的蓝光发光二极管及其发光特性。聚合物发光层用旋转涂敷的方法制备，用透明导电材料ＩＴＯ（铟锡氧化物）、金属Ａｌ作为正负电极。器件正向偏压为１３Ｖ时，可以看到蓝光发射，峰值波长为４５５ｎｍ，注入电流为５０ｍＡ／ｃｍ２时，亮度为４４ｃｄ／ｍ２。     

聚乙烯咔唑LB膜的制备及其结构形态

利用LB技术，研究了具有光电活性的聚乙烯咔唑(PVK)的单分子膜及PVK与十八胺(ODA)混合分子膜的聚集结构形态．结果表明纯PVK分子由于弱的亲水作用可以形成较好单分子膜，此时PVK分子形成片状聚集；而在混合体系中，在一定比例下PVK形成颗粒状团聚．改变不同的比例可以得到不同的纳米图案，当PVK：ODA=10：1时形成尺寸较均一的纳米球状致密覆盖分子膜；当进一步增加PVK比例时，ODA不能再调控PVK聚集，混合膜表现出平坦的PVK，ODA分相片状聚集．     

Electrical and optical properties of light emitting devices with quantum dots dispersed in PVK matrix

ABSTRACT

In this study, we fabricated QD-LEDs with QD emitters dispersed in poly(9-vinylcarbazole) (PVK) matrix. The emission layer was prepared by spin-coating of the PVK solution dispersed with red QD nanoparticles. The concentration of QDs was varied to be 0.5, 2.0, 5.0, and 10.0 mg/ml in PVK solution of 25 mg/ml. As the QD concentration increases, the current efficiency of QD-LED gradually increases and the emission from PVK matrix decreases. In addition, we investigated energy transfer system with QD and organic dopant material using same structure in emissive layer. We obtained a maximum current efficiency of 4.1 cd/A and an external quantum efficiency of 3.0% were achieved at a QD concentration of 5.0 mg/ml in QD-LEDs.     

Synthesis and characterization of light‐emitting oligo(p‐phenylene‐vinylene)s and polymeric derivatives containing three‐ and five‐conjugated phenylene rings. II. Electro‐optical properties and optimization of PLED performance

A series of multilayer polymeric light‐emitting diodes (PLEDs) containing an electron‐transporting layer (ETL), that is tris(8‐quinolinolato)‐aluminum(III) (Alq) and 2,2′,2″‐(1,3,5‐phenylene)‐tris[1‐phenyl‐1H‐benzimidazole] (TPBI), were fabricated by doping fluorescent oligo(p‐phenylene‐vinylene)s (BIII and BV) and polymer derivatives (PBV) into poly(N‐vinyl carbazole) (PVK). These PLEDs can be optimized by the design of multilayer device configurations (brightness increased 8–15 times by addition of ETL) and possess greenish electroluminescent (EL) spectra peaked about 500–540 nm. A remarkably high brightness of 56,935 cd/m² with a power efficiency of 3.25 lm/W was obtained in the device of PVK:BVOC₈‐OC₈ (100:20)/Alq (60 nm/60 nm). It suggests that the emission mechanism (including the conjugated and excimer emissions of BVOC₈‐OC₈ emitters) originates from both of BVOC₈‐OC₈ and ETL (Alq and TPBI) by varying the concentration of chromophores and adjusting the thickness of ETL. The concentration effect of the emitters in PVK (i.e. PVK:BVOC₈‐OC₈ = 100:5, 100:20, and 100:100 wt %) and the influence of the ETL (including its thickness) on the EL characteristics are also reported. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2922–2936, 2006     

Photocrosslinking of poly(N-vinylcarbazole): Implementing a complementary set of techniques to characterize the three-dimensional network formation

The crosslinking of poly(N-vinylcarbazole) PVK resulting from UV irradiation (λ > 300 nm) was studied by combining various techniques including infrared spectroscopy, size exclusion chromatography (SEC), differential scanning calorimetry (DSC), swelling ratio, positron annihilation spectroscopy (PAS) and thermoporosimetry. The results obtained from all of these techniques were correlated and allowed a complete monitoring of the crosslinking during irradiation, from the creation of the first crosslinks to the formation and densification of the three-dimensional network. From SEC analysis and determination of swelling ratios, it was demonstrated that crosslinking was the predominant mechanism during the first stages of irradiation. PAS and DSC analyses revealed a good correlation between variations of free volume and increase of glass transition (T_g) of the bulk material. In addition, the development of the polymer architecture shown by the growth of T_g was nicely correlated with the modifications of the chemical structure observed by infrared analysis. Thermoporosimetry allowed the determination of the mesh size distributions within the polymer for the longest irradiation times. Numerical relationships were established and their validity was checked.     

表面增强拉曼光谱研究聚乙烯咔唑(PVK)在银表面的吸附状况

ＰＶＫ表面增强光谱及粉末拉曼光谱的对比分析表明,ＰＶＫ分子是通过杂五环和邻 双取代苯环同衬底银表面吸附的,且ＰＶＫ分子与银原子之间存在电荷转移。