Synthesis and properties of poly(p-phenylenevinylene)s containing hole-transporting aromatic amine units

该论文以提高聚苯撑乙烯（PPV）类发光聚合物的空穴传输性能为主要目的,通过将具有较高空穴传输能力的芳胺类小分子基元引入发光聚合物分子链,设计并合成了一系列含芳胺基元的PPV聚合物.另外,还通过对分子结构进行设计和控制,获得了红绿蓝三基色发光.最后还利用在共轭分子主链上引入具有三维空间位阻的侧链基团,获得了高效率的绿色发光聚合物材料.In order to improve the hole-transporting ability of the light-emitting poly(p-phenylenenvinylene)s (PPVs), some series of novel polymers containing hole-transporting aromatic amine units on the backbone or as pendants were designed and synthesized via the improved-Wittig polycondensation reaction. By tuning the chemical structure of such polymers, light emission covering the full range of visible light (red, green and blue) was obtained. In addition, bright green emission with a highly enhanced light-emitting efficiency was obtained by introducing a three-dimensional bulky tetraphenylmethane as the pendant of triphenylamine-based PPV. The details of the work are as fellows: 1. An improved-Wittig polycondensation reaction was developed and applied to synthesize light-emitting PPVs with excellent molecular weight and high /ram'-configuration of vinylene (>95%) in excellent yields by using tributyl phosphonium salts instead of triphenyl phosphonium salts as Yild monomers. 2. Two series of PPVs, containing N-alkyl diphenylamine and N-phenyl diphenylamine units in the skeleton were designed and synthesized. The effect of the lengths of alkyl side chains and alkyloxy substituents on the properties of light-emitting polymers was evaluated. The photoluminescence (PL) spectra were remained, however, the PL intensities were enhanced as increasing of side chain Dissertation of Changchun Institute of Chemistry lengths. The improvement was assigned to the "solvent effect" of long chains and preventing from aggregation and quenching of polymeric emitters. The solubility of N-phenyl diphenylamine-based PPV was revealed to be better than that of N-alkyl diphenylamine-based PPVs, suggesting the bulky alkyloxy-phenyl substituents benefits weakening of aggregation of polymer chains. The effect of insertion of aromatic amine units on the polymer backbone on the light-emitting property was investigated by comparing to alkyloxy-based PPV (OR-PPV). As the results of both electron donating and stereo effect of aromatic amine units, the length of conjugation decreased in some extent. The emission shifted to green of TPA-PPV from green-yellow of OR-PPV. A series of triphenylamine-based PPVs with varying chemical structures were prepared via improved-Wittig polycondensation by using different tributyl phosphnium salts with varying aromatic structures. The relationship between chemical structures and PL properties was studied by means of UV-Vis absorption and PL spectra. The evaluation of performance of light-emitting diodes with different configuration (single-layer of double-layer) suggested that the incorporation of triphenyl amine units enhanced the hole-transporting ability. Aromatic amine units with different structures were introduced into the backbone of PPV, and their effects on thermal stability, absorption, light emission properties and electrochemical performance of resulting polymers were studied. Comparing to TPA-PPV, TPD-PPV and PDA-PPV exhibited lower potential of oxidation and reversibility, suggesting improved hole-transporting ability. Blue-green light emitting PPVs containing N-alkyl and N-phenyl carbazole units were designed and synthesized via Wittig reaction. The resulting PPV exhibited enhanced hole-transporting property, which can be attributed to the carbazole units. Dissertation of Changchun Institute of Chemistry 7. A green light-emitting soluble polymer containing isolated conjugated chromophore was prepared and its PL was investigated by comparing with the model compound. The conjugated chromophores were confined between non-conjugated chains. Novel high thermal-stable blue light emitting poly(aromatic ether)s bearing aromatic amine as pendants were designed and synthesized by Wittig reaction. The excellent solubility benefited from the effect of bulky aromatic amine units. The study of absorption and emission suggested there is energy transfer between aromatic amine unit TPPA and luminescent segments, which be expected to enhance the emission efficiency. Electron-withdrawing cyano groups were introduced into the vinylene by Knoevenagel condensation reaction, and the resulting polymers howed excellent solubility, thermal stability and red light emission (> 600 nm). Among them, TPA-CNPV showed very high molecular weight (Mn>10 K). The investigation of PL in different solvent and films coated from different concentration solution revealed the different maximum emission. 10. A novel high efficient green emitting triphenylamine-based PPV was designed and synthesized by attaching three-dimensional bulky tetraphenylmathane substituents on the pendants of the skeleton. The investigation of PL in different concentration solution and the enhanced EL efficiency revealed the bulky effect of tetraphenylmethane play an important role in improving of quantum efficiency