Synthesis and electroluminescence properties of novel main chain poly(p-phenylenevinylene)s possessing pendant phenylazomethine dendrons as metal ligation sites
Synthesis and electroluminescence properties of novel main chain poly(p-phenylenevinylene)s possessing pendant phenylazomethine dendrons as metal ligation sites
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DOI：
10.1021/cm049241m
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发表时间：
2004-12-28
影响因子：
8.6
通讯作者：
Yamamoto, K
中科院分区：
文献类型：
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作者：
Kimoto, A;Masachika, K;Yamamoto, K
以树枝状苯偶氮亚甲胺(DPA)的配位陷阱为催化剂，通过与稀土金属离子的初始络合，通过Heck反应合成了含树枝状苯偶氮亚甲胺(DPA-PPVs)的新型聚对苯乙叉S(PPAPPVs)。对DPA-PPV的物理性能进行了评价。研究了不同含量和不同生成的DPA对溶液性质、热性质和光学性质的影响。基于相对平面的结构和较长的共轭长度，含量较低、代数较少的DPA-PPV具有最长的吸收和荧光最大波长。这些聚合物通过与其单体模型化合物类似的光谱变化，成功地在其亚胺位置上组装了金属离子。制备了两种类型的电致发光器件：(I)ITO/PEDOT/DPA-PPV/ALQ/CSF/Al；(Ii)ITO/PEDOT/DPA-PPV/TAZ/ALQ/CSF/Al，其中Alq(三-8-羟基喹啉铝)作为电子传输层(ETL)，TAZ(3，5-二(叔丁基苯基)-4-苯基三唑)作为空穴阻挡层。在这两种器件中，DPAPPV的发光都是以较低的生成量和较少的DPA单元(3a)观察到的，这是由其物理性质解释的。对于3a的第二类器件，DPAPPV的发射、较低的驱动电压和较高的效率随后简单地与非常少量的SnCl2络合。另一方面，对于3b来说，络合增强了Alq的发射，而不是DPA-PPV的发射，3b-SnCl2主要作为空穴传输层，增强了空穴注入和复合到Alq层中，但由于DPA单元的空穴传输性能增强，这不能被完全阻止。
Novel poly(p-phenylenevinylene)s with a dendritic phenylazomethine (DPA-PPVs) were synthesized via the Heck reaction by initially complexing with rare-earth-metal ions, by filling up the coordination trap site of dendritic phenylazomethine (DPA) as the catalyst. The physical properties of the DPA-PPVs were evaluated. The solution, thermal, and optical properties affected by the various contents and generation of the DPA were investigated. DPA-PPV with the lower content and a smaller generation number showed the longest absorption and fluorescence maximum wavelength based on a relatively planar structure and a longer conjugation length. These polymers successfully assemble metal ions on their imine site supported by the spectral change similar to their monomeric model compounds. Two types of electroluminescent (EL) devices were fabricated: (I) ITO/PEDOT/DPA-PPV/Alq/CsF/Al; (II) ITO/PEDOT/DPA-PPV/TAZ/Alq/CsF/Al, where Alq (tris-8-hydroxyquinoline aluminum) acts as an electron transport layer (ETL) and TAZ (3,5-bis(tert-butylphenyl)-4phenyltriazole) acts as a hole-blocking layer. In both devices, the luminescence from DPAPPV was observed with a lower generation and a smaller amount of the DPA unit (3a), as explained by its physical properties. For the type II device with 3a, the emission from DPAPPV, the lower driving voltage and enhanced efficiency were followed by simply complexing with a very small amount of SnCl2. On the other hand, for 3b, the emission from Alq, not from DPA-PPV, was enhanced by the complexation, and 3b-SnCl2 mainly acts as a hole transport layer with the enhanced hole injection and recombination into the Alq layer, which could not be completely blocked because of the enhanced hole transport property of the DPA unit.