Synthesis and electroluminescence properties of fluorene-co-diketopyrrolopyrrole-co-phenothiazine polymers
Synthesis and electroluminescence properties of fluorene-co-diketopyrrolopyrrole-co-phenothiazine polymers
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DOI：
10.1016/j.polymer.2009.12.044
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发表时间：
2010-03
期刊：
影响因子：
4.6
通讯作者：
Zhi Qiao;Junbiao Peng;Yi Jin;Qilin Liu;Jie-Na Weng;Zhicai He;Shaohu Han;D. Cao
中科院分区：
文献类型：
--
作者：
Zhi Qiao;Junbiao Peng;Yi Jin;Qilin Liu;Jie-Na Weng;Zhicai He;Shaohu Han;D. Cao
以9，9-二己基芴-2，7-二（三亚甲基硼酸酯）、2，5-二辛基-3，6-二（4-溴苯基）吡咯并[3，4-c]吡咯-1，4-二酮和3，7-二溴-10-辛基吩噻嗪为原料，通过钯催化Suzuki偶联反应合成了一系列芴-co-二酮吡咯并吡咯（DPP）-co-吩噻嗪聚合物Flu-DPP-Phen。它们的化学结构和组成经1HNMR和元素分析确证。这些三元共聚物被发现是热稳定的，并容易溶于常见的有机溶剂。Flu-DPP-Phen三元共聚物的吸收和光致发光（PL）性质随DPP含量的增加呈现出规律性的变化。采用ITO/PEDOT/PVK/BaBa/Al和ITO/PEDOT/PVK/BaBa/Al两种器件结构对三种共聚物的电致发光性能进行了表征.由于激子对窄禁带DPP单元的限制，当DPP含量很低（0.2mol%）时，芴链段的发光被完全猝灭.所有的三元共聚物的EL光谱显示出唯一的长波长发射来自DPP单元，这意味着能量转移的聚合物是非常有效的。三元共聚物的EL颜色从橙子到红色，最大发射波长从582 nm逐渐红移到600 nm。结果表明，在ITO/PEDOT/PVK/ITO/Ba/Al的器件结构中，Flu-DPP-Phen（50：30：20）的电致发光性能最好，最大外量子效率（EQE）为0.25%，最大亮度为259 cd/m2，初步的电致发光结果表明，DPP单元能有效地提高电子亲和势，吩噻嗪单元能显著提高空穴注入能力，从而显著提高了EQE。
A series of fluorene-co-diketopyrrolopyrrole(DPP)-co-phenothiazine polymers, named as Flu-DPP-Phen, were synthesized by a palladium-catalyzed Suzuki coupling reaction with different feed ratios among 9,9-dihexylfluorene-2,7-bis(trimethylene boronate), 2,5-dioctyl-3,6-bis(4-bromophenyl)pyrrolo[3,4-c]pyrrole-1,4-dione, and 3,7-dibromo-10-octylphenothiazine. Their chemical structures and compositions were confirmed by1H NMR and elemental analysis. These terpolymers were found to be thermally stable and readily soluble in common organic solvents. Absorption and photoluminescence (PL) properties of Flu-DPP-Phen exhibit regular change with increasing of DPP contents in the terpolymers. Electroluminescence (EL) properties of all the terpolymers were characterized with the device configurations of ITO/PEDOT/terpolymer/Ba/Al and ITO/PEDOT/PVK/terpolymer/Ba/Al. Owing to exciton confinement on the narrow band gap DPP unit, the emission of fluorene segments is quenched completely with very low content of DPP (0.2mol%). The EL spectra of all the terpolymers show exclusive long-wavelength emission originating from DPP units, which implied that the energy transfer in the terpolymer is very efficient. EL colors of the terpolymers vary from orange to red, the maximum emission is gradually red-shifted from 582nm to 600nm. The best EL performance was achieved by Flu-DPP-Phen(50:30:20) with maximum external quantum efficiency (EQE) of 0.25% and maximum brightness of 259cd/m2in the device configuration of ITO/PEDOT/PVK/terpolymer/Ba/Al. The preliminary EL results proved that DPP units could effectively improve the electron affinity, and phenothiazine units could significantly enhance the hole injection ability, which resulted in the remarkable improvement of EQE.