New 9-fluorene-type trispirocyclic compounds for thermally stable hole transport materials in OLEDs
New 9-fluorene-type trispirocyclic compounds for thermally stable hole transport materials in OLEDs
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DOI：
10.1039/b502268a
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发表时间：
2005-01-01
影响因子：
--
通讯作者：
Takagi, K
中科院分区：
文献类型：
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作者：
Kimura, M;Kuwano, S;Takagi, K
通过与2-溴联苯的偶联，制备了一种新型三环烃，在truxene(5)的核心周围有三个9-芴基团；5是高熔点（约500摄氏度）固体。为了将5应用于OLED中的有效空穴输运材料（HTM），设计了一种三苯胺衍生物，在每个9-芴基团(6)的2位和7位上携带6个二苯胺基团，以获得高热稳定性，作为TPD型HTM的改进材料。用4,4′-双（二苯基氨基）-2-溴联苯(9)很容易合成6。发现三环6的玻璃化转变温度高达170℃，在溶液中电氧化时影响其稳定阳离子自由基的形成，在固体中影响其非晶薄膜的形成。采用Alq(3)作为电子输运发射极的多层电致发光器件显示出良好的电致发光特性，在14 V下的最大亮度为37 000 cd m（-2）。因此，六基斯（二苯胺）取代三环6 （TX-F6S）可以作为一种高效、热稳定的热媒材料应用于oled中。
A novel trispirocyclic hydrocarbon having three 9-fluorene moieties around the core of truxene ( 5) was prepared readily via coupling of truxenone with 2-bromobiphenyl; 5 was a high melting (> 500 degrees C) solid. For the application of 5 to an effective hole transport material (HTM) in the OLED, a triphenylamine derivative carrying six diphenylamino groups at the 2- and 7-positions of each 9-fluorene moiety ( 6) was designed in order to get high thermal stability as an improved material of the TPD type HTM. The synthesis of 6 was easily achieved using 4,4'-bis(diphenylamino)-2-bromobiphenyl (9). The trispirocyclic 6 was found to show a glass transition temperature as high as 170 degrees C. It effects the formation of its stable cation radical upon electrooxidation in solution, and amorphous thin films in solid. A multi-layered EL device for 6 as an HTM using Alq(3) as an electron transporting emitter showed good EL characteristics such as the maximum luminance of 37 000 cd m(-2) at 14 V. Thus, the hexakis( diphenylamino) substituted trispirocycle 6 (TX-F6S) can be used as an efficient and thermally stable HTM in OLEDs.