液晶性噁二唑类载流子传输材料  

Carriers Transporting Materials Containing Oxadiazole Liquid Crystalline Groups

作　　者：杨国波[1] 孙晓波[1,2] 吴英[1] 田文晶[1] 李敏[3] 

机构地区：[1]吉林大学超分子结构与材料教育部重点实验室 [2]吉林大学材料学院,吉林长春130023 [3]吉林大学材料学院

出　　处：《发光学报》2004年第1期39-43,共5页Chinese Journal of Luminescence

基　　金：国家自然科学基金资助项目 ( 2 0 0 740 13 ;2 99740 13 )

摘　　要：将液晶基团引入到载流子传输材料中合成了新型液晶性二唑类衍生物E3 和E6,利用偏光显微镜、差热扫描和广角X射线衍射的方法对其液晶性进行了研究 ,结果表明 ,E3 为单向近晶型液晶 ,E6为双向近晶型液晶。同时 ,利用紫外 可见吸收光谱和电化学方法测定了材料的能级结构参数 ,其高的LUMO能级 ,低的HOMO能级 (相对真空能级 )及较大的带隙表明 ,它们不仅有利于电子从阴极的注入 ,还对空穴和激子具有一定的阻挡作用。由于材料在有序的近晶相比在无序的各向同性相将具有高的载流子迁移率 ,因此将液晶性与传输性相结合对提高材料载流子迁移率具有非常重要的意义。Over the last two decades, much attention has been paid to mesomophic compounds containing heterocyclic units. Most of these investigated mesogens are 1,4-disubstituted six-mengered aromatic, heteroaromatic or aliphatic rings as basic units, which unit have almost linearity as required according to the classical concept of calami(tic) mesogens. Mesomorphic compounds containing five membered heterocycles have been less investigated. Liquid crystalline 1,3,4-oxadiazoles were described only in recent years. In connection with the considerable theoretical and technological interest in banana shaped achiral molecules and electron transport materials used in light-emitting diodes(LED), substituted 1,3,4-oxadiazoles become more significant. Due to the electron deficient property and poor hole accepting character of 1,3,4-oxadiazole ring, certain low molecular weight aromatic 1,3,4-oxadiazole derivatives facilitate both electron injection and transport. Aromatic 1,3,4-oxadiazoles, such as 2-(4-tert-buty-phenel)-5-biphenyl-1,3,4-oxadizole(PBD), have been synthesized and widely used as electron-conducting/hole-blocking materials in multiplayer devices. According to H.Tokohisa et al's recent investigations of liquid crystalline 1,3,4-oxadiazole derivatives, the carrier mobility is higher in the more ordered smectic phase than that in the less ordered phase. In addition, the present increasing interest in liquid crystalline oxadiazoles is due to their photoconducting properties. Here two novel liquid crystals based on 2,5-diphenyl-1,3,4-oxadiazole as mesogenic group, namely 2-[(4-methoxy) phenyl]-5-{[4-(n-methoxy) phenoxy] propyloxy} phenyl-1,3,4-oxadiazole (E_3) and 2-[(4-methoxy) phenyl]-5-{[4-(n-methoxy) phenoxy] hexyloxy} phenyl-1,3,4-oxadiazole (E_6) have been synthesized. Their liquid crystalline behaviors were studied by differential scanning calorie-meter (DSC), polarizing microscopy (POM) as well as wide angle X-ray diffraction (WAXD). The results showed that both E_3 and E_6 exhibited semetic phases. UV-Vis spectra

关 键 词：液晶 噁二唑类衍生物 有机电致发光 紫外-可见吸收光谱 能级结构 偏光显微镜 差热扫描分析 

分 类 号：TN383.1[电子电信—物理电子学] O644[理学—物理化学]