Benzene substituted with bipyridine and terpyridine as electron-transporting materials for organic light-emitting devices
作者:Musubu Ichikawa、Takayuki Yamamoto、Hyeon-Gu Jeon、Kouki Kase、Shuichi Hayashi、Makoto Nagaoka、Norimasa Yokoyama
DOI:10.1039/c2jm16274a
日期:——
New electron-transporting materials for organic light-emitting devices (OLEDs) based on trisubstituted benzene with both bipyridine and terpyridine, 1,3-bisbipyridyl-5-terpyridylbenzene (BBTB) and 1-bipyridyl-3,5-bisterpyridylbenzene (BTBB), were developed. Glass transition temperatures of BBTB and BTBB were 93 °C and 108 °C, respectively, and BTBB was completely amorphous with no melting point. Electron mobilities of BTBB exceeded the order of 10−4 cm2 V−1 s−1, while those of BBTB were very high and reached 10−3 cm2 V−1 s−1 at an electric field of approximately 500 kV cm−2. These high mobilities contributed to a low voltage operation. For example, in the case of the conventional aluminum trisquinolinol (Alq)-based fluorescent OLED with BTBB, current densities of 3.5 mA cm−2 and 100 mA cm−2 were reached at voltages of 3.0 V and 4.5 V, respectively. In addition, ionization potentials of BBTB (6.33 eV) and BTBB (6.50 eV) were sufficiently large to confine holes in common emissive layers.
基于同时具有联吡啶和特吡啶的三取代苯(1,3-双吡啶基-5-特吡啶基苯(BBTB)和 1-双吡啶基-3,5-isterpyridylbenzene(BTBB)),开发了用于有机发光器件(OLED)的新型电子传输材料。BBTB 和 BTBB 的玻璃转化温度分别为 93 ℃ 和 108 ℃,而 BTBB 则完全无定形,没有熔点。BTBB 的电子迁移率超过 10-4 cm2 V-1 s-1 的数量级,而 BBTB 的电子迁移率非常高,在约 500 kV cm-2 的电场下达到 10-3 cm2 V-1 s-1。这些高迁移率有助于低电压运行。例如,在使用 BTBB 的传统铝基三喹啉醇(Alq)荧光 OLED 中,电压为 3.0 V 和 4.5 V 时的电流密度分别为 3.5 mA cm-2 和 100 mA cm-2。此外,BBTB(6.33 eV)和 BTBB(6.50 eV)的电离电位足以将空穴限制在共同的发射层中。