Development of High-performance Organic Electroluminescent Devices Using Amorphous Molecular Materials

有机电致发光器件因其在全彩色平板显示器上的潜在应用而备受关注。为了实现高亮度和多色发光，人们对层状有机发光器件进行了广泛的研究。然而，提高器件的发光效率和耐用性仍有待解决。我们一直在研究光活性和电活性非晶态分子材料的合成、性质和应用，这些材料在室温以上极易形成非晶态玻璃。非晶态分子材料可形成稳定的非晶态薄膜，并具有较高的空穴漂移迁移率，有望成为有机电致发光器件的空穴传输材料。在本研究中，(1)我们设计并合成了新型pi-电子星爆分子，并研究了分子结构与玻璃形成难易性、玻璃稳定性和玻璃转变温度之间的关系；(2)我们研究了分子玻璃的空穴传输特性；(3)我们用非晶分子材料作为空穴传输层制备了层状有机EL器件，并发现该器件具有显著的耐用性。此外，由双孔传输层组成的EL器件具有较高的发光效率。这些结果为利用非晶态分子材料开发具有高稳定性和高发光效率的有机发光器件提供了新的策略。

Organic electroluminescent (EL) devices have received attention because of potential application to full color flat panel displays. There have been extensive studies on layred organic EL devices with the aim of achieving high brightness and multicolor emission. However, improvement in the luminance efficiency and durability of devices remains to be solved.We have been studying the synthesis, properties and applications of photo- and electro-active amorphous molecular materials which form readily amorphous glasses above room temperature. It is expected that the amorphous molecular materials function as hole transport materials of organic EL devices since they form stable amorphous film and exhibit relatively high hole drift mobility.In the present study, (1) we have designed and synthesized novel pi-electron starburst molecules and investigated the relationship between molecular structure and the ease of glass formation, glass stability, and glass-transition temperature, (2) we have investigated the hole transport properties of molecular glasses, and (3) we have fabricated layred organic EL devices using amorphous molecular materials as hole transport layr and found that the device exhibit significant durability. In addition, EL devices consisting of double hole transport layrs exhibits a high luminance efficiency. These results provide the novel strategy for developing organic EL devices with high stability and high luminance efficiency using amorphous molecular materials.