Efficient deep-blue emitters comprised of an anthracene core and terminal bifunctional groups for nondoped electroluminescence
作者:Minrong Zhu、Qiang Wang、Yu Gu、Xiaosong Cao、Cheng Zhong、Dongge Ma、Jingui Qin、Chuluo Yang
DOI:10.1039/c1jm10465a
日期:——
Four blue fluorescent host emitters with bifunctional charge transport groups appended to the 9- and 10-positions of the anthracene core have been designed and synthesized. By introducing peripheral bulky aryl-substitution groups to the emissive core, the four compounds show a decreased tendency to crystallise and have high glass transition temperatures ranging from 154 to 226 °C. The theoretical calculations reveal that the four self-hosted blue emitters possess noncoplanar structures to suppress intermolecular interaction within the films. The amorphous compounds exhibit strong deep-blue emission both in solution and the solid state. With different end-capping groups, the photophysical and electrochemical properties are tuned to produce efficient deep-blue performance with a simple device architecture. Organic light-emitting diodes (OLEDs) featuring 4 as the emitter achieve a maximum power efficiency of 2.0 lm W−1 with Commission Internationale de l'Eclairage (CIE) coordinates of (0.16, 0.10) that are very close to the National Television Standards Committee's blue standard. The well-matched energy level between the anode and 4 as well as the intrinsic good charge transport abilities results in a very low driving voltage (2.7 V), making the nondoped deep-blue electroluminescent device power efficient.
设计并合成了四种蓝色荧光宿主发射体,其中双功能电荷传输基团附加在蒽核的9位和10位。通过在发光中心引入体积较大的芳基取代基,这四种化合物显示出较低的结晶倾向,并且玻璃转变温度高,范围在154到226°C之间。理论计算显示,这四种自我宿主的蓝色发射体具有非共平面的结构,以抑制薄膜内的分子间相互作用。这些无定形化合物在溶液和固态下均表现出强烈的深蓝色发光。通过不同的端基修饰,光物理和电化学特性得以调节,从而在简单的器件架构中实现高效的深蓝色性能。以4作为发射体的有机发光二极管(OLED)实现了最高功率效率为2.0 lm W−1,国际照明委员会(CIE)坐标为(0.16, 0.10),与国家电视标准委员会的蓝色标准非常接近。阳极与4之间良好的能级匹配以及固有的良好电荷传输能力导致了非常低的驱动电压(2.7 V),使得该无掺杂深蓝色电致发光器件具有较高的能效。