the highest current and power efficiency of 47.8 cd A−1 and 29.6 lm W−1, respectively. Even at luminance as high as 1000 cd m−2, their efficient roll-off was only 4.2%, which was far better than the 6Cz–PBI host device. Because the T1 energy levels and triplet state locations of these hosts are similar, their ΔEST and charge balance property should be the main factors that influence their EL performances
设计并合成了一系列基于
咔唑和苯基
苯并咪唑(PBI)部分的双极宿主,统称为x Cz– n PBI。根据官能团的数量,比例和连接构型,详细研究了取代基对主体
材料化学,光物理和电
化学性能的影响。DFT计算和单载流子装置均表明,在分子中引入更多吸电子PBI基团的策略可以有效地增强双极主体的电子注入和传输能力,而
咔唑单元数目的增加使主体具有更小的体积。 Δ Ë ST以牺牲其电荷平衡特性为代价的有效空穴注入。结果,基于Cz-6PBI的溶液处理的绿色发光PHOLED的导通电压极低,为2.9 V,最高电流和功率效率分别为47.8 cd A -1和29.6 lm W -1。即使在高达1000 cd m -2的亮度下,其有效滚降仅为4.2%,远优于6Cz-PBI主机设备。由于这些主机的T 1能级和三重态位置相似,因此它们的ΔE ST和电荷平衡性质应是影响其EL性能的主要因素。我们得出结论,没有必要实现非常小的