作者:Bin Chen、Gang Yu、Xin Li、Yubin Ding、Cheng Wang、Zhiwei Liu、Yongshu Xie
DOI:10.1039/c3tc31751j
日期:——
Starting from two simple units of anthracene and 2,2â²-dipyridylamine, a series of new luminescent compounds 1â8 were designed and synthesized by a combined strategy of changing the connection mode between the two units, extending the conjugation size, and introducing an additional electron donor. Photophysical properties of 1â8 were investigated and discussed on the basis of solvatochromic behaviour, theoretical calculations, crystal structure, and optimized structures. Interestingly, the emission wavelengths of these compounds could be successfully tuned from violet to red both in solutions and the solid-state, and prominent positive solvatochromism was observed for the compounds with a DâÏâA framework. Consider compound 7 as an example, it shows peaks at 526 nm and 627 nm in cyclohexane and DMSO, respectively. Meanwhile, the quantum yield was decreased from 0.80 in cyclohexane to 0.12 in DMSO. The introduction of bulky groups was demonstrated to be effective for suppressing the aggregation effect and thus improving the solid state emission quantum yield. These results indicate that the combined structure modulation strategy offers a powerful tool for tuning the emission behaviour. To demonstrate the possibility of practical applications, 2 was employed as the emitting material for the fabrication of deep-blue organic light-emitting diodes (OLEDs), which showed a maximum external quantum efficiency of 2.2%. The CIE coordinates of (0.15, 0.08) are indicative of excellent blue color purity.
从两个简单的单元——蒽和2,2'-二吡啶胺出发,设计并合成了一系列新的发光化合物1-8,通过改变两个单元之间的连接方式、扩展共轭尺寸以及引入额外的电子给体的综合策略。对1-8的光物理特性进行了研究,并根据溶液色变行为、理论计算、晶体结构和优化结构进行了讨论。有趣的是,这些化合物的发射波长在溶液和固态中都成功地从紫光调谐到红光,并且在具有D-π-A框架的化合物中观察到显著的正溶剂色变。以化合物7为例,它在环己烷和DMSO中分别显示出526 nm和627 nm的峰值。同时,量子产率在环己烷中从0.80降低到DMSO中的0.12。引入大体积基团被证明对抑制聚集效应有效,从而提高固态发射量子产率。这些结果表明,结合结构调制策略为调节发射行为提供了强大的工具。为了展示实际应用的可能性,化合物2被用作深蓝色有机发光二极管(OLED)制造的发光材料,显示出最大外量子效率为2.2%。其CIE坐标(0.15,0.08)表明良好的蓝色纯度。