A novel family of non-symmetrical star-shaped cyanopyridine based discotic liquid crystals (CPBz6, CPBz8 and CPBz12) was designed and synthesized, as potential luminescent materials for optoelectronic applications. The length of one of the arms in the design was systematically varied to determine the structure–property relationships. Evidently, all of the compounds exhibited a highly prospective ordered columnar mesomorphism stabilized at ambient temperature with advantageous very low isotropization temperatures. Furthermore, their photophysical characteristics were investigated in depth, both in solution and in the liquid crystal (LC) state. The discotics were found to be intense blue emitters with reasonably good quantum efficiency. Their dynamic intramolecular charge-transfer (ICT) behaviour was confirmed by steady-state absorption and fluorescence spectral analysis in varied solvent polarity. Furthermore, their electrochemical properties were studied from the combination of an experimental method and the theoretical simulations, which elucidated the low laying frontier molecular orbitals (FMOs) with a narrow energy band gap of ∼2.0 eV. The resulted visually perceivable emission with favourable energy levels showcases their possible application in electronic display devices.

中文翻译：

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基于氰基吡啶新型非对称星形盘状液晶的光电探†

一种新型的基于不对称星形氰基吡啶的盘状液晶（CPBz6，CPBz8和CPBz12被设计和合成，作为光电应用的潜在发光材料。系统地改变了设计中的一根臂的长度，以确定结构与属性之间的关系。显然，所有化合物均表现出在环境温度下稳定且具有非常低的各向同性温度的高度预期的有序柱状同晶型。此外，在溶液和液晶（LC）状态下，都对它们的光物理特性进行了深入研究。发现圆盘片是强烈的蓝色发射体，具有相当好的量子效率。通过在不同溶剂极性下的稳态吸收和荧光光谱分析，证实了它们的动态分子内电荷转移（ICT）行为。此外，通过实验方法和理论模拟相结合的方法研究了它们的电化学性质，阐明了具有约2.0 eV的窄能带隙的低铺设前沿分子轨道（FMO）。产生的具有良好能量水平的视觉可感知发射展示了它们在电子显示设备中的可能应用。