Light-emitting electrochemical cells (LECs), which represent solid-state lighting (SSL) systems, are next generation displays to replace organic light-emitting diodes. LECs have a single active layer of organic luminescent material between two air-stable electrodes and have a unique operating mechanism. In this study, we synthesized two luminescent small molecules, PhIm and PyIm, using phenanthrene–imidazole derivatives for blue emission and demonstrated their thermal, photophysical, and electrochemical properties. In addition, we fabricated small molecule LECs (SM-LECs) to evaluate their electroluminescence performances. Both compounds showed high thermal stabilities, which means that these luminescent materials are suitable for LEC emission layers. PyIm is less influenced by the polarity of solvents than PhIm when comparing the maximum emission wavelengths of the two compounds dissolved in various solvents. The photoluminescence (PL) spectra of PhIm and PyIm showed a blue spectral region, where the maximum emission wavelengths were 461 and 454 nm in solution, respectively. The electroluminescence spectra of the two compounds, which were red-shifted with respect to the PL spectra, showed peaks at 467 and 459 nm, and their Commission Internationale de l’Eclairage coordinates were (0.24, 0.25) and (0.21, 0.22) for PhIm and PyIm, respectively. In addition, in terms of device performances, PhIm and PyIm showed maximum current efficiencies of 0.87 and 1.85 cd A⁻¹, maximum power efficiencies of 0.30 and 0.73 lm W⁻¹ and maximum external quantum efficiencies of 1.53 and 1.70%, respectively. Both compounds successfully emitted blue light and PyIm showed better performance than PhIm.

中文翻译：

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新型菲-咪唑基离子小分子在蓝色发光电化学电池中的应用

代表固态照明（SSL）系统的发光电化学电池（LEC）是替代有机发光二极管的下一代显示器。LEC在两个空气稳定电极之间具有有机发光材料的单个活性层，并具有独特的工作机制。在这项研究中，我们使用菲-咪唑衍生物进行了蓝色发射，合成了两个发光小分子PhIm和PyIm，并证明了它们的热，光物理和电化学特性。此外，我们制造了小分子LEC（SM-LEC），以评估其电致发光性能。两种化合物均显示出高的热稳定性，这意味着这些发光材料适用于LEC发射层。y当比较溶解在各种溶剂中的两种化合物的最大发射波长时，受溶剂极性的影响小于PhIm。PhIm和PyIm的光致发光（PL）光谱显示为蓝色光谱区域，溶液中的最大发射波长分别为461和454 nm。相对于PL光谱发生红移的这两种化合物的电致发光光谱在467和459 nm处显示峰值，其国际佣金坐标为（0.24，0.25）和（0.21，0.22）。PhIm和PyIm。此外，就设备性能而言，Phym和PyIm分别显示最大电流效率为0.87和1.85 cd A ^-1，最大功率效率为0.30和0.73 lm W ^-1，最大外部量子效率为1.53和1.70％。两种化合物均能成功发射蓝光，PyIm的性能优于PhIm。