【摘要】 有机发光二极管的应用已经步入我们的生活领域，但是高效率的蓝色发光材料仍然是限制其效率进一步提高的瓶颈。基于“交叉长短轴”结构模型，以菲并咪唑作为蓝光的构筑基元，设计合成了两个纯蓝光/天蓝光分子NPD和NCNPD。实验和理论计算结果表明：NCNPD分子由于N1位点引入了较强吸电子能力的氰基而表现出了更强的CT态特征，在溶液和薄膜中表现出了比NPD更红的发射和更低的荧光量子产率（PLQY），在此基础上NPD及NCNPD在非掺杂/掺杂器件的最大外量子效率（EQE）分别为1.84%/6.90%和0.76%/6.38%，充分说明在菲并咪唑长轴骨架上引入强CT态组分，以及再配合短轴修饰氰基来增强分子CT态特征，会对分子的光电性能造成不利的影响，凸显出合理调控蓝光材料激发态中的LE/CT态组分的分布和强度的必要性；基于NPD分子开发了一系列高性能的荧磷混合白光OLED，通过调控蓝光层/黄光层的厚度，暖白光及正白光器件的最大EQE达到了23.45%和15.24%；通过调控间隔层的厚度，制备了低滚降、光色稳定的正白光OLED，最高EQE为11.54%，显色指数（CRI）达到了了50。更多还原

【Abstract】 The application of organic light-emitting diodes(OLEDs) has been widely used in our life,but the high efficiency blue light-emitting materials are still the bottleneck restricting their further improvement. Based on the “crossed long-short axis” structure model,we designed and synthesized two pure-blue/sky-blue luminescent molecules,NPD and NCNPD,using phenanthroimidazole(PI) as the building block. Based on the experimental results and theoretical calculation,it is found that the NCNPD exhibits a stronger CT property due to the introduction of an electron-withdrawing cyano group at the N1 position of PI. As a result,NCNPD shows red shifted emission peaks and lower photoluminescence quantum yields(PLQYs) than NPD in solution and neat film. What’s more,the maximum external quantum efficiencies(EQEs) of NPD and NCNPD in nondoped/doped OLEDs are 1. 84%/6. 90% and 0. 76%/6. 38%,respectively,indicating that introducing strong CT components to the long-axis backbone of PI,combined with the modification of the short-axis skeleton to increase the CT intensity,will negatively affect the optoelectronic performances of molecules,and it is critical to modulate the distribution of the LE/CT component in the excited states of blue-emitting molecules in a reasonable manner. Finally,a series of highperformance hybrid white OLEDs were developed using NPD as a blue emitter. By regulating the thickness of blue-and yellow-emitting layers,the maximum EQEs of the warm-white and pure-white OLEDs reached 23. 45% and 15. 24%,respectively. On this basis,by adjusting the thickness of the interlayer,a pure-white OLED with low-efficiency roll-off and stable spectra was fabricated,achieving a maximum EQE of 11. 54% with a color rendering index(CRI) exceeding 50.更多还原