Wang Zhiheng, Li Mengke, Gan Lin, Cai Xinyi, Li Binbin, Chen Dongcheng, Su Shi-Jian
State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices South China University of Technology Guangzhou 510640 P. R. China.
Adv Sci (Weinh). 2019 Feb 13;6(7):1802246. doi: 10.1002/advs.201802246. eCollection 2019 Apr 3.
Organic light-emitting diodes (OLEDs) employing exciplex cohosts have gained attractive interest due to the promising high efficiency, low driving voltage, and potential low cost in future solid-state lighting sources and full-color displays. However, their device lifetime is still the most challenging weakness and rarely studied, which is regarded as a time consuming and complicated work. Therefore, a simplified but effective and comprehensive approach is demonstrated to give prediction for the exciplex cohosts operating lifespan and analyze their possible degradation mechanisms by considering molecular dissociated activation energy with internal exciton dynamics correlations. As a consequence, strong chemical bond stability for the hole transport moieties and rapid reactive exciton relaxation have the intrinsic talent to access potentially long-lived exciplex cohosts, achieving an extended lifetime of 10169 h for the predicted long-lived exciplex cohost OLEDs. Degradation behaviors further confirm that the deteriorated source is attributed to the formation of exciton quenchers and hole traps from excited states and charged-excited states, respectively. The current findings establish a universal technique to screen the stable exciplex cohost candidates with economic time consumption and expenses.
采用激基复合物共主体的有机发光二极管（OLED）由于在未来固态照明光源和全彩显示器方面具有高效、低驱动电压和潜在低成本的优势，已引起广泛关注。然而，它们的器件寿命仍然是最具挑战性的弱点，且很少被研究，这被认为是一项耗时且复杂的工作。因此，本文展示了一种简化但有效且全面的方法，通过考虑分子解离活化能与内部激子动力学的相关性，对激基复合物共主体的使用寿命进行预测，并分析其可能的降解机制。结果表明，空穴传输部分具有强化学键稳定性和快速的反应性激子弛豫，这使其具有实现长寿命激基复合物共主体的内在潜力，预测的长寿命激基复合物共主体OLED的寿命可延长至10169小时。降解行为进一步证实，降解源分别归因于激发态和电荷激发态形成的激子猝灭剂和空穴陷阱。当前的研究结果建立了一种通用技术，能够以经济的时间消耗和成本筛选出稳定的激基复合物共主体候选材料。
