Key Laboratory of Functional Inorganic Material Chemistry, Chinese Ministry of Education & School of Chemistry and Material Science, Heilongjiang University, 74 Xuefu Road, Harbin, 150080, P. R. China.
Adv Mater. 2020 Mar;32(10):e1906950. doi: 10.1002/adma.201906950. Epub 2020 Jan 28.
Despite their merits of environmental friendliness, low cost, and large-scale production, thermally activated delayed fluorescence (TADF) based white organic light-emitting diodes (WOLEDs) for daily lighting applications still face the formidable challenges of structural simplification and controllable exciton allocation. Here, the state-of-the-art full-TADF WOLEDs with features of the single-doped single emissive layers (EMLs) and ultrasimple trilayer structure are demonstrated. The EMLs are binary systems as yellow TADF emitter (4CzTPNBu) doped blue TADF matrix (ptBCzPO TPTZ) with the large steric hindrance and mismatched frontier molecular orbital energy levels to effectively restrain excessive blue-to-yellow triplet exciton transfer and host-dopant interaction induced triplet quenching. Simultaneously, Förster resonance energy transfer is utilized to optimize exciton allocation for the balance of blue and yellow emissions, giving rise to the photoluminescence quantum yield beyond 90%. Consequently, these single-doped EMLs endow their cool white, pure white, and warm white diodes with the high-quality and ultrastable white light and the 100% exciton utilization efficiencies through the extremely simple structures, making them competent for the diverse daily lighting applications.
尽管热致延迟荧光（TADF）基白色有机发光二极管（WOLED）具有环保、低成本和大规模生产的优点，但在日常照明应用中，仍然面临着结构简化和可控制激子分配的巨大挑战。在这里，展示了具有单掺杂单发射层（EML）和超简单三层结构特点的最先进的全 TADF WOLED。EML 是二元体系，其中黄色 TADF 发射器（4CzTPNBu）掺杂蓝色 TADF 基质（ptBCzPO TPTZ），具有较大的空间位阻和不匹配的前沿分子轨道能级，可有效抑制过多的蓝到黄三重态激子转移和主体-掺杂剂相互作用引起的三重态猝灭。同时，利用Förster 共振能量转移来优化激子分配，以平衡蓝、黄发射，使光致发光量子效率超过 90%。因此，这些单掺杂的 EML 通过极其简单的结构赋予其冷白、纯白和暖白光二极管高质量和超稳定的白光以及 100%的激子利用效率，使其能够胜任各种日常照明应用。
