Opt Lett. 2022 Nov 15;47(22):5873-5876. doi: 10.1364/OL.476088.
An exciplex with significant thermally activated delayed fluorescence properties was realized, comprising diphenyl-[3'-(1-phenyl-1H-phenanthro[9,10-d]imidazol-2-yl)-biphenyl-4-yl]-amine as a donor and 2,4,6-tris[3-(diphenylphosphinyl)phenyl]-1,3,5-triazine as an acceptor. A very small energy difference between the singlet and triplet levels and a large rate constant of the reverse intersystem crossing were attained simultaneously, contributing to the efficient upconversion of triplet excitons from the triplet state to the singlet state and thermally activated delayed fluorescence emission. A high-efficiency organic light-emitting device based on the exciplex was fabricated, which exhibited a maximum current efficiency, power efficiency, external quantum efficiency, and exciton utilization efficiency of 23.1 cd/A, 24.2 lm/W, 7.32%, and 54%, respectively. The efficiency roll-off of the exciplex-based device was slight, as illustrated by a large critical current density of 34.1 mA/cm. This efficiency roll-off was ascribed to triplet-triplet annihilation, as confirmed by the triplet-triplet annihilation model. We proved the high binding energy of the excitons and excellent charge confinement within the exciplex by performing transient electroluminescence measurements.
实现了一种具有显著热激活延迟荧光性质的激基复合物，由二苯基-[3'-(1-苯基-1H-菲并[9,10-d]咪唑-2-基)-联苯-4-基]-胺作为供体和 2,4,6-三[3-(二苯基膦基)苯基]-1,3,5-三嗪作为受体组成。单重态和三重态能级之间的能量差非常小，反向系间窜越的速率常数非常大，这有助于将三重态激子从三重态高效上转换到单重态，并产生热激活延迟荧光发射。基于该激基复合物制备了一种高效有机发光器件，其最大电流效率、功率效率、外量子效率和激子利用效率分别为 23.1 cd/A、24.2 lm/W、7.32%和 54%。该激基复合物器件的效率滚降很小，临界电流密度为 34.1 mA/cm，表明了这一点。这种效率滚降归因于三重态-三重态湮灭，这通过三重态-三重态湮灭模型得到了证实。我们通过瞬态电致发光测量证明了激子的高结合能和激基复合物内的优异电荷限制。
