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为研究红荧烯(5,6,11,12-Tetraphenylnaphthacene,Rubrene)掺杂体系中激子的反应过程,向主体材料Rubrene中掺入了1%的客体材料DBP(Tetraphenyldibenzoperiflanthene),制备了掺杂型Rubrene的有机发光器件.实验发现,其电致发光磁效应(Magneto-Electroluminescence,MEL)在室温下呈现出复杂的新特征线型:在外加磁场处于0–27mT范围内MEL随磁场的增加先小幅度上升,在27–200mT随磁场的增加迅速下降,最后200–500mT范围内再次上升.通过分析可知器件内存在3种激子反应过程:单重态-三重态激子淬灭(Singlet-Triplet Annihilation,STA)、三重态激子湮灭(Triplet-Triplet Annihilation,TTA)和单重态激子分裂(Singlet Fission,STT).可通过改变注入电流的大小调节三者的竞争:大注入电流时,器件主要是STA反应和TTA反应;注入电流逐渐减小的过程中,激子反应从以TTA为主逐渐过渡到以STT为主.同时也可通过改变掺杂层的厚度和掺杂层在器件结构中的位置,对这几种反应之间的竞争过程产生重要影响:掺杂层厚度越薄,STT越强,而STA和TTA越弱;掺杂位置越靠近阴极,STA和TTA越强,而STT越弱.这些实验发现不仅可加深对有机发光二级管中激子间相互作用的理解,也为进一步优化器件发光性能提供参考.
In order to study the reaction process of excitons in the doping system of 5,6,11,12-Tetraphenylnaphthacene (Rubrene), 1% of the guest material DBP (Tetraphenyldibenzoperiflanthene) was doped into Rubrene as the host material, Type Rubrene, we found that the new characteristic of the electroluminescent Magneto-Electroluminescence (MEL) at room temperature is complex and new characteristic linearity: MEL increases with the increase of magnetic field in the range of 0-27mT The amplitude increases slightly with the increase of magnetic field at 27-200mT and increases again in the range of 200-500mT. The analysis shows that there are three kinds of exciton reaction processes in the device: singlet-triplet exciton quenching (Singlet- Triplet Annihilation (STA), Triplet-Triplet Annihilation (TTA) and Singlet Fission (STT). The competition between the three can be adjusted by changing the size of the injected current: , The device is mainly the STA reaction and the TTA reaction; In the process of decreasing the injection current, the transition from exciton reaction to TTA is mainly dominated, and the thickness and doping level of the doping layer Device The position in the structure of the piece has an important influence on the competition between these kinds of reactions: the thinner the doping layer, the stronger the STT and the weaker the STA and TTA; the closer the doping position is to the cathode, the stronger the STA and TTA are , While the weaker STT.These experiments not only deepen the understanding of the interaction between excitons in OLED but also provide reference for further optimizing the device’s luminescent properties.