In Situ Quantifying the Physical Parameters Determining the Efficiency of OLEDs Relying on Triplet–Triplet Annihilation Up‐Conversion
In Situ Quantifying the Physical Parameters Determining the Efficiency of OLEDs Relying on Triplet–Triplet Annihilation Up‐Conversion
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DOI：
10.1002/adom.202102333
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发表时间：
2022-01
影响因子：
9
通讯作者：
Shu-Ping Xiao;Xianfeng Qiao;Chengwei Lin;Liangjia Chen;Runda Guo;Ping Lu;Lei Wang;Dongge Ma
中科院分区：
文献类型：
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作者：
Shu-Ping Xiao;Xianfeng Qiao;Chengwei Lin;Liangjia Chen;Runda Guo;Ping Lu;Lei Wang;Dongge Ma
三重态-三重态湮没（TTA）上转换是在有机发光二极管（OLED）中利用三重态激子的有效方法。然而，表征OLED工作条件下三重态激子和相关TTA过程的参数尚未量化。在这里，建立了一种原位方法来映射这些参数，以进一步确定它们对器件效率的影响。物理参数，包括三线态复合率、TTA率、典型电流JTTA和饱和比，可以通过瞬态电致发光技术进行原位定量。 JTTA的表达表明，最小化三线态猝灭和最大化TTA速率是降低JTTA的有效方法。而高效设备需要较低的 JTTA。在这些标准的指导下，通过混合两种材料来削弱三线态淬火，从而提高装置效率。这些研究建立了一种原位方法来量化物理参数，从而可以识别有用的 TTA 材料并优化器件结构的设计。
Triplet–triplet annihilation (TTA) up‐conversion is an effective way to utilize triplet excitons in organic light‐emitting diodes (OLEDs). However, the parameters characterizing the triplet excitons and relevant TTA process in OLEDs under working conditions have not been quantified. Here, an in situ method is established to map these parameters for further ascertaining their impact on device efficiency. The physical parameters, including triplet recombination rate, TTA rate, typical current JTTA, and saturated ratio, can be in situ quantified by transient electroluminescence technique. The expression of JTTA shows that minimizing the triplet quenching and maximizing the TTA rate are effective ways to lower JTTA. While highly efficient devices require a lower JTTA. Guided by these criteria, the device efficiency is promoted by weakening the triplet quenching via blending two materials. These investigations establish an in situ method to quantify the physical parameters that allow identifying the useful TTA materials and optimizing the design of device structures.