文献类型：期刊文献

英文题名：Stabilized Huang-Rhys factor in non-doped exciplex-based Firpic phosphorescent organic light emitting diodes via quantum well-like multiple emissive layer structure and investigation of carrier behaviors by transient electroluminescence

作者：Hu, Bang[1];Lu, Zhaoyue[1];Tang, Zongkai[1];Wu, Ye[1];Ji, Wenyi[1];Wang, Junling[2]

机构：[1]East China Univ Sci & Technol, Sch Phys, Shanghai 200237, Peoples R China;[2]Army Acad Armored Forces, Basic Dept, Beijing 100072, Peoples R China

年份：2023

卷号：123

外文期刊名：ORGANIC ELECTRONICS

收录：;EI(收录号：20230277093);WOS:【SCI-EXPANDED(收录号:WOS:001088262400001)】；

基金：Acknowledgements This work was supported by the Undergraduate Training Program on Innovation and Entrepreneurship (Grant No. 202210251085) .

语种：英文

外文关键词：Exciplex; Transient electroluminescence; Triplet-triplet annihilation; The Huang-Rhys factor; Quantum well

摘要：Non-doped exciplex-based blue phosphorescent organic light emitting diodes (PhOLEDs) are investigated, where exciplex is formed by the planar heterojunction of mCP/PO-T2T and ultrathin Firpic emissive layer is sandwiched between mCP and PO-T2T layers. And the devices with multiple Firpic interlayers are designed to obtain further insights about the information of carrier behavior, where different emission regions are separated by alternating PO-T2T and mCP spacer layers and quantum well-like (QW) structure is formed. The transient electroluminescent (EL) measurements are employed to elucidate the carrier recombination and EL mechanism. The transient EL decay demonstrates that the EL process is dominated by the energy transfer from exciplex (host) to Firpic (guest). The triplet-triplet annihilation (TTA) for exciplex excitons is less likely to produce due to their loosely binding. The trapped carrier recombination signal is only detected in the transient EL measurement of QW-based devices. In addition, the dependence of intensity ratio of the shoulder to the peak (i.e., the Huang-Rhys factor, S) on the Firpic layer thickness and applied voltages is discussed. The results show that S is roughly increased with the applied voltages and Firpic thickness due to stronger intermolecular interactions. The Huang-Rhys factor of Firpic phosphor is stabilized by quantum well-like multiple layer structure. Besides, QW-based devices are beneficial in high-luminance application scenarios due to lower efficiency roll-off induced by broader recombination zone and more homogenous distribution of excitons.