Tetradentate Pt(Ⅱ)complex as a singlet exciton sensitizing host for highly efficient green fluorescent organic light-emitting diodes  

作　　者：Unhyeok Jo Seung Chan Kim Chan Hee Ryu Kang Mun Lee Jae-Min Kim Jun Yeob Lee 

机构地区：[1]School of Chemical Engineering,Sungkyunkwan University,2066,Seobu-ro,Jangan-gu,Suwon-si,Gyeonggi-do 16419,Republic of Korea [2]Department of Chemistry,Institute for Molecular Science and Fusion Technology,Kangwon National University,Chuncheon,Gangwon 24341,Republic of Korea [3]Department of Advanced Materials Engineering,Chung-Ang University,4726,Seodong-daero,Daedeok-myeon,Anseong-si,Gyeonggi-do 17546,Republic of Korea [4]SKKU Advanced Institute of Nano Technology,Sungkyunkwan University,2066,Seobu-ro,Jangan-gu,Suwon,Gyeonggi 16419,Republic of Korea [5]SKKU Institute of Energy Science and Technology,Sungkyunkwan University,2066,Seobu-ro,Jangan-gu,Suwon,Gyeonggi 16419,Republic of Korea

出　　处：《Science China Materials》2024年第8期2618-2627,共10页中国科学（材料科学）（英文版）

基　　金：supported by Chung-Ang University Research Grants in 2023 and MOTIE(20018956)。

摘　　要：Efficient green fluorescent organic light-emitting diodes were designed with a phosphorescent metal complex as a singlet exciton sensitizing host(SESH)for achieving high efficiency and low efficiency roll-off through exciton and polaron management.Tetradentate Pt(Ⅱ)complex(Pt-Trz)possessing a tetradentate ligand with a bulky blocking group not only suppresses the severe formation of excimer or dimer itself but also transfers radiative excitons to fluorescent dopant effectively.The SESH assisted fluorescence(SESHF)device with Pt-Trz as the host exhibits the maximum external quantum efficiency of 13.3%and a lower efficiency roll-off compared with exciplex host device which is a general approach for harvesting triplet excitons.Numerical exciton dynamics modeling unravels that the SESHF device effectively utilizes triplet excitons in the host by intersystem crossing and resonance energy transfer from the triplet state of the host to the singlet state of the terminal emitter.Bimolecular quenching rates of the SESHF device are reduced by 11 times for triplet-triplet annihilation and 1.8 times for tripletpolaron annihilation compared with the exciplex device,which demonstrates that Pt-Trz could be a platform to be used as an efficient host for fluorophores.

关 键 词：SINGLET ANNIHILATION POLARON 

分 类 号：TN312.8[电子电信—物理电子学] O641.4[理学—物理化学]