Emission thermal quenching is commonly observed in quasi-2D perovskite emitters,which causes the severe drop in luminescence efficiency for the quasi-2D perovskite light-emitting diodes(PeLEDs)during practical operations.Hlowever,this issue is often neglected and rarely studied,and the root cause of the thermal quenching has not been completely revealed now.Here,we develop a passivation strategy via the 2,7-dibromo-9,9-bis(3'-diethoxylphosphorylpropyl)-fluorene to investigate and suppress the thermal quenching.The agent can effectively passivate coordination-unsaturated Pb2+defects of both surface and bulk of the film without affecting the perovskite crystallization,which helps to more truly demonstrate the important role of defects in thermal quenching.And our results reveal the root cause that the quenching will be strengthened by the defect-promoted exciton-phonon coupling.Ultimately,the PeLEDs with defect passivation achieve an improved external quantum efficiency(EQE)over 22％and doubled operation lifetime at room temperature,and can maintain about 85％of the initial EQE at 85℃,much higher than 17％of the control device.These findings provide an important basis for fabricating practical PeLEDs for lighting and displays.

Dezhong Zhang;Yunxing Fu;Hongmei Zhan;Chenyang Zhao;Xiang Gao;Chuanjiang Qin;Lixiang Wang

State Key Laboratory of Polymer Physics and Chemistry,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022,China;School of Applied Chemistry and Engineering,University of Science and Technology of China,Hefei 230026,China

光：科学与应用（英文版）

[1]Dezhong Zhang;Yunxing Fu;Hongmei Zhan;Chenyang Zhao;Xiang Gao;Chuanjiang Qin;Lixiang Wang-.Suppressing thermal quenching via defect passivation for efficient quasi-2D perovskite light-emitting diodes)[J].光：科学与应用（英文版）,2022(04):644-653

Hlowever,diethoxylphosphorylpropyl,Pb2+defects

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