Efficient emitting molecules in organic light-emitting diodes on the basis of the control of vibronic couplings

23rd International Symposium on the Jahn-Teller Effect

Sato, Tohru^1,2

Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto

615-8510, Japan^1

Unit of Elements Strategy Initiative for Catalysts and Batteries, Kyoto University, Nishikyo-ku, Kyoto

615-8510, Japan^2

关键词: 1 ,3-benzothiadiazole;    Exciton generation;    External quantum efficiency;    Inter-system crossings;    Non-radiative transitions;    Time dependent density functional theory;    Vibronic coupling;    Vibronic coupling constants;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/833/1/012020/pdf
DOI  :  10.1088/1742-6596/833/1/012020

来源: IOP

【 摘 要 】

A high external quantum efficiency observed in organic light-emitting diodes using PTZ-BZP (PTZ: 10-hexyl-phenothiazin, and BZP: 4-phenyl-2,1,3-benzothiadiazole) as an emitting molecule is studied based on the vibronic coupling density analyses employing the time-dependent density functional theory. The high efficiency can be attributed to a high efficiency of exciton generation which originates from reverse intersystem crossings from the higher T3and T2states than T1to the emitting S1state. The nonradiative transitions from T3and T2to the lower triplet states are suppressed because of small offdiagonal vibronic coupling constants. The small vibronic couplings originate from the multi-configurationality of these triplet states. A molecular design principle for efficient emitting molecules is discussed from the view of the control of vibronic couplings.