Enhanced performance of OLED based on molecular orientation of emission layer by optimized substrate temperature

Dongyue Cui, Shuai Wang, Shuhong Li, Yunlong Liu, Hui Du, Qianqian Du, Ling Zhao, Wenjun Wang, Xiaochen Dong

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Horizontally oriented transition dipole moment (TDM) of the molecule in emission layers (EMLs) can boost out-coupling efficiency, resulting in higher performance organic light-emitting diodes (OLEDs). As known, the substrate temperature (Ts) has a significant effect on the TDM of molecules. In this paper, the doped EMLs deposited with different Ts ranging from 30 to 100 °C were prepared and the corresponding photoluminescence quantum yield (PLQY) and TDM were measured. In addition, these EMLs with different Ts were employed to the OLED devices. The best luminous efficiency (51.4 cd/A), power efficiency (68.9 lm/W) and external quantum efficiency (EQE) (19.5%) were obtained in the OLED device where EMLs were deposited at 60 °C. However, the anisotropy factor Θ at this temperature is not the best, which is inconsistent with the common rules that high Θ causes high EQE. This phenomenon was ascribed to the in-situ annealing process for the hole transport layer (HTL) during the deposition of EMLs with different Ts. The synergy of PLQY and TDM orientation of EMLs, the hole mobility of hole only devices (HODs) contribute to the high performance of OLED device at 60 °C.

Original languageEnglish
Pages (from-to)12075-12083
Number of pages9
JournalJournal of Materials Science: Materials in Electronics
Volume32
Issue number9
DOIs
StatePublished - May 2021

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