Modeling Electron-Transfer Degradation of Organic Light-Emitting Devices

Yu Kyung Moon, Ho Jin Jang, Sanju Hwang, Seongsoo Kang, Sinheui Kim, Juwon Oh, Sangheon Lee, Dongho Kim, Jun Yeob Lee, Youngmin You

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

The operational lifetime of organic light-emitting devices (OLEDs) is governed primarily by the intrinsic degradation of the materials. Therefore, a chemical model capable of predicting the operational stability is highly important. Here, a degradation model for OLEDs that exhibit thermally activated delayed fluorescence (TADF) is constructed and validated. The degradation model involves Langevin recombination of charge carriers on hosts, followed by the generation of a polaron pair through reductive electron transfer from a dopant to a host exciton as the initiation steps. The polarons undergo spontaneous decomposition, which competes with ultrafast recovery of the intact materials through charge recombination. Electrical and spectroscopic investigations provide information about the kinetics of each step in the operation and degradation of the devices, thereby enabling the building of mass balances for the key species in the emitting layers. Numerical solutions enable predictions of temporal decreases of the dopant concentration in various TADF emitting layers. The simulation results are in good agreement with experimental operational stabilities. This research disentangles the chemical processes in intrinsic electron-transfer degradation, and provides a useful foundation for improving the longevity of OLEDs.

Original languageEnglish
Article number2003832
JournalAdvanced Materials
Volume33
Issue number12
DOIs
Publication statusPublished - 2021 Mar 25

Bibliographical note

Funding Information:
This work was supported by the Midcareer Research Program (NRF-2019R1A2C2003969), the Nano Materials Research Program (NRF-2016M3A7B4909243), the Science Research Center (SRC) Program (NRF-2020R1A5A1019141), and the Basic Research Laboratory Program (NRF-2019R1A4A1029052) through National Research Foundation grants funded by the Ministry of Science, Information, and Communication Technology (ICT) and Future Planning (MSIP).

Publisher Copyright:
© 2021 Wiley-VCH GmbH

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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