Mechanisms of TADF/Phosphorescence-Sensitized Fluorescence in OLED Emissive Layers and Their Impacts on Device Performances : A Theoretical Insight

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

View graph of relations

Author(s)

  • Yue Xie
  • Jiaqi Li
  • Shulin Luo
  • Tao Zhang
  • Xiao-Hong Zhang

Related Research Unit(s)

Detail(s)

Original languageEnglish
Pages (from-to)19767-19776
Journal / PublicationThe Journal of Physical Chemistry C
Volume128
Issue number46
Online published11 Nov 2024
Publication statusPublished - 21 Nov 2024

Abstract

Organic light-emitting diodes (OLEDs) based on thermally activated delayed fluorescence or phosphorescence-sensitized fluorescence [TADF-sensitized fluorescence (TSF) or phosphorescence-sensitized fluorescence (PSF)] open the door for devices with high efficiency, better color purity, long lifetime, and low-efficiency roll-off. However, the photophysical processes and their impact on device performances in TSF and PSF systems are not clearly understood to date. In this work, the photophysical processes for the TSF and the PSF systems are in depth investigated by combining molecular dynamics simulation and quantum-chemistry calculations. In the studied TSF [PCTF/TBRb] system and the PSF [Ir(ppy)2acac/TBRb] system, the film morphologies, electronic properties, and kinetic processes are analyzed in detail. The calculated results indicate that the [PCTF/TBRb] system and the [Ir(ppy)2acac/TBRb] system exhibit obvious TSF and PSF features, respectively. The difference between the two sensitization systems is the utilization process of the T1 excitons of the sensitizers. The rates of reverse intersystem crossing (kRISCTADF) and the triplet-singlet Förster resonance energy transfer (kT-SFRETPh-G) are the decisive factors in the internal quantum efficiency (IQE) of the TSF and the PSF systems, respectively. Moreover, it can be found that the effect of kRISCTADF on the IQE in the TSF system is stronger than the effect of kT-SFRETPh-G on the IQE in the PSF system. We hope that these results will promote an in-depth understanding of the mechanisms of the TSF and the PSF systems and their impacts on device performances, accelerating the development of highly efficient sensitized OLEDs. © 2024 American Chemical Society.

Citation Format(s)

Mechanisms of TADF/Phosphorescence-Sensitized Fluorescence in OLED Emissive Layers and Their Impacts on Device Performances: A Theoretical Insight. / Xie, Yue; Li, Jiaqi; Mei, Le et al.
In: The Journal of Physical Chemistry C, Vol. 128, No. 46, 21.11.2024, p. 19767-19776.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review