First-Principles Investigation of Thermally Activated Delayed Fluorescence Processes

ORAL

Abstract

Thermally Activated Delayed Fluorescence (TADF) compounds are promising materials for the realization of next generation Organic Light Emitting Diodes [1]. Among several TADF systems recently proposed in the literature, NAI-DMAC[2][C37H32N2O2] represents one of the few available orange-red emitters, with a remarkable 30% external quantum efficiency. We present a detailed first principle study of the NAI-DMAC compound, and we consider both the single molecule (dilute limit) and the crystal (high-packing limit). We carried out First-Principles Molecular Dynamics simulations at finite temperature with the Qbox[3] code (http://qboxcode.org) and we analyzed the structural motifs that lead to the desired energy splitting between the singlet and triplet excited states. This splitting is the key driving force of the TADF process. We also computed diabatic coupling parameters associated to the charge mobility[4] and we discuss how charge transfer processes occur in NAI-DMAC.

[1] H. Uoyama, et al., Nature, 2012, 492, 234-238;
[2] W. Zeng, et al., Adv. Mat., 2018, 30(5), 1704961;
[3] F. Gygi, IBM J. Res. Dev., 2008, 52, p.137;
[4] H. Ma, et. al., J. Comp. Chem., 2020, 41: 1859-1867.

**MURI Project (N00014-19-1-2453)

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Presenters

  • Tommaso Francese

    • University of Chicago

Authors

  • Tommaso Francese

    • University of Chicago

  • Francois Gygi

    • University of California Davis
    • University of California, Davis

  • Giulia Galli

    • The University of Chicago
    • Pritzker School of Molecular Engineering, The University of Chicago
    • Pritzker School of Molecular Engineering, University of Chicago
    • University of Chicago
    • Department of Chemistry, University of Chicago
    • Materials Science Division and Center for Molecular Engineering, Argonne National Laboratory