Optoelectronic Characterization for Some of the Thermally Activated Delayed Fluorescence (TADF) Emitters Using Density Functional Theory (DFT)

Mona Sunaydih Alsaeedi

doi:10.5281/zenodo.15712981

Authors

Mona Sunaydih Alsaeedi Taif University https://orcid.org/0000-0002-1718-1368

DOI:

https://doi.org/10.5281/zenodo.15712981

Keywords:

Density Functional Theory (DFT), Thermally activated delayed fluorescence (TADF) emitters, Optoelectronic characterization

Abstract

Materials that exhibit thermally activated delayed fluorescence (TADF) are of great interest for organic light-emitting diodes (OLEDs) due to their ability to achieve 100% external quantum efficiency (EQE) without the need to incorporate heavy atoms. Since high-efficiency blue-emitting materials are still in demand, the pyrazine core was used in this study because of its high S₁ energy and weak electron-accepting ability. Therefore, pyrazine-based multi-carbazoles compounds 1–3 were studied using density functional theory (DFT) and time-dependent DFT (TD-DFT) methods. The simulated electronic and photophysical properties of the compounds agree with experimental observations. All compounds exhibit blue emission at 2.77, 2.68, and 2.62 eV, respectively. Replacing one biphenyl group with a carbazole unit (compound 2) decreases the E_S1-T1to 1.09 eV. Replacing two biphenyl groups with carbazole units (compound 3) further reduces E_S1-T1 to 0.26 eV, facilitating the TADF mechanism. All compounds display mixed transitions of charge-transfer and locally excited character due to the increased donor ability with the addition of carbazole units.

Author Biography

Mona Sunaydih Alsaeedi, Taif University

Department of Chemistry, College of Science, Taif University, Al-Haweiah, P.O. Box 11099, Taif 21944, Saudi Arabia. E-mail: m.alsaeedi@tu.edu.sa

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