The Dimerization Effects on Electronic Properties of OLED Candidate Materials for Optimized Performance: A Quantum DFT Study

Abstract

In recent years, there has been a growing interest in organic light-emitting diode (OLED) materials, highlighting the importance of a thorough understanding of the key factors that influence their electronic and non-linear optical (NLO) properties. To achieve this objective, we considered five candidate OLED compounds: Dibenzothio-phen-sulfone-3-yl-9-phenyl-9H-carbazole (DBTS-CzP), 9H-thioxanthene-9-one-dibenzothiophene-sulfone (TXO-DBTS), spiro[fluorene-9,9-thioxanthene]-10,10-dioxide (SpDBTS), 9-[4-(Diphenylphosphoryl)-2,2-dimethyl-4-biphenylyl]-9H-carbazole (mCBPPO), and N,N-Bis[2-(pyridin-2-yl)phenyl]-N,N-di(n-butyl)phenylamine (DPA-2Py). We employed density functional theory (DFT) and time-dependent DFT (TD-DFT) methods to investigate how dimerization can affect their electronic and NLO characteristics. The results of electronic structure analyses, including HOMO-LUMO gaps and NLO characteristics, reveal that dimerization enhances dipole moments and polarizabilities, facilitating improved charge transfer and electronic transitions. Among the studied compounds, TXO-DBTS demonstrates stable electronic properties and exhibits enhanced NLO characteristics post-dimerization --such as efficient charge mobility and superior color purity-- positioning it as a promising candidate for advanced OLED applications. These findings underscore dimerized structures' potential to enhance optoelectronic device performance.