Theoretical Insights into the Optical and Excited State Properties of Donor-Phenyl Bridge-Acceptor Containing Through-Space Charge Transfer Molecules

Pandiyan Sivasakthi; Jesni M Jacob; Mahesh Kumar Ravva; Pralok K Samanta

doi:10.1021/acs.jpca.2c07055

Theoretical Insights into the Optical and Excited State Properties of Donor-Phenyl Bridge-Acceptor Containing Through-Space Charge Transfer Molecules

J Phys Chem A. 2023 Feb 2;127(4):886-893. doi: 10.1021/acs.jpca.2c07055. Epub 2023 Jan 18.

Authors

Pandiyan Sivasakthi¹, Jesni M Jacob², Mahesh Kumar Ravva², Pralok K Samanta¹

Affiliations

¹ Department of Chemistry, School of Science, GITAM University, Hyderabad502329, India.
² Department of Chemistry, SRM University-AP, Amaravati522240, Andhra Pradesh, India.

PMID: 36653147
DOI: 10.1021/acs.jpca.2c07055

Abstract

A comparative new strategy to enhance thermally activated delayed fluorescence (TADF) of through-space charge transfer (CT) molecules in organic light-emitting diodes (OLEDs) is investigated. Generally, TADF molecules adopt a twisted donor and acceptor structure to get a sufficiently small ΔE_ST and a higher value of the spin-orbit coupling matrix element (SOCME). However, molecules containing donor-phenyl bridge-acceptor (D-p-A) units and featuring π-stacked architectures have intramolecular CT contribution through space and exhibit high TADF efficiency. We have explored the insights into the TADF mechanism in D-p-A molecules using the density functional theory (DFT) and time-dependent DFT methods. The calculated optical absorption and ΔE_ST values are found to be in good agreement with available experimental data. Interestingly, we found the origin of the SOCME to be the twisted orientation of the donor and bridge moieties. Also, we predicted similar molecules with enhanced OLED efficiency with different substitutions.