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

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.

Molecular engineering to design a bright near-infrared red photosensitizer: cellular bioimaging and phototherapy

“…To meet the requirements of biological applications, ideal PSs should have the properties of water solubility, good biocompatibility, nearinfrared red (NIR) absorption or emission wavelengths, and highly efficient ROS production ability. [8][9][10] Recently, increasing research attention has been paid to the development of advanced organic PSs, which mainly include a series of derivatives based on porphyrin, 11 rhodamine, 12 and phthalocyanine units. 13 Although above-mentioned effective PSs could achieve satisfactory phototherapeutic outcomes towards tumors and bacteria, their weak uorescence intensity as well as the reduced ROS efficiency caused by stronger intermolecular p-p stacking interactions are unfavorable for their application in uorescence-imaging-guided PDT.…”

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Thiocarbonyl‐Bridged N‐Heterotriangulenes for Energy Efficient Triplet Photosensitization: A Theoretical Perspective

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