Benzo[1,2-b:4,5-b']dithiophene as a weak donor component for push-pull materials displaying thermally activated delayed fluorescence or room temperature phosphorescence

Cardeynaels, Tom; Paredis, Simon; Danos, Andrew; Vanderzande, Dirk; Monkman, Andrew P.; Champagne, Benoît; Maes, Wouter

Abstract

In the search for high-performance donor-acceptor type organic compounds displaying thermally activated delayed fluorescence (TADF), triisopropylsilyl-protected benzo[1,2-b:4,5-b']dithiophene (BDT-TIPS) is presented as a novel donor component in combination with two known acceptors: dimethyl-9H-thioxanthenedioxide (TXO2) and dibenzo[a,c]phenazinedicarbonitrile (CNQxP). For a broader comparison, the same acceptors are also combined with the well-studied 9,9-dimethyl-9,10-dihydroacridine (DMAC) donor. Optimized BDT-TIPS-containing structures show calculated dihedral angles of around 50° and well-separated highest occupied and lowest unoccupied molecular orbitals, although varying singlet-triplet energy gaps are observed experimentally. By changing the acceptor moiety and the resulting ordering of excited states, room temperature phosphorescence (RTP) attributed to localized BDT-TIPS emission is observed for TXO2-BDT-TIPS, whereas CNQxP-BDT-TIPS affords a combination of TADF and triplet-triplet annihilation (TTA) delayed emission. In contrast, strong and pure TADF is well-known for TXO2-DMAC, whereas CNQxP-DMAC shows a mixture of TADF and TTA at very long timescales. Overall, BDT-TIPS represents an alternative low-strength donor component for push-pull type TADF emitters that is also able to induce RTP properties.

Citation

Cardeynaels, T., Paredis, S., Danos, A., Vanderzande, D., Monkman, A. P., Champagne, B., & Maes, W. (2021). Benzo[1,2-b:4,5-b']dithiophene as a weak donor component for push-pull materials displaying thermally activated delayed fluorescence or room temperature phosphorescence. Dyes and Pigments, 186, https://doi.org/10.1016/j.dyepig.2020.109022

• Journal Article Type: Article
• Acceptance Date: Nov 19, 2020
• Online Publication Date: Nov 28, 2020
• Publication Date: 2021-02
• Deposit Date: Apr 8, 2021
• Publicly Available Date: Nov 28, 2022
• Journal: Dyes and Pigments
• Print ISSN: 0143-7208
• Electronic ISSN: 1873-3743
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 186
• DOI: https://doi.org/10.1016/j.dyepig.2020.109022
• Public URL: https://durham-repository.worktribe.com/output/1250119