peri-N-amine-perylenes, with and without phenyl bridge: Photophysical studies and their OLED applications

[Display omitted] •Perylene-amine dyads with direct linkage (P-N-CBZ) or with phenyl bridge (P-Ph-N-CBZ and P-Ph-N-BP) were synthesized.•DFT studies show near orthogonal geometry for directly attached perylene-amine.•Emission of P-Ph-N-CBZ showed vibronic features while for P-Ph-N-BP and P-N-BP, emi...

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Veröffentlicht in:Journal of photochemistry and photobiology. A, Chemistry. Chemistry., 2022-04, Vol.426, p.113710, Article 113710
Hauptverfasser: Dixit, Swati J.N., Gupta, Chandan V., Naidu, Gonna Somu, Bose, Sangita, Agarwal, Neeraj
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Sprache:eng
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Zusammenfassung:[Display omitted] •Perylene-amine dyads with direct linkage (P-N-CBZ) or with phenyl bridge (P-Ph-N-CBZ and P-Ph-N-BP) were synthesized.•DFT studies show near orthogonal geometry for directly attached perylene-amine.•Emission of P-Ph-N-CBZ showed vibronic features while for P-Ph-N-BP and P-N-BP, emission is broad.•Fluorescence studies suggest that the emission has significant contribution from 1CT state.•Our photophysical studies suggested weaker electronic coupling in phenyl linked dyads.•OLEDs of P-Ph-N-BP showed a higher EQE of ∼ 4.2%. Donor-bridge-acceptor framework has been studied widely for their detailed photophysical properties with the aim of efficient long range charge transfer. Carbazole attached with electron acceptors has been used for charge transfer properties, thermally activated delayed fluorescence, exciton dynamics etc. In this study, we synthesized donor–acceptor dyads of seconday amine (carbazole and diphenyl amine) attached to perylene through nitrogen, with phenyl (P-Ph-N-CBZ and P-Ph-N-BP) and without phenyl (P-N-CBZ and P-N-BP). Further their detailed photophysical and electroluminescent properties are discussed. P-N-BP is known and is used as standard in this work. DFT studies show nearly orthogonal geometry of P-N-CBZ with the dihedral angle of ∼ 71° between the planes of perylene and carbazole. For P-Ph-N-BP and P-Ph-N-CBZ, the perylene and amines are adopting almost co-planar geometries. Emission spectra of P-Ph-N-CBZ and P-N-CBZ in dichloromethane are structural with clear vibronic features while for P-Ph-N-BP and P-N-BP, the emission is structureless and broad indicating prominent electronic coupling between molecular orbitals of donor and acceptor in the latter case. Fluorescence quantum yields of phenyl-linked dyads are found to be higher than directly linked perylene-amine derivatives. High quantum yield (0.79) in non-polar hexane and polar DMSO (0.66) is observed for P-Ph-N-CBZ. It is interesting to note that the fluorescence lifetimes of these dyads are increasing while fluorescence quantum yields are decreasing with increasing polar solvents, suggesting that the emission has a significant contribution from the 1CT state. Dipole moments estimated from DFT studies and photophysical methods are higher for phenyl-linked dyads than those directly attached which is also consistent with their solvatochromism properties. Weaker electronic coupling in phenyl-linked dyads resulted due to the long distance between donor and accep
ISSN:1010-6030
1873-2666
DOI:10.1016/j.jphotochem.2021.113710