A narrowband blue circularly polarized thermally activated delayed fluorescence emitter with a hetero-helicene structure

Abstract

A narrowband blue CP-TADF emitter with a rigid hetero-helicene structure (QAO-PhCz) was synthesized and characterized. QAO-PhCz exhibits good electroluminescence performance (EQE = 14.0%) and narrow FWHM. The enantiomers of QAO-PhCz...

An S-shaped double helicene showing both multi-resonance thermally activated delayed fluorescence and circularly polarized luminescence

“…Compounds OBN-2CN-BN and OBN-4CN-BN , 84 were based loosely on Hatakeyama's DABNA-1 41 design and contain a peripheral chiral ( R / S )-octahydro-binaphthol group that is not directly implicated in the emissive short-range charge transfer excited state. 84 A similar strategy was used for QAO-PhCz , 85 by introducing a 9-phenyl-9 H -carbazole appended group to the MR-framework to lock the helical structure and obtain chirality. There are only two reports where the MR-TADF core structure shows intrinsic chirality and both are boron/nitrogen-based helicenes: compounds BN5 86 and OBN-Cz (aka 1a ).…”

Influence of charge transfer strength on emission bandwidth for multiple-resonance emitters via systematically tuning the acceptor–donor assembly

“…Until the discovery of emitters based on multiple resonance thermally activated delayed fluorescence (MR-TADF), their narrow FWHM was able to compete with LEDs based on, e.g., gallium nitrides (micro-LEDs) and CdS/ZnS or CdSe/ZnS quantum dots (QD-LEDs). 4,5 Accordingly, MR-TADF emitters with panchromatic wavelength tuning from blue [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] through green [19][20][21][22][23][24][25][26][27] to red [28][29][30] have sprung up and rushed. The key to high color purity of MR-TADF emitters, from the perspective of electronic structure and computational simulations, 5,31 seems to lie in the strong orthopositioned transition orbitals, i.e.…”

Efficient narrowband electroluminescence based on a hetero-bichromophore thermally activated delayed fluorescence dyad

“…51 Compared with the absorption band at 300–400 nm (corresponding to the higher excited state), the lower intensity of the lowest absorption band (centered at 455 nm, corresponding to the lowest excited state) indicates that the long-range ICT does work. 53 Furthermore, the lowest absorption band of BOQAO is slightly redshifted but maintains a MR-type shape compared with the absorption band of the parents t BuBO and t BuQAO (Fig. S5 in the ESI†), which indicates that the weak long-range ICT interactions between the two MR segments does not have a significant influence on the FWHM.…”