How do molecular interactions affect fluorescence behavior of AIEgens in solution and aggregate states?

Yu, Ying; Xing, Hao; Zhou, Zhicong; Liu, Junkai; Sung, Herman H. Y.; Williams, Ian D.; Halpert, Jonathan E.; Zhao, Zheng; Tang, Ben Zhong

doi:10.1007/s11426-021-1083-4

“…Chemie actions within the crystals than that in films. [23] The TPA moieties in the crystal structures showed a twisted structure, which matched well with the calculation results. The twisted structures of these AIEgens avoided long-range π-π stacking and emission quenching resulted by π-π stacking.…”

Section: Methodssupporting

confidence: 85%

Solution‐processed AIEgen NIR OLEDs with EQE Approaching 15 %

Yu

¹

,

Xing

²

,

Liú

³

et al. 2022

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Organic near‐infrared (NIR) luminogens have attracted intensive attention considering their vast potential applications in areas like bioimaging, organic light‐emitting diodes (OLEDs) and night‐vision telecommunication. However, organic NIR luminogens with high solid quantum efficiencies are scarce, limiting their applications. Here, we reported an electron‐deficient acceptor, BSM, based on dithiafulvalene and benzothiadiazole, which could work as a strong acceptor to produce highly efficient NIR emitters with aggregation‐induced emission (AIE) property. One of the AIEgens, TBSMCN emitted at 820 nm with a solid quantum yield of 10.7 %. When applied to solution‐processed OLEDs, an outstanding external quantum efficiency (EQE) of 9.4 % was achieved with a peak wavelength at 728 nm. Moreover, its non‐doped device could achieve an extraordinary EQE of 2.2 % peaking at 804 nm. In the further optimized configuration, when an extra sensitizer was added to harvest triplet excitons, the EQE unprecedentedly soared up to 14.3 % with a peak wavelength of 750 nm.

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“…Overall, the crystal structures exhibited redder emissions compared with the amorphous film states (Figure S44), suggesting the stronger intermolecular inter- actions within the crystals than that in films. [23] The TPA moieties in the crystal structures showed a twisted structure, which matched well with the calculation results. The twisted structures of these AIEgens avoided long-range π-π stacking and emission quenching resulted by π-π stacking.…”

Section: Resultssupporting

confidence: 85%

Solution‐processed AIEgen NIR OLEDs with EQE Approaching 15 %

Yu

¹

,

Xing

²

,

Liú

³

et al. 2022

Self Cite

View full text Add to dashboard Cite

Organic near‐infrared (NIR) luminogens have attracted intensive attention considering their vast potential applications in areas like bioimaging, organic light‐emitting diodes (OLEDs) and night‐vision telecommunication. However, organic NIR luminogens with high solid quantum efficiencies are scarce, limiting their applications. Here, we reported an electron‐deficient acceptor, BSM, based on dithiafulvalene and benzothiadiazole, which could work as a strong acceptor to produce highly efficient NIR emitters with aggregation‐induced emission (AIE) property. One of the AIEgens, TBSMCN emitted at 820 nm with a solid quantum yield of 10.7 %. When applied to solution‐processed OLEDs, an outstanding external quantum efficiency (EQE) of 9.4 % was achieved with a peak wavelength at 728 nm. Moreover, its non‐doped device could achieve an extraordinary EQE of 2.2 % peaking at 804 nm. In the further optimized configuration, when an extra sensitizer was added to harvest triplet excitons, the EQE unprecedentedly soared up to 14.3 % with a peak wavelength of 750 nm.

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“…The strong emission in the crystalline phase might be expected since these interactions are beneficial in restricting intramolecular motions and turning on the AEE activity. 39 Scheme 1 Synthetic route to compounds 3.…”

Section: Synthesis and Characterizationmentioning

confidence: 99%

“…In contrast, the ground structure exhibits obvious discrepancies with the RMSD value of 0.202 Å, displaying much greater molecular motions from the S 0 to S 1 state. The molecular motion freedom favors non-radiative decay 39 and results in weaker luminescence. The grinding-induced red-shifted emission is the synergistic effect of unrestricted geometric relaxation 51 and the more planar configuration (Table S2, ESI †).…”

Section: Theoretical Calculationsmentioning

confidence: 99%