Effects of the acceptor pattern and substitution position on the properties of N-phenyl-carbazolyl based donor–acceptor–donor molecules

Song, Xingyou; Wang, Min; Kong, Lingqian; Zhao, Jinsheng

doi:10.1039/c7ra01449j

Cited by 11 publications

(7 citation statements)

References 44 publications

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“…In fact, the efficiency of 0.85 Cd/A was comparable with the typical results for solution-processed OLEDs based on fluorescent small molecules [ 25 , 26 ]. The schematic diagram of the structures of OLEDs and the energy levels of the materials is shown in Figure 7 d. In [ 27 ], the spectral properties of a series of similar compounds with a carbazole donor were investigated. All compounds based on thiadiazole and selenadiazole were characterized by luminescence in the range of 500–600 nm.…”

Section: Resultsmentioning

confidence: 99%

Novel D-A-D Fluorescent Dyes Based on 9-(p-Tolyl)-2,3,4,4a,9,9a-hexahydro-1H-carbazole as a Donor Unit for Solution-Processed Organic Light-Emitting-Diodes

et al. 2021

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New fluorescent D-A-D dyes containing 9-(p-tolyl)-2,3,4,4a,9,9a-hexahydro-1H-carbazole as a donor unit and 2,1,3-benzochalcogenadiazoles as an electron-withdrawing group were synthesized. The photoluminescent and electroluminescent properties of novel dyes for fluorescent OLED application were investigated. It was demonstrated that the replacement of lightweight heteroatoms by heavier ones enables the fine tuning of the maximum emission without significantly reducing the luminescence quantum yield. The maximum quantum yield value of 62.6% for derivatives based on 2,1,3-benzoxadiazole (1a) in cyclohexane was achieved. Two devices with the architecture of glass/ITO/PEDOT-PSS/poly-TPD/EML/TPBi/LiF/Al (EML = emitting layer) were fabricated to check the suitability of the synthesized compounds as a single active emission layer in OLED. These OLEDs exhibited clear red electroluminescence of the dyes with the maximum current efficiency of 0.85 Cd/A.

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Section: Resultsmentioning

confidence: 99%

Novel D-A-D Fluorescent Dyes Based on 9-(p-Tolyl)-2,3,4,4a,9,9a-hexahydro-1H-carbazole as a Donor Unit for Solution-Processed Organic Light-Emitting-Diodes

et al. 2021

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“…37−39 Undeuterated BT-2PhCz was also synthesized as a comparison, whose electroluminescence had not been studied in previous reports. 40…”

Section: Introductionmentioning

confidence: 99%

Novel Deuterated Benzothiadiazole Derivatives with Enhancing High-Lying Reverse Intersystem Crossing for High-Efficiency Organic Light-Emitting Diodes

Dong,

Shen,

Qin

et al. 2024

J. Phys. Chem. C

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Developing efficient "hot exciton" thermally activated delayed fluorescence (TADF) materials in electroluminescence has always been a significant and challenging issue. Herein, we have designed and synthesized two deuterated yellow emitters BT-2PhCz-d 10 and BT-2PhCz-d 24 based on the commonly designed hot exciton emitter BT-2PhCz to improve the exciton utilization efficiency. Transient absorption (TA) kinetic analysis showed that deuterated BT-2PhCz-d 10 and BT-2PhCz-d 24 possessed shorter delayed lifetimes and a faster high-lying reverse intersystem crossing rate constant (k h-RISC ) than BT-2PhCz. The measured photoluminescence quantum yield (PLQY) and infrared spectrum results also experimentally confirmed that the introduction of C− D bonds played a key role in suppressing nonradiative processes. The optimized organic light-emitting diodes (OLEDs) based on these hot exciton materials exhibited a maximum external quantum efficiency (EQE) of 7.1% for BT-2PhCz, 10.0% for BT-2PhCzd 10 , and 11.8% for BT-2PhCz-d 24 , respectively, corresponding to exciton utilization efficiencies of 39.3−26.2, 50.0−33.3, and 59.4− 39.6%. These results confirm that the deuterated isotope effect realized the regulation of high-energy spin flip processes and nonradiative decay processes, providing a new strategy for designing high-performance hot exciton emitters.

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“…In addition to the mentioned structural features, it has been reported that several fluorophores and some DSEgens have Donor-Acceptor (DÀ A) or Donor-Acceptor-Donor (DÀ AÀ D) architectures. [5][6][7] This is a recurring design that helps to change the emission of the compounds by tuning their bandgap. [8] From the numerous reported DÀ A and DÀ AÀ D compounds, we noted that the heterocycle thiazole has been scarcely incorporated as the acceptor fragment, compared to other heterocycles like benzothiadiazole.…”

Section: Introductionmentioning

confidence: 99%

“…In addition to the mentioned structural features, it has been reported that several fluorophores and some DSEgens have Donor‐Acceptor (D−A) or Donor‐Acceptor‐Donor (D−A−D) architectures [5–7] . This is a recurring design that helps to change the emission of the compounds by tuning their bandgap [8] .…”

Section: Introductionmentioning

confidence: 99%

Asymmetric Dual‐State Emitters Featuring Thiazole Acceptors

et al. 2022

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This work describes a new approach to construct highly conjugated molecules with asymmetric donor-acceptor-donor' architectures (DÀ AÀ D'). Five new emissive compounds featuring thiazole, a scarcely used acceptor, were synthesized using a three-component Rh(II) catalytic reaction. The asymmetric fluorescent compounds show significant emission in solution (QY = 73 %-100 %) and the solid-state (QY = 14 %-59 %), and therefore considered Dual-State Emitters (DSE). We also evaluate the impact of O-alkyl chains with varying lengths in the photophysical properties in solution, aggregates, and solid-state. Computational studies indicate that the involved electronic transitions have a significant charge transfer character produced almost exclusively from the triphenylamine donors. According to the single crystal X-ray data of compounds 8 and 9, the conjugated structures have a twisted molecular conformation that contributes to the observed emission in the solid-state. These findings show a systematic approach to design DSE materials, which may help to stimulate their use in biological or optoelectronic applications.

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Effects of the acceptor pattern and substitution position on the properties of N-phenyl-carbazolyl based donor–acceptor–donor molecules

Abstract: Four D–A–D type molecules were designed and synthesized, and their specific properties including optical, redox and thermal stabilities were studied in detail. The influence of substitution and the heteroatom effects were also studied.

Cited by 11 publications

References 44 publications

Novel D-A-D Fluorescent Dyes Based on 9-(p-Tolyl)-2,3,4,4a,9,9a-hexahydro-1H-carbazole as a Donor Unit for Solution-Processed Organic Light-Emitting-Diodes

Novel D-A-D Fluorescent Dyes Based on 9-(p-Tolyl)-2,3,4,4a,9,9a-hexahydro-1H-carbazole as a Donor Unit for Solution-Processed Organic Light-Emitting-Diodes

Novel Deuterated Benzothiadiazole Derivatives with Enhancing High-Lying Reverse Intersystem Crossing for High-Efficiency Organic Light-Emitting Diodes

Asymmetric Dual‐State Emitters Featuring Thiazole Acceptors

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