Aggregation‐Induced Delayed Fluorescence

Líu, Hao; Guo, Jingjing; Zhao, Zujin; Tang, Ben Zhong

doi:10.1002/cptc.201900118

Cited by 33 publications

(26 citation statements)

References 65 publications

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“…[219] Recently, Zhao et al developed a new system showing aggregationinduced delayed fluorescence (AIDF), which would allow for the utilization of triplet-state energy in the aggregate state. [220][221][222][223] The working mechanism of AIDF was elucidated in Figure 12A. In solution, the intersystem crossing (ISC) from singlet excited state (S*) to triplet excited state (T*) was feasible but the reverse ISC (RISC) pathway was blocked because the unhindered molecular motion promoted the non-radiative decay of both S* and T*.…”

Section: One-component Aggregatesmentioning

confidence: 99%

Aggregate Science: From Structures to Properties

et al. 2020

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Molecular science entails the study of structures and properties of materials at the level of single molecules or small interacting complexes of molecules. Moving beyond single molecules and well‐defined complexes, aggregates (i.e., irregular clusters of many molecules) serve as a particularly useful form of materials that often display modified or wholly new properties compared to their molecular components. Some unique structures and phenomena such as polymorphic aggregates, aggregation‐induced symmetry breaking, and cluster excitons are only identified in aggregates, as a few examples of their exotic features. Here, by virtue of the flourishing research on aggregation‐induced emission, the concept of “aggregate science” is put forward to fill the gaps between molecules and aggregates. Structures and properties on the aggregate scale are also systematically summarized. The structure–property relationships established for aggregates are expected to contribute to new materials and technological development. Ultimately, aggregate science may become an interdisciplinary research field and serves as a general platform for academic research.

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Section: One-component Aggregatesmentioning

confidence: 99%

Aggregate Science: From Structures to Properties

et al. 2020

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“…Pioneering works have been done by Zhao and coworkers in recent years. [33,34] As shown in Figure 4A, DMF-BP-PXZ, consisting of electron-donating phenoxazine (PXZ) and fluorene derivatives coupled with an electronwithdrawing benzoyl core, just showed a faint emission with quantum efficiency as low as 2.6% and a short emission lifetime of 2.3 ns in THF solution. [33] With the addition of large volume of water to form aggregate, the PL intensity was gradually enhanced and the fluorescence lifetime became much longer with notable delayed fluorescence in the microsecond level, showing the typical AIDF.…”

Section: Aggregation-induced Delayed Fluorescence (Aidf)mentioning

confidence: 99%

Organic luminescent materials: The concentration on aggregates from aggregation‐induced emission

2020

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The research of organic luminescent materials in aggregate has drawn more and more attention for their wide applications. To adjust the luminescent properties for aggregates, a deep understanding of the corresponding internal mechanism is needed. In this short review, a brief introduction of aggregation‐induced emission (AIE) and some other solid state luminescence behaviors derived from or parallel to AIE is presented. Particularly, the relationship between emission property and intermolecular/intramolecular interactions is summarized, with the aim to guide the further development of organic optoelectronic materials in aggregate.

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“…[3][4][5][6][7] With regard to the TADF mechanism, a nearly degenerate energy (a very small energy difference, ΔE ST ) exists between the lowest excited singlet (S 1 ) and triplet (T 1 ) states, enabling the occurrence of reverse intersystem crossing (RISC) from triplet to singlet states and resulting in delayed fluorescence with the aid of thermal energy. 8,9 Since the first purely organic TADF material was discovered in 1961, 10 TADF material has been continuously developed, and recently Adachi and latter researchers [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] have made important progress. Generally, the access to TADF includes several categories of molecular systems as follows: (1) fullerenes, whose TADF is primarily due to the highly delocalized π electrons over the whole sphere 12 ; (2) some metal-organic complexes, which show TADF with a small ΔE ST and a stable T 1 arising from a Chart 1 | Molecular structures of TADF materials in this and previous works in this area.…”

Section: Introductionmentioning

confidence: 99%

Thermally Activated Delayed Fluorescence of Aggregates Induced by Strong π–π Interactions and Reversible Dual-Responsive Luminescence Switching

Zhang

Zhou

et al. 2022

CCS Chem

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A reversible dual-responsive luminescent material was introduced by our group to show the simultaneous color and lifetime switching in response to external stimuli. Pristine crystalline powder of (E)-2-(benzo[d]thiazol-2-yl)-3-(pyren-1-yl)acrylonitrile (Py-BZTCN) shows the ordered π-π stacking with only near-monomer-normal orange-yellow fluorescence, but it exhibits red emission with thermally activated delayed fluorescence (TADF) after grinding, which can be reversibly recovered by heating or fuming treatment. Grinding disturbs the ordered π-π stacking of pristine powder, leading to the formation of small aggregates with compressed distance and increased overlap of π-π stacking between adjacent molecules. The cause of switching was verified by single-crystal X-ray diffraction experiments of two corresponding crystals. This strong π-π interaction effectively promotes the excited-state energy splitting and substantially decreases the singlet-triplet energy gap (ΔE ST ) of aggregates, resulting in the red TADF emission of aggregates through reverse intersystem crossing. This finding proposes a new route to realizing the TADF emission of aggregates through strong intermolecular interactions based on non-TADF monomer, thereby enabling a novel high-contrast dualresponsive luminescence switching.

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Aggregation‐Induced Delayed Fluorescence

Cited by 33 publications

References 65 publications

Aggregate Science: From Structures to Properties

Aggregate Science: From Structures to Properties

Organic luminescent materials: The concentration on aggregates from aggregation‐induced emission

Thermally Activated Delayed Fluorescence of Aggregates Induced by Strong π–π Interactions and Reversible Dual-Responsive Luminescence Switching

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