Fluorescence imaging in the second near‐infrared (NIR‐II) window facilitated by aggregation‐induced emission luminogens (AIEgens) is an emerging research field. NIR‐II AIEgens overcome limitations ...imposed by penetration depth and fluorescence efficiency, offering high‐performance imaging with enhanced precision. Some reported NIR‐II AIEgens demonstrate capabilities for fluorescence and photoacoustic bimodal imaging, and fluorescence imaging guided photothermal therapy, which not only improves diagnosis accuracy but provides an efficient theranostic platform to accelerate preclinical translation as well. This minireview summarizes recent efforts on exploiting NIR‐II AIEgens with regard to molecular design strategies and bioapplications, and puts forward current challenges and promising prospects. This timely sketch should benefit the further exploitation of diverse and multifunctional NIR‐II AIEgens for a wide array of applications.
Fluorescence imaging facilitated by NIR‐II emissive aggregation‐induced emission luminogens (AIEgens) is an emerging research field. This minireview summarizes recent efforts on developing novel NIR‐II AIEgens in terms of molecular design strategies and bioapplications, and discusses current challenges and future prospects.
Conspectus Fluorescent sensing has emerged as a powerful tool for detecting various analytes and visualizing numerous biological processes by virtue of its superb sensitivity, rapidness, excellent ...temporal resolution, easy operation, and low cost. Of particular interest is activity-based sensing (ABS), a burgeoning sensing approach that is actualized on the basis of dynamic molecular reactivity rather than conventional lock-and-key molecular recognition. ABS has been recognized to possess some distinct advantages, such as high specificity, extraordinary sensitivity, and accurate signal outputs. A majority of ABS sensors are constructed by modifying conventional fluorogens, which are strongly emissive when molecularly dissolved in solvents but experience emission quenching upon aggregate formation or concentration increase. The aggregation-caused quenching (ACQ) phenomenon leads to a limited amount of labeling of the analyte with the sensor and low photobleaching resistance, which could impede practical applications of the ABS protocol. As an anti-ACQ phenomenon, aggregation-induced emission (AIE) provides a straightforward solution to the ACQ problem. Thanks to their intrinsic advantages, including high photobleaching threshold, high signal-to-noise ratio, fluorescence turn-on nature, and large Stokes shift, AIE-active luminogens (AIEgens) represent a class of extraordinary fluorogen alternatives for the ABS protocol. The use of AIEgen-involved ABS can integrate the advantages of AIEgens and ABS, and additionally, the AIE process offers some unique properties to the ABS approach. For instance, in some cases of water-soluble AIEgen-involved ABS, chemical reaction not only leads to a chang in the emission color of the AIEgens but also causes solubility variations, which could result in specific “light-up” signaling. In this Account, the basic concepts and mechanistic insights of the ABS approach involving the AIE principle are briefly summarized, and then we highlight the new breakthroughs, seminal studies, and trends in the area that have been most recently reported by our group. This emerging sensing protocol has been successfully utilized for detecting an array of targets including ions, small molecules, biomacromolecules, and microenvironments, all of which closely relate to human health, medical, and public concerns. These detections are smoothly achieved on the basis of various reactions (e.g., hydrolysis, boronate cleavage, dephosphorylation, addition, cyclization, and rearrangement reactions) through different sensing principles. In these studies, the AIEgen-involved ABS strategy generally shows good biocompatibility, high selectivity, excellent reliability and high signal contrast, strongly indicating its great potential for high-tech innovations in the sensing field, among which bioprobing is of particular interest. With this Account, we hope to spark new ideas and inspire new endeavors in this emerging research area, further promoting state-of-the-art developments in the field of sensing.
Aggregation‐induced emission (AIE) describes a photophysical phenomenon in which molecular aggregates exhibit stronger emission than the single molecules. Over the course of the last 20 years, AIE ...research has made great strides in material development, mechanistic study and high‐tech applications. The achievements of AIE research demonstrate that molecular aggregates show many properties and functions that are absent in molecular species. In this review, we summarize the advances in the field of AIE and its related areas. We specifically focus on the new properties of materials attained by molecular aggregates beyond the microscopic molecular level. We hope this review will inspire more research into molecular ensembles at and beyond the meso level and lead to the significant progress in material and biological science.
The importance of the whole picture: Aggregation‐induced emission (AIE) research demonstrates that many properties and functions that are absent in molecular species can be found in molecular aggregates. AIE research thus emphasizes the significance of aggregate science in addition to molecular science for materials development.
AIE polymers: Synthesis and applications Hu, Rong; Qin, Anjun; Tang, Ben Zhong
Progress in polymer science,
January 2020, 2020-01-00, Letnik:
100
Journal Article
Recenzirano
Organic luminescent materials with aggregation-induced emission (AIE) feature have attracted great attention in diverse fields because of their unique properties. AIE polymers possess advantages of ...multifunction, well film-forming property and synergistic effect, which could well meet various practical applications. This review briefly introduces the preparation of AIE polymers based on one-, two- and multi-component polymerizations, and gives a deep insight for the structure-property relationship and the applications in optoelectronic devices, chemo-/biosensors and biomedicines. Furthermore, perspectives on the future direction of AIE polymers are also discussed.
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Organic luminescent materials with aggregation-induced emission (AIE) feature have attracted great attention in various fields because of their unique properties. Compared to the well studied low-mass AIE luminogens, AIE polymers have been paid less attention even though they present outstanding advantages of high emission efficiency in aggregate and solid states, amplification effect of the signals, good processability and multiple functionalization, etc. This review briefly summarizes the synthetic strategies towards AIE polymers based on one-, two- and multi-component polymerizations. Afterward, the structure-property relationship, such as the effect of the skeleton and side-chains on the photophysical property is discussed. More importantly, nonconventional luminescent polymers and their mechanisms are specially introduced. Furthermore, the high-tech applications of AIE polymers in optoelectronic devices, chemo-/biosensors and biomedicine are illustrated. Finally, the perspectives on the future development direction of AIE polymers are briefly discussed. It is hoped that this review can serve as a trigger for future innovation in AIE research.
The study of purely organic room‐temperature phosphorescence (RTP) has drawn increasing attention because of its considerable theoretical research and practical application value. Currently, organic ...RTP materials with both high efficiency (ΦP > 20%) and a long lifetime (τP > 10 s) in air are still scarce due to the lack of related design guidance. Here, a new strategy to increase the phosphorescence performance of organic materials by integrating the RTP host and RTP guest in one doping system to form a triplet exciplex, is reported. With these materials, the high‐contrast labeling of tumors in living mice and encrypted patterns in thermal printing are both successfully realized by taking advantage of both the long afterglow time (up to 25 min in aqueous media) and high phosphorescence efficiency (43%).
A series of simple organic phosphorescence host–guest materials with high performance are successfully developed. With these materials, high‐contrast labeling of tumors in living mice and encrypted patterns in thermal printing are successfully realized by taking advantage of both their long afterglow time (up to 25 min in aqueous media) and high phosphorescence efficiency (43%).
Non‐doped organic light‐emitting diodes (OLEDs) possess merits of higher stability and easier fabrication than doped devices. However, luminescent materials with high exciton use are generally ...unsuitable for non‐doped OLEDs because of severe emission quenching and exciton annihilation in neat films. Herein, we wish to report a novel molecular design of integrating aggregation‐induced delayed fluorescence (AIDF) moiety within host materials to explore efficient luminogens for non‐doped OLEDs. By grafting 4‐(phenoxazin‐10‐yl)benzoyl to common host materials, we develop a series of new luminescent materials with prominent AIDF property. Their neat films fluoresce strongly and can fully harvest both singlet and triplet excitons with suppressed exciton annihilation. Non‐doped OLEDs of these AIDF luminogens exhibit excellent luminance (ca. 100000 cd m−2), outstanding external quantum efficiencies (21.4–22.6 %), negligible efficiency roll‐off and improved operational stability. To the best of our knowledge, these are the most efficient non‐doped OLEDs reported so far. This convenient and versatile molecular design is of high significance for the advance of non‐doped OLEDs.
Robust emitters, affording high‐performance non‐doped organic light‐emitting diodes with outstanding external quantum efficiencies (EQE) of up to 22.6 % and negligible efficiency roll‐off, have been obtained by molecularly integrating an aggregation‐induced delayed fluorescence (AIDF) luminogen into a host material.
Herein the novel tetraphenylethylene (TPE) derivative 1 was designed with an integration of aggregation‐induced emission (AIE), multi‐state mechanochromism and self‐recovery photochromism. The ...molecule was susceptible to grinding, heating and vapor fuming and showed corresponding transition of its emission colors. The heated powder or single crystal of 1 exhibited reversible photochromism. After a short period of UV irradiation, it showed a bright red color, but recovered to its original white appearance within 1 min. The photochromism is due to the formation of photocyclization intermediates upon UV irradiation, while the eversible mechanochromism is attributed to the weak molecular interactions derived from head‐to‐tail stacking of the molecules. This reversible multi‐state, high‐contrasted and rapid responsive mechanochromic and photochromic property cooperatively provide double enhancement of a multimode guarantee in advanced anti‐counterfeiting.
Forgery‐proof: A novel AIE molecule 1 is designed with high‐contrasted and multi‐state mechanochromic and photochromic properties. Based on these properties, 1 shows great potential for application in advanced multidimensional anti‐counterfeiting, which was demonstrated by fabrication of a model banknote.
Superior artificial light‐harvesting systems (ALHSs) require exceptional capacity in harvesting light and transferring energy. In this work, we report a novel strategy to build ALHSs with an ...unprecedented antenna effect (35.9 in solution and 90.4 in solid film). The ALHSs made use of a conjugated polymeric supramolecular network (CPSN), a crosslinked network obtained from the self‐assembly of a pillar5arene‐based conjugated polymeric host (CPH) and conjugated ditopic guests (Gs). The excellent performance of the CPSN could be attributed to the following factors: 1) The “molecular wire effect” of the conjugated polymeric structure, 2) aggregation‐induced enhanced emission (AEE) moieties in the CPH backbone, and 3) high capacity of donor–acceptor energy transfer, and 4) crosslinked structures triggered by the host–guest binding between Gs and CPH. Moreover, the emission of the CPSN could be tuned by using different Gs or varying the host/guest ratio, thus reaching a 96 % sRGB area.
You're the antenna: A conjugated polymeric supramolecular network with aggregation‐induced emission enhancement has been developed as an excellent light‐harvesting system with an unprecedented antenna effect (35.9 in solution and 90.4 in solid film). Moreover, the emission of this network could be tuned, reaching 96 % sRGB area.
Multicolor fluorescent polymeric hydrogels (MFPHs) are three‐dimensionally crosslinked hydrophilic polymer networks with tunable emission color. Different from the classic fluorescent materials that ...are used primarily in dry solid states or solutions, MFPHs exist as highly water‐swollen quasi‐solids. They thus present many promising properties of both solids and solution, including tissue‐like mechanical properties, an intrinsic soft and wet nature, fabulous biocompatibility, along with a responsive volume, shape, and fluorescence color change. These advantageous properties hold great potential in many applications such as sensing, bioimaging, information encoding, encryption, biomimetic actuators, and soft robotics. This Review gives an in‐depth overview of recent progress in the field of MFPHs, with a particular focus on the diverse construction methods and important demonstrated applications. Current challenges and future perspectives on MFPHs are also discussed.
Multicolor fluorescent polymeric hydrogels (MFPHs), rising stars of luminescent materials, are the marriage of multicolor fluorescent materials and polymeric hydrogels. They have many extraordinary properties, such as a tissue‐like modulus, an intrinsic soft and wet nature, and fluorescence color change. In this Review, recent progress in MFPHs is summarized, with a particular focus on the construction methods and important applications.
Twenty years ago, the concept of aggregation‐induced emission (AIE) was proposed, and this unique luminescent property has attracted scientific interest ever since. However, AIE denominates only the ...phenomenon, while the details of its underlying guiding principles remain to be elucidated. This minireview discusses the basic principles of AIE based on our previous mechanistic study of the photophysical behavior of 9,10‐bis(N,N‐dialkylamino)anthracene (BDAA) and the corresponding mechanistic analysis by quantum chemical calculations. BDAA comprises an anthracene core and small electron donors, which allows the quantum chemical aspects of AIE to be discussed. The key factor for AIE is the control over the non‐radiative decay (deactivation) pathway, which can be visualized by considering the conical intersection (CI) on a potential energy surface. Controlling the conical intersection (CI) on the potential energy surface enables the separate formation of fluorescent (CI:high) and non‐fluorescent (CI:low) molecules control of conical intersection accessibility (CCIA). The novelty and originality of AIE in the field of photochemistry lies in the creation of functionality by design and in the active control over deactivation pathways. Moreover, we provide a new design strategy for AIE luminogens (AIEgens) and discuss selected examples.
What is essential in the aggregation‐induced emission (AIE) mechanism? This question is addressed by using the photophysical processes associated with 9,10‐bis(N,N‐dialkylamino)anthracene as a case study. The AIE phenomenon requires control of the non‐radiative decay (deactivation) pathway, that is, controlling the conical intersection (CI) on the potential energy surface enables the formation of fluorescent molecules (CI high) and non‐fluorescent (CI low) molecules separately.
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