With recent progress in photothermal materials, organic small molecules featured with flexibility, diverse structures, and tunable properties exhibit unique advantages but have been rarely applied in ...solar‐driven water evaporation owing to limited sunlight absorption resulting in low solar–thermal conversion. Herein, a stable croconium derivative, named CR‐TPE‐T, is designed to exhibit the unique biradical property and strong π–π stacking in the solid state, which facilitate not only a broad absorption spectrum from 300 to 1600 nm for effective sunlight harvesting, but also highly efficient photothermal conversion by boosting nonradiative decay. The photothermal efficiency is evaluated to be 72.7% under 808 nm laser irradiation. Based on this, an interfacial‐heating evaporation system based on CR‐TPE‐T is established successfully, using which a high solar‐energy‐to‐vapor efficiency of 87.2% and water evaporation rate of 1.272 kg m−2 h−1 under 1 sun irradiation are obtained, thus making an important step toward the application of organic‐small‐molecule photothermal materials in solar energy utilization.
A stable croconium derivative, “CR‐TPE‐T”, is designed to exhibit the unique biradical property and strong π–π stacking in the solid state, which facilitate not only a broad absorption spectrum from 300 to 1600 nm for effective sunlight harvesting, but also highly efficient photothermal conversion by boosting nonradiative decay, enabling a high solar‐energy‐to‐vapor efficiency of 87.2% under one sun irradiation.
Many luminescent stimuli responsive materials are based on fluorescence emission, while stimuli-responsive room temperature phosphorescent materials are less explored. Here, we show a kind of ...stimulus-responsive room temperature phosphorescence materials by the covalent linkage of phosphorescent chromophore of arylboronic acid and polymer matrix of poly(vinylalcohol). Attributed to the rigid environment offered from hydrogen bond and B-O covalent bond between arylboronic acid and poly(vinylalcohol), the yielded polymer film exhibits ultralong room temperature phosphorescence with lifetime of 2.43 s and phosphorescence quantum yield of 7.51%. Interestingly, the RTP property of this film is sensitive to the water and heat stimuli, because water could destroy the hydrogen bonds between adjacent poly(vinylalcohol) polymers, then changing the rigidity of this system. Furthermore, by introducing another two fluorescent dyes to this system, the color of afterglow with stimulus response effect could be adjusted from blue to green to orange through triplet-to-singlet Förster-resonance energy-transfer. Finally, due to the water/heat-sensitive, multicolor and completely aqueous processable feature for these three afterglow hybrids, they are successfully applied in multifunctional ink for anti-counterfeit, screen printing and fingerprint record.
As a new non-invasive treatment method, photodynamic therapy (PDT) has attracted great attention in biomedical applications. The advantages of possessing fluorescence for photosensitizers have made ...it possible to combine imaging and diagnosis together with PDT. The unique features of aggregation-induced emission (AIE) fluorogens provide new opportunities for facile design of light-up probes with high signal-to-noise ratios and improved theranostic accuracy and efficacy for image-guided PDT. In this review, we summarize the recent advances of AIE light-up probes for PDT. The strategies and principles to design AIE photosensitizers and light-up probes are firstly introduced. The application of AIE light-up probes in photodynamic antitumor and antibacterial applications is further elaborated in detail, from binding/targeting-mediated, reaction-mediated, and external stimuli-mediated light-up aspects. The challenges and future perspectives of AIE light-up probes in the PDT field are also presented with the hope to encourage more promising developments of AIE materials for phototheranostic applications and translational research.
AIE fluorogens provide new opportunities for the development of light-up probes for photodynamic therapy.
Nonradiative decay invariably competes with radiative decay during the deexcitation process of matter. In the community of luminescence research, nonradiative decay has been deemed less attractive ...than radiative decay. However, all things in their being are good for something and so is nonradiative decay. As the molecular motion‐facilitated nonradiative decay (MMFND) effect is inevitable in photophysical processes, it provides a new avenue to convert the harvested light energy into exploitable forms by harnessing molecular motion. In many cases, active molecular motion enables thermal deactivation from excited states. In this Minireview, recent advances in photothermal and photoacoustic systems with MMFND character are summarized. We believe that this presentation of the rational engineering of molecular motion for efficient photothermal generation will deepen the understanding of the relationship between molecular motion and nonradiative decay and navigate people to rethink the positive aspects of nonradiative decay for the establishment of new light‐controllable techniques.
In the past few years, the molecular motion‐facilitated nonradiative decay (MMFND) effect has been widely used to develop efficient photothermal and photoacoustic systems. To give a timely summary of this emerging field, the present Minireview systematically highlights the underlying mechanism, molecular design principles, and advanced applications of photothermal transduction agents with flexible molecular groups.
High-quality fluorescence bioimaging requires organic exogenous contrast agents with biocompatibility, brightness, and photostability. The recently discovered and rapidly developed ...aggregation-induced emission luminogens (AIEgens) are excellent candidates because they exhibit enhanced emission upon the restriction of intramolecular motions (RIM) effect. AIEgens are individually lit up once bound with biomolecules or influenced by the surrounding bio-environment, and abundant biological information can be acquired on the basis of high-sensitivity fluorescence imaging. In addition, AIEgen-incorporated nanoparticles possess bright fluorescence and improved photostability, which is beneficial to long-term bioimaging with high contrast and spatial resolution. In this review, we summarize the latest advances in AIEgen-based fluorescence bioimaging, as well as the relevant applications in theranostics.
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For mankind, good health is the basis of well-being; thus, frontier biomedical and (pre-)clinical studies always draw great attention from scientists. Aggregation-induced emission (AIE) is an opposite phenomenon to that documented in classic textbooks, called aggregation-caused quenching (ACQ). AIE luminogens (AIEgens) are weak or nonemissive molecules with free intramolecular motions, but they “light up” when they form aggregates and are excellent candidates as fluorescent bioprobes. In this review, we summarize the latest advances in AIEgen-based fluorescence bioimaging and theranostics. The working mechanisms of specific AIE light-up bioprobes and their biomedical applications are the key learning points. In the future, more exciting and practical ideas will be triggered to promote AIEgens for a wide range of biomedical and (pre-)clinical applications. For further information on AIE, readers are directed to our series of recently published review articles.
The rapidly developed AIEgens are ideal candidates as exogenous organic fluorescent agents. In this review, we focus on the latest advances in AIEgen-based high-quality fluorescence bioimaging, as well as the relevant applications in theranostics, including cellular imaging, cancer cell therapy, and in vivo imaging and theranostics. The biosamples of interest range from organelles to living animals.
Driven by the high demand for sensitive and specific tools for optical sensing and imaging, bioprobes with various working mechanisms and advanced functionalities are flourishing at an incredible ...speed. Conventional fluorescent probes suffer from the notorious effect of aggregation-caused quenching that imposes limitation on their labelling efficiency or concentration to achieve desired sensitivity. The recently emerged fluorogens with an aggregation-induced emission (AIE) feature offer a timely remedy to tackle the challenge. Utilizing the unique properties of AIE fluorogens (AIEgens), specific light-up probes have been constructed through functionalization with recognition elements, showing advantages such as low background interference, a high signal to noise ratio and superior photostability with activatable therapeutic effects. In this tutorial review, we summarize the recent progress in the development of specific AIEgen-based light-up bioprobes. Through illustration of their operation mechanisms and application examples, we hope to provide guidelines for the design of more advanced AIE sensing and imaging platforms with high selectivity, great sensitivity and wide adaptability to a broad range of biomedical applications.
This review summarizes the synthesis, the operation mechanism and design principles of specific AIE light-up bioprobes with applications in bio-analyte sensing, cell imaging and cancer therapy.
Triplet excitons in organic molecules underscore a variety of processes and technologies as a result of their long lifetime and spin multiplicity. Organic phosphorescence, which originates from ...triplet excitons, has potential for the development of a new generation of organic optoelectronic materials and biomedical agents. However, organic phosphorescence is typically only observed at cryogenic temperatures and under inert conditions in solution, which severely restricts its practical applications. In the past few years, room-temperature-phosphorescent systems have been obtained based on organic aggregates. Rapid advances in molecular-structure design and aggregation-behaviour modulation have enabled substantial progress, but the mechanistic picture is still not fully understood because of the high sensitivity and complexity of triplet-exciton behaviour. This Review analyses key photophysical processes related to triplet excitons, including intersystem crossing, radiative and non-radiative decay, and quenching processes, to illustrate the intrinsic structure–property relationships and draw clear and integrated design principles. The resulting strategies for the development of efficient and persistent room-temperature-phosphorescent systems are discussed, and newly emerged applications based on these materials are highlighted.Advances in molecular-structure design and modulation of the aggregation behaviour have enabled much progress in the observation of room-temperature phosphorescence from organic aggregates. This Review analyses key photophysical processes related to triplet excitons, illustrating the intrinsic structure–property relationships and identifying strategies to design efficient and persistent room-temperature-phosphorescent systems.
New, biocompatible materials with favorable antibacterial activity are highly desirable. In this work, we develop a unique conjugated polymer featuring aggregation‐induced emission (AIE) for reliable ...bacterial eradication. Thanks to the AIE and donor‐π‐acceptor structure, this polymer shows a high reactive oxygen species (ROS)‐generation ability compared to a low‐mass model compound and the common photosensitizer Chlorin E6. Moreover, the selective binding of pathogenic microorganisms over mammalian cells was found, demonstrating its biocompatibility. The effective growth inhibition of bacteria upon polymer treatment under light irradiation was validated in vitro and in vivo. Notably, the recovery from infection after treatment with our polymer is faster than that with cefalotin. Thus, this polymer holds great promise in fighting against bacteria‐related infections in practical applications.
Sunlight is the best disinfectant: A benzothiadiazole‐ and tetraphenylethene‐containing conjugated polymer (PTB‐APFB) with high ROS‐generation ability and selectivity for pathogenic microorganisms over mammalian cells was developed. In vitro and in vivo results show that PTB‐APFB inhibits growth of bacteria efficiently, leading to recovery from infection 3 days faster than cefalotin.
Organic phosphors exhibiting room‐temperature phosphorescence (RTP) in amorphous phase are good candidates for optoelectronic and biomedical applications. In this proof‐of‐concept work, a rational ...strategy to activate wide‐color ranged and persistent RTP from amorphous films by embedding electron‐rich organic phosphor into electron‐deficient matrix polyacrylonitrile (PAN) is presented. Through tailoring noncovalent interactions between the electron‐deficient PAN matrix and electron‐rich organic phosphors, an ultralong lifetime of 968.1 ms is obtained for doped film TBB‐6OMe@PAN. Control experiments conducted on the polymers polymethyl methacrylate (PMMA) and polystyrene (PS) without electron‐withdrawing groups, and organic phosphors containing electron‐withdrawing groups indicate that the persistent RTP of doped films may be triggered by strong electrostatic interactions between electron‐deficient PAN and electron‐rich organic phosphor. Further theoretical calculations including electrostatic potential distributions, binding energies, and energy decomposing analysis demonstrate that both electrostatic and dispersion interactions between electron‐deficient PAN and electron‐rich organic phosphor are responsible for the activation of persistent RTP of doped films. In addition, the doped film TBB‐6OMe@PAN still maintains brightness even after soaking in water for 12 weeks. This excellent water resistance not only is favorable for future applications but also demonstrates an advantage of electrostatic and dispersion interactions over hydrogen bonding interactions.
An instructive design rule based on the tuning of intermolecular noncovalent interactions between the electron‐deficient polyacrylonitrile (PAN) matrix and electron‐rich organic phosphors to trigger persistent room‐temperature phosphorescence (RTP) of amorphous films is presented. Both electrostatic and dispersion interactions between the PAN matrix and electron‐rich organic phosphors contribute to the activation of persistent RTP of doped PAN films.
“Aggregation‐induced emission research has brought us to the meso territory, where the synergy and cooperation between many molecules in the aggregate make it different from its elementary ...components. … Let's enthusiastically embrace the opportunity to develop meso science and to innovate meso technology, and make our planet a brighter place to live!” Read more in the Guest Editorial by B. Liu and B. Z. Tang.
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