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Limited by the energy gap law, purely organic materials with efficient near‐infrared room temperature phosphorescence are rare and difficult to achieve. Additionally, the exciton transition process among different emitting species in host–guest phosphorescent materials remains elusive, presenting a significant academic challenge. Herein, using a modular nonbonding orbital‐π bridge‐nonbonding orbital (n‐π‐n) molecular design strategy, we develop a series of heavy atom‐free phosphors. Systematic modification of the π‐conjugated cores enables the construction of a library with tunable near‐infrared phosphorescence from 655 to 710 nm. These phosphors exhibit excellent performance under ambient conditions when dispersed into a 4‐bromobenzophenone host matrix, achieving an extended lifetime of 11.25 ms and a maximum phosphorescence efficiency of 4.2 %. Notably, by eliminating the interference from host phosphorescence, the exciton transition process in hybrid materials can be visualized under various excitation conditions. Spectroscopic analysis reveals that the improved phosphorescent performance of the guest originates from the triplet‐triplet energy transfer of abundant triplet excitons generated independently by the host, rather than from enhanced intersystem crossing efficiency between the guest singlet state and the host triplet state. The findings provide in‐depth insights into constructing novel near‐infrared phosphors and exploring emission mechanisms of host–guest materials. [ABSTRACT FROM AUTHOR]

Understanding the properties of the precursor can provide deeper insight into the crystallization and nucleation mechanisms of perovskites, which is vital for the solution‐process device performance. Herein, we conducted a detailed investigation into the photophysics properties of CsPbBr3 precursors in a broad concentration and various solvents. The precursor transformed from the solution state into the colloidal state and exhibited aggregation‐induced emission character as the concentration increased. The aggregative luminescence from the precursors originates from the polybromide plumbous that is formed through the coordination of solvent molecules to the lead metal center. Two adducts with monodentate (PbBr2 ⋅ solvent) and bidentate (PbBr2 ⋅ 2solvent) ligands can be obtained, accompanied by emission with photoluminescence at 610 and 565 nm, respectively. Furthermore, the aggregative luminescence intensity and color could be regulated by changing the solvent and precursor ratio. Besides, we discussed the difference between the molecular aggregate in the organic system and the ionic aggregate in the inorganic system: the ionic aggregate is composed of solvated ions rather than individual molecules as in organic systems, which could possess properties that ions do not have. The fluorescence that is sensitive to Pb2+ coordination reported here could be applied to screen perovskite additives and judge the precursor aging. [ABSTRACT FROM AUTHOR]

Transition metal-containing materials with aggregation-induced emission (AIE) have brought new opportunities for the development of biological probes, optoelectronic materials, stimuli-responsive materials, sensors, and detectors. Coordination compounds containing the platinum metal have emerged as a promising option for constructing effective AIE platinum complexes. In this review, we classified AIE platinum complexes based on the number of ligands. We focused on the development and performance of AIE platinum complexes with different numbers of ligands and discussed the impact of platinum ion coordination and ligand structure variation on the optoelectronic properties. Furthermore, this review analyzes and summarizes the influence of molecular geometries, stacking models, and aggregation environments on the optoelectronic performance of these complexes. We provided a comprehensive overview of the AIE mechanisms exhibited by various AIE platinum complexes. Based on the unique properties of AIE platinum complexes with different numbers of ligands, we systematically summarized their applications in electronics, biological fields, etc. Finally, we illustrated the challenges and opportunities for future research on AIE platinum complexes, aiming at giving a comprehensive summary and outlook on the latest developments of functional AIE platinum complexes and also encouraging more researchers to contribute to this promising field. [ABSTRACT FROM AUTHOR]

Organic photosensitizers (PSs) with aggregation‐induced emission (AIE) characteristics have shown several advantages in photodynamic therapy (PDT). However, how to design PSs with the required optical and biological properties is a formidable challenge. In this work, a series of AIE active pyridine‐ and pyridinium‐functionalized carbazole with different substituents are designed and synthesized. Compared to other analogs, BK‐Pys‐BP containing benzophenone moiety on the pyridinium unit produces reactive oxygen species (ROS) efficiently in the presence of light due to its large spin‐orbit coupling constant to promote efficient intersystem crossing. Based on its structure, three molecules with enhanced donor–acceptor strength and conjugation are further investigated to realize emission covering the whole visible region. The cationic nature and excellent ROS generation ability of benzophenone‐containing AIE photosensitizers allows for specific imaging of mitochondria, killing cancer cells, and as a singlet oxygen donor to catalyze the formation of endoperoxides. Thus, the present work presents an effective strategy for creating AIE photosensitizers with efficient ROS generation for wide biological applications. [ABSTRACT FROM AUTHOR]

Life science has progressed with applications of fluorescent probes—fluorophores linked to functional units responding to biological events. To meet the varied demands across experiments, simple organic reactions to connect fluorophores and functional units have been developed, enabling the on‐demand selection of fluorophore‐functional unit combinations. However, organic synthesis requires professional equipment and skills, standing as a daunting task for life scientists. In this study, we present a simple, fast, and convenient strategy for probe preparation: co‐aggregation of hydrophobic molecules. We focused on tetrazine—a difficult‐to‐prepare yet useful functional unit that provides effective bioorthogonal reactivity and strong fluorogenicity. Simply mixing the tetrazine molecules and aggregation‐induced emission (AIE) luminogens in water, co‐aggregation is induced, and the emission of AIE luminogens is quenched. Subsequent click reaction bioorthogonally turns on the emission, identifying these coaggregates as fluorogenic probes. Thanks to this bioorthogonal fluorogenicity, we established a new time‐gated fluorescence bioimaging technique to distinguish overlapping emission signals, enabling multi‐organelle imaging with two same‐color fluorophores. Our study showcases the potential of this co‐aggregation method for the on‐demand preparation of fluorescent probes as well as protocols and molecular design principles in this approach, offering an effective solution to evolving needs in life science research. [ABSTRACT FROM AUTHOR]

Glioma is one of the most common malignant tumors of the central nervous system, leading high mortality rates in human. Aggregation‐induced emission (AIE) photosensitizers‐based photodynamic therapy (PDT) has emerged as a promising therapeutic strategy for least‐invasive treatment of glioma, which involves local irradiation of the tumor using an external near‐infrared (NIR) laser. Unfortunately, most AIE photosensitizers suffered from poorly penetration of the visible light excitation, bad spatiotemporal resolution in deep tissues and low efficient blood‐brain barrier (BBB) crossing ability, which greatly limited the clinical practice of AIE photosensitizers for especially deep‐seated brain tumor treatment. In this work, we developed a multifunctional NIR‐driven theranostic agent through hybrid of AIE photosensitizers TIND with rare‐earth doping nanoparticles (RENPs) NaGdF4:Nd/Yb/Tm with up/down dual‐mode conversion luminescence. The theranostic agent was further decorated with D‐type neuropeptide DNPY for crossing BBB and targeting glioma. Under the 808‐nm light irradiation, the down‐conversion NIR‐II luminescence could indicate the position glioma and the upconversion NIR‐I luminescence could trigger the AIE photosensitizers producing reactive oxygen species to inhibit orthotopic glioma tumor growth in situ. These results demonstrate that the integration of D‐type neuropeptide, AIE photosensitizers and RENPs could be promising candidates for in vivo NIR‐II fluorescence image‐guided through‐skull PDT treatments of brain tumors. [ABSTRACT FROM AUTHOR]