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Single‐benzene fluorophores have attracted increasing interest owing to their simple molecular structure and unique photophysical properties. Developing novel single‐benzene fluorophores with facile synthesis, bright and tunable dual‐state emissions, and diversified functions is highly desirable. Herein, a strategy of controlling electron density on amino of 2,5‐diaminoterephthalates is proposed to modulate their dual‐state emission, acidichromism, Cu2+ detection, and lipid droplets (LDs) staining. A series of efficient dual‐state single‐benzene fluorophores based on 2,5‐diaminoterephthalate skeleton with tunable emissions in blue to red region and large Stokes shifts is facilely developed. The obtained fluorophores with various substituents on amino groups exhibit different acidichromism property. Two of fluorophores (ABB and ABM) with high electron density on amino groups exhibit high sensitivity and selectivity toward Cu2+ detection with a ratiometric and "turn‐off" fluorescence mechanism for ABM and ABB, respectively. The limit of detection for Cu2+ is determined to be 1.40 × 10−7 and 4.35 × 10−9 mol L−1 for ABB and ABM, respectively. Moreover, three of fluorophores (ABT, ABB, and ABM) with green to red emission display superior LDs‐targeting capability with high specificity, and brightness. This molecular design philosophy provides a new way of designing highly bright dual‐state fluorophores for practical applications. [ABSTRACT FROM AUTHOR]

The development of semiconducting polymers (SPs) with simultaneous second near‐infrared (NIR‐II) absorption and multimodal phototheranostic functions is highly desired in the field of oncotherapy. Aggregation‐induced emission luminogens (AIEgens) have been acknowledged to possess unique potential in integrating multiple diagnostic and therapeutic modalities into one organic molecule. Nevertheless, SPs are hard to achieve AIE activity due to their extended π‐conjugated skeletons as well as the large and planar configuration of commonly‐used electrophilic acceptor moieties. Herein, an ingenious acceptor dimerization‐based acceptor distortion strategy is proposed in current work by taking advantage of the sterically encumbered acceptors with large and planar structure for the successful construction of AIE‐active SPs. Through further finely adjusting the molecular donor–acceptor interaction strength, one of the obtained AIE‐active SPs named SP3 bearing the highest intramolecular charge transfer effect presented desired NIR‐II absorption and aggregation‐induced NIR‐II fluorescence emission, good reactive oxygen species production ability, as well as superior photothermal conversion performance. Accordingly, SP3 is selected to fabricate into nanoparticles and successfully applied in the NIR‐II laser‐triggered fluorescence‐photoacoustic imaging‐guided photodynamic‐photothermal therapy of tumors. This study represents the first NIR‐II excitable AIE‐active SP, and offers a new perspective on designing advanced multimodal phototheranostic polymers for efficient treatment of malignant tumor. [ABSTRACT FROM AUTHOR]

The traditional design strategy for constructing highly bright solid‐state luminescent materials relies on incorporating aggregation‐induced emission (AIE) scaffolds, molecular rotors, or bulky substituents to prevent close cofacial packing, which limits the strategy diversity in developing new materials. Herein, a strategy of tuning molecular packing by twisting molecular structure of conventional aggregation‐caused quenching fluorophore is proposed to endow materials with AIE effect and enhance the solid‐state fluorescence. Accordingly, a series of 1,4‐bis(diphenylamino)‐2,5‐disubstituted benzene fluorophores exhibiting AIE characteristics, high solid‐state fluorescence efficiency (up to 0.99), wide emission color tunability, and good near‐infrared (NIR) two‐photon absorption is facilely developed. All these luminogens can specifically stain intracellular lipid droplets with a high signal‐to‐noise ratio, high biocompatibility, and good photostability. Besides, the luminogens exhibit effective reactive oxygen species (ROS) generation capability upon low‐power white light irradiation. Among them, the AIE luminogen, named BDBDC, integrating the NIR emission, good NIR two‐photon absorption and strongest ROS generation demonstrates superior performances in two‐photon fluorescence imaging of various tissues and photodynamic cancer therapy. This molecular design philosophy provides a new way of designing highly bright solid‐state fluorophores for practical applications. [ABSTRACT FROM AUTHOR]

Bacterial infection at wound sites can easily induce robust inflammation. M1 macrophages at wound sites can cause cascade inflammatory reactions to mediate a vicious inflammation cycle. Meanwhile, the hypoxia situation further aggravates the destruction and contraction of blood vessels in the wound microenvironment, therefore, hindering the infected wound healing process. Here, a thermosensitive hydrogel is reported to solve the above challenges by eliminating bacteria based on the photothermal effect, regulating the inflammatory immune microenvironment, and providing oxygen (O2). In vitro and in vivo experiments confirmed that the hydrogel has great O2‐producing properties. Based on the excellent photothermal properties of AIEgens, the hydrogel has a good bactericidal effect against S. aureus (100%) and E. coli (98.85%). The RNA‐sequencing revealed that Cur@AIE@MnO2/gel can interfere with the metabolic process and genetic material repair process to impact bacteria proliferation and biofilm dispersal, thus achieving excellent anti‐bacterial efficacy. Moreover, Cur@AIE@MnO2/gel can also up‐regulate anti‐inflammatory genes, down‐regulate pro‐inflammatory genes in macrophages, and facilitate the promotion of macrophage polarization from M1 to M2 to relieve inflammation. The therapeutic experiments show that this hydrogel accelerated the wound‐healing process. Therefore, this work may open new avenues for the development of novel dressings for bacterial‐infected wounds. [ABSTRACT FROM AUTHOR]

Accurate and sensitive analysis of cancer‐associated microRNAs in living tissue is of great significance for the early diagnosis and treatment of cancer. Herein, a hierarchical nanoprobe denoted as UCNP‐QDs‐GNPs is delicately designed, where a near‐infrared (NIR) absorptive upconversion nanoparticle (UCNP) serves as the core, broad‐absorptive and bright emissive quantum dots (QDs) and emission‐quencher gold nanoparticles (GNPs) surround as satellites for microRNA imaging and image‐guided cancer therapy. Through the programmed assembly of heterobivalent DNA‐conjugated QDs with DNA‐modified GNPs and UCNPs, the well‐defined nanostructured UCNP‐QDs‐GNPs are generated with quenched fluorescence. Upon encountering the microRNA‐21 target, GNPs underwent catalytic disassembly, resulting in the concurrent recovery and amplification of fluorescence from QDs and UCNPs, which enabled sensitive imaging and quantification of microRNA‐21 within living cells. Furthermore, dithiol‐constituted aggregation‐induced emission (AIE) photosensitizers bonded on the surface of QDs, are effectively photosensitized by the QDs. The NIR excitation harvested by UCNPs is therefore efficiently transferred to QDs and subsequently converged on the AIE photosensitizers, boosting photodynamic activity for image‐guided therapy in deep‐seated tumors. The DNA‐programmed (de)hybridization strategy, facilitating the conversion of NIR excitation into imaging signals and photodynamic activity, offers a promising avenue for the early theranostics of malignancies. [ABSTRACT FROM AUTHOR]

Polymer‐based room‐temperature phosphorescence (RTP) materials show promising applications in anti‐counterfeiting. To further realize multiscale and/or multimodal anti‐counterfeiting, it is highly desirable to develop polymeric afterglow materials with multiple security features. Herein, a facile strategy is presented to endow polymeric afterglow materials with ultralong lifetime, wide color‐tunability, persistent near‐infrared (NIR) luminescence, and good water solubility via constructing non‐traditional phosphorescence resonance energy transfer (PRET) and two‐step sequential resonance energy transfer systems. Specifically, the 1‐bromocarbazole derivatives with ultralong blue‐color RTP property act as the energy donor while traditional dyes with red/NIR luminescence act as the energy acceptor. By simply regulating the doping composition and concentration of these non‐traditional energy transfer systems, persistent and multicolor organic afterglow covering from the visible to NIR region is successfully realized. Notably, compared to the single‐step PRET, the two‐step sequential resonance energy transfer has the unique advantages of higher transfer efficiency of triplet excitons from the initial donor, a wider range of color‐tunability mediated by the intermediary acceptor, and enhanced delayed fluorescence efficiency of the final acceptor. Finally, these water‐soluble polymeric afterglow materials with ultralong lifetime, wide color‐tunability, and persistent NIR luminescence show great potential applications in advanced anti‐counterfeiting and information security technologies. [ABSTRACT FROM AUTHOR]

Aggregate materials have attracted tremendous attention because of their modified or totally different properties compared with their molecular counterparts. Among various mesoscopic aggregate materials, polymeric micromaterials possess the advantages of diverse structures and flexible manufacturing, enabling them to serve as excellent carriers for aggregation‐induced emission luminogens (AIEgens) and good platforms for the research of aggregate science. In recent years, polymeric micromaterials constructed from AIEgens have witnessed rapid development and show great application potential in various fields, such as environmental sensing, multicolor displaying, and energy conversion. This review summarizes the recent progress on the design, preparation, structure, and applications of AIEgen‐based polymeric micromaterials. According to the structure features, AIEgen‐based polymeric micromaterials are divided into three categories, including microsphere, microfiber, and other‐shaped microparticles. The most representative examples in each category are highlighted by focusing on their subdivision structures such as solid microsphere, porous microsphere, microcapsule, microfiber doped‐ or coated with AIEgens, and core–shell microfiber. Finally, the challenges and prospects in this research field are also discussed. It is hoped that this review can provide readers with an overall view on the development of AIEgen‐based polymeric micromaterials and boost their further research. [ABSTRACT FROM AUTHOR]

The limited tissue penetration depth and spatial resolution are the major bottlenecks for deep‐brain imaging. In this study, molecular engineering by tailoring electron donors is conducted to develop for the first time an NIR‐II (second near‐infrared) emissive fluorescence probe, namely DCTBT, for effective deep‐brain two‐photon fluorescence imaging. Benefiting from its good biocompatibility, high photostability, bright NIR‐II emission as aggregates and large two‐photon fluorescence action cross section at the 1700 nm excitation window, DCTBT offers the imaging depths of 2180 and 1135 µm in mouse brain with removed and intact skull, respectively. These results are the record depths for brain imaging, compared to all kinds of fluorescent probes and all modalities of multiphoton microscopy at all demonstrated excitation wavelengths. Moreover, with DCTBT labeling, hemodynamic imaging of blood flow in mouse brain vessels down to a depth of 714 µm with the intact skull is achieved. Multiphoton fluorescence imaging with the NIR‐II probe DCTBT excited at the 1700 nm window may readily provide methodology for deep‐brain structural and hemodynamic research. [ABSTRACT FROM AUTHOR]

The "hot exciton" mechanism based on high-lying reverse intersystem crossing process has great advantages in achieving high-performance deep-blue organic light-emitting diodes (OLEDs). Nevertheless, how to solve the loss of high-lying excitons to improve device performance further is a pressing and challenging issue. To break through this shackle, a novel deep-blue emitter based on "exciton recovery" strategy is successfully design, namely CAT. By combining the transient absorption spectrum, theoretical calculation, magneto-electroluminescence, and transient-electroluminescence measurements, the multi-channeled pathways of excitons utilization via hot exciton and triplet-triplet annihilation processes is comprehensively demonstrated, and the proportion of singlet excitons by each channel. Finally, a high exciton utilization efficiency is successfully achieved, and the non-doped OLED based on CAT exhibit an excellent external quantum efficiency of 10.39% with the CIE coordinates of (0.15, 0.087). Furthermore, the sensitized blue fluorescent OLED by CAT as host also achieves excellent performance. More importantly, the operational lifetime of the "multi-channel" sensitized device is evaluated for the first time, performing the remarkable LT50 (lifetime to 50% of the initial luminance) of 320 h at 540 cd m-2. These results fully reveal the significance of the "exciton recovery" strategy and give new inspiration for exploring highperformance blue OLEDs. [ABSTRACT FROM AUTHOR]

Photoactivatable agent is a powerful tool in biomedicine studies due to high‐precision spatiotemporal control of light. However, those previously reported agents generally suffer from short wavelength, fluorescence self‐quenching effect, and the lack of photosensitizing property, which severely restrict their practical applications. To address these issues, molecular engineering of 1,4‐dihydropyridine derivatives is conducted to obtain an optimized agent, namely TPA‐DHPy‐Py, which exhibits low oxidation potential, high photoactivation efficiency, and excellent type I/II combined photodynamic activity. Concurrently, its photoactivated counterpart is featured by aggregation‐induced near‐infrared emission and remarkable reactive oxygen species (ROS) production efficiency. Upon photoactivation, TPA‐DHPy‐Py is capable of precisely identifying cancer cells from co‐culturing cancer cells and normal cells without the assistance of any extra targeting units, and in situ monitoring lipid droplets and endoplasmic reticulum alteration under ROS stress, as well as achieving fluorescent visualization of tumor in vivo with supremely high imaging contrast. Furthermore, the unprecedented performance on photodynamic cancer therapy is demonstrated by the significant inhibition of tumor growth. Therefore, the photoactivatable TPA‐DHPy‐Py with dual‐organelle‐targeted and excellent photodynamic activity associated with self‐monitoring ability is highly promising for cancer theranostics in clinical trials. [ABSTRACT FROM AUTHOR]

Organic ultralong room‐temperature phosphorescence (RTP) materials have promising applications in anti‐counterfeiting. To improve the encryption level, the exploration of organic materials with tunable solid‐state long persistent luminescence is in urgent need. Herein, a series of organic ultralong RTP polymeric systems are prepared by doping versatile indolocarbazole isomers into the poly(vinyl alcohol) (PVA) matrix. Notably, the doping film 11,12‐ICz@PVA exhibits excellent RTP property with an ultralong lifetime of 2.04 s and a high phosphorescence quantum yield of 44.1%. Theoretical calculations reveal that this excellent RTP property can be attributed to the strong electrostatic attraction resulting from the synergistic double hydrogen‐bond between the isomer 11,12‐ICz and PVA matrix. More impressively, color‐tunable and time‐dependent long persistent luminescence is successfully achieved through efficient phosphorescence energy transfer between the indolocarbazole isomers with ultralong blue RTP emissions and commercially available fluorescent dyes with emission colors ranging from green to red doped into the PVA matrix. Besides, diversified encryption patterns are fabricated to demonstrate the promising applications of these water‐soluble doping PVA systems with tunable solid‐state persistent luminescence in advanced anti‐counterfeiting technology. [ABSTRACT FROM AUTHOR]