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A CsCu2I3 SA-based passively mode-locking fiber laser was demonstrated. The fiber laser could operate stably for at least five months, which will potentially unlock the pathways for ultrafast photonics based on lead-free halide perovskites.

We report a single-frequency linearly polarized Q-switched fiber laser based on a Nb2GeTe4 saturable absorber (SA). The Nb2GeTe4 SA triggers passive Q-switching of the laser, and an un-pumped Yb-doped fiber together with a 0.08-nm-bandwidth polarization-maintaining fiber Bragg grating act as an ultra-narrow bandwidth filter to realize single-longitudinal-mode (SLM) oscillation. The devices used in the laser are all polarization-maintaining to ensure linearly polarized laser output. Stable SLM linearly polarized Q-switching operation at 1064.6 nm is successfully achieved with a shortest pulse width of 1.36 μs, a linewidth of 28.4 MHz, a repetition rate of 28.3-95.9 kHz, and a polarization extinction ratio of about 30 dB. It is believed that the single-frequency linearly polarized pulsed fiber laser studied in this paper has great application value in gravitational wave detection, beam combining, nonlinear frequency conversion, and other fields.

Tantalum disulfide (TaS2), an emerging group VB transition metal dichalcogenide, with unique layered structure, rich phase diagrams, metallic behavior, higher carrier concentration and mobility is emerging as a prototype for revealing basic physical phenomena and developing practical applications. However, its photonics properties and even engineering-related processes are still rare. Here, the top-down experiment demonstration, including synthesis, thickness optimization and nonlinear optical application, has been reported. In addition, the ultrafast (∼373 fs) erbium-doped fiber pulse with a small time-bandwidth product (∼0.34) and long-term stability (∼25 days) was realized using the nonlinear absorption properties of the high-quality 2H-TaS2 nanosheet. These results suggest an experimental route for further ultrafast photonics exploration based on metallic transition metal dichalcogenides.

Gallium sulfide (GaS), with a hexagonal structure, has received extensive attention due to its graphene-like structure and derived optical properties. Here, high-quality GaS was obtained via chemical vapor synthesis and then prepared as a saturable absorber by the stamp-assisted localization-transfer technique onto fiber end face. The stability of the material and the laser damage threshold are maintained due to the optimized thickness and the cavity integration form. The potential of the GaS for nonlinear optics is explored by constructing a GaS-based Erbium-doped mode-locked fiber laser. Stable femtosecond (~448 fs) mode-locking operation of the single pulse train is achieved, and the robust mode-locked operation (>30 days) was recorded. Experimental results show the potential of GaS for multi-functional ultrafast high-power lasers and promote continuous research on graphene-like materials in nonlinear optics and photonics.

Two-dimensional (2D) arsenic–phosphorus (AsP), as a derivative of black phosphorus (BP), has achieved great progress in regards to preparation methods, property modulation, and front application, which can be attributed to the following two points. The first is that a method has been developed of alloying BP with the congener element arsenic to produce high-quality AsP; the second is that stable AsP possesses unique electronic and optical properties. To conclude the continuous and extensive research, this review focuses on synthesis details, modulation strategies, and application advances of stable AsP. Firstly, several pathways to prepare AsP with different phases are listed. Secondly, multiple solutions to optimize the electronic properties of AsP are discussed, such as strain regulation and composition tuning, and especially composition tuning of AsP including element modification, atomic substitution, and dopant participation, which can bring about adjustments of the lattice structure, bandgaps, and electronic properties. Based on the regulated AsP, applications in infrared photodetectors, high-performance transistors, and efficient-energy storage devices and so on have been widely developed. Although there are challenges ahead, this review may bring new insights into and inspirations for further development of 2D AsP-based materials and devices.

Traditional human activity recognition (HAR) based on a motion sensor adopts sliding window labeling and prediction. This method faces the multi-class window problem, which mistakenly labels different classes of sampling points within a window as a class. In this paper, we propose a novel HAR method based on U-Net to overcome the multi-class problem, performing activity labeling and prediction of each sampling point. The motion sensor data collected from the wearable sensors are mapped into an image with the single-pixel column and multi-channel, and then, it is input into the U-Net network to complete the pixel-level activity recognition function. We design a complete HAR framework based on U-Net to realize the dense prediction of motion sensor data, including data preprocessing, dense prediction, and post analysis. In order to further improve the dense prediction performance, we propose the post-correction algorithm for the dense prediction results on the basis of the activity misalignment analysis. The extensive experimental results demonstrate that our U-Net method performs better than the traditional machine learning and deep learning methods based on the sliding window prediction. And it also outperforms full convolutional network (FCN), SegNet, and Mask R-CNN based on the dense prediction on the four datasets. Moreover, it also shows the better robustness and excellent performance of recognition on the short-term activities and minority classes. We release a new dataset named Sanitation, which includes seven types of daily work activity data of sanitation workers to evaluate the HAR algorithm's performance.

In this paper, the enhanced photonic spin hall effect (PSHE) of reflected light at terahertz (THz) frequencies is achieved by using a multilayer structure consisting of Bi2Se3, spacer layer, and distributed Bragg reflector structure. This enhanced spin hall effect (SHE) phenomenon originates from the excitation of optical Tamm states (OTSs) at the interface between the Bi2Se3 and distributed Bragg reflector structure. It is found that the PSHE of the reflected light can be flexibly controlled by properly varying the Fermi energy of the topological insulators. Moreover, the spin behavior of the composite structure is also proved sensitive to incidence angle and the dispersion characteristics of the spacer layer, thus making this configuration an effective candidate for developing photonic devices based on photonic PSHE at the terahertz range.

A bioprobe, TPE-Zn

Here we propose a planar graphene/dielectric multilayer configuration to realize low threshold optical bistability at terahertz frequencies. This low-threshold optical bistability is achieved by field enhancement owing to the couple of the surface plasmon polaritons and the planar waveguide mode. We discussed the influence of graphene sheets and planar waveguide mode on the hysteretic response of the TM-polarization reflected light. It is found that the switch-up and switch-down threshold electric fields required to observe the optical bistable behavior are affected markedly by the excitation of surface plasmon polaritons or planar waveguide mode. Besides, the switching threshold value can be further reduced by coupling the surface plasmon polaritons and planar waveguide mode, hence providing a way of realizing low threshold and tunable optical bistable devices.

Two-dimensional (2D) materials have attracted extensive interests due to their wide range of electronic and optical properties. After continuous and extensive research, Black phosphorus (BP), a novel member of two-dimensional layered semiconductor material, benefit for the unique in-plane anisotropic structure, controllable direct bandgap characteristic, and high charge carrier mobility, has attracted tremendous attention and successfully applied in ultrafast pulse generation. This article, which focuses on near-infrared ultrafast laser demonstration of BP, present discussion of preparation methods for high quality BP nanosheet, various BP based ultrafast lasers in the spatial/temporal domain, and the future research needs.

The development of new polymerization reactions conducted under monomer non-stoichiometric conditions has great academic and industrial significance. Herein we report such a new route for synthesizing functional polynaphthalenes (PNs). The polycoupling reactions of benzoic acid and its derivatives (1) with 4,4′-(1,6-hexylenedioxy)bis(diphenylacetylene) (2) proceed smoothly in o-xylene in the presence of [Cp*IrCl2]2 and Ag2CO3 at 140 °C, generating multisubstituted PNs with high molecular weights (Mw up to 228 700) in high yields (up to 98%). The effect of monomer stoichiometry on the polymerization was systematically investigated and the best result was obtained at a molar feed ratio of 1 : 2 of 2 : 1. The associated mechanism for the monomer non-stoichiometry enhancement effect was proposed. All the obtained PNs show good thermal stability and excellent optical transparency. They possess good film-forming ability and their thin films exhibit high refractive indices (n = 1.7653–1.6354). Polymers constructed from non-emissive monomers show light emission in solutions due to the generation of fluorophores in situ during the polymerization. The polymer carrying a tetraphenylethene motif is weakly emissive in solution but emits intensely when aggregated, demonstrating a phenomenon of aggregation-induced emission. The efficient solid-state emission and good photosensitivity enable it to be utilized as a material for fabricating two-dimensional fluorescent photopatterns by irradiating its thin films under UV light through copper masks.

We herein report a facile and efficient multicomponent click polymerization route to construct fused heterocyclic polymers with advanced functionalities. Mediated by CuI and trimethylamine at room temperature, diynes, disulfonyl azide, and salicylaldehyde, or o-hydroxylacetophenone undergo polymerizations efficiently and smoothly, affording high-molecular-weight poly(iminocoumarin)s (Mw up to 64 600) in satisfactory yields (up to 99%). This multicomponent click polymerization approach enjoys remarkable merits of both multicomponent reactions and click reactions, such as simple operation, high reaction efficiency and isolation yield, mild reaction conditions, and common substrates. The resulting polymers possess outstanding film-forming ability, high thermal stability, and good morphological stability. With tetraphenylethene luminogens embedded in the polymer chains, their solutions fluoresce weakly, whereas their aggregates emit intensely, demonstrative of a typical feature of aggregation-enhanced emissio...

A bioprobe, TPE-Zn2BDPA, with aggregation-induced emission characteristics was designed and synthesized to differentiate the early and late stages of apoptosis mediated by H2O2. TPE-Zn2BDPA does not respond to healthy cells, but it selectively lights up the membrane of apopotic cells in both stages with brighter fluorescence in the late apoptotic stage.

An atom-economical and straightforward polymerization method to generate functional isocoumarin-containing polymers was developed in this work. The oxidative polycoupling of 4,4′-(1,2-diphenyl-1,2-ethenylene)dibenzoic acid and 1,6-bis[4-(phenylethynyl)phenoxy]hexane proceeds efficiently in dimethylformamide under nitrogen or air in the presence of [Cp*RhCl2]2 and a catalytic amount of Cu(OAc)2·H2O at 120 °C for 24 h, generating a polymer with a high molecular weight of up to 42 900 in a high yield of up to 92.9%. An isocoumarin framework forms in situ during the polymerization from readily accessible and inexpensive monomers. The resulting polymer possesses good thermal stability, optical transparency and film-forming ability. Its thin film exhibits high and UV-tunable refractive indices (n = 1.9697–1.6507) in a wide wavelength region of 390–890 nm. A two-dimensional fluorescent photopattern can be readily fabricated by irradiating its thin film under UV light through a copper mask. Due to the incorporation of tetraphenylethene units in the monomer, the polymer obtained is weakly emissive in solution but it emits intensely when aggregated, demonstrating a phenomenon of aggregation-induced emission.

Green chemistry shows the advantages of a simple synthetic process, low cost of production, a clean working environment and reduction of harmful wastes. In this work, we used naturally occurring materials to prepare functional polymers. The polymerizations of 1,2-bis(4-ethynylphenyl)-1,2-diphenylethene, disulfonyl azide, and water together with ethanol were catalyzed by copper(I) iodide and triethylamine in a mild, efficient and atom-economical fashion, generating soluble polymers with high molecular weights in satisfactory isolation yields. By controlling the adding amount of water and ethanol, the ratio of amide and imidate units in the polymer chain could be readily modulated. Their good solubility allows the polymers to show outstanding film-forming ability. Due to the tetraphenylethene moieties embedded in the polymer chains, the polymer solutions emit faintly, but their aggregates fluoresce intensely, demonstrating a characteristic of aggregation-induced emission. Such results are anticipated to accelerate the development of efficient and economical one-pot multicomponent polymerizations toward functional polymeric materials.

Multicomponent sequential reactions have recently received much attention owing to their outstanding advantages, such as simple operation, atom economy, and environmental benefit. In this work, we report a new multicomponent sequential reaction and the corresponding multicomponent sequential polymerization approach to construct conjugated structures with advanced functionalities. By employing 1,8-diazabicyclo[5.4.0]undec-7-ene as an additive, alkynes, carbonyl chloride and amino ester salts undergo a one-pot three-component sequential reaction successfully. Similarly, the derived multicomponent sequential polymerizations of diyne, terephthaloyl chloride and amino ester proceed smoothly in a regio- and stereoregular manner and generate conjugated nitrogen-substituted poly(enaminone)s with high molecular weights in satisfactory yields. All the resulting polymers are soluble in common solvents, and possess high thermal stability and good film-forming ability. Interestingly, the incorporation of optically active chiral amino esters as pendants leads to polymeric products with helical rotating backbones, as revealed by their circular dichroism spectra in the solutions and as cast films. With fluorescent tetraphenylethene moieties embedded in the polymer chains, the polymers display a phenomenon of aggregation-enhanced emission. They emit weakly in the solution state, but fluoresce intensely as aggregates. Moreover, the thin films of the polymers exhibit high light refractivity (n = 1.9305–1.5992) in a wide wavelength region (400–1000 nm), which can be readily modulated by UV irradiation. Additionally, the polymeric products with photosensitivity can generate highly resolved two-dimensional luminescent patterns by UV treatment.

The development of an efficient transition metal-free polymerization route has been an active research topic in polymer science owing to its low synthetic cost and decreased metal residue and hence elevated material performance in the products. In this work, we report a new such method for constructing conjugated polydiynes based on the organic reaction of 1-haloalkyne. In the presence of potassium iodide, the polymerizations of 1,2-bis[4-(iodoethynyl)phenyl]-1,2-diphenylethene (1), 1,4-bis(2-iodoethynyl)benzene (2) and 4,4′-bis(2-iodoethynyl)-1,1′-biphenyl (3) proceed smoothly in N,N-dimethylformamide at 120 °C under nitrogen, producing P1–3 consisting of alternate aromatic and 1,3-diyne moieties in moderate to satisfactory yields. While P1 possesses good solubility in common organic solvents, P2 and P3 are insoluble due to their rigid structures. All the polymers are thermally stable, losing 5% of their weight at a high temperature of up to 352 °C. A homogeneous film of P1 can be readily obtained by spin-coating its solution, which shows high and UV-tunable refractive index (n = 2.1125–1.7747) in a wide wavelength range (400–900 nm). A well-defined fluorescent photopattern can be generated by UV irradiation of the polymer film through a copper mask. This work thus opens a new avenue for constructing conjugated polymers with advanced functionalities.

A metal-free, multicomponent polymerization route for the facile construction of stereoregular functional polymers has been developed in this work. Boron trichloride-mediated polycoupling of terminal diynes and monoaldehydes was carried out in a stereoselective manner in dichloromethane under mild conditions and nitrogen, affording poly(dichloro pentadiene)s (PDPDs) with a predominant (E,Z)-configuration in high yields (up to 92%) with high molecular weights (Mw up to 174300) in several hours. All the polymers possessed good solubility in common organic solvents and showed high thermal stability, losing merely 5% of their weight at high temperatures of up to 384 °C. PDPDs carrying tetraphenylethylene (TPE) moieties exhibited a unique photophysical phenomenon of aggregation-induced emission (AIE): the emission of their weakly emissive solutions was turned on upon aggregation formation. Thin solid films of the polymers with good quality were readily fabricated on silica substrates by a simple spin-coating technique, and showed pretty high refractive indices (RI = 1.7937–1.4873) in a wide wavelength region of 400–890 nm. The PDPDs are photosensitive and such a property enables them to be promising materials for fabricating fluorescence patterns by the photolithography process.

Heterocyclic polymers have gained enormous attention for their unique functionalities and wide applications. In contrast with the well-studied polymer systems with five- or six-membered heterocycles, functional polymers with readily openable small-ring heterocycles have rarely been explored due to their large synthetic difficulty. Herein, a facile one-pot multicomponent polymerization to such polymers is developed. A series of functional polymers with multisubstituted and heteroatom-rich azetidine frameworks are efficiently generated at room temperature in high atom economy from handy monomers. The four-membered azetidine rings in the polymer skeletons can be easily transformed into amide and amidine moieties via a fast and efficient acid-mediated ring-opening reaction, producing brand-new polymeric materials with distinctive properties. All the as-prepared azetidine-containing polymers exhibit intrinsic visible luminescence in the solid state under long-wavelength UV irradiation even without conventionally conjugated structures. Such unconventional luminescence is attributed to the clusteroluminogens formed by through-space electronic interactions of heteroatoms and phenyl rings. All the obtained polymers show excellent optical transparency, high and tunable refractive indices, low optical dispersions and good photopatternability, which make them promising materials in various advanced electronic and optoelectronic devices. The ring-opened polymers can also function as a lysosome-specific fluorescent probe in biological imaging.

The development of efficient multicomponent polymerization (MCP) to prepare heteroatom-rich macromolecules, especially those with complicated structures and multifunctionality, is gathering increasing research interest from chemists. In this work, we report a facile one-pot three-component polymerization method to prepare multifunctional polymers. The Cu-catalyzed polycoupling reactions of aromatic diynes, disulfonyl azide, and optically active amino esters proceeded in a mild manner under room temperature, furnishing regular poly(N-sulfonylamidine)s with high molecular weights (Mw up to 35 900) and in satisfactory yields (up to 87%). The model compound was synthesized to verify the complete transformation from monomers to the desired polymeric products. All the polymers possess excellent solubility in common organic solvents, good film-forming ability, and high thermal stability. The backbones of the polymers are induced to helically rotate by the optically active chiral amino esters, resulting in the ci...

Multicomponent tandem reactions (MCTRs), with multiple bonds formed in a highly concise fashion in a single vessel, have been noted as one of the most powerful and popular synthetic strategies in modern organic chemistry. Attracted by their operational simplicity, synthetic efficiency, high atom economy, and environmental benefit, the MCTRs and the corresponding multicomponent tandem polymerizations (MCTPs) of alkynes, carbonyl chlorides, and aliphatic/aromatic thiols were developed. By combining the Sonogashira coupling reaction between alkynes and carbonyl chlorides, and the hydrothiolation reaction of electron-deficient alkynone intermediates, high atom economy was achieved in such one-pot, two-step, three-component reactions/polymerizations. The MCTPs can proceed efficiently under mild conditions near room temperature to afford sulfur-rich polymers with high molecular weight, high yield, high regioselectivity, and good stereoselectivity. Through the MCTPs of different combination of monofunctional and...

Herein we reported a new facile one-pot multicomponent sequential polymerization approach for the construction of conjugated nitrogen-substituted polymers. Catalyzed by Pd(PPh3)2Cl2/CuI at room temperature, the coupling-hydroamination polymerizations of 1,2-bis(4-ethynylphenyl)-1,2-diphenylethene, terephthaloyl chloride and secondary aliphatic amines proceeded smoothly in a regioregular and stereoselective manner, furnishing poly(arylene enaminone)s (PAEs) with high molecular weights (Mw up to 34 600) in satisfactory yields (up to 91%). A model compound was elaborately designed and synthesized to verify the chemical structures of the corresponding polymeric products. All the PAEs exhibited good solubility in common organic solvents and were thermally stable with degradation temperatures of up to 313 °C under nitrogen. They possessed good film-forming ability and their thin solid films showed high refractive indices (RI = 1.9318–1.6320) in a wide wavelength region of 400–1000 nm, whose value could be further modulated by UV irradiation. Although the model compound and the PAEs possessed a typical aggregation-induced emission luminogen of tetraphenylethene, they were weakly emissive either in solution or in the aggregated state, due to the photoinduced electron transfer (PET) effect. Their strong emission in the aggregated state could be readily recovered by the blockage of the PET effect through protonation of the amino groups. Thus, this work demonstrated a powerful polymerization tool to access conjugated polymeric materials with pH-responsive properties.

Self-assembling of luminescent molecules into one-dimensional nanostructures is of particular interest in fabricating nanoscale electronic and photonic devices. Herein, we report the rational design and synthesis of a chiral fluorescent tetraphenylethylene derivative containing L-leucine methyl ester moiety (TPE-Leu). In solution, TPE-Leu is non-emissive and CD silent, but becomes highly emissive and CD active upon aggregation, exhibiting aggregation-induced emission (AIE) and chirality (AIC). Upon evaporation of its solution, TPE-Leu readily self-assembles into helical fluorescent micro/nanofibers, which show circularly polarized luminescence (CPL) and have the CPL dissymmetry factors in the range of 0.02–0.07. This molecular design combines the AIE effect, chirality, and self-assembling capability together, and is highly efficient in constructing novel functional micro/nanomaterials with well-defined structures and enhanced emission.

Polyhydroaminations for the synthesis of stable nitrogen-substituted conjugated polymers with well-defined structures remain a great challenge and the control of the regio- and stereochemistry of the enamine product of the hydroamination is non-trivial. Herein we report an efficient tandem polymerization of alkynes, carbonyl chlorides and primary amines to afford regio- and stereoregular conjugated poly(enaminone)s. The atom-economical one-pot sequential polycoupling–hydroamination polymerization catalyzed by Pd(PPh3)2Cl2/CuI proceeded smoothly under mild conditions, furnishing nitrogen-substituted conjugated polymers with high molecular weights (up to 46 100) and high regio-/stereoregularities (100%) in nearly quantitative yields (up to 99%). The single crystal structure of the model compound, together with the NMR spectra comparison of the model compound and polymers provided direct insight into the stereoselectivity of the polymerization, verifying the sole Z-vinylene isomer of the polymers. Through the exquisite structural design strategy of the intramolecular hydrogen bond of the resulting hydroamination product, the tautomerization between enamine and imine as well as E/Z isomerization was successfully avoided, providing products with high chemical stability and sole Z-vinylene isomers. The conjugated polymers display excellent solubility in common organic solvents, good film-forming ability, and high thermal stability. The hydrogen bond formation of the polymer helps to block the potential photo-induced electron transfer process and the polymer shows a unique aggregation-enhanced emission phenomenon: their solutions are weakly emissive, while their nanoaggregates or thin films are brightly emissive. Furthermore, thin films of the polymers enjoy high refractive indices (1.9103–1.6582) in a wide wavelength region of 400–1000 nm, which can be further modulated by UV irradiation. Meanwhile, well-resolved fluorescent photopatterns of the polymers can be fabricated through the UV irradiation of thin films via a copper photomask.

Organic luminescent materials carrying no phenyl rings have attracted much interest from researchers due to their excellent biocompatibility and good biodegradability, which make them available for...

The metal-free click polymerization (MFCP) of activated alkynes and azides or activated azide and alkynes have been developed into powerful techniques for the construction of polytriazoles without the obsession of metallic catalyst residues problem. However, the MFCP of activated azides and alkynes is rarely applied in preparation of functional polytriazoles. In this paper, soluble multifunctional polytriazoles (PIa and PIb) with high weight-average molecular weights (Mw up to 32 000) are prepared via the developed metal-free poly-cycloaddition of activated azide and alkynes in high yields (up to 90%). The resultant PIa and PIb are thermally stable, and show aggregation-induced emission characteristics, enabling their aggregates to detect explosives with superamplification effect. Moreover, thanks to their containing aromatic rings and polar moieties, PIa and PIb exhibit high refractive indices. In addition, they can also be cross-linked upon UV irradiation to generate 2D fluorescent patterning due to their remaining azide groups and containing ester groups. Thus, these multifunctional polytriazoles are potentially applicable in the optoelectronic and sensing fields.

The development of efficient multicomponent tandem polymerization is attractive but challenging, owing to the limitations such as the required strict stoichiometric balance, the poor solubility and low molecular weight of the polymer products, etc. In this work, an efficient one-pot three-component polymerization of alkyne, carbonyl chloride and ethyl 2-mercaptoacetate was reported. The polymerization of aromatic diyne (1), diaroyl chloride (2), and ethyl 2-mercaptoacetate (3) catalyzed by Pd(PPh3)2Cl2/CuI proceeded smoothly under mild conditions at room temperature without strict stoichiometric balance of the monomers, affording poly(arylene thiophenylene) (P1) with high molecular weights (Mw up to 156 000) in excellent yields (up to 97%). Single crystal structure of model compound 4 was obtained, aiding in verification of the complete transformation to the desired polymer product. The thiophene-containing conjugated polymer possesses good solubility in common organic solvents, good film-forming ability ...

The self-assembly of fluorescent molecules is of general interest due to the potential fabrication of nanostructured materials. The fabrication of fluorescent nanowires remains challenging because the inherent aggregation in the self-assembly process quenches the fluorescence of the molecules in many cases. In this work, new aggregation-induced emission-active tetraphenylethene derivatives were used to fabricate fluorescent nanowires facilely by self-assembly processes. Moreover, the fluorescent nanowires can further self-assemble to form macroscopic fluorescent thin films in the solution. The detailed self-assembly processes from nanospheres to nanowires, and further to fluorescent macroscopic thin films were elucidated and evidenced by SEM imaging. A phenomenon of photo-induced emission enhancement was observed, owing to the photo-induced ring-closing oxidative reaction of the tetraphenylethene core.

A mitochondrion-specific AIEgen is a theranostic molecule, with the function of lighting up and killing cancer cells rather than normal cells., Cancer is the leading cause of death worldwide. With the advantages of low cost, high sensitivity and ease of accessibility, fluorescence imaging has been widely used for cancer detection in the scientific field. Aggregation-induced emission luminogens (AIEgens) are a class of synthesized fluorescent probes with high brightness and photostability in the aggregate state. Herein, a new positively-charged AIEgen, abbreviated as TPE-IQ-2O, is designed and characterized. TPE-IQ-2O not only can distinguish cancer cells from normal cells with high contrast with the aid of the difference in mitochondrial membrane potential as well as the quantity of mitochondria, but it also works as a promising photosensitizer to kill cancer cells through generation of reactive oxygen species upon white light irradiation, thus making it a promising AIE theranostic system.

The 1,3-dipolar cycloaddition of azides and active internal alkynes has been well studied, but is rarely utilized as a tool for polymer preparation. In this work, an efficient polymerization route is developed. Polycycloaddition of diazide (4) and bis(benzoylethynyl)-benzenes and -butane (3) at elevated temperature has produced the first examples of soluble 1,4,5-trisubstituted polytriazoles PI with satisfactory molecular weights (M(w) up to 16 400) in excellent yields (up to 98.6%). All the obtained polymers are thermally stable, losing merely 5% of their weights at temperatures higher than 367 °C. They exhibit higher refractive indices than some commercial plastics and can be crosslinked upon UV irradiation to generate a 3D photopattern with high resolution. The metal-free feature of such a methodology offers a facile tool to prepare functional materials free from the contamination of metal species.

A luminogen with aggregation-induced emission characteristics is reported for bacterial imaging and antibiotics screening studies. The luminogen can light up bacteria in a wash-free manner, which simplifies the imaging process and increases its accuracy in bacterial detection. It can also be applied to high-throughput screening of antibiotics and fast evaluation of bacterial susceptibility, giving reliable results in less than 5 h.

We report a dual functional aggregation-enhanced emission (AEE) molecule, TPE-IQ, which could target and illuminate mitochondria in both live and fixed cells with superb selectivity and high signal-to-noise ratio. More intriguingly, TPE-IQ can serve as a photosensitizer to generate reactive oxygen species (ROS) in the mitochondria region to induce cell apoptosis.