High Fluorescence Efficiency Research Articles

Organic Nanoparticles with Aggregation-Induced Emission and Two-Photon Excitation for Fluorescence Imaging of Living Cells/Tissues.

Aggregation-induced emission (AIE) nanoparticles (NPs) have been applied in bioimaging for cancer diagnosis due to high fluorescence efficiency. However, the poor cell permeability as well as autofluorescence of biological cells/tissues caused by ultraviolet (UV) irradiation is still the key problem of AIE luminophores for biological imaging. Here, we report green-emitting organic AIE luminophores for fluorescence imaging of living cells/tissues, which possess high fluorescence quantum yields and strong AIE under two-photon excitation with near-infrared light beyond 800 nm. These AIE luminophores can bind with bovine serum albumin (BSA) to form biocompatible BSA/AIE-NPs due to their terminal aldehyde groups providing specific anchor sites with the receptor groups in BSA. Furthermore, one/two-photon fluorescence bioimaging for Hela cancer cells has been successfully carried out with BSA/AIE-NPs as the fluorescent probe, and BSA/AIE-NPs show excellent stain properties with a fast permeability of only 5 min, high cellular uptakes, and strong fluorescence. The results demonstrate the great advantages of BSA/AIE-NPs in fast fluorescence biological imaging as well as further cancer diagnosis and therapy.

Novel BODIPY Conjugates with Myrtenol: Design, Spectral Characteristics, and Possibilities for Practical Application

The synthesis of new fluorescent probes, based on biocompatible luminophors and exhibiting various specificities, is intensively developed worldwide. Many luminophors contain a hydrophobic group that limits their application for cell staining under vital conditions. Herein, we report the synthesis of two BODIPY molecules—BF2-meso-(4-butan/pentanamido-N-(((1S,5R)-6,6-dimethylbicyclo [3.1.1]hept-2-en-2-yl)methyl)-N,N-dimethylpropan-1-aminium)-3,3′,5,5′-tetramethyl-2,2′-dipyrromethene bromides—designed as 10, 11 with a spacer of either four or three CH2 groups in length, respectively. These molecules present conjugates of BODIPY luminophors with (+)-myrtenol via a quaternary ammonium group. Both terpene-BODIPY conjugates demonstrated high fluorescence efficiency in various solvents such as OctOH, DMSO and water, and were characterized by their stability at pH 1.65–9.18. The fusion of the myrtenol, a monocyclic terpene, to the BODIPY fluorophore in the meso-substituent facilitated their penetration into the filamentous fungi Fusarium solani, while impairing the binding of the latter with S. aureus, K. pneumoniae and P. aeruginosa. The additional quaternary ammonium group between the myrtenol and fluorophore moieties restored the bacterial cell-staining while it did not affect the staining of fungi. Finally, the BODIPY conjugate 11 was able to stain both Gram-positive and Gram-negative bacteria by its interaction with their cell wall (or the membrane), as well as penetrating into filamentous fungi F. solani and staining their mitochondria.

Synthesis and characterization of 8-aminoquinoline photocages for biological applications

Inspired by the 8-dimethylaminoquinoline (8-DMAQ) caging chromophore, photocleavable 8-aminoquinoline derivatives were prepared with the aim of furnishing a robust synthetic pathway for novel cage scaffolds. The four-step versatile process allows a facile introduction of various amino-substituents and its overall yield is feasible for scale-up. The novel photocages showed high photolysis efficiency and low fluorescence, comparable to literature reference compounds (as 8-DMAQ-OAc, BHQ-OAc and CyHQ-OAc), demonstrating the utility of the probes for uncaging applications. Several derivatives allow further functionalizations on the side chain, therefore could serve as building blocks for the design of more complex photoresponsive systems.

Solid-state fluorophores featuring a combined hybridized local and charge transfer excited state and aggregation-induced emission as efficient emitters for electroluminescent devices

Solid-state fluorophores with high fluorescence efficiency and charge transportation have always been of great interest as emitters for organic light-emitting diodes (OLEDs). Mostly, donor (D)-acceptor (A) molecules holding prominent intramolecular charge transfer exhibit low fluorescence quantum yield. Here, we report a series of D–A–D type hybridized local and charge transfer (HLCT) excited state fluorophores (TBz, T2FBz, TFBz, TBBz, TPyBz, and TNz) containing benzo[c][1,2,5]thiadiazole (Bz) and its derivatives (5,6-difluoro-2,1,3-benzo[c][1,2,5]thiadiazole (2FBz), 5–2,1,3-benzo[c][1,2,5]thiadiazole (FBz), naphtho[1,2-c:5,6-c']bis([1,2,5]thiadiazole) (BBz), [1,2,5]thiadiazolo[3,4-c]pyridine (PyBz), and naphtho[2,3-c][1,2,5]thiadiazole (Nz)) as acceptor cores end-capped with tetraphenylethylene (TPE) as a donor and aggregation-induced emission (AIE)-luminogen. The different variations in the molecular structures of the cores render compounds with wide-ranging electronic and photophysical properties. The HLCT and AIE properties of these compounds are confirmed by theoretical calculations, solvatochromic behaviors, and transient decay lifetimes analyses. They show intense fluorescence emissions with good thermal stability and hole mobility, leading to effective utilization as emitters in OLEDs. The resulting devices demonstrate strong green to orange-red electroluminescent (EL) emissions with decent EL performance (Lmax of 6030–20220 cd m−1, CEmax of 6.26–13.18 cd A−1, and EQEmax of 3.51–5.11%). Among them, OLED fabricated with TBBz realized the best EL performance (Lmax of 11115 cd m−2, CEmax of, 12.03 cd A−1, EQEmax of 5.11%) with orange emission (λEL = 592 nm, CIE coordinates (0.53, 0.46)).

Dynamic bioorthogonal imaging using a tetrazine NIR-AZA fluorogenic probe

Tetrazine fluorogenic probes are of high value due to their ability to modulate emission intensity from low to high in response to inverse electron demand Diels-Alder cycloadditions with dienophiles. In this study, a tetrazine substituted BF2-azadipyrromethene probe and a related model tetrazine were investigated for their reactivity with strained alkyne and alkene dienophiles to identify the optimal probe for cellular use. Specifically, the reactivity of 2-deoxy-d-glucose substituted 1-methyl cyclopropene and bicyclononyne was tested, with the latter demonstrating superior reactivity with complete reactions observed within 15 min. Moreover, the tetrazine substituted BF2-azadipyrromethene showed a strong fluorogenic response at a λmax of 715 nm in aqueous solution as the cycloaddition proceeded. The high reaction efficiency and significant 43-fold fluorescence enhancement factor encouraged its translation to bioorthogonal cell imaging. Pre-incubating HeLa Kyoto cells with 2-deoxy-glucose-alkyne dienophile followed by treatment with the BF2-azadipyrromethene fluorogenic probe, allowed dynamic imaging of the bioorthogonal reaction in live cells. Pre-incubation of 2-deoxy-glucose alkyne for 24 h with subsequent fluorogenic cycloaddition indicated that bioorthogonal reaction occurred in subcellular regions such as the mitochondria. This study showed the potential for real-time observation of intra-cellular fluorogenic cycloadditions in the near-infrared spectral region.

Ultra-stable perovskite quantum dot composites encapsulated with mesoporous SiO2 and PbBr(OH) for white light-emitting diodes.

Lead halide perovskite quantum dots (QDs) with high fluorescence efficiency and high color purity have a broad application prospect in the field of backlight display, but poor stability has been a key factor limiting their commercialization. Herein, we successfully synthesized CsPbBr3 QDs-KIT-6 (CsPbBr3 -K6) composite by using KIT-6 molecular sieve as the limited template with a simple high temperature solid-phase method. Further, the semi-protected CsPbBr3 QDs in KIT-6 frame will spontaneously hydrolyze when encountering water, and finally the double-encapsulated CsPbBr3 QDs-KIT-6@PbBr(OH) (CsPbBr3 -K6@PbBr(OH)) composite are obtained. CsPbBr3 -K6@PbBr(OH) composite shows excellent green emission properties, including a photoluminescence quantum yield (PLQY) (~73%) and a narrow emission linewidth of 25 nm. It is interesting that, the composite has excellent stability, including water stability without attenuation of fluorescence intensity after soaking in water for 60 days, thermal stability of 120°C heating-cooling cycle, and excellent optical stability without attenuation under continuous ultraviolet irradiation.

Efficient Reverse Intersystem Crossing in Carbene‐Copper‐Amide TADF Emitters via an Intermediate Triplet State

AbstractThe mechanism behind reverse intersystem crossing (rISC) in metal‐based TADF emitters is still under debate. Thermal rISC necessitates small singlet/triplet energy gaps as realized in donor‐acceptor systems with charge‐transfer excited states. However, their associated spin‐orbit couplings are too small to account for effective rISC. Here, we report the first nonadiabatic dynamics simulation of the rISC process in a carbene‐copper(I)‐carbazolyl TADF emitter. Efficient rISC on a picosecond time scale is demonstrated for an initial triplet minimum geometry that exhibits a perpendicular orientation of the ligands. The dynamics involves an intermediate higher‐lying triplet state of metal‐to‐ligand charge transfer character (3MLCT), which enables large spin‐orbit couplings with the lowest singlet charge transfer state. The mechanism is completed in the S1 state, where the complex can return to a co‐planar coordination geometry that presents high fluorescence efficiency.

Efficient Reverse Intersystem Crossing in Carbene-Copper-Amide TADF Emitters via an Intermediate Triplet State.

The mechanism behind reverse intersystem crossing (rISC) in metal-based TADF emitters is still under debate. Thermal rISC necessitates small singlet/triplet energy gaps as realized in donor-acceptor systems with charge-transfer excited states. However, their associated spin-orbit couplings are too small to account for effective rISC. Here, we report the first nonadiabatic dynamics simulation of the rISC process in a carbene-copper(I)-carbazolyl TADF emitter. Efficient rISC on a picosecond time scale is demonstrated for an initial triplet minimum geometry that exhibits a perpendicular orientation of the ligands. The dynamics involves an intermediate higher-lying triplet state of metal-to-ligand charge transfer character (3 MLCT), which enables large spin-orbit couplings with the lowest singlet charge transfer state. The mechanism is completed in the S1 state, where the complex can return to a co-planar coordination geometry that presents high fluorescence efficiency.

Twisted-terphenyl conjugated carbazole derivatives with aggregation-induced emission enhancement for deep-blue fluorescence in the solid state

Scarcity of highly efficient, stable and pure deep-blue chromophores is a key impact on application of OLEDs. In this study, four bipolar molecules were designed and synthesized using carbazolyl as donor and oxadiazole/triazole as acceptors via a twisted terphenyl bridge substituted with trimethylsilyl group. These materials show high thermal/morphological stabilities and deep-blue emission benefited by the twisted structures with high fluorescent efficiency in the solid states. The dual emission properties are well tuned via different acceptors and conjugation sites with aggregation-induced emission enhancement. Electroluminescent device using p-CSiTO as a dopant was fabricated and this device emits deep-blue light at 437 nm with Commission Internationale de l’Eclairage (CIEx',y) of (0.159, 0.110) and good colour purity with full width half maximum (FWHM) of 66 nm.

Aptamer-locker probe coupling with truncated aptamer for high-efficiency fluorescence polarization detection of zearalenone

Zearalenone (ZEN) is a kind of mycotoxin with estrogen-like effect. The presence of ZEN in cereals is potentially harmful to the health of humans. Herein, for the first time, the binding mechanism of ZEN aptamer with 19 bases (Z19) were systematically studied by molecular dynamics, circular dichroism and isothermal titration calorimetry. The binding driving forces, key bases of Z19 to ZEN, the conformational changes and thermodynamic information were originally found. On this basis, by employing the inherent rapid nature of fluorescence polarization and target recycling induced by Exo III, a novel fluorescence polarization aptasensor was constructed. The realized “add and measure” detection mode can be completed within one hour. Under the optimal conditions, the detection platform showed excellent analytical performance with a linear range of 0.01–100 ng/mL and a limit of detection as low as 0.004 ng/mL. Moreover, the practicability and reliability of the constructed strategy were confirmed with standard HPLC-MS method in corn and wheat samples. The established aptasensor with enhanced sensitivity broaden the application scope of fluorescence polarization technique, especially in detection targets of low molecular weight.

Revisiting molecularly conformation-planarized organic dyes for NIR-II fluorescence imaging.

Fluorescence imaging in the second window (NIR-II, 1000-1700 nm) provides deeper penetration depth and higher resolution, but there is still a dilemma for designing NIR-II dyes for simultaneously enhancing fluorescence efficiency and prolonging excitation wavelength. Herein, a molecular conformation planarization strategy has been revisited to guide the synthesis of two donor-acceptor-donor dyes (named T-BBT and BT-BBT). On the one hand, conformational planarization can extend the absorption peaks of T-BBT and BT-BBT to the NIR region with high molar extinction coefficients of 30.5 × 103 and 16.4 × 103 L (mol-1 cm-1) at 1064 nm, respectively. On the other hand, structural rigidity can weaken electronic vibration coupling-related non-radiative decay pathways, whereby both T-BBT and BT-BBT display rather high fluorescence efficiencies of 3.6% and 13.5% in solution. Furthermore, a molecular doping strategy is adopted to alleviate fluorescence quenching in the aggregated state by suppressing long-distance energy migration, and 2.5 wt% doped BT-BBT nanoparticles show a high fluorescence efficiency of 2.0%, which enables the application of in vivo deep NIR-II fluorescence imaging for vessels and tumors with high resolution under 980 nm excitation. This work demonstrates that organic dyes with structural planarization can bridge the gap between NIR-II absorption and fluorescence efficiency.

Metal-regulated d10 coordination polymers constructed from bis(pyridyl)-bis(amide) ligands with different spacers as high-efficiency fluorescence sensors for identifying chlortetracycline and furaltadone

Three new Cd(ii)/Zn(ii) coordination polymers derived from two bis(pyridyl)-bis(amide) ligands with different spacers and trimellitic acid (H3MTC) were designed and synthesized, which can effectively detect chlortetracycline and furaltadone.

Nonblinking Core–Multishell InP/ZnSe/ZnS Quantum Dot Bioconjugates for Super-resolution Imaging

Colloidal quantum dots (QDs) are vital fluorescent probes with several optical features superior to those found in organic dyes for microscopy imaging. However, the emission blinking behavior of a single QD is an intrinsic drawback for stimulated emission depletion microscopy (STED) or structured illumination microscopy techniques. Herein, we present a rational strategy for the synthesis of a type of deterministic, environmentally friendly, small nonblinking core–multishell InP/ZnSe/ZnS QD using a hydrofluoric acid (HF) etching passivation. The strategy includes four steps: synthesis of the InP core, synthesis of oil-phase core–multishell InP/ZnSe/ZnS QDs using hydrogen fluoride and trioctylphosphine etching passivation, promotion of the water solubility of QDs modified by 3-mercaptopropionic acid (MPA), and enhanced biotargeting of core–multishell InP/ZnSe/ZnS QDs by surface coupling technology. The suppressed blinking mechanism was primarily attributed to surface wrapping shells and HF etching passivation of surface dangling bonds, which reduced surface nonradiative recombination. Nonblinking QDs exhibit high fluorescence efficiency (∼90%), good photostability (>20 min), a large Stokes shift (>135 nm), biocompatibility of the cell viability (>90%), and high targeting. Furthermore, super-resolution multifocal structured illumination microscopy imaging of subcellular structures labeled using these QDs confirmed a resolution improvement of greater than 2.6-fold compared to wide-field microscopy. The results indicate that the nonblinking QDs can function as excellent probes for use in the long-term super-resolution visualization of subcellular dynamics.

Luminescent properties of a double-perovskite Rb2KScF6:Mn4+ red-emitting phosphor for white light-emitting diodes

Searching for efficient Mn4+ red phosphors for white lighting and display backlighting has drawn great attention. In this work, an efficient Mn4+-doped fluoroscandate, Rb2KScF6:Mn4+, with short fluorescence lifetime is prepared via a facile co-precipitation method. It was found that the nonequivalent occupation of Mn4+ for Sc3+ leads to the identifications of sharp red emissions, enhanced zero-phonon line, high quantum efficiency and short fluorescence lifetime upon blue light excitation. Thanks to the luminescent properties, good optical parameters of high color rendering index, low correlated color temperature, and acceptable color gamut were achieved by coating the red Rb2KScF6:Mn4+ phosphor with yellow Y3Al5O12:Ce3+ or green β-SiAlON:Eu2+ phosphor in various white light-emitting diodes, demonstrating its potential role for white light illumination and backlight display applications.

Dandelion-like covalent organic frameworks with high-efficiency fluorescence for ratiometric sensing and visual tracking-by-detection of Fe3+

Iron ions, one of the most common heavy metal pollutants in industrial waste materials, are continuously actively or passively delivered to the environment. Meanwhile, the importance of Fe3+ in biological processes in vivo can not be neglected due to its crucial role in maintaining normal physiological function. Therefore, a ratiometric fluorescence covalent organic framework (TD-COF) was constructed for tracking-by-detection of Fe3+. Alkynes-extended 1,3,6,8-tetrakis(4-ethynyl benzaldehyde)-pyrene (TEBPY) with complete planar structure and 2,5-dihydroxyterephthalohydrazide (DHTH) with functional group –OH were selected as the building blocks. The ratiometric fluorescence TD-COF with a dandelion-like structure exhibited its dual emission peaked at 510 nm and 630 nm. It displayed an obvious fluorescence color variation of yellow-red-black in the presence of Fe3+. Benefiting from the high luminescent efficiency (QY of 36.4%) and multiple identical binding sites, TD-COF exhibited a wide linear range to Fe3+ (0.005–50 μM) with a detection limit of 10.9 nM. Additionally, a smartphone visual sensing platform integrated with TD-COF was developed based on the color transformation and successfully applied to visual smart real-time monitoring Fe3+. More surprisingly, the maximum adsorption capacity of TD-COF towards Fe3+ was 833.3 mg/g due to the coordination interaction and cationic π-effect. The practicability of the smartphone-integrated ratiometric sensing platform for visual tracking-by-detection of Fe3+ was verified by choosing tap water as the actual sample, and the recoveries were calculated to be 98.71–100.88%. This work thus developed COF-based ratiometric sensing of Fe3+, which is an attractive candidate for further application in fluorescent sensing and visual monitoring.

Facile fabrication of helical hybrid silica ribbons with high-efficiency circularly polarized luminescence

• A bis(triethoxysilane) with aggregation-induced emission properties was synthesized. • Self-assemblies of a natural triterpenoid-based amphiphile were used as templates. • Hybrid silica ribbons were fabricated by supramolecular templating polymerization. • Hybrid silicas exhibited circularly polarized luminescence with efficient emission. We present a facile strategy for the construction of single-handed helical organic–inorganic hybrid silica micro/nanomaterials with circularly polarized luminescence (CPL) properties and high fluorescence efficiency. Two right-handed helical hybrid silica ribbons were fabricated through a supramolecular templating polymerization of tetraethoxysilane (TEOS) and organosiloxanes with aggregation-induced emission (AIE) characteristics, using the self-assemblies of a natural triterpenoid-based amphiphile as the templates. It was found that the chirality has been transferred from the supramolecular templates to the hybrid silica ribbons. The resultant hybrid silicas exhibited high thermal stabilities and intense CPL with the luminescence dissymmetry factor up to –8.8 × 10 -3 and the absolute fluorescence quantum yield up to 55.2%.

Persistent and Efficient Multimodal Imaging for Tyrosinase Based on Two-Photon Excited Fluorescent and Room-Temperature Phosphorescent Probes.

Tyrosinase is crucial to regulate the metabolism of phenol derivatives, playing an important role in the biosynthesis of melanin pigments, whereas an abnormal level of tyrosinase would lead to severe diseases. It is rather necessary to develop a sensitive and selective imaging tool to assess the level of tyrosinase in vivo. We thoroughly researched the luminous mechanism of the existing TPTYR probe and provided design strategies to improve its two-photon excited fluorescence properties. The designed probes benza2-TPTYR and product benza2-TPTYR-coumarin have large two-photon absorption cross sections at the NIR spectral region (41 GM/706 nm, 71 GM/852 nm), while benza2-TPTYR-coumarin possesses easily distinguishable spectrum in the visible region and a high fluorescence efficiency (ΦF = 0.27). What is more, novel two-photon excited multimodal imaging based on the pure organic small molecule benza1-TPTYR-coumarin (61 GM/936 nm) is proposed first, simultaneously possessing strong instantaneous fluorescent (563.79 nm) and persistent room-temperature phosphorescent emissions (767.68 nm, 0.54 ms).

Effect of cyano substituent on the functional properties of blue emitting Imidazo[1,2-a]pyridine derivatives

High fluorescence efficiency and balanced charge transportation in organic emitters are desirable characteristics for application in OLEDs. Generally, donor-acceptor compounds showing pronounced intramolecular charge transfer exhibit low fluorescence quantum yield. Here, we report D-A fluorophores containing CN-substituted 2-phenylimidazo[1,2-a]pyridine acceptor unit which exhibit good fluorescence characteristics. The positions of donors (triphenylamine/carbazole) and cyano substituents are respectively interchanged to get a series of isomers. All the fluorophores exhibit high fluorescence quantum yield (Фf≥ 0.70) and excellent thermal stability (Td10≥ 390 °C). A dye comprising triphenylamine unit at para-position of C2 phenyl ring exhibited red-shifted emission maxima with larger Stokes shift in the series. Moreover, all the isomers displayed excited-state solvatochromism attributable to the photo-induced intramolecular charge transfer between donors and cyano-imidazo[1,2-a]pyridine acceptor. Addition of the cyano group on imidazopyridine restrained the formation of aggregates in the solid-state and stabilized the lowest unoccupied molecular orbital. Among the all, doped devices constructed with 3 wt% of triphenylamine containing dye revealed excellent performance in the series with a maximum EQE of 6.9%, 2759 cd/m2 luminance, and CIE coordinates (0.16, 0.08) which is very close to the NTSC blue standard.

Structural Insight of Anthracene Orientation by Halogen Substitution: Impact on Solid-State Fluorescence and Stimuli-Induced Fluorescence Switching

The orientation of an anthracene π-conjugated aromatic group and excimer formation significantly influenced the fluorescence efficiency and functions of the resulting smart fluorescent materials. Herein, we have synthesized an alpha-cyanostyrene-integrated anthracene (1) fluorophore and investigated a halogen (F, C, and Br) effect on anthracene arrangement and solid-state fluorescence. Naphthalene-type excimer formation was observed in para-F and para-Cl, whereas unsubstituted 1 and meta-F and meta-Cl produced anthracene-type excimer. meta-F showed strong π···π interaction and higher overlapping of anthracene units, but meta-Cl exhibited alternative π···π and C–H···π interactions and produced isolated discrete dimers. However, Br isomers showed good separation of anthracene units without any significant overlapping. The strong π···π stacking arrangements of anthracene in meta-F resulted in complete quenching of fluorescence, whereas good separation of anthracene in Br isomers led to enhanced solid-state fluorescence (ΦF = 61.9%). Contrary to a traditional heavy-atom quenching effect, bromo-derivatives showed high fluorescence efficiency because of their structural arrangement. The columnar stacking arrangements of anthracene units caused off–on fluorescence switching upon crushing/heating or solvent exposure. Powder X-ray diffraction studies indicated the reversible transformation between crystalline and amorphous/partial amorphous phases upon crushing and heating/solvent exposure, which caused reversible fluorescence switching. Overall, the present studies provided structural insight for controlling anthracene orientation via halogen substitution for developing efficient solid-state smart fluorescent materials.

Combined Skeleton and Spatial Rigidification of AIEgens in 2D Covalent Organic Frameworks for Boosted Fluorescence Emission and Sensing of Antibiotics.

AIEgens show relatively weak fluorescence performance owing to the existence of π-π interlayer accumulation, molecular layer planarization, and intramolecular rotation in aggregation-induced emission (AIE) molecules, which limit its application scope. Herein, we put forward a combined skeleton and spatial rigidification method to boost the fluorescence emission efficiency of AIEgens. As a proof-of-concept experiment, two highly fluorescent covalent organic frameworks (COFs) were designed and constructed by the Knoevenagel condensation reaction. The experimental results show that the combined skeleton and spatial rigidification endowed excellent fluorescence emission for the resulting F-COF-2 by destruction of the π-π interlayer accumulation, interference of the molecular layer planarization, and restriction of the intramolecular rotation of the AIEgen unit. F-COF-2 displayed highly sensitive and selective NFT and NZF detection. Particularly, the Ksv value and limit of detection of F-COF-2 toward NFT were estimated to be 9.12 × 105 M-1 and 3.35 ppb, respectively, which surpassed all the reported crystalline porous fluorescent materials. The mechanism study proved that its outstanding fluorescence detection property was ascribed to the formation of a nonfluorescent complex induced by hydrogen bond interactions and electron transfer between F-COF-2 and NFT and NZF. This work not only proposes a combined skeleton and spatial rigidification strategy to improve the fluorescence efficiency of AIE molecules but also develops a sensor with high fluorescence efficiency, high chemical stability, and highly efficient detection of antibiotics.