AIE Fluorescent Gelators with Thermo‐, Mechano‐, and Vapochromic Properties

A series of aggregation‐induced emission (AIE) fluorescent gelators (TPE‐C_n‐Chol) were synthesized by attaching tetraphenylethylene (TPE) to cholesterol through an alkyl chain. The properties of the gel, nano‐/microaggregate, and condensed phases were studied carefully. TPE‐C_n‐Chol molecules form AIE fluorescent gels in acetone and in DMF. Their fluorescence can be reversibly switched between the “on” and “off” states by a gel–sol phase transition upon thermal treatment. The AIE properties of aggregated nano‐/microstructures in acetone/water mixtures with different water fractions were studied by using fluorescence spectrometry and scanning electron microscopy (SEM). In different acetone/water mixtures, the TPE‐C_n‐Chol molecules formed different nano‐/microaggregates, such as rodlike crystallites and spherical nanoparticles that showed different fluorescence colors. Finally, the condensed phase behavior of TPE‐C_n‐Chol was studied by using polarizing microscopy (POM), differential scanning calorimetry (DSC), fluorescence spectrometry, fluorescence optical microscopy, and wide‐angle X ray scattering (WAXS). The clover‐shaped TPE unit introduced into the rodlike cholesterol mesogen inhibits not only the formation of a liquid‐crystal phase but also recrystallization upon cooling from the isotropic liquid phase. Very interestingly, TPE‐C_n‐Chol molecules in the condensed state change their fluorescence color under external stimuli, such as melting, grinding, and solvent fuming. The phase transition is the origin of these thermo‐, mechano‐, and vapochromic properties. These findings offer a simple and interesting platform for the creation of multistimuli‐responsive fluorescent sensors.     

Highly Fluorescent and Water‐Soluble Diketopyrrolopyrrole Dyes for Bioconjugation

The preparation of highly water‐soluble and strongly fluorescent diketopyrrolopyrrole (DPP) dyes using an unusual taurine‐like sulfonated linker has been achieved. Exchanging a phenyl for a thienyl substituent shifts the emission wavelength to near λ=600 nm. The free carboxylic acid group present in these new derivatives was readily activated and the dyes were subsequently covalently linked to a model protein (bovine serum albumin; BSA). The bioconjugates were characterized by electronic absorption, fluorescence spectroscopy and MALDI‐TOF mass spectrometry, thus enabling precise determination of the labeling density (ratio DPP/BSA about 3 to 8). Outstanding values of fluorescence quantum yield (30 % to 59 %) for these bioconjugates are obtained. The photostability of these DPP dyes is considerably greater than that of fluorescein under the same irradiation conditions. Remarkably low detection limits between 80 and 300 molecules/μm² were found for the BSA bioconjugates by fluorescence imaging with a epifluorescence microscope.     

Tunable fluorescence conjugated copolymers consisting of tetraphenylethylene and fluorene units: From aggregation‐induced emission enhancement to dual‐channel fluorescence response

A series of new conjugated polymers PTPE_xF_y, which consist of tetraphenylethylene (TPE) units and fluorene (F) units, have been designed and synthesized by Suzuki cross‐coupling polymerization. The polymers PTPE_xF_y exhibited aggregation‐induced emission enhancement and dual‐channel fluorescence response (DCFR) when they were aggregated in solution, and these properties are related with their TPE‐to‐F ratio in the polymer backbone. For PTPE and PTPE_0.5F_0.5 , the fluorescence emission was enhanced by aggregation when water was added into their THF solutions. For the copolymers PTPE_0.3F_0.7 , PTPE_0.2F_0.8 , and PTPE_0.1F_0.9 , the DCFRs were observed when they were aggregated by adding water into their solution, which can be attributed to the different responses of fluorene segments and TPE segments to aggregation. The fluorene segments have an aggregation‐caused quenching characteristic, whereas the TPE segments have an aggregation‐induced emission characteristic. According to the fluorescence lifetime and quantum yield data of the polymer solutions, we have discovered that the polymer's natural life time increases as its TPE content increases. In the solid film, PTPE_0.3F_0.7 and PTPE_0.2F_0.8 showed better quantum yield than other polymers, due to the combination of the excellent fluorescent property of the fluorene groups and the nonplanar conformation of the TPE groups. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

From Dark to Light to Fluorescence Resonance Energy Transfer (FRET): Polarity‐Sensitive Aggregation‐Induced Emission (AIE)‐Active Tetraphenylethene‐Fused BODIPY Dyes with a Very Large Pseudo‐Stokes Shift

The work presented herein is devoted to the fabrication of large Stokes shift dyes in both organic and aqueous media by combining dark resonance energy transfer (DRET) and fluorescence resonance energy transfer (FRET) in one donor–acceptor system. In this respect, a series of donor–acceptor architectures of 4,4‐difluoro‐4‐bora‐3a,4a‐diaza‐s‐indacene (BODIPY) dyes substituted by one, two, or three tetraphenylethene (TPE) luminogens were designed and synthesised. The photophysical properties of these three chromophore systems were studied to provide insight into the nature of donor–acceptor interactions in both THF and aqueous media. Because the generation of emissive TPE donor(s) is strongly polarity dependent, due to its aggregation‐induced emission (AIE) feature, one might expect the formation of appreciable fluorescence emission intensity with a very large pseudo‐Stokes shift in aqueous media when considering FRET process. Interestingly, similar results were also recorded in THF for the chromophore systems, although the TPE fragment(s) of the dyes are non‐emissive. The explanation for this photophysical behaviour lies in the DRET. This is the first report on combining two energy‐transfer processes, namely, FRET and DRET, in one polarity‐sensitive donor–acceptor pair system. The accuracy of the dark‐emissive donor property of the TPE luminogen is also presented for the first time as a new feature for AIE phenomena.     

Synthesis,photoluminescence, and electroluminescence characterization of double tetraphenylethene‐tethered BODIPY luminogens

Three double tetraphenylethene (TPE)‐tethered 4‐difluoro‐4‐bora‐3a,4a‐diaza‐s‐indance (BODIPY) fluorophores, 35TPEBODP , 88TPEBODP , and 26TPEBODP , have been synthesized and characterized. The green 35TPEBODP with deep red fluorescence shows serious thermal decomposition in the purification process of sublimation, which prohibits its test for an organic light‐emitting diode (OLED) fabricated by the vacuum–thermal evaporation process. The tethered TPE is attached to BODIPY at three different positions, resulting in different photoluminescence (emission wavelength and quantum yield) and electroluminescence (EL). Different from TPE‐tethered BODIPY fluorophores reported in literature, none of the BODIPY fluorophores studied here exhibits aggregation‐induced emission (AIE), aggregation‐induced enhanced emission (AIEE), or twisted intramolecular charge transfer (TICT) characteristics. Although solution (10^?5 M THF) photoluminescence quantum yields (?s) are relatively high at 78%, 68%, and 86% for 35TPEBODP , 88TPEBODP , and 26TPEBODP , respectively, which are all higher than 41% of PhBODP (a non‐TPE‐tethered BODIPY), the ? is significantly decreased to 1–6% in 5 wt% dopant polystyrene thin film or as a solid powder, except for 13% of 26TPEBODP . Therefore, due to the low ? of dopant thin film or solid powder, either dopant or nondopant OLEDs exhibit inferior external quantum efficiency (EQE) and intensity of EL. The best OLED in this study is the 26TPEBODP device, and its EQE reaches 1.3%, and the highest EL intensity is approximately 1,600 cd/m².     

A Red to Near‐IR Fluorogen: Aggregation‐Induced Emission,Large Stokes Shift,High Solid Efficiency and Application in Cell‐Imaging

A tetraphenylethene (TPE) derivative modified with the strong electron acceptor 2‐dicyano‐methylene‐3‐cyano‐4,5,5‐trimethyl‐2,5‐dihydrofuran (TCF) was obtained in high yield by a simple two‐step reaction. The resultant TPE‐TCF showed evident aggregation‐induced emission (AIE) features and pronounced solvatochromic behavior. Changing the solvent from apolar cyclohexane to highly polar acetonitrile, the emission peak shifted from 560 to 680 nm (120 nm redshift). In an acetonitrile solution and in the solid powder, the Stokes shifts are as large as 230 and 190 nm, respectively. The solid film emits red to near‐IR (red‐NIR) fluorescence with an emission peak at 670 nm and a quantum efficiency of 24.8 %. Taking the advantages of red‐NIR emission and high efficiency, nanoparticles (NPs) of TPE‐TCF were fabricated by using tat‐modified 1,2‐distearoylsn‐glycero‐3‐phosphor‐ethanol‐amine‐N‐[methoxy‐(polyethyl‐eneglycol)‐2000] as the encapsulation matrix. The obtained NPs showed perfect membrane penetrability and high fluorescent imaging quality of cell cytoplasm. Upon co‐incubation with 4,6‐diamidino‐2‐phenylindole (DAPI) in the presence of tritons, the capsulated TPE‐TCF nanoparticles could enter into the nucleus and displayed similar staining properties to those of DAPI.     

Cross‐linking induced thermoresponsive hydrogel with light emitting and self‐healing property

Development of self‐healing hydrogels with thermoresponse is very important for artificial smart materials. In this article, the self‐healing hydrogels with reversible thermoresponses were designed through across‐linking‐induced thermoresponse (CIT) mechanism. The hydrogels were prepared from ketone group containing copolymer bearing tetraphenyl ethylene (TPE) and cross‐linked by naphthalene containing acylhydrazide cross‐linker. The mechanical property, light emission, self‐healing, and thermo‐response of the hydrogels were investigated intensively. With regulation of the copolymer composition, the hydrogels showed thermoresponse with the LCST varied from above to below body temperature. At the same time, the hydrogels showed self‐healing property based on the reversible characteristic of the acylhydrazone bond. The hydrogel also showed temperature‐regulated light emission behavior based on AIE property of the TPE unit. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 869–877     

Dendron‐Containing Tetraphenylethylene Compounds: Dependence of Fluorescence and Photocyclization Reactivity on the Dendron Generation

The synthesis and characterization of four dendron‐containing tetraphenylethylenes (TPEs), 1₁ – 1₄ , were synthesized, along with a TPE compound that contained four OCH₂Ph groups (referred to as 1₀ ) for comparison. Photophysical studies revealed that the TPE core became emissive after linking dendrons onto its periphery. Moreover, the fluorescence intensity was significantly enhanced when high‐generation dendrons were linked onto the TPE core; the fluorescence intensity increased in the following order: 1₁ < 1₂ < 1₃ < 1₄ . This phenomenon was tentatively attributed to an enhancement in the energy barrier for internal rotation and torsion of the TPE core to which four dendrons were connected. In addition, the photocyclization of the TPE core into the respective 9,10‐diphenylphenanthrene was facilitated when high‐generation dendrons were linked to the TPE core. Again, the photocycliztion reactivity increased in the following order: 1₁ < 1₂ < 1₃ < 1₄ . We found that the fluorescence and photocyclization reactivity of TPE could be modulated by covalent interactions with dendrons, and such modulation was strongly dependent on the dendron‐generation.     

Improved Spectral Coverage and Fluorescence Quenching in Donor–acceptor Systems Involving Indolo[3‐2‐b]carbazole and Boron‐dipyrromethene or Diketopyrrolopyrrole

A novel π‐conjugated triad and a polymer incorporating indolo[3,2‐b]‐carbazole (ICZ) and 4,4‐difluoro‐4‐bora‐3a,4a‐diaza‐s‐indacene (BODIPY) were synthesized via a Sonogashira coupling. Compared to the parent BODIPY the absorption and fluorescence spectrum were for both compounds broader and redshifted. The redshift of the fluorescence and the decrease of the fluorescence quantum yield and decay time upon increasing solvent polarity were attributed to the formation of a partial charge‐transfer state. Upon excitation in the ICZ absorption band the ICZ fluorescence was quenched in both compounds mainly due to energy transfer to the BODIPY moiety. In a similar ICZ–π–DPP polymer (where DPP is diketopyrrolopyrrole), a smaller redshift of the absorption and fluorescence spectra compared to the parent DPP was observed. A less efficient quenching of the ICZ fluorescence in the ICZ–π–DPP polymer could be related to the unfavorable orientation of the transition dipoles of ICZ and DPP. The rate constant for energy transfer was for all compounds an order of magnitude smaller than predicted by Förster theory. While in a solid film of the triad a further redshift of the absorption maximum of nearly 100 nm was observed, no such shift was observed for the ICZ–π–BODIPY polymer.     

Hexaphenylbenzene‐Based, π‐Conjugated Snowflake‐Shaped Luminophores: Tunable Aggregation‐Induced Emission Effect and Piezofluorochromism

In this work, two rigid, multiple tetraphenylethene (TPE)‐substituted, π‐conjugated, snowflake‐shaped luminophores BT and BPT were facilely synthesized by using a 6‐fold Suzuki coupling reaction. These molecules are constructed based on the nonplanar structure of propeller‐shaped hexaphenylbenzene (HPB) or benzene as core groups and TPE as end groups. As a result, they reserve the intrinsic aggregation‐induced emission (AIE) property of the TPE moiety. Meanwhile, both fluorescence quantum yield and piezochromic behavior in the solid state can be tuned or switched by inserting the phenyl bridges through changing the twisting conformation. The more extended structure BPT showed a much stronger AIE effect and higher Φ_F,f in the solid state in comparison with that of BT. Furthermore, an excellent optical waveguide application of these molecules was achieved. However, the revisable piezofluorochromic behavior has only appeared when BT was ground using a pestle and treated with solvent.     

Synthesis of π‐conjugated network polymers based on fluoroarene and fluorescent units via direct arylation polycondensation and their porosity and fluorescent properties

In this study, we report the synthesis of π‐conjugated network polymers including unique fluorescent units via palladium‐catalyzed direct (C? H) arylation polycondensation of 1,2,4,5‐tetrafluorobenzene with tetrabromoarenes. The obtained polymers, including tetraphenylethene (TPE) or pyrene (PYR) units, had microporous structures with the specific Brunauer–Emmett–Teller (BET) surface areas at 508 and 824 m² g^?1, respectively. These polymers possessed narrow pore distributions (<15 nm). These analyses supported that π‐conjugated microporous polymers (CMPs) were synthesized by the direct arylation. Similar to the result of BET surface areas, carbon capture capacity of CMP based on PYR unit was higher than that of CMP based on TPE unit. Because the nitrogen capture capacity of these CMPs was low (≈ 0), selectivity of carbon dioxide adsorption was very high. TPE is a typical aggregation‐induced emission unit but PYR is an aggregation‐caused quenching (ACQ) molecule. The incorporation of TPE unit into the microporous polymer gave green‐colored fluorescence (Φ = 0.12). The polymer including PYR units also showed the green‐colored fluorescence (Φ = 0.05) even though the ACQ property. These synthesized CMPs exhibited characteristic solvatofluorochromism. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 3862–3867     

Anion‐Coordination‐Induced Turn‐On Fluorescence of an Oligourea‐Functionalized Tetraphenylethene in a Wide Concentration Range

A tetrakis(bisurea)‐decorated tetraphenylethene (TPE) ligand ( L² ) was designed, which, upon coordination with phosphate ions, displays fluorescence “turn‐on” over a wide concentration range, from dilute to concentrated solutions and to the solid state. The fluorescence enhancement can be attributed to the restriction of the intramolecular rotation of TPE by anion coordination. The crystal structure of the A₄L₂ (A=anion) complex of L² with monohydrogen phosphate provides direct evidence for the coordination mode of the anion. This “anion‐coordination‐induced emission” (ACIE) is another approach for fluorescence turn‐on in addition to aggregation‐induced emission (AIE).     

Polysiloxane‐Modified Tetraphenylethene: Synthesis,AIE Properties,and Sensor for Detecting Explosives

Polysiloxane‐modified tetraphenylethene (PTPESi) is successfully synthesized by attaching tetraphenylethene (TPE) units onto methylvinyldiethoxylsiloxane and subsequent polycondensation. Introducing polysiloxane into TPE has minimal effect on the photophysical properties and aggregation‐induced emission behavior of TPE. The highest occupied and lowest unoccupied molecular orbital (HOMO and LUMO) energy levels of PTPESi are located mainly on the tetraphenylethene moieties. The fluorescence intensity and the half width of the emission peak of PTPESi before and after annealing at 120 °C for 12 h are nearly the same, indicating high thermal stability and morphological stability. In addition, use of PTPESi film as a sensor toward the vapor‐phase detection of explosives is also studied and it displays quite high fluorescence quenching efficiency and good reversibility.

     

Synthesis,spectral, DFT calculations and antibacterial studies of Fe(III) complexes of new fluorescent Schiff bases derived from imidazo[4',5':3,4]benzo[1,2‐c]isoxazole

New fluorescent heterocyclic ligands were synthesized by the reaction of 8‐(4‐chlorophenyl)‐3‐alkyl‐3H‐imidazo[4',5':3,4]benzo [1,2‐c]isoxazol‐5‐amine with p‐hydroxybenzaldehyde and p‐chlorobenzaldehyde in good yields. The coordination ability of the ligands with Fe³⁺ ion was examined in an aqueous metanolic solution. Schiff base ligands and their metal complexes were characterized by elemental analyses, IR, UV–vis, mass, and NMR spectra. The optical properties of the compounds were investigated and the results showed that the fluorescence of all compounds is intense and their obtained emission quantum yields are around 0.15 – 0.53. Optimized geometries and assignment of the IR bands and NMR chemical shifts of the new complexes were also computed by using density functional theory (DFT) methods. The DFT‐calculated vibrational wavenumbers and NMR chemical shifts are in good agreement with the experimental values, confirming suitability of the optimized geometries for Fe(III) complexes. Also, the 3D‐distribution map for HOMO and LUMO of the compounds were obtained. The new compounds showed potent antibacterial activity and their antibacterial activity (MIC) against Gram‐positive and Gram‐negative bacterial species were also determined. Results of antibacterial test revealed that coordination of ligands to Fe(III) leads to improvement in the antibacterial activity.     

A New Approach to Prepare Efficient Blue AIE Emitters for Undoped OLEDs

Two aggregation‐induced emission active luminogens (TPE–pTPA and TPE–mTPA) were successfully synthesized. For comparison, another six similar compounds were prepared. Because of the introduced hole‐dominated triphenylamine (TPA), fluorene groups with high luminous efficiency, and unconjugated linkages, the π conjugation length of the obtained luminogens is effectively restricted to ensure their blue emission. The undoped organic light‐emitting diodes based on TPE–pTPA and TPE–mTPA exhibited blue or deep‐blue emissions, low turn‐on voltages (3 V), and high electroluminescence efficiencies with L_max, η_C,max, and η_P,max values of up to 26 697 cd m^?2, 3.37 cd A^?1, and 2.40 Lm W^?1.     

Tunable AICPL of (S)‐Binaphthyl‐Based Three‐Component Polymers via FRET Mechanism

Five three‐component chiral polymers incorporating (S )‐1,1′‐binaphthyl, tetraphenylethene (TPE) and fluorene moieties are designed and synthesized by Pd‐catalyzed Sonogashira reaction. All these polymers show obvious aggregation induced emission enhancement response behavior in the fluorescence emission region of 460–480 nm. Interestingly, three of them show aggregation‐induced circularly polarized luminescence (AICPL) signals in tetrahydrofuran–H₂O mixtures. Most importantly, these AICPL signals can be tuned by changing the molar ratios of TPE and fluorene components through fluorescence resonance energy transfer and give the highest glum = ±4.0 × 10⁻³. This work provides a novel strategy for developing AICPL‐enhanced materials.

     

White‐Light Electroluminescence with Tetraphenylethylene as Emitting Layer of Aggregation‐Induced Emissions Enhancement

Tetraphenylethylene (TPE) based molecules with easy synthesis, good thermal stability, and especially their aggregation‐induced emissions enhancement (AIEE) effect recently become attractive organic emitting materials due to their potentially practical application in OLEDs. Herein, the AIEE behaviors of tetraphenylethylene dyes (TMTPE and TBTPE) were investigated. Fabricated luminesent device using TMTPE dye as emitting layer displays two strong emitting bands: the blue emission coming from the first‐step aggregation and the yellow emission attributed to the second‐step aggregation. Thus, it can be utilized to fabricate the white‐light OLEDs (WOLEDs) of the single‐emitting‐component. A three‐layer device with the brightness of 1200 cd·m^?2 and current ef?ciency of 0.78 cd·A^?1 emits the close to white light with the CIE coordinates of x=0.333 andy=0.358, when applied voltage from 8–13 V, verifying that the TPE‐based dyes of AIEE effect can be effectively applied in single‐emitting‐component WOLEDs fabrication.     

A 1,3‐Indandione‐Functionalized Tetraphenylethene: Aggregation‐Induced Emission,Solvatochromism, Mechanochromism,and Potential Application as a Multiresponsive Fluorescent Probe

A tetraphenylethene (TPE) derivative substituted with the electron‐acceptor 1,3‐indandione (IND) group was designed and prepared. The targeted IND‐TPE reserves the intrinsic aggregation‐induced emission (AIE) property of the TPE moiety. Meanwhile, owing to the decorated IND moiety, IND‐TPE demonstrates intramolecular charge‐transfer process and pronounced solvatochromic behavior. When the solvent is changed from apolar toluene to highly polar acetonitrile, the emission peak redshifts from 543 to 597 nm. IND‐TPE solid samples show an evident mechanochromic process. Grinding of the as‐prepared powder sample induces a redshift of emission from green (peak at 515 nm) to orange (peak at 570 nm). The mechanochromic process is reversible in multiple grinding–thermal annealing and grinding–solvent‐fuming cycles, and the emission of the solid sample switches between orange (ground) and yellow (thermal/solvent‐fuming‐treated) colors. The mechanochromism is ascribed to the phase transition between amorphous and crystalline states. IND‐TPE undergoes a hydrolysis reaction in basic aqueous solution, thus the red‐orange emission can be quenched by OH^? or other species that can induce the generation of sufficient OH^?. Accordingly, IND‐TPE has been used to discriminatively detect arginine and lysine from other amino acids, due to their basic nature. The experimental data are satisfactory. Moreover, the hydrolyzation product of IND‐TPE is weakly emissive in the resultant mixture but becomes highly blue‐emissive after the illumination for a period by UV light. Thus IND‐TPE can be used as a dual‐responsive fluorescent probe, which may extend the application of TPE‐based molecular probes in chemical and biological categories.     

Pyridinium‐Substituted TetraphenylethyleneEntailing Alkyne Moiety: Enhancement of Photosensitizing Efficiency and Antimicrobial Activity

Apart from sensing and imaging, luminogens with aggregation‐induced emission (AIE) are also interesting for photosensitizing. The photosensitizing behavior and bacteria‐killing performance of a pyridinium‐substituted tetraphenylethylene with an alkyne group ( TPE‐A‐Py⁺ ) is reported herein. Interestingly, TPE‐A‐Py⁺ exhibits higher photosensitizing efficiency than TPE‐Py⁺ (without alkyne group) when I⁻ was used as a counteranion. This is well explained by the fact that the ΔΕ _ST between the excited singlet state (S ₁) and triplet state (T ₁) was lower for TPE‐A‐Py⁺ than for TPE‐Py⁺ , according to theoretical calculations. Moreover, replacement of I ⁻ with other anions (PF₆⁻, N(SO₂CF₃)₂⁻ and BPh₄⁻) led to a decrease of photosensitizing efficiency for TPE‐A‐Py⁺ . Notably, TPE‐A‐Py⁺ could be used as an efficient photosensitizer to photo‐inactivate ampicillin‐resistant (amp^r) E. coli at low concentration under white‐light irradiation very quickly.     

Structure‐Dependent cis/trans Isomerization of Tetraphenylethene Derivatives: Consequences for Aggregation‐Induced Emission

The isomerization and optical properties of the cis and trans isomers of tetraphenylethene (TPE) derivatives with aggregation‐induced emission (AIEgens) have been sparsely explored. We have now observed the tautomerization‐induced isomerization of a hydroxy‐substituted derivative, TPETH‐OH, under acidic but not under basic conditions. Replacing the proton of the hydroxy group in TPETH‐OH with an alkyl group leads to the formation of TPETH‐MAL, for which the pure cis and trans isomers were obtained and characterized by HPLC analysis and NMR spectroscopy. Importantly, cis‐TPETH‐MAL emits yellow fluorescence in DMSO at ?20 °C whereas trans‐TPETH‐MAL shows red fluorescence under the same conditions. Moreover, the geometry of cis‐ and trans‐TPETH‐MAL remains unchanged when they undergo thiol–ene reactions to form cis‐ and trans‐TPETH‐cRGD, respectively. Collectively, our findings improve our fundamental understanding of the cis/trans isomerization and photophysical properties of TPE derivatives, which will guide further AIEgen design for various applications.