Similar or Totally Different: The Control of Conjugation Degree through Minor Structural Modifications,and Deep‐Blue Aggregation‐Induced Emission Luminogens for Non‐Doped OLEDs

Four 4,4′‐bis(1,2,2‐triphenylvinyl)biphenyl (BTPE) derivatives, 4,4′‐bis(1,2,2‐triphenylvinyl)biphenyl, 2,3′‐bis(1,2,2‐triphenylvinyl)biphenyl, 2,4′‐bis(1,2,2‐triphenylvinyl)biphenyl, 3,3′‐bis(1,2,2‐triphenylvinyl)biphenyl and 3,4′‐bis(1,2,2‐triphenylvinyl)biphenyl (oTPE‐mTPE, oTPE‐pTPE, mTPE‐mTPE, and mTPE‐pTPE, respectively), are successfully synthesized and their thermal, optical, and electronic properties fully investigated. By merging two simple tetraphenylethene (TPE) units together through different linking positions, the π‐conjugation length is effectively controlled to ensure the deep‐blue emission. Because of the minor but intelligent structural modification, all the four fluorophores exhibit deep‐blue emissions from 435 to 459 nm with Commission Internationale de l'Eclairage (CIE) chromaticity coordinates of, respectively, (0.16, 0.14), (0.15, 0.11), (0.16, 0.14), and (0.16, 0.16), when fabricated as emitters in organic light‐emitting diodes (OLEDs). This is completely different from BTPE with sky‐blue emission (0.20, 0.36). Thus, these results may provide a novel and versatile approach for the design of deep‐blue aggregation‐induced emission (AIE) luminogens.     

NIR‐II Light Activated Photosensitizer with Aggregation‐Induced Emission for Precise and Efficient Two‐Photon Photodynamic Cancer Cell Ablation

Near infrared (NIR) light excitable photosensitizers are highly desirable for photodynamic therapy with deep penetration. Herein, a NIR‐II light (1200 nm) activated photosensitizer TQ‐BTPE is designed with aggregation‐induced singlet oxygen (¹O₂) generation for two‐photon photodynamic cancer cell ablation. TQ‐BTPE shows good two‐photon absorption and bright aggregation‐induced NIR‐I emission upon NIR‐II laser excitation. The ¹O₂ produced by TQ‐BTPE in an aqueous medium is much more efficient than that of commercial photosensitizer Ce6 under white light irradiation. Upon NIR‐II excitation, the two‐photon photosensitization of TQ‐BTPE is sevenfold higher than that of Ce6. The TQ‐BTPE molecules internalized by HeLa cells are mostly located in lysosomes as small aggregate dots with homogeneous distribution inside the cells, which favors efficient photodynamic cell ablation. The two‐photon photosensitization of TQ‐BTPE upon NIR‐I and NIR‐II excitation shows higher ¹O₂ generation efficiency than under NIR‐I excitation owing to the larger two‐photon absorption cross section at 920 nm. However, NIR‐II light exhibits better biological tissue penetration capability after passing through a fresh pork tissue, which facilitates stronger two‐photon photosensitization and better cancer cell ablation performance. This work highlights the promise of NIR‐II light excitable photosensitizers for deep‐tissue photodynamic therapy.     

Engineering Sensor Arrays Using Aggregation‐Induced Emission Luminogens for Pathogen Identification

Lacking rapid and reliable pathogen diagnostic platforms, inadequate or delayed antimicrobial therapy could be made, which greatly threatens human life and accelerates the emergence of antibiotic‐resistant pathogens. In this contribution, a series of simple and reliable sensor arrays based on tetraphenylethylene (TPE) derivatives are successfully developed for detection and discrimination of pathogens. Each sensor array consists of three TPE‐based aggregation‐induced emission luminogens (AIEgens) that bear cationic ammonium group and different hydrophobic substitutions, providing tunable logP (n‐octanol/water partition coefficient) values to enable the different multivalent interactions with pathogens. On the basis of the distinctive fluorescence response produced by the diverse interaction of AIEgens with pathogens, these sensor arrays can identify different kinds of pathogens, even normal and drug‐resistant bacteria, with nearly 100% accuracy. Furthermore, blends of pathogens can also be identified accurately. The sensor arrays exhibit rapid response (about 0.5 h), high‐throughput, and easy‐to‐operate without washing steps.     

Multifunctional AIEgens: Ready Synthesis,Tunable Emission,Mechanochromism, Mitochondrial,and Bacterial Imaging

Luminogens with aggregation‐induced emission characteristics (AIEgens) are intriguing due to its rapid expansion in various high‐tech applications. However, there is still in high demand on the development of novel AIEgens with easy preparation and functionalization, stable structures, tunable emissions, and high quantum efficiency. In this contribution, three AIEgens based on diphenyl isoquinolinium (IQ) derivatives are reported. They can be facilely synthesized and possess high structural stability, favorable visible light excitation, large Stokes shifts, high quantum yields, tunable colors, and sufficient two‐photon absorption of near‐infrared light. Importantly, they exhibit multifunctionalities. They exhibit mechanochromic property, making them capable to be applied for rewritable papers. They can also be applied in mitochondrial imaging with high specificity, cell permeability, brightness, biocompatibility, and photostability. They are promising for the applications in evaluation of mitochondrial membrane potential and image‐guided cancer cell ablation. Last, they are able to stain bacteria in a wash‐free manner. All these intriguing results suggest such readily accessible and multifunctional diphenyl IQ‐based AIEgens provide a new platform for construction of advanced materials for practical applications.     

Polymorphism‐Dependent Emission for Di(p‐methoxylphenyl)dibenzofulvene and Analogues: Optical Waveguide/Amplified Spontaneous Emission Behaviors

The synthesis and optical investigations of di(p‐methoxylphenyl)dibenzofulvene ( 1 ) and its analogues 2 , 3 , 4 , 5 , 6, and 7 with different lengths of alkoxyl chains are presented. All of these molecules exhibit emission in the solid state. The following interesting properties are reported for compound 1 : 1) the solid‐state fluorescence of 1 is dependent on the polymorphism forms; the two crystalline forms 1a and 1b are strongly blue‐ and yellow‐green‐emissive, whereas the amorphous solid is weakly fluorescent with orange emission; 2) on the basis of crystal‐structural analysis, the intermolecular interactions will restrict the internal rotations, leading to fluorescence enhancement for the two crystalline forms 1a and 1b ; however, the difference in emission color between 1a and 1b is ascribed to the molecular conformational alteration; 3) the solid‐state fluorescence of 1 can be tuned by heating and cooling as well as grinding. Importantly, microrods of 1a and 1b exhibit outstanding optical waveguide behaviors. Moreover, amplified spontaneous emission for 1b and multimode‐lasing behavior for 1a are presented. Besides the studies of compound 1 , the crystal structures and solid‐state fluorescence behaviors of 2 , 3 , 4 , 5 , 6, and 7 are also described.     

Facile Synthesis of Red/NIR AIE Luminogens with Simple Structures,Bright Emissions,and High Photostabilities,and Their Applications for Specific Imaging of Lipid Droplets and Image‐Guided Photodynamic Therapy

Red/near‐infrared (NIR) fluorescent molecules with aggregation‐induced emission (AIE) characteristics are of great interest in bioimaging and therapeutic applications. However, their complicated synthetic approaches remain the major barrier to implementing these applications. Herein, a one‐pot synthetic strategy to prepare a series of red/NIR‐emissive AIE luminogens (AIEgens) by fine‐tuning their molecular structures and substituents is reported. The obtained AIEgens possess simple structures, good solubilities, large Stokes shifts, and bright emissions, which enable their applications toward in vitro and in vivo imaging without any pre‐encapsulation or ‐modification steps. Excellent targeting specificities to lipid droplets (LDs), remarkable photostabilities, high brightness, and low working concentrations in cell imaging application make them remarkably impressive and superior to commercially available LD‐specific dyes. Interestingly, these AIEgens can efficiently generate reactive oxygen species upon visible light irradiation, endowing their effective application for photodynamic ablation of cancer cells. This study, thus, not only demonstrates a facile synthesis of red/NIR AIEgens for dual applications in simultaneous imaging and therapy, but also offers an ideal architecture for the construction of AIEgens with long emission wavelengths.     

Red AIE‐Active Fluorescent Probes with Tunable Organelle‐Specific Targeting

Cell staining is a fascinating research area where monitoring and visualizing different cell organelles can be done using fluorescence techniques. However, the design and synthesis of organelle‐targeting fluorophores is still a challenge for several specific organelles. Herein, a platform for synthesizing efficient red‐emitting aggregation‐induced emission luminogens (AIEgens) with donor–acceptor characteristics is reported. The core molecule can be easily functionalized in order to modulate organelle targeting. The three synthesized AIEgens exhibit quantum yields of up to 39.3% and two‐photon absorption cross‐section values of up to 162 GM. The two zwitterionic AIEgens, CDPP‐3SO₃ and CDPP‐4SO_3, with the sulfonate function group, are successfully utilized for specific one‐photon and two‐photon imaging of the endoplasmic reticulum (ER) in live human cells. Substituting the zwitterionic nature with a singly positive charge group, one‐photon and two‐photon imaging of CDPP‐BzBr shows mitochondrial specificity, indicating the importance of the zwitterionic group for ER‐targeting. Owing to the good in vitro photostability, cell viability, and high efficiency, these red dyes serve as a good potential candidate for specific organelle targeting, as well as illustrate how such a platform can easily aid in the study of structure–property relationships for designing such probes.     

Novel Quercetin Aggregation‐Induced Emission Luminogen (AIEgen) with Excited‐State Intramolecular Proton Transfer for In Vivo Bioimaging

Aggregation‐induced emission luminogens (AIEgens) that undergo excited‐state intramolecular proton transfer (ESIPT) have many applications in bioimaging since they have high quantum efficiency in the aggregated state and a low background signal in aqueous solutions because of their large Stokes shift. One disadvantage of many of the AIEgens with ESIPT that has been described so far is that they require time‐consuming synthesis and the use of toxic reagents. Another disadvantage with most of these materials is that they are only used for bioimaging in cells and are unsuitable for in vivo bioimaging. Herein, a new AIEgen with ESIPT, quercetin (QC) is described, which is easily prepared from Sophora japonica. AIE is attributed to crystallization‐promoted keto emission. The fluorescence is temperature dependent and shows strong resistance to photobleaching. QC AIEgen with ESIPT is shown to have excellent biocompatibility and is successfully used for bioimaging both in cellular cytoplasm and in vivo.     

Organic Light‐Emitting Diodes with a White‐Emitting Molecule: Emission Mechanism and Device Characteristics

The unique and unprecedented electroluminescence behavior of the white‐emitting molecule 3‐(1‐(4‐(4‐(2‐(2‐hydroxyphenyl)‐4,5‐diphenyl‐1H‐imidazol‐1‐yl)phenoxy)phenyl)‐4,5‐diphenyl‐1H‐imidazol‐2‐yl)naphthalen‐2‐ol (W1), fluorescence emission from which is controlled by the excited‐state intramolecular proton transfer (ESIPT) is investigated. W1 is composed of covalently linked blue‐ and yellow‐color emitting ESIPT moieties between which energy transfer is entirely frustrated. It is demonstrated that different emission colors (blue, yellow, and white) can be generated from the identical emitter W1 in organic light‐emitting diode (OLED) devices. Charge trapping mechanism is proposed to explain such a unique color‐tuned emission from W1. Finally, the device structure to create a color‐stable, color reproducible, and simple‐structured white organic light‐emitting diode (WOLED) using W1 is investigated. The maximum luminance efficiency, power efficiency, and luminance of the WOLED were 3.10 cd A^?1, 2.20 lm W^?1, 1 092 cd m^?2, respectively. The WOLED shows white‐light emission with the Commission Internationale de l′Eclairage (CIE) chromaticity coordinates (0.343, 0.291) at a current level of 10 mA cm^?2. The emission color is high stability, with a change of the CIE chromaticity coordinates as small as (0.028, 0.028) when the current level is varied from 10 to 100 mA cm^?2.     

Synthesis of Imidazole‐Based AIEgens with Wide Color Tunability and Exploration of their Biological Applications

Research on aggregation‐induced emission (AIE) has become increasingly popular recently and various AIE luminogens (AIEgens) have been developed based on tetraphenylethene, hexaphenylsilole, distyrylanthracene, tetraphenylpyrazine, etc. However, facile tuning of the AIEgen emissions in a wide range remains challenging. Herein, a novel series of AIEgens is reported, based on imidazole‐cored molecular rotors, with facile synthesis and emission colors covering the whole visible spectrum. Moreover, these imidazole derivatives exhibit biological functions unique among the AIEgens, including mitochondria‐specific imaging and antifungal activity. Benefiting from the easy preparation and the tunable emission, the imidazole derivatives are expected to not only diversify the family of AIEgens but also enrich their biological applications.     

Low Amplified Spontaneous Emission Threshold from Organic Dyes Based on Bis‐stilbene

Advanced organic laser dyes exhibiting high solubility and bipolar behavior are developed based on a structure combining bis‐stilbene with carbazole (BSBCz). The materials show high photoluminescence quantum yields and large radiative rate constants in solutions, crystals, and blend and neat films. The introduction of alkyl groups significantly improves the solubility of BSBCz, and solution‐processed films of the alkyl‐substituted derivatives exhibit amplified spontaneous emission thresholds as low as 0.59 µJ cm^?2, which is comparable to those of vacuum‐deposited BSBCz films. On the other hand, cyano‐substitution on BSBCz (BSBCz‐CN) increases electron‐accepting properties, resulting in a bathochromic shift of the emission wavelength and improved bipolar behavior. In a BSBCz‐CN‐doped film, a low ASE threshold of 0.63 µJ cm^?2 is achieved, which is one of the lowest values for organic laser dyes with green emission. In addition, organic light‐emitting diodes based on BSBCz‐CN neat films exhibit external quantum efficiencies of 1.8% and could withstand injection of high current densities of up to 500 A cm^?2 under pulse operation. These properties along with low excited‐state absorption cross sections make these materials an outstanding addition to the existing library of organic laser dyes, especially for consideration in electrically pumped lasers.     

Amplified Spontaneous Green Emission and Lasing Emission From Carbon Nanoparticles

In this work, the optical properties of carbon nanoparticles (CNPs) can be modulated by the dopant‐N atom and sp² C‐contents. CNPs prepared with the low urea mass ratio of 0.2:1 (CNP1) exhibit blue emission (maximum PL quantum yield: 15%). Increasing sp² C‐ and dopant‐N atom contents, as determined in CNPs prepared with high urea mass ratio of 2:1 (CNP2), lead to green emission (maximum PL quantum yield up to 36% in ethanol aqueous solution). Amplified spontaneous emission (ASE) can be observed only in CNP2 ethanol aqueous solution. Green lasing emission is achieved from CNP2 ethanol aqueous solution in a linear long Fabry‐Perot cavity, indicating the potential of CNP2 as a gain medium for lasing. CNP2 shows superior photostability compared with C545T dye. The green emission from CNP2 is speculated to arise from electron‐hole recombination (intrinsic state emission). The high PL quantum yield and small overlap between absorption and emissions of CNP2 ethanol aqueous solution are the key factors in realizing lasing emission.     

Tailoring the Molecular Properties with Isomerism Effect of AIEgens

It is challenging to achieve precise control on the properties of organic π‐functional materials to widen their practical applications. On the other hand, the study of aggregation‐induced emission luminogens (AIEgens) helps achieve such goals because of inherent relationships between their luminescence behaviors and conformational variations that allow for the visual monitoring of the changes in the material properties. Inspired by this, in this work, three AIE isomers are fabricated in structures consisting of tetraphenylpyrazine and triphenylethene units with para‐, meta‐, and ortho‐position linkages, respectively. The isomerism effect brings about significantly decreased luminescence efficiency, subtly blueshifted emission, basically reduced AIE effect but boosted porosity in the aggregate state as the conformation of AIEgens evolves from an extended to a folded one. Based on the distinct properties, their respective use in blue organic light‐emitting diodes, nanofluorescent probes, and molecule‐capturing porous crystals are investigated. This work not only achieves precise property control by using the isomerism effect of AIEgens but also provides useful information on the future design of π‐conjugated materials with advanced functionalities.     

Biocompatible Nanoparticles with Aggregation‐Induced Emission Characteristics as Far‐Red/Near‐Infrared Fluorescent Bioprobes for In Vitro and In Vivo Imaging Applications

Light emission of 2‐(2,6‐bis((E)‐4‐(diphenylamino)styryl)‐4H‐pyran‐4‐ylidene)malononitrile (TPA‐DCM) is weakened by aggregate formation. Attaching tetraphenylethene (TPE) units as terminals to TPA‐DCM dramatically changes its emission behavior: the resulting fluorogen, 2‐(2,6‐bis((E)‐4‐(phenyl(4′‐(1,2,2‐triphenylvinyl)‐[1,1′‐biphenyl]‐4‐yl)amino)styryl)‐4H‐pyran‐4‐ylidene)malononitrile (TPE‐TPA‐DCM), is more emissive in the aggregate state, showing the novel phenomenon of aggregation‐induced emission (AIE). Formulation of TPE‐TPA‐DCM using bovine serum albumin (BSA) as the polymer matrix yields uniformly sized protein nanoparticles (NPs) with high brightness and low cytotoxicity. Applications of the fluorogen‐loaded BSA NPs for in vitro and in vivo far‐red/near‐infrared (FR/NIR) bioimaging are successfully demonstrated using MCF‐7 breast‐cancer cells and a murine hepatoma‐22 (H₂₂)‐tumor‐bearing mouse model, respectively. The AIE‐active fluorogen‐loaded BSA NPs show an excellent cancer cell uptake and a prominent tumor‐targeting ability in vivo due to the enhanced permeability and retention effect.     

Malonitrile‐Functionalized Tetraphenylpyrazine: Aggregation‐Induced Emission,Ratiometric Detection of Hydrogen Sulfide,and Mechanochromism

Development of new aggregation‐induced emission (AIE) luminogens has been a hot research topic because they thoroughly solve the notorious aggregation‐caused quenching effect confronted in conventional fluorogens and their promising applications in, for example, organic light‐emitting diodes, chemo‐ and biosensors and bioimaging. Many AIE luminogens (AIEgens) have been prepared but most of them are silole, tetraphenylethene, distyrylanthracene, and their derivatives. In this work, based on the skeleton of tetraphenylpyrazine (TPP), a new AIEgen, named TPP‐PDCV, is generated by functionalizing TPP with malonitrile group. TPP‐PDCV can serve as a sensitive ratiometric fluorescent probe for detecting hydrogen sulfide with high speciality and low detection limit of down to 0.5 × 10^?6m . The mechanism for such detection is fully investigated and deciphered. Unlike most reported mechanochromic AIEgens, which undergo turn‐off or ‐on emission or emission bathochromic shift in the presence of external stimuli, TPP‐PDCV exhibits an abnormal and reversible mechanochromism with hypsochromic effect. These indicate that TPP‐PDCV possesses a huge potential for high‐tech applications through rational modification of TPP core.     

Organic Light‐Emitting Diodes: Organic Light‐Emitting Diodes with a White‐Emitting Molecule: Emission Mechanism and Device Characteristics (Adv. Funct. Mater. 4/2011)

The unique and unprecedented electroluminescence behavior of the white‐emitting molecule 3‐(1‐(4‐(4‐(2‐(2‐hydroxyphenyl)‐4,5‐diphenyl‐1H‐imidazol‐1‐yl)phenoxy)phenyl)‐4,5‐diphenyl‐1H‐imidazol‐2‐yl)naphthalen‐2‐ol (W1), fluorescence emission from which is controlled by the excited‐state intramolecular proton transfer (ESIPT) is investigated. W1 is composed of covalently linked blue‐ and yellow‐color emitting ESIPT moieties between which energy transfer is entirely frustrated. It is demonstrated that different emission colors (blue, yellow, and white) can be generated from the identical emitter W1 in organic light‐emitting diode (OLED) devices. Charge trapping mechanism is proposed to explain such a unique color‐tuned emission from W1. Finally, the device structure to create a color‐stable, color reproducible, and simple‐structured white organic light‐emitting diode (WOLED) using W1 is investigated. The maximum luminance efficiency, power efficiency, and luminance of the WOLED were 3.10 cd A^?1, 2.20 lm W^?1, 1 092 cd m^?2, respectively. The WOLED shows white‐light emission with the Commission Internationale de l′Eclairage (CIE) chromaticity coordinates (0.343, 0.291) at a current level of 10 mA cm^?2. The emission color is high stability, with a change of the CIE chromaticity coordinates as small as (0.028, 0.028) when the current level is varied from 10 to 100 mA cm^?2.     

Manipulation of Charge and Exciton Distribution Based on Blue Aggregation‐Induced Emission Fluorophors: A Novel Concept to Achieve High‐Performance Hybrid White Organic Light‐Emitting Diodes

The aggregation‐induced emission (AIE) phenomenon is important in organic light‐emitting diodes (OLEDs), for it can potentially solve the aggregation‐caused quenching problem. However, the performance of AIE fluorophor‐based OLEDs (AIE OLEDs) is unsatisfactory, particularly for deep‐blue devices (CIEy < 0.15). Here, by enhancing the device engineering, a deep‐blue AIE OLED exhibits low voltage (i.e., 2.75 V at 1 cd m^?2), high luminance (17 721 cd m^?2), high efficiency (4.3 lm W^?1), and low efficiency roll‐off (3.6 lm W^?1 at 1000 cd m^?2), which is the best deep‐blue AIE OLED. Then, blue AIE fluorophors, for the first time, have been demonstrated to achieve high‐performance hybrid white OLEDs (WOLEDs). The two‐color WOLEDs exhibit i) stable colors and the highest efficiency among pure‐white hybrid WOLEDs (32.0 lm W^?1); ii) stable colors, high efficiency, and very low efficiency roll‐off; or iii) unprecedented efficiencies at high luminances (i.e., 70.2 cd A^?1, 43.4 lm W^?1 at 10 000 cd m^?2). Moreover, a three‐color WOLED exhibits wide correlated color temperatures (10 690–2328 K), which is the first hybrid WOLED showing sunlight‐style emission. These findings will open a novel concept that blue AIE fluorophors are promising candidates to develop high‐performance hybrid WOLEDs, which have a bright prospect for the future displays and lightings.     

Metal‐Free Click Polymerization: Synthesis and Photonic Properties of Poly(aroyltriazole)s

Regioselective 1,3‐dipolar polycycloadditions of tetraphenylethene (TPE)‐containing diazides 1 – 3 and bis(aroylacetylene) 4 are initiated by simple heating, affording poly(aroyltriazole)s (PATAs) P I –P III with high molecular weights in high yields. The PATAs are completely soluble in common organic solvents and stable at temperatures up to 358 °C. Thanks to their TPE units, the polymers show aggregation‐induced emission and work as explosive sensors with high sensitivity. The PATAs are optically transparent in the whole visible spectral region. Their refractive indexes can be tuned to a great extent (Δn ≈ 0.08) by simply changing their alkyl spacer lengths. The modified Abbé numbers of the PATAs are very high (up to 273), indicative of very low optical dispersions in the telecommunication‐important wavelength region. UV irradiation through a photomask quenches the light emissions of the polymers, enabling the generation of two‐dimensional fluorescent images without development. The polymers can be readily photo‐crosslinked, yielding three‐dimensional patterns with high resolutions.     

Efficient Bipolar Blue AIEgens for High‐Performance Nondoped Blue OLEDs and Hybrid White OLEDs

Blue organic luminescent materials play a crucial role in full‐color display and white lighting but efficient ones meeting commercial demands are very rare. Herein, the design and synthesis of tailor‐made bipolar blue luminogens with an anthracene core and various functional groups are reported. The thermal stabilities, photophysical properties, electronic structures, electrochemical behaviors, carrier transport abilities, and electroluminescence performances are systematically investigated. The luminogen TPE‐TAPBI containing a tetraphenylethene moiety shows aggregation‐induced emission, while another luminogen TriPE‐TAPBI bearing a triphenylethene unit exhibits light aggregation‐caused quenching. In comparison with TriPE‐TAPBI, TPE‐TAPBI has stronger blue emission in neat film and functions more efficiently in nondoped organic light‐emitting diodes (OLEDs). High maxima current, power, and external quantum efficiencies of 7.21 cd A^?1, 6.78 lm W^?1, and 5.73%, respectively, are attained by the nondoped blue OLED of TPE‐TAPBI (CIE_x,y = 0.15, 0.16). Moreover, efficient two‐color hybrid warm white OLEDs (CIE_x,y = 0.457, 0.470) are achieved using TPE‐TAPBI neat film as the blue‐emitting component, which provide total current, power, external quantum efficiencies of up to 70.5 lm W^?1, 76.0 cd A^?1, and 28% at 1000 cd m^?2, respectively. These blue and white OLEDs are among the most efficient devices with similar colors in the literature.     

Rational Design of Perylenediimide‐Substituted Triphenylethylene to Electron Transporting Aggregation‐Induced Emission Luminogens (AIEgens) with High Mobility and Near‐Infrared Emission

Organic materials with both high electron mobility and strong solid‐state emission are rare although for their importance to advanced organic optoelectronics. In this paper, triphenylethylenes with varying number of perylenediimide (PDI) unit (TriPE‐nPDIs, n = 1?3) are synthesized and their optical and charge‐transporting properties are systematically investigated. All the molecules exhibit strong solid‐stated near infrared (NIR) emission and some of them exhibit aggregation‐enhanced emission characteristics. Organic field‐effect transistors (OFETs) using TriPE‐nPDIs are fabricated. TriPE‐3PDI shows the best performance with maximum quantum yield of ≈30% and optimized electron mobility of over 0.01 cm² V^?1 s^?1, which are the highest values among aggregation‐induced emission luminogens with NIR emissions reported so far. Photophysical property investigation and theoretical calculation indicate that the molecular conformation plays an important role on the optical properties of TriPE‐nPDI, while the result from film microstructure study reveals that the film crystallinity influences greatly their OFET device performance.