In contrast to the predominant mono or difunctionalization of alkenes,the multi-site functionalization of alkenes involving the synergistic formation of more than two new C–C or C–X bonds is much challenging,especia...In contrast to the predominant mono or difunctionalization of alkenes,the multi-site functionalization of alkenes involving the synergistic formation of more than two new C–C or C–X bonds is much challenging,especially for developing new reaction pathway to afford the functional heterocycle compounds with aggregation-induced emission(AIE)property has been rarely reported.In present work,the multi-site functionalization of in situ generated alkenes with indoles has been developed for the synthesis of diversely functionalized carbazoles through the synergistic construction of multiple C–C bonds and C=O bond.A proposed reaction sequence involving C–H alkenylation/radical oxygen atom transfer/Diels-Alder cycloaddition/dehydrogenative aromatization was supported by experiments and density functional theory calculations.Further derivative carbazole-linked-quinoxaline skeletons represent a class of AIEgens with acceptor-donor-acceptor configuration,which generated the desired twisted intramolecular charge transfer(TICT)AIE properties and could be used as fluorescent probes for detecting the micrometer-sized phase separation of polymer blends.The protocol provides a concise route for the synthesis and application of carbazole-based AIE luminogens.展开更多
This review summarizes the recent progress of efficient room temperature phosphorescence（RTP） from pure organic luminogens achieved by crystallization-induced phosphorescence（CIP）,with focus on the advances in our...This review summarizes the recent progress of efficient room temperature phosphorescence（RTP） from pure organic luminogens achieved by crystallization-induced phosphorescence（CIP）,with focus on the advances in our group.Besides homocrystals,mixed crystals and cocrystals are also discussed.Meanwhile,intriguing RTP emission from the luminogens without conventional chromophores is demonstrated.展开更多
Fabrication of efficient solid luminogens with tunable emission is both fundamentally significant and technically important. Herein, based on our previous strategy for the construction of efficient and multifunctional...Fabrication of efficient solid luminogens with tunable emission is both fundamentally significant and technically important. Herein, based on our previous strategy for the construction of efficient and multifunctional solid luminogens through the combination of diverse aggregation-induced emission （ALE） units with other functional moieties, a group of luminophores with electron donor-acceptor （D-A） structure and typical intramolecular charge transfer （ICT） characteristics, namely CZ-DCDPP, DPA-DCDPP and DBPA-DCDPP were synthesized and investigated. The presence of twisting and AlE-active 2,3- dicyano-S,6-diphenylpyrazine （DCDPP） moiety endows them highly emissive in the solid states, whereas the introduction of arylamines with varied electron-donating capacity and different conjugation render them with tunable solid emissions from green to red. While CZ-DCDPP and DPA-DCDPP solids exhibit distinct mechanochromism, both DPA-DCDPP and DBPA-DCDPP solids can generate efficient red emission. Owing to their high efficiency, remarkable thermal and morphological stabilities and moreover red emission, they are promising for diverse optoelectronic and biological applications.展开更多
The development of nontraditional luminogens(NTLs)with superior photoluminescence(PL)properties is of great scientific and practical significance and has drawn rapidly growing interest in recent years.An extremely imp...The development of nontraditional luminogens(NTLs)with superior photoluminescence(PL)properties is of great scientific and practical significance and has drawn rapidly growing interest in recent years.An extremely important but unresolved question is that if there are any distinct differences in the structures and PL mechanisms between traditional luminogens(TLs)and NTLs.In this work,four dihydropyridine derivatives with strong non-aromatic through-bond conjugation(TBC)were designed and synthesized,and the influence of strong non-aromatic TBC and through-space conjugation(TSC)effects on their PL behaviors was studied.These compounds in solutions show significant concentration-dependent emission(CDE)and excitation-dependent emission(EDE),which are typical PL behaviors of NTLs.In solid state,the compounds show wide excitation spectra while narrow emission spectra,with high quantum yields up to 57.4%,but they do not show significant EDE,similar to TLs.And very impressively,two kinds of crystals also exhibit optical waveguide property,which is the first report in NTLs.The UV–vis spectra,crystal structures,and theoretical calculations prove the presence of large non-aromatic TBC interactions in these NTLs,and strong non-aromatic TSC can be formed among the molecules that are in a planar conformation and stacked into layers through intermolecular hydrogen bonding and π…π interactions.The combined effect of strong non-aromatic TBC and TSC endows the compounds unique PL behaviors that are between those of TLs and NTLs,thus bridging the gap between TLs and NTLs.展开更多
Photoluminescence(PL)mechanisms of nontraditional luminogens(NTLs)have attracted great interest,and they are generally explained with intra/intermolecular through-space conjugation(TSC)of nonconventional chromophores....Photoluminescence(PL)mechanisms of nontraditional luminogens(NTLs)have attracted great interest,and they are generally explained with intra/intermolecular through-space conjugation(TSC)of nonconventional chromophores.Here a new concept of nonaromatic through-bond conjugation(TBC)is proposed and it is proved that it plays an important role in the PL of NTLs.The PL behaviors of the three respective isomers of cyclohexanedione and gemdimethyl-1,3-cyclohexanedione were studied and correlated with their chemical and aggregate structures.These compounds show differentfluorescence emissions as well as dif-ferent concentration,excitation and solvent-dependent emissions.The compounds which undergo keto-enol tautomerism and hence with a conjugated ketone-enol structure(i.e.,nonaromatic TBC)show more red-shifted emissions.TBC effect reduces the energy gaps and facilitates the formation of stronger TSC in the aggre-gate state.The compounds in the ketone-enol form are also prone to occur excited state intra/intermolecular proton transfer(ESIPT).The cooperative effect of nonaro-matic TBC and TSC determines the PL behaviors of NTLs.This work provides a novel understanding of the PL mechanisms of NTLs and is of great importance for directing the design and synthesis of novel NTLs.展开更多
Aggregation-induced emission(AIE)is a phenomenon characterized by certain fluorescent molecules that exhibit weak or no luminescence in solution but demonstrate significantly enhanced luminescence upon aggregation.Acc...Aggregation-induced emission(AIE)is a phenomenon characterized by certain fluorescent molecules that exhibit weak or no luminescence in solution but demonstrate significantly enhanced luminescence upon aggregation.Accordingly,AIE materials have successfully addressed the limitations associated with aggregation-caused quenching effects and have made significant progress in the application of various fields of medicine in recent years.At present,the application of AIE materials in gastrointestinal(GI)diseases is mainly in GI imaging,diagnosis and treatment.In this review,we summarize the applications of AIE materials in GI pathogens and GI diseases,including inflammatory bowel disease and GI tumors,and outline combined treatment methods of AIE materials in GI tumor therapy.展开更多
Luminogens that exhibit stimulus-responsive room temperature phosphorescence(RTP)have attracted significant attention for their applications in a wide range of fields such as data storage,sensors,and bio-imaging.Howev...Luminogens that exhibit stimulus-responsive room temperature phosphorescence(RTP)have attracted significant attention for their applications in a wide range of fields such as data storage,sensors,and bio-imaging.However,very few such materials are known,partly because of the unclear internal mechanism.In this review,we summarize recent advances in the field of stimulusresponsive RTP in purely organic luminogens,focusing on their unique emission behaviors and internal mechanisms governing the phenomena.We also attempt to identify the relationship between the mechanism,luminogens,and possible applications.展开更多
The room temperature phosphorescences（RTP）are of growing interest owing to their promising applications in material science and bioimaging.To date,the lumiogens showing persistent RTP effect mainly contain the noble...The room temperature phosphorescences（RTP）are of growing interest owing to their promising applications in material science and bioimaging.To date,the lumiogens showing persistent RTP effect mainly contain the noble metals which have the shortcomings such as high cost,potential toxicity.The exploration of metal free luminogens,i.e.,purely organic RTP luminogens,is thus of great importance for the community.展开更多
Organic light-emitting materials have attracted considerable attention because of their promising applications in diverse areas.Most fluorophores emit brightly in either dilute solutions or aggregate states;the former...Organic light-emitting materials have attracted considerable attention because of their promising applications in diverse areas.Most fluorophores emit brightly in either dilute solutions or aggregate states;the former generally suffer from aggregation-caused quenching problem,and the latter encounter intensity loss at low concentrations.Herein,we propose a new strategy to overcome these dilemmas by balancing the planar and distorted structures of terphenyl-based luminogens and obtain three luminogens,2PB-AC,2Me2PB-AC,and 2T2PB-AC,with bright emission in both solution and aggregate states.Among them,2PB-AC shows absolute photoluminescence quantum yields(ФPL)higher than 90%in both tetrahydrofuran solution(90.2%)and aggregate states(92.7%for powder and 95.3%for crystal).Thus,2PB-AC could be an efficient probe to realize dual-channel explosive detection in both solution and aggregate states.Moreover,it could be used to image live-cell lipid droplets at a wide range of concentrations.In addition,benefiting from its thermodynamically favorable intersystem crossing process,2Me2PB-AC could be doped in polymethyl methacrylate matrix to provide efficient room-temperature phosphorescence.Thus,this work provides a feasible strategy for the design of luminogens with highly efficient emission in both solution and aggregate states,greatly facilitating and broadening their practical applications.展开更多
Achieving high-efficiency deep blue emitter with CIE_(y)<0.06(CIE,Commission Internationale de L’Eclairage)and external quantum efficiency(EQE)>10%has been a long-standing challenge for traditional fluorescent ...Achieving high-efficiency deep blue emitter with CIE_(y)<0.06(CIE,Commission Internationale de L’Eclairage)and external quantum efficiency(EQE)>10%has been a long-standing challenge for traditional fluorescent materials in organic light-emitting diodes(OLEDs).Here,we report the rational design and synthesis of two new deep blue luminogens:4-(10-(4’-(9 H-carbazol-9-yl)-2,5-dimethyl-[1,1’-biphe nyl]-4-yl)anthracen-9-yl)benzonitrile(2 M-ph-pCzAnBzt)and 4-(10-(4-(9 H-carbazol-9-yl)-2,5-dimethyl phenyl)anthracen-9-yl)benzonitrile(2 M-pCzAnBzt).In particular,2 M-ph-pCzAnBzt produces saturated deep blue emissions in a non-doped electroluminescent device with an exceptionally high EQE of 10.44% and CIE_(x,y)(0.151,0.057).The unprecedented electroluminescent efficiency is attributed to the combined effects of higher-order reversed intersystem crossing and triplet-triplet up-conversion,which are supported by analysis of theoretical calculation,triplet sensitization experiments,as well as nanosecond transient absorption spectroscopy.This research offers a new approach to resolve the shortage of high efficiency deep blue fluorescent emitters.展开更多
In recent years, nonconventional luminogens free of aromatic groups have attracted extensive attention due to their academic importance and promising wide applications. Whilst previous studies generally focused on flu...In recent years, nonconventional luminogens free of aromatic groups have attracted extensive attention due to their academic importance and promising wide applications. Whilst previous studies generally focused on fluorescence from aliphatic amine or carbonylcontaining systems, less attention has been paid to room temperature phosphorescence(RTP) and the systems with predominant oxygen functionalities. In this work, photophysical properties of the polyhydroxy polymers, including microcrystalline cellulose(MCC), 2-hydroxyethyl cellulose(HEC), hydroxypropyl cellulose(HPC), and cellulose acetate(CA), were studied and compared. While MCC,HEC, and HPC solids showed bright emission alongside distinct RTP, CA demonstrated relatively low intensity of solid emission without noticeable RTP. Their emissions were explained in terms of the clustering-triggered emission(CTE) mechanism and conformation rigidification. Additionally, on account of its intrinsic emission, concentrated HEC aqueous solution could be used as the probe for the detection of 2,4,6-trinitrophenol(TNP).展开更多
Polymorphism has been frequently used in tuning the singlet emissions of pure organic dyes. The modulation of triplet-involved emissions, particularly room temperature phosphorescence(RTP),however, is scarcely reporte...Polymorphism has been frequently used in tuning the singlet emissions of pure organic dyes. The modulation of triplet-involved emissions, particularly room temperature phosphorescence(RTP),however, is scarcely reported. Herein, polymorphism is reported to tune the triplet-involved emissions of 2 CZBZL, a newly designed pure organic luminogen consisting of twisted benzil and two planar carbazole moieties. Other than the conventional modulation through changing molecular conformation and packing, vibration can also finely tune the triplet-involved emissions. Besides prompt fluorescence(PF),polymorph B with relatively extended conformation emits thermally activated delayed fluorescence(TADF), whereas the others(A, C–E) with similarly more twisted conformations generate predominant RTP or simultaneous DF and RTP. These results demonstrate the fascinating chance to regulate the tripletinvolved emissions through controlling conformation and vibration.展开更多
Many large-scale and complex structural components are applied in the aeronautics and automobile industries.However,the repeated alternating or cyclic loads in service tend to cause unexpected fatigue fractures.Theref...Many large-scale and complex structural components are applied in the aeronautics and automobile industries.However,the repeated alternating or cyclic loads in service tend to cause unexpected fatigue fractures.Therefore,developing real-time and visible monitoring methods for fatigue crack initiation and propagation is critically important for structural safety.This paper proposes a machine learning-based fatigue crack growth detection method that combines computer vision and machine learning.In our model,computer vision is used for data creation,and the machine learning model is used for crack detection.Then computer vision is used for marking and analyzing the crack growth path and length.We apply seven models for the crack classification and find that the decision tree is the best model in this research.The experimental results prove the effectiveness of our method,and the crack length measurement accuracy achieved is 0.6 mm.Furthermore,the slight machine learning models help us realize real-time and visible fatigue crack detection.展开更多
Ten novel butterfly-shaped dithienobenzosilole-based luminogens,which are peripherally installed with a variety of substituents including hydrogen,phenyl and substituted phenyl groups,have been readily prepared via an...Ten novel butterfly-shaped dithienobenzosilole-based luminogens,which are peripherally installed with a variety of substituents including hydrogen,phenyl and substituted phenyl groups,have been readily prepared via an iodine-induced intramolecular electrophilic double-cyclisation reaction and subsequent deiodination or coupling reactions.The optical and electrochemical properties of these compounds were systematically investigated to clarify the relationships between their structures and properties,supported by theoretical calculations.These compounds exhibit deep-blue to sky-blue emissions and high photoluminescence quantum yields up to 0.84 in solution and solid states which are regulated by the functional blades and their steric hindrance on theα–andβ–positions of thiophene rings.Their high thermal-and photo-stabilities have been revealed and mainly attributed to the dithienobenzosilole core.展开更多
Fluorescence navigation is a novel technique for accurately identifying hepatocellular carcinoma(HCC)lesions during hepatectomy,enabling real-time visualization.Indocyanine green-based fluorescence guidance has been c...Fluorescence navigation is a novel technique for accurately identifying hepatocellular carcinoma(HCC)lesions during hepatectomy,enabling real-time visualization.Indocyanine green-based fluorescence guidance has been commonly used to demarcate HCC lesion boundaries,but it cannot distinguish between benign and malignant liver tumors.This review focused on the clinical applications and limitations of indocyanine green,as well as recent advances in novel fluorescent probes for fluorescence-guided surgery of HCC.It covers traditional fluorescent imaging probes such as enzymes,reactive oxygen species,reactive sulfur species,and pH-sensitive probes,followed by an introduction to aggregation-induced emission probes.Aggregation-induced emission probes exhibit strong fluorescence,low background signals,excellent biocompatibility,and high photostability in the aggregate state,but show no fluorescence in dilute solutions.Design strategies for these probes may offer insights for developing novel fluorescent probes for the real-time identification and navigation of HCC during surgery.展开更多
Organic fluorescent materials with multistimuli-responsive behaviors have attracted much attention because of their promising applications in diverse fields.Most chromophores exhibit bright emission in either dilute s...Organic fluorescent materials with multistimuli-responsive behaviors have attracted much attention because of their promising applications in diverse fields.Most chromophores exhibit bright emission in either dilute solutions or aggregation states,which inevitably suffer from the aggregation-caused quenching(ACQ)problem or encounter serious energy loss at low concentration.To overcome these limitations,dual-state emissive(DSE)materials with bright emission in both solution and solid states have been developed.However,most DSE materials only involve one or two stimulus-responsive behaviors.Herein,through combining characteristics of imidazopyridine N1 as well as manipulation of electronic structure and intermolecular interaction,DSE molecule TPA-IPBA with four multistimuli-responsive behaviors has been rationally and accurately prepared,which could be easily converted to ACQ(TPA-IPB)and AIE(aggregation-induced emission)(TPA-IPBCN)molecules.Under external stimuli,four types of multistimuli-responsive behaviors have been successfully achieved,including solvatochromism(redshift of 124 nm),mechanofluorochromism(redshift of 6 or 30 nm),reversible tricolor acidichromism(redshift of 148 nm)and solidphase polymorphism with solvent-dependent solid emission(from B-state to G-state,redshift of 52 nm).We explained four types of multistimuli-responsive behaviors in detail through nuclear magnetic resonance spectroscopies,theoretical calculations,single crystal analysis,and PXRD characterization.In addition,on the basis of our biological research on imidazo[1,2-α]-pyridines,we found that TPA-IPBA serves as a fluorescent probe to dynamically detect biological lipid droplets with high co-localization ability(PC=0.95).These results provide new insight into developing DSE materials via a delicate manipulation of molecular structure with acceptor-dependent tunable multistimuli-responsive properties and bioimaging applications.展开更多
Pure organic luminogens with room temperature phosphorescence(RTP) have drawn much attention due to their fundamental importance and promising applications in optoelectronic devices, bioimaging, sensing, etc. Fluoresc...Pure organic luminogens with room temperature phosphorescence(RTP) have drawn much attention due to their fundamental importance and promising applications in optoelectronic devices, bioimaging, sensing, etc. Fluorescence-phosphorescence dual emission at room temperature, however, is rarely observed in pure organic materials. Herein, we reported a metal-and heavy-atom free pure organic luminogen with tert-butyl groups, DtBuCZBP, which is ready to form organogels in dimethylsulfoxide(DMSO).It emits prompt and delayed fluorescence, as well as RTP, namely dual emission in as-prepared solid, gels and polymeric films.To the best of our knowledge, it is the first example of metal-and heavy-atom free pure organic gelator with RTP emission. Such unique RTP and moreover dual emission properties in different states make DtBuCZBP a potential material for diverse applications.展开更多
The research of organic luminescent materials in aggregate has drawn more and more attention for their wide applications.To adjust the luminescent properties for aggregates,a deep understanding of the corresponding in...The research of organic luminescent materials in aggregate has drawn more and more attention for their wide applications.To adjust the luminescent properties for aggregates,a deep understanding of the corresponding internal mechanism is needed.In this short review,a brief introduction of aggregation-induced emission(AIE)and some other solid state luminescence behaviors derived from or parallel to AIE is presented.Particularly,the relationship between emission property and intermolecular/intramolecular interactions is summarized,with the aim to guide the further development of organic optoelectronic materials in aggregate.展开更多
Organic molecular aggregates have attracted widespread attention over the past decade owing to their unique optoelectronic properties in the aggregate state,which mainly involves the effects of aggregation structure a...Organic molecular aggregates have attracted widespread attention over the past decade owing to their unique optoelectronic properties in the aggregate state,which mainly involves the effects of aggregation structure as well as molecular packing mode.Although many examples of H-and J-aggregates defined by molecular exciton model have been found,there are also other types of unconventional aggregates,especially for aggregation-induced emission(AIE)system.In this review,the recent progress of some examples of basic and novel aggregate forms,as well as coassembled forms,presenting distinctive optical features,such as optical waveguide and polarization emission,polymorph-dependent emission and stimuli-responsive luminescence are presented.The systematic insight into the relationship between the aggregation structure and emission property is discussed.Guidelines are therefore anticipated and will direct the future preprogramming molecular design so as to fine-tune the emission feature through a specific aggregation model for developing organic molecular aggregates with desirable optoelectronic properties.展开更多
Intrinsic emission from unorthodox luminogens without traditional conjugated building blocks is drawing increasing attention.However,the emission mechanism is still controversial.Herein,we demonstrate the intriguing e...Intrinsic emission from unorthodox luminogens without traditional conjugated building blocks is drawing increasing attention.However,the emission mechanism is still controversial.Herein,we demonstrate the intriguing emission from perfluorosulfonate ionomers(PFSIs),which can be explained by the clustering triggered emission(CTE)mechanism.Despite being free of any conventional chromophores,PFSIs exhibit bright emission and multi-color phosphorescence(77 K)in concentrated solutions,powders and membranes with obvious aggregation-induced emission(AIE)characteristics.Clustered sulfonic acids are responsible for the light emission,and their connection and evolution are deeply explored via X-ray diffraction(XRD)and small angel X-ray scattering(SAXS),in which the electron overlap determined by the clustered status results in the extended conjugation and simultaneously rigidified conformations.These results demonstrate that it is feasible to use fluorescence analysis to explore the ionic cluster structure and evolution of PFSI,and it can be applied in the pure organic luminescent field as well.展开更多
文摘In contrast to the predominant mono or difunctionalization of alkenes,the multi-site functionalization of alkenes involving the synergistic formation of more than two new C–C or C–X bonds is much challenging,especially for developing new reaction pathway to afford the functional heterocycle compounds with aggregation-induced emission(AIE)property has been rarely reported.In present work,the multi-site functionalization of in situ generated alkenes with indoles has been developed for the synthesis of diversely functionalized carbazoles through the synergistic construction of multiple C–C bonds and C=O bond.A proposed reaction sequence involving C–H alkenylation/radical oxygen atom transfer/Diels-Alder cycloaddition/dehydrogenative aromatization was supported by experiments and density functional theory calculations.Further derivative carbazole-linked-quinoxaline skeletons represent a class of AIEgens with acceptor-donor-acceptor configuration,which generated the desired twisted intramolecular charge transfer(TICT)AIE properties and could be used as fluorescent probes for detecting the micrometer-sized phase separation of polymer blends.The protocol provides a concise route for the synthesis and application of carbazole-based AIE luminogens.
基金financially supported by the National Natural Science Foundation of China(No.51473092)the Shanghai Rising-Star Program(No.15QA1402500)the SMC-Chenxing Young Scholar Program of Shanghai Jiao Tong University
文摘This review summarizes the recent progress of efficient room temperature phosphorescence（RTP） from pure organic luminogens achieved by crystallization-induced phosphorescence（CIP）,with focus on the advances in our group.Besides homocrystals,mixed crystals and cocrystals are also discussed.Meanwhile,intriguing RTP emission from the luminogens without conventional chromophores is demonstrated.
基金supported by the National Natural Science Foundation of China (No. 51473092)the Shanghai Rising-Star Program (No. 15QA1402500)
文摘Fabrication of efficient solid luminogens with tunable emission is both fundamentally significant and technically important. Herein, based on our previous strategy for the construction of efficient and multifunctional solid luminogens through the combination of diverse aggregation-induced emission （ALE） units with other functional moieties, a group of luminophores with electron donor-acceptor （D-A） structure and typical intramolecular charge transfer （ICT） characteristics, namely CZ-DCDPP, DPA-DCDPP and DBPA-DCDPP were synthesized and investigated. The presence of twisting and AlE-active 2,3- dicyano-S,6-diphenylpyrazine （DCDPP） moiety endows them highly emissive in the solid states, whereas the introduction of arylamines with varied electron-donating capacity and different conjugation render them with tunable solid emissions from green to red. While CZ-DCDPP and DPA-DCDPP solids exhibit distinct mechanochromism, both DPA-DCDPP and DBPA-DCDPP solids can generate efficient red emission. Owing to their high efficiency, remarkable thermal and morphological stabilities and moreover red emission, they are promising for diverse optoelectronic and biological applications.
基金supported by National Natural Science Foundation of China(Grant 22472010)the Program for Changjiang Scholars and Innovative Research Team(PCSIRT)in university.
文摘The development of nontraditional luminogens(NTLs)with superior photoluminescence(PL)properties is of great scientific and practical significance and has drawn rapidly growing interest in recent years.An extremely important but unresolved question is that if there are any distinct differences in the structures and PL mechanisms between traditional luminogens(TLs)and NTLs.In this work,four dihydropyridine derivatives with strong non-aromatic through-bond conjugation(TBC)were designed and synthesized,and the influence of strong non-aromatic TBC and through-space conjugation(TSC)effects on their PL behaviors was studied.These compounds in solutions show significant concentration-dependent emission(CDE)and excitation-dependent emission(EDE),which are typical PL behaviors of NTLs.In solid state,the compounds show wide excitation spectra while narrow emission spectra,with high quantum yields up to 57.4%,but they do not show significant EDE,similar to TLs.And very impressively,two kinds of crystals also exhibit optical waveguide property,which is the first report in NTLs.The UV–vis spectra,crystal structures,and theoretical calculations prove the presence of large non-aromatic TBC interactions in these NTLs,and strong non-aromatic TSC can be formed among the molecules that are in a planar conformation and stacked into layers through intermolecular hydrogen bonding and π…π interactions.The combined effect of strong non-aromatic TBC and TSC endows the compounds unique PL behaviors that are between those of TLs and NTLs,thus bridging the gap between TLs and NTLs.
基金Program for Changjiang Scholars and Innovative Research Team(PCSIRT)in UniversityNational Natural Science Foundation of China,Grant/Award Number:21574015。
文摘Photoluminescence(PL)mechanisms of nontraditional luminogens(NTLs)have attracted great interest,and they are generally explained with intra/intermolecular through-space conjugation(TSC)of nonconventional chromophores.Here a new concept of nonaromatic through-bond conjugation(TBC)is proposed and it is proved that it plays an important role in the PL of NTLs.The PL behaviors of the three respective isomers of cyclohexanedione and gemdimethyl-1,3-cyclohexanedione were studied and correlated with their chemical and aggregate structures.These compounds show differentfluorescence emissions as well as dif-ferent concentration,excitation and solvent-dependent emissions.The compounds which undergo keto-enol tautomerism and hence with a conjugated ketone-enol structure(i.e.,nonaromatic TBC)show more red-shifted emissions.TBC effect reduces the energy gaps and facilitates the formation of stronger TSC in the aggre-gate state.The compounds in the ketone-enol form are also prone to occur excited state intra/intermolecular proton transfer(ESIPT).The cooperative effect of nonaro-matic TBC and TSC determines the PL behaviors of NTLs.This work provides a novel understanding of the PL mechanisms of NTLs and is of great importance for directing the design and synthesis of novel NTLs.
基金Supported by The Science and Technology Program of Gansu Province,No.23JRRA1015.
文摘Aggregation-induced emission(AIE)is a phenomenon characterized by certain fluorescent molecules that exhibit weak or no luminescence in solution but demonstrate significantly enhanced luminescence upon aggregation.Accordingly,AIE materials have successfully addressed the limitations associated with aggregation-caused quenching effects and have made significant progress in the application of various fields of medicine in recent years.At present,the application of AIE materials in gastrointestinal(GI)diseases is mainly in GI imaging,diagnosis and treatment.In this review,we summarize the applications of AIE materials in GI pathogens and GI diseases,including inflammatory bowel disease and GI tumors,and outline combined treatment methods of AIE materials in GI tumor therapy.
基金the starting Grants of Tianjin University,Grant/Award Number:001Natural Science Foundation of Tianjin City+3 种基金National Natural Science Foundation of ChinaTianjin Universitythe starting Grants of Tianjin University and Tianjin Government,National Natural Science Foundation of China(No.51903188)Natural Science Foundation of Tianjin City(No.19JCQNJC04500)for financial support.
文摘Luminogens that exhibit stimulus-responsive room temperature phosphorescence(RTP)have attracted significant attention for their applications in a wide range of fields such as data storage,sensors,and bio-imaging.However,very few such materials are known,partly because of the unclear internal mechanism.In this review,we summarize recent advances in the field of stimulusresponsive RTP in purely organic luminogens,focusing on their unique emission behaviors and internal mechanisms governing the phenomena.We also attempt to identify the relationship between the mechanism,luminogens,and possible applications.
文摘The room temperature phosphorescences（RTP）are of growing interest owing to their promising applications in material science and bioimaging.To date,the lumiogens showing persistent RTP effect mainly contain the noble metals which have the shortcomings such as high cost,potential toxicity.The exploration of metal free luminogens,i.e.,purely organic RTP luminogens,is thus of great importance for the community.
基金This work was financially supported by the National Natural Science Foundation of China(grant no.21788102)the Natural Science Foundation of Guangdong Province(grant nos.2019B030301003 and 2016A030312002)the Innovation and Technology Commission of Hong Kong(grant no.ITC-CNERC14S01).
文摘Organic light-emitting materials have attracted considerable attention because of their promising applications in diverse areas.Most fluorophores emit brightly in either dilute solutions or aggregate states;the former generally suffer from aggregation-caused quenching problem,and the latter encounter intensity loss at low concentrations.Herein,we propose a new strategy to overcome these dilemmas by balancing the planar and distorted structures of terphenyl-based luminogens and obtain three luminogens,2PB-AC,2Me2PB-AC,and 2T2PB-AC,with bright emission in both solution and aggregate states.Among them,2PB-AC shows absolute photoluminescence quantum yields(ФPL)higher than 90%in both tetrahydrofuran solution(90.2%)and aggregate states(92.7%for powder and 95.3%for crystal).Thus,2PB-AC could be an efficient probe to realize dual-channel explosive detection in both solution and aggregate states.Moreover,it could be used to image live-cell lipid droplets at a wide range of concentrations.In addition,benefiting from its thermodynamically favorable intersystem crossing process,2Me2PB-AC could be doped in polymethyl methacrylate matrix to provide efficient room-temperature phosphorescence.Thus,this work provides a feasible strategy for the design of luminogens with highly efficient emission in both solution and aggregate states,greatly facilitating and broadening their practical applications.
基金supported by the National Natural Science Foundation of China(62004074,51727809)the Science and Technology Department of Hubei Province(2019AAA063,2020BAA016)。
文摘Achieving high-efficiency deep blue emitter with CIE_(y)<0.06(CIE,Commission Internationale de L’Eclairage)and external quantum efficiency(EQE)>10%has been a long-standing challenge for traditional fluorescent materials in organic light-emitting diodes(OLEDs).Here,we report the rational design and synthesis of two new deep blue luminogens:4-(10-(4’-(9 H-carbazol-9-yl)-2,5-dimethyl-[1,1’-biphe nyl]-4-yl)anthracen-9-yl)benzonitrile(2 M-ph-pCzAnBzt)and 4-(10-(4-(9 H-carbazol-9-yl)-2,5-dimethyl phenyl)anthracen-9-yl)benzonitrile(2 M-pCzAnBzt).In particular,2 M-ph-pCzAnBzt produces saturated deep blue emissions in a non-doped electroluminescent device with an exceptionally high EQE of 10.44% and CIE_(x,y)(0.151,0.057).The unprecedented electroluminescent efficiency is attributed to the combined effects of higher-order reversed intersystem crossing and triplet-triplet up-conversion,which are supported by analysis of theoretical calculation,triplet sensitization experiments,as well as nanosecond transient absorption spectroscopy.This research offers a new approach to resolve the shortage of high efficiency deep blue fluorescent emitters.
基金financially supported by the National Natural Science Foundation of China (Nos. 51603050 and 51863006)the Natural Science Foundation of Guangxi (Nos. 2016GXNSFBA380196, 2016GXNSFBA380064)+1 种基金Guangxi University Young and Middle-aged Teachers Basic Ability Promotion Project (No. KY2016YB316)The Open Project Foundation of Guangxi Ministry-Province Jointly-Constructed Cultivation Base for State Key Laboratory of Processing for Non-ferrous Metal and Featured Materials (15-KF-10)
文摘In recent years, nonconventional luminogens free of aromatic groups have attracted extensive attention due to their academic importance and promising wide applications. Whilst previous studies generally focused on fluorescence from aliphatic amine or carbonylcontaining systems, less attention has been paid to room temperature phosphorescence(RTP) and the systems with predominant oxygen functionalities. In this work, photophysical properties of the polyhydroxy polymers, including microcrystalline cellulose(MCC), 2-hydroxyethyl cellulose(HEC), hydroxypropyl cellulose(HPC), and cellulose acetate(CA), were studied and compared. While MCC,HEC, and HPC solids showed bright emission alongside distinct RTP, CA demonstrated relatively low intensity of solid emission without noticeable RTP. Their emissions were explained in terms of the clustering-triggered emission(CTE) mechanism and conformation rigidification. Additionally, on account of its intrinsic emission, concentrated HEC aqueous solution could be used as the probe for the detection of 2,4,6-trinitrophenol(TNP).
基金financially supported by the National Natural Science Foundation of China (Nos. 51822303, 51473092)
文摘Polymorphism has been frequently used in tuning the singlet emissions of pure organic dyes. The modulation of triplet-involved emissions, particularly room temperature phosphorescence(RTP),however, is scarcely reported. Herein, polymorphism is reported to tune the triplet-involved emissions of 2 CZBZL, a newly designed pure organic luminogen consisting of twisted benzil and two planar carbazole moieties. Other than the conventional modulation through changing molecular conformation and packing, vibration can also finely tune the triplet-involved emissions. Besides prompt fluorescence(PF),polymorph B with relatively extended conformation emits thermally activated delayed fluorescence(TADF), whereas the others(A, C–E) with similarly more twisted conformations generate predominant RTP or simultaneous DF and RTP. These results demonstrate the fascinating chance to regulate the tripletinvolved emissions through controlling conformation and vibration.
基金supported by the National Key Research and Development Program of China(2018YFC0808600)the National Natural Science Foundation of China(52075368,51605325,11772219)and JSPS KAKENHI(18K18337).
文摘Many large-scale and complex structural components are applied in the aeronautics and automobile industries.However,the repeated alternating or cyclic loads in service tend to cause unexpected fatigue fractures.Therefore,developing real-time and visible monitoring methods for fatigue crack initiation and propagation is critically important for structural safety.This paper proposes a machine learning-based fatigue crack growth detection method that combines computer vision and machine learning.In our model,computer vision is used for data creation,and the machine learning model is used for crack detection.Then computer vision is used for marking and analyzing the crack growth path and length.We apply seven models for the crack classification and find that the decision tree is the best model in this research.The experimental results prove the effectiveness of our method,and the crack length measurement accuracy achieved is 0.6 mm.Furthermore,the slight machine learning models help us realize real-time and visible fatigue crack detection.
基金supported by the National Natural Science Foundation of China(No.21501135)。
文摘Ten novel butterfly-shaped dithienobenzosilole-based luminogens,which are peripherally installed with a variety of substituents including hydrogen,phenyl and substituted phenyl groups,have been readily prepared via an iodine-induced intramolecular electrophilic double-cyclisation reaction and subsequent deiodination or coupling reactions.The optical and electrochemical properties of these compounds were systematically investigated to clarify the relationships between their structures and properties,supported by theoretical calculations.These compounds exhibit deep-blue to sky-blue emissions and high photoluminescence quantum yields up to 0.84 in solution and solid states which are regulated by the functional blades and their steric hindrance on theα–andβ–positions of thiophene rings.Their high thermal-and photo-stabilities have been revealed and mainly attributed to the dithienobenzosilole core.
基金supported by the National Natural Science Foundation of China(Grants 82170642,82172754,81874208,22405079)the Opening Project of Hubei Key Laboratory of Purification and Application of Plant Anti-cancer Active Ingredients(HLPAI2023001).
文摘Fluorescence navigation is a novel technique for accurately identifying hepatocellular carcinoma(HCC)lesions during hepatectomy,enabling real-time visualization.Indocyanine green-based fluorescence guidance has been commonly used to demarcate HCC lesion boundaries,but it cannot distinguish between benign and malignant liver tumors.This review focused on the clinical applications and limitations of indocyanine green,as well as recent advances in novel fluorescent probes for fluorescence-guided surgery of HCC.It covers traditional fluorescent imaging probes such as enzymes,reactive oxygen species,reactive sulfur species,and pH-sensitive probes,followed by an introduction to aggregation-induced emission probes.Aggregation-induced emission probes exhibit strong fluorescence,low background signals,excellent biocompatibility,and high photostability in the aggregate state,but show no fluorescence in dilute solutions.Design strategies for these probes may offer insights for developing novel fluorescent probes for the real-time identification and navigation of HCC during surgery.
基金supported by the National Natural Science Foundation of China(21803059,22401267)the Training Program for Young Backbone Teachers in Higher Education Institutions of Henan Province(2024GGJS011)the Natural Science Foundation of Henan Province(252300421282)。
文摘Organic fluorescent materials with multistimuli-responsive behaviors have attracted much attention because of their promising applications in diverse fields.Most chromophores exhibit bright emission in either dilute solutions or aggregation states,which inevitably suffer from the aggregation-caused quenching(ACQ)problem or encounter serious energy loss at low concentration.To overcome these limitations,dual-state emissive(DSE)materials with bright emission in both solution and solid states have been developed.However,most DSE materials only involve one or two stimulus-responsive behaviors.Herein,through combining characteristics of imidazopyridine N1 as well as manipulation of electronic structure and intermolecular interaction,DSE molecule TPA-IPBA with four multistimuli-responsive behaviors has been rationally and accurately prepared,which could be easily converted to ACQ(TPA-IPB)and AIE(aggregation-induced emission)(TPA-IPBCN)molecules.Under external stimuli,four types of multistimuli-responsive behaviors have been successfully achieved,including solvatochromism(redshift of 124 nm),mechanofluorochromism(redshift of 6 or 30 nm),reversible tricolor acidichromism(redshift of 148 nm)and solidphase polymorphism with solvent-dependent solid emission(from B-state to G-state,redshift of 52 nm).We explained four types of multistimuli-responsive behaviors in detail through nuclear magnetic resonance spectroscopies,theoretical calculations,single crystal analysis,and PXRD characterization.In addition,on the basis of our biological research on imidazo[1,2-α]-pyridines,we found that TPA-IPBA serves as a fluorescent probe to dynamically detect biological lipid droplets with high co-localization ability(PC=0.95).These results provide new insight into developing DSE materials via a delicate manipulation of molecular structure with acceptor-dependent tunable multistimuli-responsive properties and bioimaging applications.
基金supported by the National Natural Science Foundation of China (51473092)the Shanghai Rising-Star Program (15QA1402500)
文摘Pure organic luminogens with room temperature phosphorescence(RTP) have drawn much attention due to their fundamental importance and promising applications in optoelectronic devices, bioimaging, sensing, etc. Fluorescence-phosphorescence dual emission at room temperature, however, is rarely observed in pure organic materials. Herein, we reported a metal-and heavy-atom free pure organic luminogen with tert-butyl groups, DtBuCZBP, which is ready to form organogels in dimethylsulfoxide(DMSO).It emits prompt and delayed fluorescence, as well as RTP, namely dual emission in as-prepared solid, gels and polymeric films.To the best of our knowledge, it is the first example of metal-and heavy-atom free pure organic gelator with RTP emission. Such unique RTP and moreover dual emission properties in different states make DtBuCZBP a potential material for diverse applications.
基金National Natural Science Foundation of China,Grant/Award Number:51903188Natural Science Foundation ofTianjin City,Grant/Award Number:19JCQNJC04500。
文摘The research of organic luminescent materials in aggregate has drawn more and more attention for their wide applications.To adjust the luminescent properties for aggregates,a deep understanding of the corresponding internal mechanism is needed.In this short review,a brief introduction of aggregation-induced emission(AIE)and some other solid state luminescence behaviors derived from or parallel to AIE is presented.Particularly,the relationship between emission property and intermolecular/intramolecular interactions is summarized,with the aim to guide the further development of organic optoelectronic materials in aggregate.
基金National Natural Science Foundation of China,Grant/Award Numbers:21835001,52073116,51773080。
文摘Organic molecular aggregates have attracted widespread attention over the past decade owing to their unique optoelectronic properties in the aggregate state,which mainly involves the effects of aggregation structure as well as molecular packing mode.Although many examples of H-and J-aggregates defined by molecular exciton model have been found,there are also other types of unconventional aggregates,especially for aggregation-induced emission(AIE)system.In this review,the recent progress of some examples of basic and novel aggregate forms,as well as coassembled forms,presenting distinctive optical features,such as optical waveguide and polarization emission,polymorph-dependent emission and stimuli-responsive luminescence are presented.The systematic insight into the relationship between the aggregation structure and emission property is discussed.Guidelines are therefore anticipated and will direct the future preprogramming molecular design so as to fine-tune the emission feature through a specific aggregation model for developing organic molecular aggregates with desirable optoelectronic properties.
基金supported by the Petrochina Petrochemical Research Institute(LH-17-02-07-05)Open Foundation from State Key Laboratory of Fluorinated Functional Membrane Material。
文摘Intrinsic emission from unorthodox luminogens without traditional conjugated building blocks is drawing increasing attention.However,the emission mechanism is still controversial.Herein,we demonstrate the intriguing emission from perfluorosulfonate ionomers(PFSIs),which can be explained by the clustering triggered emission(CTE)mechanism.Despite being free of any conventional chromophores,PFSIs exhibit bright emission and multi-color phosphorescence(77 K)in concentrated solutions,powders and membranes with obvious aggregation-induced emission(AIE)characteristics.Clustered sulfonic acids are responsible for the light emission,and their connection and evolution are deeply explored via X-ray diffraction(XRD)and small angel X-ray scattering(SAXS),in which the electron overlap determined by the clustered status results in the extended conjugation and simultaneously rigidified conformations.These results demonstrate that it is feasible to use fluorescence analysis to explore the ionic cluster structure and evolution of PFSI,and it can be applied in the pure organic luminescent field as well.
