With the increasing development of English globalization,the trend of combining English with local cultures has become more evident.This research focuses on five schools in the Wenzhou overseas Chinese hometown to inv...With the increasing development of English globalization,the trend of combining English with local cultures has become more evident.This research focuses on five schools in the Wenzhou overseas Chinese hometown to investigate the current status of English education from the perspectives of teachers,students,and textbooks.The aim was to propose bilingual education strategies for the education of transnational left-behind children(TLC).By examining the situation of English education in this specific context,this study sought to address the unique challenges faced by TLC and provide effective educational approaches.Interviews,observations,and document analysis were employed to gather data by means of questionnaire research methods.The findings of this study settled on the improvement of bilingual education for TLC and insights into enhancing English education in multicultural settings.展开更多
Sciatic nerve tissue was obtained from the gluteus maximus muscle segment of normal human cadavers and amniotic membrane tissue was obtained from healthy human puerperant placentas. Both tissues were analyzed for thei...Sciatic nerve tissue was obtained from the gluteus maximus muscle segment of normal human cadavers and amniotic membrane tissue was obtained from healthy human puerperant placentas. Both tissues were analyzed for their stress relaxation and creep properties to determine suitability for transplantation applications. Human amniotic membrane and sciatic nerve tissues had similar tendencies for stress relaxation and creep properties. The stress value of the amniotic membrane stress relaxation group decreased to a greater extent compared with the sciatic nerve stress relaxation group. Similarly, the stress value of the amniotic membrane creep group increased to a greater extent compared with the sciatic nerve creep group. The stress relaxation curve for human amniotic membrane and sciatic nerve showed a logarithm correlation, while the creep curve showed an exponential correlation. These data indicate that amniotic membrane tissue has better stress relaxation and creep properties compared with sciatic nerve tissue.展开更多
High-efficiency long-wavelength phosphorescence emissions of large singlet-triplet energy gap(ΔE_(ST))materials are essential for applications in biology and display.However,few long-wavelength phosphorescence emissi...High-efficiency long-wavelength phosphorescence emissions of large singlet-triplet energy gap(ΔE_(ST))materials are essential for applications in biology and display.However,few long-wavelength phosphorescence emissions of largeΔE_(ST)materials have been reported due to the weak spin-orbit coupling(SOC)and strong non-radiative transitions.Herein,we develop a strategy to achieve highly efficient long-wavelength room temperature phosphorescence(RTP)emission of largeΔE_(ST)materials,which display bright red RTP emission with above 400μs lifetime and 6.5%phosphorescent quantum efficiency.Our experiments and theoretical calculations reveal that the fishbone-like packing and the zig-zag interactions provide favorable conditions for suppressing the non-radiative transitions of triplet state excitons,and heavy atoms effectively promote the intersystem crossing(ISC)process for highly efficient long-wavelength phosphorescence emission.The universality of the method for highly efficient long-wavelength RTP emission of largeΔE_(ST)materials was further investigated in various guests.Moreover,these materials with largeΔE_(ST)manifest the advantages of large color contrast on the display and utilization potentiality in information encryption.This strategy paves the way for the high contrast display and development of information encryption with RTP emission.展开更多
Small-molecule photothermal agents(PTAs)with intense second near-infrared(NIR-Ⅱ,1,000 to 1,700 nm)absorption and high photothermal conversion efficiencies(PCEs)are promising candidates for treating deep-seated tumors...Small-molecule photothermal agents(PTAs)with intense second near-infrared(NIR-Ⅱ,1,000 to 1,700 nm)absorption and high photothermal conversion efficiencies(PCEs)are promising candidates for treating deep-seated tumors such as osteosarcoma.To date,the development of small-molecule NIR-Ⅱ PTAs has largely relied on fabricating donor–acceptor–donor(D–A–D/D′)structures and limited success has been achieved.Herein,through acceptor engineering,a donor–acceptor–acceptor(D–A–A′)-structured NIR-Ⅱ aza-boron-dipyrromethene(aza-BODIPY)PTA(SW8)was readily developed for the 1,064-nm laser-mediated phototheranostic treatment of osteosarcoma.Changing the donor groups to acceptor groups produced remarkable red-shifts of absorption maximums from first near-infrared(NIR-Ⅰ)regions(~808 nm)to NIR-Ⅱ ones(~1,064 nm)for aza-BODIPYs(SW1 to SW8).Furthermore,SW8 self-assembled into nanoparticles(SW8@NPs)with intense NIR-Ⅱ absorption and an ultrahigh PCE(75%,1,064 nm).This ultrahigh PCE primarily originated from an additional nonradiative decay pathway,which showed a 100-fold enhanced decay rate compared to that shown by conventional pathways such as internal conversion and vibrational relaxation.Eventually,SW8@NPs performed highly efficient 1,064-nm laser-mediated NIR-Ⅱ photothermal therapy of osteosarcoma via concurrent apoptosis and pyroptosis.This work not only illustrates a remote approach for treating deep-seated tumors with high spatiotemporal control but also provides a new strategy for building high-performance small-molecule NIR-Ⅱ PTAs.展开更多
Organic scintillators,materials with the ability to exhibit luminescence when exposed to X-rays,have aroused increasing interest in recent years.However,the enhancement of radioluminescence and improving X-ray absorpt...Organic scintillators,materials with the ability to exhibit luminescence when exposed to X-rays,have aroused increasing interest in recent years.However,the enhancement of radioluminescence and improving X-ray absorption of organic scintillators lie in the inherent dilemma,due to the waste of triplet excitons and weak X-ray absorption during scintillation.Here,we employ halogenated thermally activated delayed fluorescence materials to improve the triplet exciton utilization and X-ray absorption simultaneously,generating efficient scintillation with a low detection limit,which is one order of magnitude lower than the dosage for X-ray medical diagnostics.Through experimental study and theoretical calculation,we reveal the positive role of X-ray absorption,quantum yields of prompt fluorescence,and intersystem crossing in promoting the radioluminescence intensity.This finding offers an opportunity to design diverse types of organic scintillators and expands the applications of thermally activated delayed fluorescence.展开更多
Ultralong organic phosphorescence(UOP)materials have received considerable attention in the field of organic optoelectronics due to their long lifetime,high exciton utilization,large Stokes shift,and so on.Great advan...Ultralong organic phosphorescence(UOP)materials have received considerable attention in the field of organic optoelectronics due to their long lifetime,high exciton utilization,large Stokes shift,and so on.Great advancements have been achieved through manipulating intermolecular interactions for high-performance UOP materials in recent years.This review will discuss the influence of various intermolecular interactions,includingπ-πinteractions,n-πinteractions,halogen bonding,hydrogen bonding,coordinative bonding,and ionic bonding on phosphorescent properties at room temperature,respectively.We summarize the rule of manipulating intermolecular interactions for UOP materials with superior phosphorescent properties.This review will provide a guideline for developing new UOP materials with superior phosphorescent properties for potential applications in organic electronics and bioelectronics.展开更多
Nonaromatic amino acids are generally believed to be nonemissive, owing to their lack of apparently remarkable conjugation within individual molecules. Here we report the intrinsic visible emission of nonaromatic amin...Nonaromatic amino acids are generally believed to be nonemissive, owing to their lack of apparently remarkable conjugation within individual molecules. Here we report the intrinsic visible emission of nonaromatic amino acids and poly(amino acids) in concentrated solutions and solid powders. This unique and widespread luminescent characteristic can be well rationalized by the clustering-triggered emission(CTE) mechanism, namely the clustering of nonconventional chromophores(i.e. amino, carbonyl,and hydroxyl) and subsequent electron cloud overlap with simultaneous conformation rigidification. Such CTE mechanism is further supported by the single crystal structure analysis, from which 3 D through space electronic communications are uncovered.Besides prompt fluorescence, room temperature phosphorescence(RTP) is also detected from the solids. Moreover, persistent RTP is observed in the powders of exampled poly(amino acids) of ε-poly-L-lysine(.-PLL) after ceasing UV irradiation. These results not only illustrate the feasibility of employing the building blocks of nonaromatic amino acids in the exploration of new luminescent biomolecules, but also provide significant implications for the emissions of peptides and proteins at aggregated or crystalline states. Meanwhile, they may also shed lights on further understanding of autofluorescence from biological systems.展开更多
Ultralong organic phosphorescence(UOP)materials have roused considerable attention in the field of photonics and optoelectronics owing to the feature of long-lived emission lifetimes.However,to develop UOP materials w...Ultralong organic phosphorescence(UOP)materials have roused considerable attention in the field of photonics and optoelectronics owing to the feature of long-lived emission lifetimes.However,to develop UOP materials with color-tunability is still a formidable challenge.Here,we report a class of UOP materials containing carbonyl,amino or amide groups,exhibiting colortunable persistent luminescence ranging from blue(458 nm)to yellow-green(508 nm)under different UV wavelength excitation.Taken theoretical and experimental results together,we conclude that the excitation dependent color-tunable UOP emission is ascribed to multiple emission centers from single molecular and aggregated states in crystal.Given color-tunable UOP feature,these materials are used to successfully realize visual UV-light detection.This finding not only provides a strategy to design new organic phosphorescent molecules with colorful emission,but also extends the scope of the applications of purely organic phosphorescent materials.展开更多
Room-temperature phosphorescence(RTP)with a dynamic feature endows organic luminescent materials with promising application in optoelectronic fields.However,it remains a formidable challenge to obtain dynamic RTP mate...Room-temperature phosphorescence(RTP)with a dynamic feature endows organic luminescent materials with promising application in optoelectronic fields.However,it remains a formidable challenge to obtain dynamic RTP materials.Herein,we reported a strategy for dynamic RTP via reversible transformation of radicals under external stimuli.RTP gradually disappeared with continuous UV-light irradiation owing to the conversion of NDIA to NDIA^(·-)in NDIA/PVA film,which can be recovered by oxidation with oxygen.Regarding the excellent reversibility and repeatability,the potential applications for round-the-clock anticounterfeiting and tag were first demonstrated.This finding not only outlines a principle to synthesize new RTP materials with dynamic behavior,but also expands the scope of applications of dynamic RTP materials.展开更多
Mulit-enzyme cascades are a major type of chemical transformations and play a crucial role in biological signal transduction and metabolism. Herein, a trienzyme cascade-triggered fluorescent immunosensor platform was ...Mulit-enzyme cascades are a major type of chemical transformations and play a crucial role in biological signal transduction and metabolism. Herein, a trienzyme cascade-triggered fluorescent immunosensor platform was constructed by sequentially integrating alkaline phosphatase(ALP), tyrosinase(TYR)and horseradish peroxidase(HRP). The proposed platform was based on HRP-induced a rapid in situ fluorogenic reaction between dopamine(DA) and 1,5-dihydroxynaphthalene(DHA) to produce a strong yellow azamonardine fluorescent compound(AFC). The obtained AFC was clearly characterized by highresolution mass spectrum,1H NMR,^(13)C NMR and theoretical calculations. The integration of the twoenzyme system(TYR and HRP) or three-enzyme system(ALP, TYR and HRP) led to a maximum of 400.0-fold and 250.0-fold fluorescence enhancements, respectively. Using cardiac troponin I(c Tn I) as the model antigen, a trienzyme cascade-triggered fluorescent immunosensor platform was developed for quantitative detecting c Tn I in a wide linear range from 2 ng/m L to 150 ng/m L with a detection limit of 0.67ng/m L. In addition, the proposed platform was successfully applied in detection of c Tn I in serum of clinical patients. Overall, the developed fluorescent immunosensor performs powerful implications for researching enzyme cascade systems in the field of biomedicine.展开更多
Purely organic phosphorescent materials with dynamically tunable optical properties and persistent luminescent characteristics enable more novel applications in intelligent optoelectronics.Herein,we reported a concise...Purely organic phosphorescent materials with dynamically tunable optical properties and persistent luminescent characteristics enable more novel applications in intelligent optoelectronics.Herein,we reported a concise and universal strategy to achieve photoactivated ultralong phosphorescence at room temperature through stereo-hindrance engineering.Such dynamically photoactivated phosphorescence behavior was ascribed to the suppression of non-radiative transitions and improvement of spin-orbit coupling(SOC)as the variation of the distorted molecular conformation by the synergistic effect of electrostatic repulsion and steric hindrance.This“trainable”phosphorescent behavior was first proposed to mimic biological synaptic plasticity,especially for unique experience-dependent plasticity,by the manipulation of pulse intensity and numbers.This study not only outlines a principle to design newly dynamic phosphorescent materials,but also broadens their utility in intelligent sensors and robotics.展开更多
Developing ultralong organic phosphorescence(UOP)materials with smart response to external stimuli is of great interest in photonics applications,whereas the manipulation of molecular stacking on tuning such dynamic U...Developing ultralong organic phosphorescence(UOP)materials with smart response to external stimuli is of great interest in photonics applications,whereas the manipulation of molecular stacking on tuning such dynamic UOP is still a formidable challenge.Herein,we have reported two polymorphs with distinct photoactivated dynamic UOP behavior based on a pyridine derivative for the first time.Our experiment revealed that the dynamic UOP behavior including photoactivation and deactivation feature is highly dependent on irradiation intensity and environmental atmosphere.Additionally,given the unique dynamic UOP feature,these phosphors have been successfully applied to phosphorescence-dependent molecular logic gate and timing data storage.This result not only paves a way to design smart functional materials but also expands the scope of the applications on organic phosphorescence materials.展开更多
Organic phosphorescence materials demonstrate potential optoelectronic applications due to their remarkably ultralong organic phosphorescence(UOP)lifetime and abundant optical characteristics prior to the fluorescence...Organic phosphorescence materials demonstrate potential optoelectronic applications due to their remarkably ultralong organic phosphorescence(UOP)lifetime and abundant optical characteristics prior to the fluorescence materials.For a better insight into the intrinsic relationship among regioisomeric molecules,crystalline interactions,and phosphorescence properties,three crystalline dicarbazol-9-yl pyrazine-based regioisomers with para-,meta-and ortho-convergent substitutions(p-DCzP,m-DCzP,and o-DCzP)were designed and presented gradually increased UOP lifetimes prolonging from 63.14,127.93 to 350.46 ms,respectively,due to the regioisomerism effect(RIE)which would be an effective strategy for better understanding of structure-property of UOP materials.展开更多
Supramolecular organic frameworks(SOFs),due to the atomically precise integration of the repeated building units,exhibit intriguing properties and consequently potential applications in chemical and materials science ...Supramolecular organic frameworks(SOFs),due to the atomically precise integration of the repeated building units,exhibit intriguing properties and consequently potential applications in chemical and materials science communities.However,it remains a great challenge to achieve SOFs with ultralong organic phosphorescence(UOP)in a singlecomponent system.Herein,we report metal-free organic compound 9,9′-(6-(2-bromophenethoxy)-1,3,5-triazine-2,4-diyl)bis(9H-carbazole)(DCzPO)with UOP behavior.Owing to the combination of multiple supramolecular interactions,DCzPO formed a SOF structure with regular hexagonal holes,which shows an ultralong emission lifetime of 398 ms and a phosphorescence efficiency of 3%.So far as we know,among the reported luminescent SOFs,this one is the most highly efficient.This single-component SOF with ultralong phosphorescence will provide a new platform to rationally combine UOP and porous materials.展开更多
Ultralong organic phosphorescent materials have invoked considerable attention for their great potential in sensing,data encryption,information anti-counterfeiting and so forth.However,effective ways to achieve highly...Ultralong organic phosphorescent materials have invoked considerable attention for their great potential in sensing,data encryption,information anti-counterfeiting and so forth.However,effective ways to achieve highly efficient ultralong organic phosphorescence(UOP)in metal-free organic materials remain a great challenge.Herein,we designed three isomers based on asymmetric triazines with various bromine substituted positions.Impressively,phosphorescence efficiency of p-BrAT in solid state can reach up to 9.7%with a long lifetime of 386 ms,which was one of the highest efficient UOP materials reported so far.Theoretical calculations further demonstrated that para-substitution exhibited the most effective radiative transition for triplet excitons.These results will provide an effective approach to achieving highly efficient UOP materials.展开更多
Ultralong organic phosphorescence(UOP)crystals have attracted increased attention due to the distinct photophysical property of a long-lived lifetime.However,organic crystals are generally brittle,leading to a serious...Ultralong organic phosphorescence(UOP)crystals have attracted increased attention due to the distinct photophysical property of a long-lived lifetime.However,organic crystals are generally brittle,leading to a serious problem for their application in flexible technology.Herein,we report three types of elastic organic crystals(EOCs)with ultralong phosphorescence via introducing halogen atoms(Cl,Br,I)intoπ-conjugated phosphorescent molecules.Especially,the crystal containing iodine atoms displayed both excellent elasticity(ε=3.01%)and high phosphorescent efficiency(Φ_(Ph)=19.1%)owing to the strong halogen bonds.Taking advantage of its highly efficient UOP and excellent elasticity,we successfully used a DCz4I crystal for anti-counterfeiting application.These findings may provide guidance for the development of elastic crystals with afterglow and expand the scope of potential applications on flexible materials.展开更多
基金the result of a general project titled“Research on the Spread of Chinese Characteristic Culture from the Perspective of English Glocalization”(23WSK133YBM)funded by the Annual Philosophy and Social Science Planning Project of Wenzhou City.It is also the result of a horizontal project titled“Research on Improving the Overall Education Level of Ouhai District-Taking Junior High Education as an Example”(2021031)+1 种基金funded by Ouhai District of Wenzhou City.Additionally,it includes the achievements of“I am Chinese”bilingual innovation practice team of the School of Foreign Languages of Wenzhou University in constructing the practice base for the spiritual and civilized education of underage children in Wenzhouthe results of a horizontal project titled“Research on the Bilingual Patriotic Education Path for Overseas Left-behind Children on the Basis of Volunteer Practice of the Team Titled‘I am Chinese’”(2023-152),funded by Ouhai District of Wenzhou City。
文摘With the increasing development of English globalization,the trend of combining English with local cultures has become more evident.This research focuses on five schools in the Wenzhou overseas Chinese hometown to investigate the current status of English education from the perspectives of teachers,students,and textbooks.The aim was to propose bilingual education strategies for the education of transnational left-behind children(TLC).By examining the situation of English education in this specific context,this study sought to address the unique challenges faced by TLC and provide effective educational approaches.Interviews,observations,and document analysis were employed to gather data by means of questionnaire research methods.The findings of this study settled on the improvement of bilingual education for TLC and insights into enhancing English education in multicultural settings.
文摘Sciatic nerve tissue was obtained from the gluteus maximus muscle segment of normal human cadavers and amniotic membrane tissue was obtained from healthy human puerperant placentas. Both tissues were analyzed for their stress relaxation and creep properties to determine suitability for transplantation applications. Human amniotic membrane and sciatic nerve tissues had similar tendencies for stress relaxation and creep properties. The stress value of the amniotic membrane stress relaxation group decreased to a greater extent compared with the sciatic nerve stress relaxation group. Similarly, the stress value of the amniotic membrane creep group increased to a greater extent compared with the sciatic nerve creep group. The stress relaxation curve for human amniotic membrane and sciatic nerve showed a logarithm correlation, while the creep curve showed an exponential correlation. These data indicate that amniotic membrane tissue has better stress relaxation and creep properties compared with sciatic nerve tissue.
基金supported by the National Natural Science Foundation of China(62288102)the National Key R&D Program of China(2020YFA0709900)。
文摘High-efficiency long-wavelength phosphorescence emissions of large singlet-triplet energy gap(ΔE_(ST))materials are essential for applications in biology and display.However,few long-wavelength phosphorescence emissions of largeΔE_(ST)materials have been reported due to the weak spin-orbit coupling(SOC)and strong non-radiative transitions.Herein,we develop a strategy to achieve highly efficient long-wavelength room temperature phosphorescence(RTP)emission of largeΔE_(ST)materials,which display bright red RTP emission with above 400μs lifetime and 6.5%phosphorescent quantum efficiency.Our experiments and theoretical calculations reveal that the fishbone-like packing and the zig-zag interactions provide favorable conditions for suppressing the non-radiative transitions of triplet state excitons,and heavy atoms effectively promote the intersystem crossing(ISC)process for highly efficient long-wavelength phosphorescence emission.The universality of the method for highly efficient long-wavelength RTP emission of largeΔE_(ST)materials was further investigated in various guests.Moreover,these materials with largeΔE_(ST)manifest the advantages of large color contrast on the display and utilization potentiality in information encryption.This strategy paves the way for the high contrast display and development of information encryption with RTP emission.
基金the National Key R&D Program of China(2020YFA0709900)the National Natural Science Foundation of China(62288102,22077101,62175201,and 22004099)+3 种基金the Joint Research Funds of Department of Science&Technology of Shaanxi Province and North-western Polytechnical University(2020GXLH-Z-008,2020GXLH-Z-021 and 2020GXLH-Z-023)the Open Project Program of Wuhan National Laboratory for Optoelectronics(Nos.2020WNLOKF023 and 2022WNLOKF009)The Natural Science Foundation of Ningbo(202003N4049 and 202003N4065)the Natural Science Foundation of Shaanxi Province(2022JM-130).
文摘Small-molecule photothermal agents(PTAs)with intense second near-infrared(NIR-Ⅱ,1,000 to 1,700 nm)absorption and high photothermal conversion efficiencies(PCEs)are promising candidates for treating deep-seated tumors such as osteosarcoma.To date,the development of small-molecule NIR-Ⅱ PTAs has largely relied on fabricating donor–acceptor–donor(D–A–D/D′)structures and limited success has been achieved.Herein,through acceptor engineering,a donor–acceptor–acceptor(D–A–A′)-structured NIR-Ⅱ aza-boron-dipyrromethene(aza-BODIPY)PTA(SW8)was readily developed for the 1,064-nm laser-mediated phototheranostic treatment of osteosarcoma.Changing the donor groups to acceptor groups produced remarkable red-shifts of absorption maximums from first near-infrared(NIR-Ⅰ)regions(~808 nm)to NIR-Ⅱ ones(~1,064 nm)for aza-BODIPYs(SW1 to SW8).Furthermore,SW8 self-assembled into nanoparticles(SW8@NPs)with intense NIR-Ⅱ absorption and an ultrahigh PCE(75%,1,064 nm).This ultrahigh PCE primarily originated from an additional nonradiative decay pathway,which showed a 100-fold enhanced decay rate compared to that shown by conventional pathways such as internal conversion and vibrational relaxation.Eventually,SW8@NPs performed highly efficient 1,064-nm laser-mediated NIR-Ⅱ photothermal therapy of osteosarcoma via concurrent apoptosis and pyroptosis.This work not only illustrates a remote approach for treating deep-seated tumors with high spatiotemporal control but also provides a new strategy for building high-performance small-molecule NIR-Ⅱ PTAs.
基金This work was financially supported by the National Key R&D Program of China(grant no.2020YFA0709900)National Basic Science Center of Flexible Electronics(62288102)+1 种基金the National Natural Science Foundation of China(62134007,21975120,21875104,and 21973043)the Primary Research and Development Plan of Jiangsu Province(BE2016770).
文摘Organic scintillators,materials with the ability to exhibit luminescence when exposed to X-rays,have aroused increasing interest in recent years.However,the enhancement of radioluminescence and improving X-ray absorption of organic scintillators lie in the inherent dilemma,due to the waste of triplet excitons and weak X-ray absorption during scintillation.Here,we employ halogenated thermally activated delayed fluorescence materials to improve the triplet exciton utilization and X-ray absorption simultaneously,generating efficient scintillation with a low detection limit,which is one order of magnitude lower than the dosage for X-ray medical diagnostics.Through experimental study and theoretical calculation,we reveal the positive role of X-ray absorption,quantum yields of prompt fluorescence,and intersystem crossing in promoting the radioluminescence intensity.This finding offers an opportunity to design diverse types of organic scintillators and expands the applications of thermally activated delayed fluorescence.
基金National Natural Science Foundation of China,Grant/Award Numbers:22105038,21912750Fujian Province Natural Science Foundation of China,Grant/Award Number:2022J01654Fujian Normal University Start-up Grant,Grant/Award Number:Y0720306K13。
文摘Ultralong organic phosphorescence(UOP)materials have received considerable attention in the field of organic optoelectronics due to their long lifetime,high exciton utilization,large Stokes shift,and so on.Great advancements have been achieved through manipulating intermolecular interactions for high-performance UOP materials in recent years.This review will discuss the influence of various intermolecular interactions,includingπ-πinteractions,n-πinteractions,halogen bonding,hydrogen bonding,coordinative bonding,and ionic bonding on phosphorescent properties at room temperature,respectively.We summarize the rule of manipulating intermolecular interactions for UOP materials with superior phosphorescent properties.This review will provide a guideline for developing new UOP materials with superior phosphorescent properties for potential applications in organic electronics and bioelectronics.
基金supported by the National Natural Science Foundation of China(51473092)the Shanghai Rising-Star Program(15QA1402500)
文摘Nonaromatic amino acids are generally believed to be nonemissive, owing to their lack of apparently remarkable conjugation within individual molecules. Here we report the intrinsic visible emission of nonaromatic amino acids and poly(amino acids) in concentrated solutions and solid powders. This unique and widespread luminescent characteristic can be well rationalized by the clustering-triggered emission(CTE) mechanism, namely the clustering of nonconventional chromophores(i.e. amino, carbonyl,and hydroxyl) and subsequent electron cloud overlap with simultaneous conformation rigidification. Such CTE mechanism is further supported by the single crystal structure analysis, from which 3 D through space electronic communications are uncovered.Besides prompt fluorescence, room temperature phosphorescence(RTP) is also detected from the solids. Moreover, persistent RTP is observed in the powders of exampled poly(amino acids) of ε-poly-L-lysine(.-PLL) after ceasing UV irradiation. These results not only illustrate the feasibility of employing the building blocks of nonaromatic amino acids in the exploration of new luminescent biomolecules, but also provide significant implications for the emissions of peptides and proteins at aggregated or crystalline states. Meanwhile, they may also shed lights on further understanding of autofluorescence from biological systems.
基金supported by the National Natural Science Foundation of China(21875104,21975120,21973043,91833304,51673095)the Natural Science Fund for Distinguished Young Scholars of Jiangsu Province(BK20180037)the Fundamental Research Funds for the Central Universities。
文摘Ultralong organic phosphorescence(UOP)materials have roused considerable attention in the field of photonics and optoelectronics owing to the feature of long-lived emission lifetimes.However,to develop UOP materials with color-tunability is still a formidable challenge.Here,we report a class of UOP materials containing carbonyl,amino or amide groups,exhibiting colortunable persistent luminescence ranging from blue(458 nm)to yellow-green(508 nm)under different UV wavelength excitation.Taken theoretical and experimental results together,we conclude that the excitation dependent color-tunable UOP emission is ascribed to multiple emission centers from single molecular and aggregated states in crystal.Given color-tunable UOP feature,these materials are used to successfully realize visual UV-light detection.This finding not only provides a strategy to design new organic phosphorescent molecules with colorful emission,but also extends the scope of the applications of purely organic phosphorescent materials.
基金supported by the National Key R&D Program of China(2020YFA0709900)the National Natural Science Foundation of China(21975120,62134007,21875104,21973043)+2 种基金Talented of Nanjing Tech University(201983)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX21-1101)China National Postdoctoral Program for Innovative Talents(BX20200278)。
文摘Room-temperature phosphorescence(RTP)with a dynamic feature endows organic luminescent materials with promising application in optoelectronic fields.However,it remains a formidable challenge to obtain dynamic RTP materials.Herein,we reported a strategy for dynamic RTP via reversible transformation of radicals under external stimuli.RTP gradually disappeared with continuous UV-light irradiation owing to the conversion of NDIA to NDIA^(·-)in NDIA/PVA film,which can be recovered by oxidation with oxygen.Regarding the excellent reversibility and repeatability,the potential applications for round-the-clock anticounterfeiting and tag were first demonstrated.This finding not only outlines a principle to synthesize new RTP materials with dynamic behavior,but also expands the scope of applications of dynamic RTP materials.
基金the National Natural Science Foundation of China (Nos. 22174065, 21974119)the Science and Technology Planning Project of Hunan Province (No. 2020RC_(3)046)Hunan Provincial Natural Science Foundation of China (No.2019JJ30020)。
文摘Mulit-enzyme cascades are a major type of chemical transformations and play a crucial role in biological signal transduction and metabolism. Herein, a trienzyme cascade-triggered fluorescent immunosensor platform was constructed by sequentially integrating alkaline phosphatase(ALP), tyrosinase(TYR)and horseradish peroxidase(HRP). The proposed platform was based on HRP-induced a rapid in situ fluorogenic reaction between dopamine(DA) and 1,5-dihydroxynaphthalene(DHA) to produce a strong yellow azamonardine fluorescent compound(AFC). The obtained AFC was clearly characterized by highresolution mass spectrum,1H NMR,^(13)C NMR and theoretical calculations. The integration of the twoenzyme system(TYR and HRP) or three-enzyme system(ALP, TYR and HRP) led to a maximum of 400.0-fold and 250.0-fold fluorescence enhancements, respectively. Using cardiac troponin I(c Tn I) as the model antigen, a trienzyme cascade-triggered fluorescent immunosensor platform was developed for quantitative detecting c Tn I in a wide linear range from 2 ng/m L to 150 ng/m L with a detection limit of 0.67ng/m L. In addition, the proposed platform was successfully applied in detection of c Tn I in serum of clinical patients. Overall, the developed fluorescent immunosensor performs powerful implications for researching enzyme cascade systems in the field of biomedicine.
基金The authors acknowledge the support from the National Basic Science Center of Flexible Electronics(62288102)the National Key R&D Program of China(grant no.2020YFA0709900)+1 种基金the National Natural Science Foundation of China(21975120,62134007,and 21973043)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX21_1096).Cultivation Program for The Excellent Doctoral Dissertation of Nanjing Tech University.
文摘Purely organic phosphorescent materials with dynamically tunable optical properties and persistent luminescent characteristics enable more novel applications in intelligent optoelectronics.Herein,we reported a concise and universal strategy to achieve photoactivated ultralong phosphorescence at room temperature through stereo-hindrance engineering.Such dynamically photoactivated phosphorescence behavior was ascribed to the suppression of non-radiative transitions and improvement of spin-orbit coupling(SOC)as the variation of the distorted molecular conformation by the synergistic effect of electrostatic repulsion and steric hindrance.This“trainable”phosphorescent behavior was first proposed to mimic biological synaptic plasticity,especially for unique experience-dependent plasticity,by the manipulation of pulse intensity and numbers.This study not only outlines a principle to design newly dynamic phosphorescent materials,but also broadens their utility in intelligent sensors and robotics.
基金This work is supported by the National Natural Science Foundation of China(21875104,21975120,21973043,51673095,and 91833302)Natural Science Fund for Distinguished Young Scholars of Jiangsu Province(BK20180037).
文摘Developing ultralong organic phosphorescence(UOP)materials with smart response to external stimuli is of great interest in photonics applications,whereas the manipulation of molecular stacking on tuning such dynamic UOP is still a formidable challenge.Herein,we have reported two polymorphs with distinct photoactivated dynamic UOP behavior based on a pyridine derivative for the first time.Our experiment revealed that the dynamic UOP behavior including photoactivation and deactivation feature is highly dependent on irradiation intensity and environmental atmosphere.Additionally,given the unique dynamic UOP feature,these phosphors have been successfully applied to phosphorescence-dependent molecular logic gate and timing data storage.This result not only paves a way to design smart functional materials but also expands the scope of the applications on organic phosphorescence materials.
基金supported by the National Natural Science Foundation of China(Nos.21975126,51673095,21875104,21875191,21603104)the Natural Science Foundation of Jiangsu Province(Nos.BK20171470,BK20160991,BK20150064,BK20130912)+1 种基金973 Program(No.2015CB932200)Ministry of Education and Synergetic Innovation Center for Organic Electronics and Information Displays for financial support
文摘Organic phosphorescence materials demonstrate potential optoelectronic applications due to their remarkably ultralong organic phosphorescence(UOP)lifetime and abundant optical characteristics prior to the fluorescence materials.For a better insight into the intrinsic relationship among regioisomeric molecules,crystalline interactions,and phosphorescence properties,three crystalline dicarbazol-9-yl pyrazine-based regioisomers with para-,meta-and ortho-convergent substitutions(p-DCzP,m-DCzP,and o-DCzP)were designed and presented gradually increased UOP lifetimes prolonging from 63.14,127.93 to 350.46 ms,respectively,due to the regioisomerism effect(RIE)which would be an effective strategy for better understanding of structure-property of UOP materials.
基金supported by the National Natural Science Foundation of China(nos.21975120,21875104,21973043,91833304,and 91833302)the National Key R&D Program of China(no.2020YFA0709900)+2 种基金the Natural Science Fund for Distinguished Young Scholars of Jiangsu Province(no.BK20180037)the China National Postdoctoral Program for Innovative Talents(no.BX20200278)the China Postdoctoral Science Foundation(no.2020M673478).
文摘Supramolecular organic frameworks(SOFs),due to the atomically precise integration of the repeated building units,exhibit intriguing properties and consequently potential applications in chemical and materials science communities.However,it remains a great challenge to achieve SOFs with ultralong organic phosphorescence(UOP)in a singlecomponent system.Herein,we report metal-free organic compound 9,9′-(6-(2-bromophenethoxy)-1,3,5-triazine-2,4-diyl)bis(9H-carbazole)(DCzPO)with UOP behavior.Owing to the combination of multiple supramolecular interactions,DCzPO formed a SOF structure with regular hexagonal holes,which shows an ultralong emission lifetime of 398 ms and a phosphorescence efficiency of 3%.So far as we know,among the reported luminescent SOFs,this one is the most highly efficient.This single-component SOF with ultralong phosphorescence will provide a new platform to rationally combine UOP and porous materials.
基金supported by the National Natural Science Foundation of China(Nos.21875104 and 51673095)National Basic Research Program of China(973 Program,No.2015CB932200)+4 种基金Natural Science Fund for Distinguished Young Scholars(No.BK20180037)the Natural Science Fund for Colleges and Universities(No.17KJB430020)"High-Level Talents in Six Industries"(No.XCL-025)of Jiangsu ProvinceNanjing Tech Start-up Grant(Nos.3983500158 and 3983500169)the High Performance Computing Centre of Nanjing Tech University for supporting the computational resources
文摘Ultralong organic phosphorescent materials have invoked considerable attention for their great potential in sensing,data encryption,information anti-counterfeiting and so forth.However,effective ways to achieve highly efficient ultralong organic phosphorescence(UOP)in metal-free organic materials remain a great challenge.Herein,we designed three isomers based on asymmetric triazines with various bromine substituted positions.Impressively,phosphorescence efficiency of p-BrAT in solid state can reach up to 9.7%with a long lifetime of 386 ms,which was one of the highest efficient UOP materials reported so far.Theoretical calculations further demonstrated that para-substitution exhibited the most effective radiative transition for triplet excitons.These results will provide an effective approach to achieving highly efficient UOP materials.
基金supported by the National Natural Science Foundation of China(21875104,21975120,21973043,9183330461935017,and 51673095)Natural Science Fund for Distinguished Young Scholars of Jiangsu Province(BK20180037)+1 种基金Projects of International Cooperation and Exchanges NSFC(51811530018)the Fundamental Research Funds for the Central Universities。
文摘Ultralong organic phosphorescence(UOP)crystals have attracted increased attention due to the distinct photophysical property of a long-lived lifetime.However,organic crystals are generally brittle,leading to a serious problem for their application in flexible technology.Herein,we report three types of elastic organic crystals(EOCs)with ultralong phosphorescence via introducing halogen atoms(Cl,Br,I)intoπ-conjugated phosphorescent molecules.Especially,the crystal containing iodine atoms displayed both excellent elasticity(ε=3.01%)and high phosphorescent efficiency(Φ_(Ph)=19.1%)owing to the strong halogen bonds.Taking advantage of its highly efficient UOP and excellent elasticity,we successfully used a DCz4I crystal for anti-counterfeiting application.These findings may provide guidance for the development of elastic crystals with afterglow and expand the scope of potential applications on flexible materials.
