Atomically precise metal nanoclusters(MNCs),as a potential type of photoacoustic(PA)contrast agent,are limited in application due to their low PA conversion efficiency(PACE).Here,with hydrophilic Au25SR18(SR=thiolate)...Atomically precise metal nanoclusters(MNCs),as a potential type of photoacoustic(PA)contrast agent,are limited in application due to their low PA conversion efficiency(PACE).Here,with hydrophilic Au25SR18(SR=thiolate)as model NCs,we present a result that weakly polar solvent induces aggregation,which effectively enhances PA intensity and PACE.The PA intensity and PACE are highly dependent on the degree of aggregation,while the aggregation-enhanced PA intensity(AEPA)positively correlates to the protected ligands.Such an AEPA phenomenon indicates that aggregation actually accelerates the intramolecular motion of Au NCs,and enlarges the proportion of excited state energy dissipated through vibrational relaxation.This result conflicts with the restriction of intramolecular motion mechanism of aggregation-induced emission.Further experiments show that the increased energy of AEPA originates from the aggregation inhibiting the intermolecular energy transfer from excited Au NCs to their surrounding medium molecules,including solvent molecule and dissolved oxygen,rather than restricting radiative relaxations.This study develops a new strategy for enhancing the PA intensity of Au NCs,and contributes to a deeper understanding of the origin of the PA signal and the excited state energy dissipation processes for MNCs.展开更多
Organic light-emitting diodes(OLEDs)fabricated using organic thermally activated delayed fluorescence materials as sensitizers have recently achieved significant advancements,but the serious efficiency roll-offs are s...Organic light-emitting diodes(OLEDs)fabricated using organic thermally activated delayed fluorescence materials as sensitizers have recently achieved significant advancements,but the serious efficiency roll-offs are still troublesome in most cases.Herein,a tailor-made multifunctional luminogen SBF-BP-SFAC containing 9,9′-spirobifluorene(SBF)and spiro[acridine-9,9-fluorene](SFAC)as electron donors and carbonyl as an electron acceptor is synthesized and characterized.SBF-BPSFAC has the advantages of high thermal stability,aggregation-enhanced delayed fluorescence,and balanced carrier transport ability,and prefers horizontal dipole orientation.Highly efficient OLEDs employing SBF-BP-SFAC as an emitter radiate intense cyan light with outstanding external quantum efficiencies(ηexts)of up to 30.6%.SBF-BP-SFAC can also serve as an excellent sensitizer for orange fluorescence,phosphorescence,and delayed fluorescence materials,providing excellent η exts of up to 30.3% with very small efficiency roll-offs due to the fast Förster energy transfer as well as exciton annihilation suppression by bulky spiro donors.These outstanding performances demonstrate the great potential of SBF-BP-SFAC as an emitter and sensitizer for OLEDs.展开更多
Severe efficiency instability is still a huge challenge for most organic light-emitting diodes(OLEDs)based on thermally activated delayed fluorescence(TADF)molecules,frustrating their industrial application.To address...Severe efficiency instability is still a huge challenge for most organic light-emitting diodes(OLEDs)based on thermally activated delayed fluorescence(TADF)molecules,frustrating their industrial application.To address this issue,herein we report two robust luminogens,3,6-bis(9,9-dimethylacridin-10-yl)-xanthen9-one(BDMAC-XT)and 3,6-bis(9,9-diphenylacridin-10-yl)-xanthen-9-one(BDPAC-XT),comprised of electron-accepting 3,6-dibromoxanthen-9-one and electron-donating 9,9-dimethyl-9,10-dihydroacridine and 9,9-diphenyl-9,10-dihydroacridine.展开更多
A polymer (poly(9,10)anthracenevinylene-alt-4,4'-(9,9-bis(4-(4'-(1,2,2'-triphenyviny)phenoxy)butyl)-9H- fluorene-2,7-diyl) dibenzaldehyde), P1) was successfully synthesized through the Wittig-Horner re...A polymer (poly(9,10)anthracenevinylene-alt-4,4'-(9,9-bis(4-(4'-(1,2,2'-triphenyviny)phenoxy)butyl)-9H- fluorene-2,7-diyl) dibenzaldehyde), P1) was successfully synthesized through the Wittig-Horner reaction by employing fluorene and 9,10-distyrylanthracene moieties as building blocks for backbone and tetraphenylethenes as pendant groups. Photophysical and thermal properties of the resulting polymeric emitter were fully characterized by ultraviolet-visible (UV- Vis) absorption and photoluminescence (PL) spectra, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). While P1 emits an orange-light centered at 567 nm in dilute tetrahydrofuran (THF) solution, the solid powder of the polymer exhibits strong yellow emission peaked at 541 nm. It is also found that the as-synthesized polymer shows unique property of aggregation-enhanced emission (AEE). In addition, P1 possesses high thermal stability with a decomposition temperature (Td,5%) of 430 ℃ and high morphological stability with a glass transition temperature (Tg) of 171℃. Under the stimulus of mechanical force, the emission of P1 can be changed from yellow to red (△λmax = 61 rim), showing a remarkable mechanochromism. The results from XRD analysis suggest that such mechanochromic phenomenonof PI is probably caused by the destruction of crystalline structure, which leads to the conformational planarization of the distyrylanthracene moieties forming by the polymerization and the increase of molecular conjugation of the backbone.展开更多
A new silole derivative, 2,5-bis(7-(dimesitylboranyl)-9,9-dimethylfluoren-2-yl)- 1 -methyl- 1,3,4-triphenylsilole ((MesBF)2MTPS), is synthesized and characterized. (MesBF)2MTPS shows a good fluorescence effi...A new silole derivative, 2,5-bis(7-(dimesitylboranyl)-9,9-dimethylfluoren-2-yl)- 1 -methyl- 1,3,4-triphenylsilole ((MesBF)2MTPS), is synthesized and characterized. (MesBF)2MTPS shows a good fluorescence efficiency of 15% in THF solution and a higher efficiency of 86% in solid film, presenting an aggregation-enhanced emission charac- teristic. It is thermally and morphologically stable, with high decomposition and glass-transition temperatures of 257 and 171 ℃, respectively. The LUMO energy level (-2.96 eV) of (MesBF)zMTPS is lower than that of TPBi, revealing its electron-transporting potential. Efficient organic light-emitting diodes (OLEDs) are fabricated using (MesBF)2MTPS as emitter, which radiates yellow light at 554 nm, and affords high maximum luminance, current efficiency, and external quantum efficiency of 48348 cd·m^-2, 12.3 cd·A^-1, and 4.1%, respectively.展开更多
Conjugation,as an essential chemical term used to describe electron delocalization,can be roughly grouped into two categories,through-bond conjugation(TBC)and through-space conjugation(TSC).A hybrid conjugation system...Conjugation,as an essential chemical term used to describe electron delocalization,can be roughly grouped into two categories,through-bond conjugation(TBC)and through-space conjugation(TSC).A hybrid conjugation system integrating both TBC and TSC is rarely studied and utilized,for lack of a well-established model and difficulty of structure modification and property tuning,despite its theoretical significance and potential applications.Herein,various foldamers with a tetraphenylethene(TPE)core are employed as hybrid conjugation models to investigate structure–property correlation by introducing heterocycles of furan/thiophene into theπ-stacking TSC component.For comparison,two kinds of TPE-cored foldamers with different stacking models,a benzene–heterocycle stacking model and a benzene–benzene stacking model,are designed.Combining experimental measurements and theoretical calculations,the impact of benzene–heterocycle interaction on the hybrid conjugation natures and photophysical properties has been studied systematically.The results reveal that the benzene–heterocycle stacking model can fabricate a hybrid conjugation nature with an improved TSC component to make a more dominant contribution to the electronic transition natures than the benzene–benzene stacking model,leading to the distinguishing photophysical behavior.This work provides valuable guidance for the design of new functional materials with hybrid conjugation systems.展开更多
Through-space conjugated molecules are interesting building blocks for the construction of functional materials that allow multi-dimensional transport of carrier and energy.However,the well explored through-space conj...Through-space conjugated molecules are interesting building blocks for the construction of functional materials that allow multi-dimensional transport of carrier and energy.However,the well explored through-space conjugated molecules are quite limited,which defers their structure-property correlation establishment and wide-scale application.In this review,we introduce a kind of newly-emerging folded tetraphenylethene derivatives featuring through-space conjugation.Their synthesis,crystal and electronic structures,and optical properties are described,and their representative applications as bipolar charge-transporting materials in organic light-emitting diodes and as single-molecule wires in molecular devices are presented,which are anticipated to provide guidance for the further expansion of through-space conjugated systems.展开更多
Discrimination of glycoproteins and cell types is a significant but difficult issue.Herein,we presented a novel fluorescence sensor array for the detection and identification of glycoproteins and cancer cells based on...Discrimination of glycoproteins and cell types is a significant but difficult issue.Herein,we presented a novel fluorescence sensor array for the detection and identification of glycoproteins and cancer cells based on the specific affinity between boronic acid-containing carbon dots(BA-CDs)and cis-diol residues of polysaccharides.The differential binding affinity of three BA-CDs to various glycoproteins resulted in a different fluorescence turn-on signal pattern caused by aggregation-enhanced emission(AEE),along with negligible response from other proteins.Therefore,BA-CDs encompassing sensing elements and signal indicator into one can enable a fast and accurate discrimination of glycoproteins with simple and easy operation.Seven glycoproteins could be well discriminated at a very low concentration of 10 nmol/L.The discriminating capability of glycoproteins is not sacrificed in both human urine and serum.Notably,different glycoprotein compositions of cancer cells provide more recognizable features for identification of cancer cells,comparing to the total protein.Five cell types could be identified in 15 min at a low concentration of 1000 cells/mL.This method is fast,accurate,and easy operation,and has a potential application in cancer diagnosis.展开更多
基金Natural Science Foundation of Shandong Province,Grant/Award Number:ZR2020MB063Taishan Scholar Program of Shandong Province,Grant/Award Number:ts201511027。
文摘Atomically precise metal nanoclusters(MNCs),as a potential type of photoacoustic(PA)contrast agent,are limited in application due to their low PA conversion efficiency(PACE).Here,with hydrophilic Au25SR18(SR=thiolate)as model NCs,we present a result that weakly polar solvent induces aggregation,which effectively enhances PA intensity and PACE.The PA intensity and PACE are highly dependent on the degree of aggregation,while the aggregation-enhanced PA intensity(AEPA)positively correlates to the protected ligands.Such an AEPA phenomenon indicates that aggregation actually accelerates the intramolecular motion of Au NCs,and enlarges the proportion of excited state energy dissipated through vibrational relaxation.This result conflicts with the restriction of intramolecular motion mechanism of aggregation-induced emission.Further experiments show that the increased energy of AEPA originates from the aggregation inhibiting the intermolecular energy transfer from excited Au NCs to their surrounding medium molecules,including solvent molecule and dissolved oxygen,rather than restricting radiative relaxations.This study develops a new strategy for enhancing the PA intensity of Au NCs,and contributes to a deeper understanding of the origin of the PA signal and the excited state energy dissipation processes for MNCs.
基金National Natural Science Foundation of China,Grant/Award Number:21788102Natural Science Foundation of Guangdong Province,Grant/Award Number:2019B030301003。
文摘Organic light-emitting diodes(OLEDs)fabricated using organic thermally activated delayed fluorescence materials as sensitizers have recently achieved significant advancements,but the serious efficiency roll-offs are still troublesome in most cases.Herein,a tailor-made multifunctional luminogen SBF-BP-SFAC containing 9,9′-spirobifluorene(SBF)and spiro[acridine-9,9-fluorene](SFAC)as electron donors and carbonyl as an electron acceptor is synthesized and characterized.SBF-BPSFAC has the advantages of high thermal stability,aggregation-enhanced delayed fluorescence,and balanced carrier transport ability,and prefers horizontal dipole orientation.Highly efficient OLEDs employing SBF-BP-SFAC as an emitter radiate intense cyan light with outstanding external quantum efficiencies(ηexts)of up to 30.6%.SBF-BP-SFAC can also serve as an excellent sensitizer for orange fluorescence,phosphorescence,and delayed fluorescence materials,providing excellent η exts of up to 30.3% with very small efficiency roll-offs due to the fast Förster energy transfer as well as exciton annihilation suppression by bulky spiro donors.These outstanding performances demonstrate the great potential of SBF-BP-SFAC as an emitter and sensitizer for OLEDs.
基金supported by the National Natural Science Foundation of China(no.21788102)the Natural Science Foundation of Guangdong Province(no.2019B030301003)the Research Grants Council of Hong Kong(no.16305518).
文摘Severe efficiency instability is still a huge challenge for most organic light-emitting diodes(OLEDs)based on thermally activated delayed fluorescence(TADF)molecules,frustrating their industrial application.To address this issue,herein we report two robust luminogens,3,6-bis(9,9-dimethylacridin-10-yl)-xanthen9-one(BDMAC-XT)and 3,6-bis(9,9-diphenylacridin-10-yl)-xanthen-9-one(BDPAC-XT),comprised of electron-accepting 3,6-dibromoxanthen-9-one and electron-donating 9,9-dimethyl-9,10-dihydroacridine and 9,9-diphenyl-9,10-dihydroacridine.
基金financially supported by the National Natural Science Foundation of China(Nos.51473185,51603233 and 21672267)863 Program(No.SS2015AA031701)+1 种基金the Fundamental Research Funds for the Central UniversitiesGuangdong Science and Technology Plan(Nos.2015B090913003 and 2015B090915003)
文摘A polymer (poly(9,10)anthracenevinylene-alt-4,4'-(9,9-bis(4-(4'-(1,2,2'-triphenyviny)phenoxy)butyl)-9H- fluorene-2,7-diyl) dibenzaldehyde), P1) was successfully synthesized through the Wittig-Horner reaction by employing fluorene and 9,10-distyrylanthracene moieties as building blocks for backbone and tetraphenylethenes as pendant groups. Photophysical and thermal properties of the resulting polymeric emitter were fully characterized by ultraviolet-visible (UV- Vis) absorption and photoluminescence (PL) spectra, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). While P1 emits an orange-light centered at 567 nm in dilute tetrahydrofuran (THF) solution, the solid powder of the polymer exhibits strong yellow emission peaked at 541 nm. It is also found that the as-synthesized polymer shows unique property of aggregation-enhanced emission (AEE). In addition, P1 possesses high thermal stability with a decomposition temperature (Td,5%) of 430 ℃ and high morphological stability with a glass transition temperature (Tg) of 171℃. Under the stimulus of mechanical force, the emission of P1 can be changed from yellow to red (△λmax = 61 rim), showing a remarkable mechanochromism. The results from XRD analysis suggest that such mechanochromic phenomenonof PI is probably caused by the destruction of crystalline structure, which leads to the conformational planarization of the distyrylanthracene moieties forming by the polymerization and the increase of molecular conjugation of the backbone.
文摘A new silole derivative, 2,5-bis(7-(dimesitylboranyl)-9,9-dimethylfluoren-2-yl)- 1 -methyl- 1,3,4-triphenylsilole ((MesBF)2MTPS), is synthesized and characterized. (MesBF)2MTPS shows a good fluorescence efficiency of 15% in THF solution and a higher efficiency of 86% in solid film, presenting an aggregation-enhanced emission charac- teristic. It is thermally and morphologically stable, with high decomposition and glass-transition temperatures of 257 and 171 ℃, respectively. The LUMO energy level (-2.96 eV) of (MesBF)zMTPS is lower than that of TPBi, revealing its electron-transporting potential. Efficient organic light-emitting diodes (OLEDs) are fabricated using (MesBF)2MTPS as emitter, which radiates yellow light at 554 nm, and affords high maximum luminance, current efficiency, and external quantum efficiency of 48348 cd·m^-2, 12.3 cd·A^-1, and 4.1%, respectively.
基金This research was made possible as a result of a generous grant from the National Natural Science Foundation of China(nos.21788102 and 21673082)the Natural Science Foundation of Guangdong Province(no.2019B030301003)the Fundamental Research Funds for the Central Universities.
文摘Conjugation,as an essential chemical term used to describe electron delocalization,can be roughly grouped into two categories,through-bond conjugation(TBC)and through-space conjugation(TSC).A hybrid conjugation system integrating both TBC and TSC is rarely studied and utilized,for lack of a well-established model and difficulty of structure modification and property tuning,despite its theoretical significance and potential applications.Herein,various foldamers with a tetraphenylethene(TPE)core are employed as hybrid conjugation models to investigate structure–property correlation by introducing heterocycles of furan/thiophene into theπ-stacking TSC component.For comparison,two kinds of TPE-cored foldamers with different stacking models,a benzene–heterocycle stacking model and a benzene–benzene stacking model,are designed.Combining experimental measurements and theoretical calculations,the impact of benzene–heterocycle interaction on the hybrid conjugation natures and photophysical properties has been studied systematically.The results reveal that the benzene–heterocycle stacking model can fabricate a hybrid conjugation nature with an improved TSC component to make a more dominant contribution to the electronic transition natures than the benzene–benzene stacking model,leading to the distinguishing photophysical behavior.This work provides valuable guidance for the design of new functional materials with hybrid conjugation systems.
基金the financial support from the National Natural Science Foundation of China(No.51273053)the National Basic Research Program of China(973 Program,Nos.2015CB655004 and 2013CB834702)+5 种基金the Guangdong Natural Science Funds for Distinguished Young Scholar(No.2014A030306035)the Guangdong Innovative Research Team Program of China(No.201101C0105067115)the Science and Technology Project of Guangdong Province(No.2016B090907001)the ITC-CNERC14S01,the Fundamental Research Funds for the Central Universities(Nos.2015PT020 and 2015ZY013)the Natural Science Foundation of Guangdong Province(No.2016A030312002)the National Undergraduate Innovative and Entrepreneurial Training Program(No.201410561032)
文摘Through-space conjugated molecules are interesting building blocks for the construction of functional materials that allow multi-dimensional transport of carrier and energy.However,the well explored through-space conjugated molecules are quite limited,which defers their structure-property correlation establishment and wide-scale application.In this review,we introduce a kind of newly-emerging folded tetraphenylethene derivatives featuring through-space conjugation.Their synthesis,crystal and electronic structures,and optical properties are described,and their representative applications as bipolar charge-transporting materials in organic light-emitting diodes and as single-molecule wires in molecular devices are presented,which are anticipated to provide guidance for the further expansion of through-space conjugated systems.
基金financially supported by the National Natural Science Foundation of China(Nos.21922402,21874017 and21727811)Liaoning Provincial Program for Promoting Talents(Nos.XLYC1807005 and XLYC1802016)the Key Laboratory of Data Analytics and Optimization for Smart Industry(Northeastern University,Ministry of Education,China,111 Project,No.B16009)。
文摘Discrimination of glycoproteins and cell types is a significant but difficult issue.Herein,we presented a novel fluorescence sensor array for the detection and identification of glycoproteins and cancer cells based on the specific affinity between boronic acid-containing carbon dots(BA-CDs)and cis-diol residues of polysaccharides.The differential binding affinity of three BA-CDs to various glycoproteins resulted in a different fluorescence turn-on signal pattern caused by aggregation-enhanced emission(AEE),along with negligible response from other proteins.Therefore,BA-CDs encompassing sensing elements and signal indicator into one can enable a fast and accurate discrimination of glycoproteins with simple and easy operation.Seven glycoproteins could be well discriminated at a very low concentration of 10 nmol/L.The discriminating capability of glycoproteins is not sacrificed in both human urine and serum.Notably,different glycoprotein compositions of cancer cells provide more recognizable features for identification of cancer cells,comparing to the total protein.Five cell types could be identified in 15 min at a low concentration of 1000 cells/mL.This method is fast,accurate,and easy operation,and has a potential application in cancer diagnosis.