The photoisomerization abilities of secondary thioxopeptide bond(CS-NH) and thioxo prolyl bond(CS-N) incorporated into the C-terminal pentapeptide of insect kinin were compared.H-Phe-Phe-Ψ[CS-NH]-D-Ala-Trp-Gly-NH_2 a...The photoisomerization abilities of secondary thioxopeptide bond(CS-NH) and thioxo prolyl bond(CS-N) incorporated into the C-terminal pentapeptide of insect kinin were compared.H-Phe-Phe-Ψ[CS-NH]-D-Ala-Trp-Gly-NH_2 and H-Phe-Tyr-Ψ[CS-N]- Pro-Trp-Gly-NH_2 were studied by UV-vis absorption.The isomerization energy barriers of the two segments,Ac-Phe-Ψ[CS-NH]- D-Ala-NH_2 and Ac-Tyr-Ψ[CS-N]-Pro-NH_2 picked from the two peptides,were calculated using ab initio method.The cis isomer of CS-N is more stable than th...展开更多
Tetraphenylethene(TPE),a star building block with promising aggregationinduced emission,has received much interest.Given that its intramolecular Woodward-Hoffmann cyclic intermediate instantaneously converts back to t...Tetraphenylethene(TPE),a star building block with promising aggregationinduced emission,has received much interest.Given that its intramolecular Woodward-Hoffmann cyclic intermediate instantaneously converts back to the original state within several picoseconds,the essentially photochromic characteristic of TPE is little investigated.Achieving a visible photocyclization of TPE is still an unsolved issue and considered as the bottleneck in the further advancement of applications.We report a strategy of attaching carbonate ester onto the TPE skeleton(TPE-4C)to enhance TPE photocyclization stability.As demonstrated,the incorporated cholesteryloxycarbonyloxy substituents in TPE-4C can increase the energy barrier for cycloreversion,thereby exhibiting extremely thermal stability of photocyclic intermediate upon UV irradiation,prolonging its lifetime from 63 picoseconds to 46 s by 7.2×10^(11)-fold.The photoinduced cyclization of TPE-4C could be monitored with naked eyes,and the photocyclization/cycloreversion is achieved by turning on/off UV light along with a relative fatigue resistance.Encapsulation of TPE-4C into the liquid crystal can induce a striking phase transformation(achiral↔chiral),which can be applicable to encode optical information.Employing carbonate ester into the TPE unit plays a vital role in enhancing the unprecedented TPE photocyclization stability,providing a toolbox to allow TPE-based photocyclization to be visually monitored.展开更多
An interest in the fluorescent protein asFP595 is due to unexplained puzzles in its photophysical behavior. We report the results of calculations of structures, absorption, and emission bands in asFP595 by considering...An interest in the fluorescent protein asFP595 is due to unexplained puzzles in its photophysical behavior. We report the results of calculations of structures, absorption, and emission bands in asFP595 by considering model molecular clusters in the coordinate-locking scheme. Both trans and cis conformations of the anionic chromophore are considered. Equilibrium geometry coordinates on the ground potential energy surface were optimized in the density functional theory approaches by considering both large- and reduced-size clusters. The cluster size was reduced to locate positions of the minimum energy points on the excited-state potential surface by using the configuration interaction singles approach. Vertical excitation energies and oscillator strengths were computed by using the ZINDO method. We show that consideration of large clusters mimicking the protein-containing pocket is an essential issue to calculate positions of absorption and emission bands with the accuracy compatible to experiments.展开更多
Inspired by nature,dynamic self-organized helical superstructures are becoming attractive as building blocks in soft photonic crystals and advanced chiroptical devices.Herein,a chirality invertible hydrazone photoswit...Inspired by nature,dynamic self-organized helical superstructures are becoming attractive as building blocks in soft photonic crystals and advanced chiroptical devices.Herein,a chirality invertible hydrazone photoswitch,possessing high helical twisting power(HTP)was judiciously designed and synthesized.Due to the photoinduced configuration changes of the hydrazone photoswitch,it displayed superior thermal stability and strikingly reversible HTP changes.By incorporating a novel chiral hydrazone(CH)into the liquid crystal(LC)host,a handedness invertible cholesteric liquid crystal(CLC)helical superstructure with high thermal stability and light-modulated photonic bandgap was prepared.We inferred that the mechanism of chirality inversion of the novel CH photoswitch derived from changes in the dihedral angle between the two naphthalene rings induced by hydrazone isomerization.Therefore,the influence of chemical structures on its photoresponsiveness was explored.Finally,the potential applications of this advanced light-driven CLC in soft photonic crystals,showing erasable and rewritable colorful patterns and chiroptical templates to induce handedness invertible circularly polarized luminescence were illustrated.展开更多
Solid materials with dynamically tunable circularly polarized luminescence(CPL) feature higher security levels and devicefriendly characteristics, showing great superiority in the field of information technology and a...Solid materials with dynamically tunable circularly polarized luminescence(CPL) feature higher security levels and devicefriendly characteristics, showing great superiority in the field of information technology and anti-counterfeiting. To address the limited photoisomerization of fluorescent photoswitch in CPL-active solid materials, here a cholesteric liquid crystal elastomer(CLCE) containing a hydrogen-bonded(H-bonded) polymerizable fluorescent switch AHBA-PSD is prepared. Owing to the good flexibility and low glass-transition temperature of CLCE, AHBA-PSD shows a fast and fully reversible photocyclization/cycloreversion with fluorochromic behavior in CLCE. Further, by controlling the spectral overlapping area between the emission and reflection bands, the CLCE exhibits a strong CPL with a g_(lum) value of up to 0.76 accompanied by a reversible phototunable CPL signal. Meanwhile, the H-bond helps to stabilize the mechanical property, and the force-induced switching-off of CPL signal could be achieved due to the destroyed helical structures by external force. Finally, an automatically-recognized identification card with abundant chiroptical information is demonstrated.展开更多
Precise modulation of photoluminescence(PL)of nanomaterials by external control is of great interest in such diverse areas as photocatalysis,memory and sensing.Recent studies have combined colloidal quantum dots(QDs)w...Precise modulation of photoluminescence(PL)of nanomaterials by external control is of great interest in such diverse areas as photocatalysis,memory and sensing.Recent studies have combined colloidal quantum dots(QDs)with photochromic molecules to construct optically switchable PL systems.However,it still remains challenging to switch the PL on and off in the near-infrared(NIR)region with multi-stimuli such as light and heat.Here,we present light and heat triggered modulation of the NIR PL of PbS QDs using adjacent spiropyran derivatives.The NIR PL of PbS was reversibly switched on and off through the isomerization process of spiropyran molecules that can be triggered by either light irradiation or heating.The PL intensity of the off state is low enough to yield an on/off ratio as high as 54.Transient absorption measurements revealed ultrafast photoinduced hole transfer from PbS to spiropyran,the rate and efficiency of which depend critically on the driving force that can be deeply modulated through spiropyran isomerization.This study not only establishes a novel multi-stimuli switchable PL system in the NIR,but also provides fundamental guidelines for the design for such systems for a variety of emerging applications.展开更多
Photochromic materials with multicolor upconversion reversible modulations are attractive in optical switching devices.Herein,the fabricated YNbO_(4):Er^(3+)/Tm^(3+)/Yb^(3+) materials exhibit excellent photochromism a...Photochromic materials with multicolor upconversion reversible modulations are attractive in optical switching devices.Herein,the fabricated YNbO_(4):Er^(3+)/Tm^(3+)/Yb^(3+) materials exhibit excellent photochromism and multicolor upconversion properties from green,red to near infrared(NIR) emissions with increasing Yb concentrations.Reversible multiband upconversion modulations are achieved by alternating light(365 and 405 nm) or thermal stimuli.After 365 nm irradiation,the luminescence color changes from yellow to red,the luminescent photoswitching contrast reaches up to 86.21%(green),82.12%(red) and 77.38%(NIR) in the Y_(0.83)Er_(0.01)Tm_(0.01)NbO_(4):0.15 Yb sample.Besides,the upconversion emission intensity before and after photochromic reaction shows remarkable change in a wide temperature range of 298-718 K.These results indicate that the Er^(3+)/Tm^(3+)/Yb^(3+) tri-doped YNbO_(4) materials can be a good candidate in optical switching and data storage applications.展开更多
Light-induced recognition,assemblies,and materials are intensive areas of research due to their high spatiotemporal resolution.Herein,we demonstrated photoswitchable molecular recognition via dithienylethene-triggered...Light-induced recognition,assemblies,and materials are intensive areas of research due to their high spatiotemporal resolution.Herein,we demonstrated photoswitchable molecular recognition via dithienylethene-triggeredreversible structural regulation of dynamic covalent hydrazone bonds.By combining dithienylethenes and cyclic hemiacetals,the photochemical open-ring and closed-ring forms enabled turningoff and on the creation of awide range of hydrazones when desired.Light-induced bidirectional switching between hydrazones and their cyclization structures promoted by a neighboring carboxyl group was further achieved.By taking advantage of reversible structural changes totoggleon andoff the binding pocket,photoswitchable recognitionofmetal ionswas realized.Finally,the construction of an acylhydrazone polymer offered a facile way for light-mediated selective extraction/release.The strategies and results reported here should find applications in many contexts,such asdynamicassemblies,molecular switches,and smart materials.展开更多
The mixed-dimensional integration of two-dimensional (2D) materials with non-2D materials can give rise to prominent advances in performance or function.To date,the mixed-dimensional one-dimensional (1D)/2D heterostru...The mixed-dimensional integration of two-dimensional (2D) materials with non-2D materials can give rise to prominent advances in performance or function.To date,the mixed-dimensional one-dimensional (1D)/2D heterostructures have been fabricated using various physical assembly approaches.However,direct epitaxial growth method which has notable advantages in preparing large-scale products and obtaining perfect interfaces is rarely investigated.Herein,we demonstrate for the first time the direct synthesis of the 1D/2D mixed-dimensional heterostructures by sequential vapor-phase growth of Sb2Se3 nanowires on WS2 monolayers.X-ray diffraction (XRD) pattern and Raman spectrum confirm the composition of the Sb2Se3/NS2 heterostructures.Transmission electron microscope (TEM) measurement demonstrates high quality of the heterostructures.Electrical transport characterization reveals that Sb2Se3 nanowire exhibits p-type characteristic and that WS2 monolayer exhibits n-type behavior,and that the p-n diode from 1D/2D mixed-dimensional Sb2Se3/WS2 heterostructure possesses obvious current rectification behavior.Optoelectronic measurements of the heterostructures show apparent photovoltaic response with an open-circuit voltage of 0.19 V,photoresponsivity of 1.51 A/W (Vds =5 V) and fast response time of less than 8 ms.The van der Waals epitaxial growth mode of Sb2Se3 nanowires on WS2 monolayers is verified by stripping the Sb2Se3 nanowire from the heterostructures using tape.Together,the direct van der Waals epitaxy opens a facile pathway to 1D/2D mixed-dimensional heterostructures for functional electronic and optoelectronic devices.展开更多
Photochromic diarylethenes have been widely used in many fields. However, their cyclization process must be induced by UV light. In this article, a simple strategy is developed by extending π-conjugation with electro...Photochromic diarylethenes have been widely used in many fields. However, their cyclization process must be induced by UV light. In this article, a simple strategy is developed by extending π-conjugation with electron donating groups. The modified dirylethene derivative can photocyclolize under 405-nm light with a good photochromic efficiency. Meanwhile, its absorption and moderate fluorescence can be switched effectively in both directions by visible lights(405 and 520 nm, respectively) in different solutions and in living cells. We believe that this simple method will become a versatile strategy for developing various dirylethylenes with visible-light photochromism.展开更多
For the main purpose of manipulating the functions of molecules, researchers have made great achievements on photoresponsive molecules using light as a trigger. Light has become a promising scientific tool due to it b...For the main purpose of manipulating the functions of molecules, researchers have made great achievements on photoresponsive molecules using light as a trigger. Light has become a promising scientific tool due to it being a clean and noninvasive external stimulant. By attachment of photoresponsive moieties to molecules, the biological activities of molecules can be attenuated by light activation. With wide applications of laser in life sciences, it will be possible to achieve high spatiotemporal resolution. In this review, we focus on photoresponsive nucleic acids for photomodulating gene expression with light activation. With incorporation of photoswitchable or photocleavable moieties, biological behaviors of nucleic acids are photoregulated reversibly or irreversibly. Recent development and applications of photoresponsive nucleic acid in vitro and in vivo have shown a very promising future for manipulation of specific functional genes or disease genes. We expect that photoresponsive nucleic acids will be powerful scientific tools for studying biological events as well as gene therapy agents for genetic diseases.展开更多
The control of protein functions with light is valuable for spatiotemporal probing of biological systems.Current small-molecule photo-modulation methods include the light-induced uncaging of inhibitors and chromophore...The control of protein functions with light is valuable for spatiotemporal probing of biological systems.Current small-molecule photo-modulation methods include the light-induced uncaging of inhibitors and chromophore-assisted light inactivation with reactive oxygen species(ROS).However,the constant target protein expression results in inadequate photo-modulation efficiency,particularly for less potent inhibitors and chromophores.Herein,we report a novel bifunctional small-molecule ligands strategy to photo-modulate gene-editing enzymes CRISPR/Cas9.A coumarin-derived small-molecule ligand Bhc-BRD0539 is developed to uncage the active inhibitor upon light irradiation and to generate ROS in the Cas9 proximity for the dual inhibition of Cas9 activity.Our results highlight the synergistic photo-modulation with bifunctional small-molecule ligands,which offers a valuable addition to current CRISPR/Cas9 photo-modulation technologies and may extend to other protein classes.展开更多
Photo-responsive azobenzene （ABZ） derivatives with different end groups （R） as photoswitchable molecules were employed to construct self-assembled monolayers （SAMs） on silicon substrate by using 3-glycidoxypropy...Photo-responsive azobenzene （ABZ） derivatives with different end groups （R） as photoswitchable molecules were employed to construct self-assembled monolayers （SAMs） on silicon substrate by using 3-glycidoxypropyltrimethoxysilane （GPTS） as the bridging molecules. The assembly process was optimized by changing various parameters, including the type and concentration of ABZ derivatives, reaction time, etc. The obtained SAMs were fully characterized and evaluated using UV spectroscopy, atomic force microscope （AFM）, elllipsometer, static contact angle and X-ray photoelectron spectroscopy （XPS）. It is found that the end group property of azobenzene derivatives is critical to the obtained SAMs＇ photoresponsive properties. Compared with hydrophobic compounds （4-（4＇-aminophenylazo） benzoic acid, ABZ-CF3）, the hydrophilic compounds （4-（4＇-aminophenylazo） benzoic acid, ABZ-COOH） show excellent reversible photoswitching performance with a large contact angle change of 35° under oDtimized process, and the SAMs are removable bv thermal treatment at 240 ℃ in air for onlv 5 min.展开更多
Recently reported plasmon-induced transparency(PIT)in metamaterials endows the optical structures in classical systems with quantum optical effects.In particular,the nonreconfigurable nature in metamaterials makes mul...Recently reported plasmon-induced transparency(PIT)in metamaterials endows the optical structures in classical systems with quantum optical effects.In particular,the nonreconfigurable nature in metamaterials makes multifunctional applications of PIT effects in terahertz communications and optical networks remain a great challenge.Here,we present an ultrafast process-selectable modulation of the PIT effect.By incorporating silicon islands into diatomic metamaterials,the PIT effect is modulated reversely,depending on the vertical and horizontal configurations,with giant modulation depths as high as 129%and 109%.Accompanied by the enormous switching of the transparent window,remarkable slow light effect occurs.展开更多
Smart proton conductive metal-organic framework(MOF) membranes with dynamic remote control over proton conduction show high potential for use in advanced applications, such as sensors and bioprocesses. Here, we report...Smart proton conductive metal-organic framework(MOF) membranes with dynamic remote control over proton conduction show high potential for use in advanced applications, such as sensors and bioprocesses. Here, we report a photoswitchable proton conductive ZIF-8 membrane by coencapsulating polystyrene sulfonate and graphene quantum dots into a ZIF-8 matrix(GQDs-PSS@ZIF-8) via a solidconfined conversion process. The proton conductivity of the GQDs-PSS@ZIF-8 membrane is 6.3 times higher than that of pristine ZIF-8 and can be reversibly switched by light due to photoluminescence quenching and the photothermal conversion effect, which converts light into heat. The local increase in temperature allows water molecules to escape from the porous channels, which cuts off the proton transport pathways and results in a decrease in proton conductivity. The proton conductivity is restored when the light is off owing to regaining water molecules, which act as proton carriers, from the surroundings. The GQDs-PSS@ZIF-8 membrane responds efficiently to light and exhibits an ON/OFF ratio of 12.8. This photogated proton conduction in MOFs has potential for the development and application of MOF-based protonic solids in advanced photoelectric devices.展开更多
We experimentally demonstrate for the first time an active all-optical ultrafast modulation of electromagnetically induced transparency-like effect in a hybrid device of sapphire/Si/metamaterial. From numerical simula...We experimentally demonstrate for the first time an active all-optical ultrafast modulation of electromagnetically induced transparency-like effect in a hybrid device of sapphire/Si/metamaterial. From numerical simulations, it can be deducted that the tuning process is attributed to the coupling between the dark mode existing in split-ring resonators and the bright mode existing in cut wire resonators. The transmission amplitude modulation is accompanied by the slow-light effect. In addition, the ultrafast formation process is measured to be as fast as 2 ps. This work should make an important contribution to novel chip-scale photonic devices and terahertz communications.展开更多
The fluorine-substituted benzoate ester rod-shaped liquid crystals containing an azobenzene side chain linked with terminal double bonds were synthesized and characterized.The mesophase and photoswitching properties w...The fluorine-substituted benzoate ester rod-shaped liquid crystals containing an azobenzene side chain linked with terminal double bonds were synthesized and characterized.The mesophase and photoswitching properties were determined by polarizing optical microscopy（POM）,differential scanning calorimetry（DSC） and UV-visible spectrometry.The rod-shaped compound 4a having an odd number of carbon atoms in the alkyl chains exhibits nematic phase and SmA type phase whereas compound 4b having an even number of carbon atoms showed only nematic phase.Both fluorinecontaining compounds 4c and 4d showed only SmA type phases.The photoswitching properties of these compounds showed a rate of trans to cis isomerization ranging 19-20 s,whereas reverse process took around 230 min in solution.These materials may be ideal in the field of optically rewritable applications where both on and off rates should be crucial.展开更多
Stimulated Raman scattering(SRS)microscopy has shown superior chemical resolution due to the much narrower vibrational spectral bandwidth than its fluorescence counterpart.However,breaking the diffraction-limited spat...Stimulated Raman scattering(SRS)microscopy has shown superior chemical resolution due to the much narrower vibrational spectral bandwidth than its fluorescence counterpart.However,breaking the diffraction-limited spatial resolution of SRS imaging is much more challenging because of the intrinsically weak scattering cross section and inert/stable nature of molecular bond vibrations.We report superresolution SRS(SR-SRS)nanoscopy based on reversible-switchable vibrational photochromic probes integrated with point spread function engineering strategy.By introducing a Gaussian-shaped ultraviolet excitation beam and a donut-shaped visible depletion beam in addition to the pump and Stokes beams,SR-SRS could reach sub-100 nm resolution on photoswitchable nanoparticles(NPs).Furthermore,NP-treated live cell imaging was demonstrated with resolution improvement by a factor of∼4.Our proof-of-principle work provides the potential for SR vibrational imaging to assist research on complex biological systems.展开更多
The preparation and performance characterization of〈50 nm spirobenzopyran-based photochromic nanocomposites with photoswitchable fluorescence are presented.The nanocomposites were fabricated by means of a modifed min...The preparation and performance characterization of〈50 nm spirobenzopyran-based photochromic nanocomposites with photoswitchable fluorescence are presented.The nanocomposites were fabricated by means of a modifed miniemulsion polymerization process,in which the hydrophobic spirobenzopyran was covalently attached to the polymer chains and the matched fluorescent dyes were noncovalently embedded in the nanoscale cross-linked polymeric matrix,respectively.The obtained nanocomposites with a high relative fluorescence quantum yield（Q）exhibited superior fluorescent photoswitchable performance due to the effective photo-induced intermolecular energy transfer.The stability of photomerocyanine was also improved.展开更多
基金supported by the grant from National Natural Science Foundation of China(No.30870526)
文摘The photoisomerization abilities of secondary thioxopeptide bond(CS-NH) and thioxo prolyl bond(CS-N) incorporated into the C-terminal pentapeptide of insect kinin were compared.H-Phe-Phe-Ψ[CS-NH]-D-Ala-Trp-Gly-NH_2 and H-Phe-Tyr-Ψ[CS-N]- Pro-Trp-Gly-NH_2 were studied by UV-vis absorption.The isomerization energy barriers of the two segments,Ac-Phe-Ψ[CS-NH]- D-Ala-NH_2 and Ac-Tyr-Ψ[CS-N]-Pro-NH_2 picked from the two peptides,were calculated using ab initio method.The cis isomer of CS-N is more stable than th...
基金supported by NSFC/China(21788102,21636002,21622602,21875143,21908146,and 21908060)Shanghai Municipal Science and Technology Major Project(2018SHZDZX03)+3 种基金Innovation Program of Shanghai Municipal Education Commission,Scientific Committee of Shanghai(15XD1501400)Programme of Introducing Talents of Discipline to Universities(B16017)China Postdoctoral Science Foundation(2019M651417)Innovation Research Foundation of Shenzhen(JCYJ20180507182229597).
文摘Tetraphenylethene(TPE),a star building block with promising aggregationinduced emission,has received much interest.Given that its intramolecular Woodward-Hoffmann cyclic intermediate instantaneously converts back to the original state within several picoseconds,the essentially photochromic characteristic of TPE is little investigated.Achieving a visible photocyclization of TPE is still an unsolved issue and considered as the bottleneck in the further advancement of applications.We report a strategy of attaching carbonate ester onto the TPE skeleton(TPE-4C)to enhance TPE photocyclization stability.As demonstrated,the incorporated cholesteryloxycarbonyloxy substituents in TPE-4C can increase the energy barrier for cycloreversion,thereby exhibiting extremely thermal stability of photocyclic intermediate upon UV irradiation,prolonging its lifetime from 63 picoseconds to 46 s by 7.2×10^(11)-fold.The photoinduced cyclization of TPE-4C could be monitored with naked eyes,and the photocyclization/cycloreversion is achieved by turning on/off UV light along with a relative fatigue resistance.Encapsulation of TPE-4C into the liquid crystal can induce a striking phase transformation(achiral↔chiral),which can be applicable to encode optical information.Employing carbonate ester into the TPE unit plays a vital role in enhancing the unprecedented TPE photocyclization stability,providing a toolbox to allow TPE-based photocyclization to be visually monitored.
文摘An interest in the fluorescent protein asFP595 is due to unexplained puzzles in its photophysical behavior. We report the results of calculations of structures, absorption, and emission bands in asFP595 by considering model molecular clusters in the coordinate-locking scheme. Both trans and cis conformations of the anionic chromophore are considered. Equilibrium geometry coordinates on the ground potential energy surface were optimized in the density functional theory approaches by considering both large- and reduced-size clusters. The cluster size was reduced to locate positions of the minimum energy points on the excited-state potential surface by using the configuration interaction singles approach. Vertical excitation energies and oscillator strengths were computed by using the ZINDO method. We show that consideration of large clusters mimicking the protein-containing pocket is an essential issue to calculate positions of absorption and emission bands with the accuracy compatible to experiments.
基金supported by the National Natural Science Foundation of China(grant nos.52202081,52073028,52073081,and 51720105002)the Natural Science Foundation of Jiangxi Province,China(grant no.20232BAB204030).
文摘Inspired by nature,dynamic self-organized helical superstructures are becoming attractive as building blocks in soft photonic crystals and advanced chiroptical devices.Herein,a chirality invertible hydrazone photoswitch,possessing high helical twisting power(HTP)was judiciously designed and synthesized.Due to the photoinduced configuration changes of the hydrazone photoswitch,it displayed superior thermal stability and strikingly reversible HTP changes.By incorporating a novel chiral hydrazone(CH)into the liquid crystal(LC)host,a handedness invertible cholesteric liquid crystal(CLC)helical superstructure with high thermal stability and light-modulated photonic bandgap was prepared.We inferred that the mechanism of chirality inversion of the novel CH photoswitch derived from changes in the dihedral angle between the two naphthalene rings induced by hydrazone isomerization.Therefore,the influence of chemical structures on its photoresponsiveness was explored.Finally,the potential applications of this advanced light-driven CLC in soft photonic crystals,showing erasable and rewritable colorful patterns and chiroptical templates to induce handedness invertible circularly polarized luminescence were illustrated.
基金supported by the National Natural Science Foundation of China (52073017, 51773009)the High Performance Computing Platform of Beijing University of Chemical Technology。
文摘Solid materials with dynamically tunable circularly polarized luminescence(CPL) feature higher security levels and devicefriendly characteristics, showing great superiority in the field of information technology and anti-counterfeiting. To address the limited photoisomerization of fluorescent photoswitch in CPL-active solid materials, here a cholesteric liquid crystal elastomer(CLCE) containing a hydrogen-bonded(H-bonded) polymerizable fluorescent switch AHBA-PSD is prepared. Owing to the good flexibility and low glass-transition temperature of CLCE, AHBA-PSD shows a fast and fully reversible photocyclization/cycloreversion with fluorochromic behavior in CLCE. Further, by controlling the spectral overlapping area between the emission and reflection bands, the CLCE exhibits a strong CPL with a g_(lum) value of up to 0.76 accompanied by a reversible phototunable CPL signal. Meanwhile, the H-bond helps to stabilize the mechanical property, and the force-induced switching-off of CPL signal could be achieved due to the destroyed helical structures by external force. Finally, an automatically-recognized identification card with abundant chiroptical information is demonstrated.
基金support from the National Natural Science Foundation of China(Nos.21803070,22103072,and 22173098)the Fundamental Research Funds for the Central Universities(No.20720220009).
文摘Precise modulation of photoluminescence(PL)of nanomaterials by external control is of great interest in such diverse areas as photocatalysis,memory and sensing.Recent studies have combined colloidal quantum dots(QDs)with photochromic molecules to construct optically switchable PL systems.However,it still remains challenging to switch the PL on and off in the near-infrared(NIR)region with multi-stimuli such as light and heat.Here,we present light and heat triggered modulation of the NIR PL of PbS QDs using adjacent spiropyran derivatives.The NIR PL of PbS was reversibly switched on and off through the isomerization process of spiropyran molecules that can be triggered by either light irradiation or heating.The PL intensity of the off state is low enough to yield an on/off ratio as high as 54.Transient absorption measurements revealed ultrafast photoinduced hole transfer from PbS to spiropyran,the rate and efficiency of which depend critically on the driving force that can be deeply modulated through spiropyran isomerization.This study not only establishes a novel multi-stimuli switchable PL system in the NIR,but also provides fundamental guidelines for the design for such systems for a variety of emerging applications.
基金Project supported by the National Natural Science Foundation of China(52062042,51802164)the Natural Science Foundation of Inner Mongolia(2020MS05044)。
文摘Photochromic materials with multicolor upconversion reversible modulations are attractive in optical switching devices.Herein,the fabricated YNbO_(4):Er^(3+)/Tm^(3+)/Yb^(3+) materials exhibit excellent photochromism and multicolor upconversion properties from green,red to near infrared(NIR) emissions with increasing Yb concentrations.Reversible multiband upconversion modulations are achieved by alternating light(365 and 405 nm) or thermal stimuli.After 365 nm irradiation,the luminescence color changes from yellow to red,the luminescent photoswitching contrast reaches up to 86.21%(green),82.12%(red) and 77.38%(NIR) in the Y_(0.83)Er_(0.01)Tm_(0.01)NbO_(4):0.15 Yb sample.Besides,the upconversion emission intensity before and after photochromic reaction shows remarkable change in a wide temperature range of 298-718 K.These results indicate that the Er^(3+)/Tm^(3+)/Yb^(3+) tri-doped YNbO_(4) materials can be a good candidate in optical switching and data storage applications.
基金supported by National Natural Science Foundation of China(grant nos.22071247,92156010,22101283,and 22101284)the Strategic Priority Research Program(grant no.XDB20000000)+1 种基金the Key Research Program of Frontier Sciences(grant no.QYZDBSSW-SLH030)of the Chinese Academy of Sciences,Natural Science Foundation of Fujian Province(grant nos.2020J06035 and 2022J05085)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(grant no.2021ZR112).
文摘Light-induced recognition,assemblies,and materials are intensive areas of research due to their high spatiotemporal resolution.Herein,we demonstrated photoswitchable molecular recognition via dithienylethene-triggeredreversible structural regulation of dynamic covalent hydrazone bonds.By combining dithienylethenes and cyclic hemiacetals,the photochemical open-ring and closed-ring forms enabled turningoff and on the creation of awide range of hydrazones when desired.Light-induced bidirectional switching between hydrazones and their cyclization structures promoted by a neighboring carboxyl group was further achieved.By taking advantage of reversible structural changes totoggleon andoff the binding pocket,photoswitchable recognitionofmetal ionswas realized.Finally,the construction of an acylhydrazone polymer offered a facile way for light-mediated selective extraction/release.The strategies and results reported here should find applications in many contexts,such asdynamicassemblies,molecular switches,and smart materials.
基金supported by the National Natural Science Foundation of China(NSFC,52273206,52173278,and 51833011)Hunan Provincial Natural Science Foundation of China(2021JJ10029,2020JJ3021,and 2021JJ40192)+1 种基金the Open Fund of Hunan Provincial Key Laboratory of Controllable Preparation and Functional Application of Fine Polymers(E22125)the Science and Technology Innovation Program of Hunan Province(2022RC1075 and 2021RC5028)。
基金the Fundamental Research Funds of the Central Universities (No.531107051078)the Double First-Class University Initiative of Hunan University (No.531109100004). We also acknowledge the support from the National Natural Science Foundation of China (No.751214296)+1 种基金Hunan Key Laboratory of Two-Dimensional Materials (No.801200005)Strategic Priority Research Program of Chinese Academy of Science (No.XDB30000000).
文摘The mixed-dimensional integration of two-dimensional (2D) materials with non-2D materials can give rise to prominent advances in performance or function.To date,the mixed-dimensional one-dimensional (1D)/2D heterostructures have been fabricated using various physical assembly approaches.However,direct epitaxial growth method which has notable advantages in preparing large-scale products and obtaining perfect interfaces is rarely investigated.Herein,we demonstrate for the first time the direct synthesis of the 1D/2D mixed-dimensional heterostructures by sequential vapor-phase growth of Sb2Se3 nanowires on WS2 monolayers.X-ray diffraction (XRD) pattern and Raman spectrum confirm the composition of the Sb2Se3/NS2 heterostructures.Transmission electron microscope (TEM) measurement demonstrates high quality of the heterostructures.Electrical transport characterization reveals that Sb2Se3 nanowire exhibits p-type characteristic and that WS2 monolayer exhibits n-type behavior,and that the p-n diode from 1D/2D mixed-dimensional Sb2Se3/WS2 heterostructure possesses obvious current rectification behavior.Optoelectronic measurements of the heterostructures show apparent photovoltaic response with an open-circuit voltage of 0.19 V,photoresponsivity of 1.51 A/W (Vds =5 V) and fast response time of less than 8 ms.The van der Waals epitaxial growth mode of Sb2Se3 nanowires on WS2 monolayers is verified by stripping the Sb2Se3 nanowire from the heterostructures using tape.Together,the direct van der Waals epitaxy opens a facile pathway to 1D/2D mixed-dimensional heterostructures for functional electronic and optoelectronic devices.
基金supported by the National Natural Science Foundation of China (21877011, 21576038, 21421005)the Fundamental Research Funds for the Central Universities of China (DUT16TD21)+1 种基金Science Program of Dalian City (2014J11JH133, 2015J12JH207)the Supercomputing Center of Dalian University of Technology
文摘Photochromic diarylethenes have been widely used in many fields. However, their cyclization process must be induced by UV light. In this article, a simple strategy is developed by extending π-conjugation with electron donating groups. The modified dirylethene derivative can photocyclolize under 405-nm light with a good photochromic efficiency. Meanwhile, its absorption and moderate fluorescence can be switched effectively in both directions by visible lights(405 and 520 nm, respectively) in different solutions and in living cells. We believe that this simple method will become a versatile strategy for developing various dirylethylenes with visible-light photochromism.
基金State Key Laboratory of Natural and Biomimetic Drugs and Peking University(bmu2009137-121)
文摘For the main purpose of manipulating the functions of molecules, researchers have made great achievements on photoresponsive molecules using light as a trigger. Light has become a promising scientific tool due to it being a clean and noninvasive external stimulant. By attachment of photoresponsive moieties to molecules, the biological activities of molecules can be attenuated by light activation. With wide applications of laser in life sciences, it will be possible to achieve high spatiotemporal resolution. In this review, we focus on photoresponsive nucleic acids for photomodulating gene expression with light activation. With incorporation of photoswitchable or photocleavable moieties, biological behaviors of nucleic acids are photoregulated reversibly or irreversibly. Recent development and applications of photoresponsive nucleic acid in vitro and in vivo have shown a very promising future for manipulation of specific functional genes or disease genes. We expect that photoresponsive nucleic acids will be powerful scientific tools for studying biological events as well as gene therapy agents for genetic diseases.
基金supported by the National Natural Science Foundation of China(22337005,22277133,91753126)the Youth Innovation Promotion Association(CAS 2023266)+1 种基金the CAS Interdisciplinary Innovation Team(JCTD-2020-16)the Program of Shanghai Academic/Technology Research Leader(21XD1424700).
文摘The control of protein functions with light is valuable for spatiotemporal probing of biological systems.Current small-molecule photo-modulation methods include the light-induced uncaging of inhibitors and chromophore-assisted light inactivation with reactive oxygen species(ROS).However,the constant target protein expression results in inadequate photo-modulation efficiency,particularly for less potent inhibitors and chromophores.Herein,we report a novel bifunctional small-molecule ligands strategy to photo-modulate gene-editing enzymes CRISPR/Cas9.A coumarin-derived small-molecule ligand Bhc-BRD0539 is developed to uncage the active inhibitor upon light irradiation and to generate ROS in the Cas9 proximity for the dual inhibition of Cas9 activity.Our results highlight the synergistic photo-modulation with bifunctional small-molecule ligands,which offers a valuable addition to current CRISPR/Cas9 photo-modulation technologies and may extend to other protein classes.
基金financially supported by The Dow Chemical Company
文摘Photo-responsive azobenzene （ABZ） derivatives with different end groups （R） as photoswitchable molecules were employed to construct self-assembled monolayers （SAMs） on silicon substrate by using 3-glycidoxypropyltrimethoxysilane （GPTS） as the bridging molecules. The assembly process was optimized by changing various parameters, including the type and concentration of ABZ derivatives, reaction time, etc. The obtained SAMs were fully characterized and evaluated using UV spectroscopy, atomic force microscope （AFM）, elllipsometer, static contact angle and X-ray photoelectron spectroscopy （XPS）. It is found that the end group property of azobenzene derivatives is critical to the obtained SAMs＇ photoresponsive properties. Compared with hydrophobic compounds （4-（4＇-aminophenylazo） benzoic acid, ABZ-CF3）, the hydrophilic compounds （4-（4＇-aminophenylazo） benzoic acid, ABZ-COOH） show excellent reversible photoswitching performance with a large contact angle change of 35° under oDtimized process, and the SAMs are removable bv thermal treatment at 240 ℃ in air for onlv 5 min.
基金supported by the National Natural Science Foundation of China(Nos.11804387,11802339,11805276,11902358,61805282,and 61801498)the Scientific Researches Foundation of National University of Defense Technology(Nos.ZK18-03-22,ZK18-01-03,and ZK18-03-36)。
文摘Recently reported plasmon-induced transparency(PIT)in metamaterials endows the optical structures in classical systems with quantum optical effects.In particular,the nonreconfigurable nature in metamaterials makes multifunctional applications of PIT effects in terahertz communications and optical networks remain a great challenge.Here,we present an ultrafast process-selectable modulation of the PIT effect.By incorporating silicon islands into diatomic metamaterials,the PIT effect is modulated reversely,depending on the vertical and horizontal configurations,with giant modulation depths as high as 129%and 109%.Accompanied by the enormous switching of the transparent window,remarkable slow light effect occurs.
基金supported by the National Natural Science Foundation of China (21875212)the Key Program of National Natural Science Foundation (51632008)+2 种基金the Major R&D Plan of Zhejiang Natural Science Foundation (LD18E020001)the National Key Research and Development Program (2016YFA0200204)the Fundamental Research Funds for the Central Universities。
文摘Smart proton conductive metal-organic framework(MOF) membranes with dynamic remote control over proton conduction show high potential for use in advanced applications, such as sensors and bioprocesses. Here, we report a photoswitchable proton conductive ZIF-8 membrane by coencapsulating polystyrene sulfonate and graphene quantum dots into a ZIF-8 matrix(GQDs-PSS@ZIF-8) via a solidconfined conversion process. The proton conductivity of the GQDs-PSS@ZIF-8 membrane is 6.3 times higher than that of pristine ZIF-8 and can be reversibly switched by light due to photoluminescence quenching and the photothermal conversion effect, which converts light into heat. The local increase in temperature allows water molecules to escape from the porous channels, which cuts off the proton transport pathways and results in a decrease in proton conductivity. The proton conductivity is restored when the light is off owing to regaining water molecules, which act as proton carriers, from the surroundings. The GQDs-PSS@ZIF-8 membrane responds efficiently to light and exhibits an ON/OFF ratio of 12.8. This photogated proton conduction in MOFs has potential for the development and application of MOF-based protonic solids in advanced photoelectric devices.
基金supported by the National Natural Science Foundation of China (NSFC)(Nos. 11802339,11805276,61805282,61801498,11804387,and 11902358)the Scientific Researches Foundation of National University of Defense Technology (Nos. ZK16-03-59,ZK18-01-03,ZK18-03-36,ZK18-03-22)+5 种基金the Natural Science Foundation of Hunan Province (No. 2016JJ1021)the Hunan Provincial Innovation Foundation for Postgraduate (No. CX2018B006)the Open Director Fund of State Key Laboratory of Pulsed Power Laser Technology (No. SKL2018ZR05)the Open Research Fund of Hunan Provincial Key Laboratory of High Energy Technology (No. GNJGJS03)the Open Foundation of State Key Laboratory of Laser Interaction with Matter(No. SKLLIM1702)the Youth Talent Lifting Project(No. 17-JCJQ-QT-004)。
文摘We experimentally demonstrate for the first time an active all-optical ultrafast modulation of electromagnetically induced transparency-like effect in a hybrid device of sapphire/Si/metamaterial. From numerical simulations, it can be deducted that the tuning process is attributed to the coupling between the dark mode existing in split-ring resonators and the bright mode existing in cut wire resonators. The transmission amplitude modulation is accompanied by the slow-light effect. In addition, the ultrafast formation process is measured to be as fast as 2 ps. This work should make an important contribution to novel chip-scale photonic devices and terahertz communications.
基金supported by UMP Research(No.RDU 100338)RAGS(No.RDU131408)
文摘The fluorine-substituted benzoate ester rod-shaped liquid crystals containing an azobenzene side chain linked with terminal double bonds were synthesized and characterized.The mesophase and photoswitching properties were determined by polarizing optical microscopy（POM）,differential scanning calorimetry（DSC） and UV-visible spectrometry.The rod-shaped compound 4a having an odd number of carbon atoms in the alkyl chains exhibits nematic phase and SmA type phase whereas compound 4b having an even number of carbon atoms showed only nematic phase.Both fluorinecontaining compounds 4c and 4d showed only SmA type phases.The photoswitching properties of these compounds showed a rate of trans to cis isomerization ranging 19-20 s,whereas reverse process took around 230 min in solution.These materials may be ideal in the field of optically rewritable applications where both on and off rates should be crucial.
基金the financial support from the National Key Research and Development Program of China(Grant No.2021YFF0502900)the National Natural Science Foundation of China(Grant Nos.61975033 and 81771930)+2 种基金the Shanghai Municipal Science and Technology Major Project(Grant Nos.2017SHZDZX01 and 2018SHZDZX01)the financial support from the Shenzhen Science and Technology Innovation Commission(Grant No.KQTD20170810111314625)the National Key Research and Development Program of China(Grant No.2018YFB0407200).
文摘Stimulated Raman scattering(SRS)microscopy has shown superior chemical resolution due to the much narrower vibrational spectral bandwidth than its fluorescence counterpart.However,breaking the diffraction-limited spatial resolution of SRS imaging is much more challenging because of the intrinsically weak scattering cross section and inert/stable nature of molecular bond vibrations.We report superresolution SRS(SR-SRS)nanoscopy based on reversible-switchable vibrational photochromic probes integrated with point spread function engineering strategy.By introducing a Gaussian-shaped ultraviolet excitation beam and a donut-shaped visible depletion beam in addition to the pump and Stokes beams,SR-SRS could reach sub-100 nm resolution on photoswitchable nanoparticles(NPs).Furthermore,NP-treated live cell imaging was demonstrated with resolution improvement by a factor of∼4.Our proof-of-principle work provides the potential for SR vibrational imaging to assist research on complex biological systems.
文摘The preparation and performance characterization of〈50 nm spirobenzopyran-based photochromic nanocomposites with photoswitchable fluorescence are presented.The nanocomposites were fabricated by means of a modifed miniemulsion polymerization process,in which the hydrophobic spirobenzopyran was covalently attached to the polymer chains and the matched fluorescent dyes were noncovalently embedded in the nanoscale cross-linked polymeric matrix,respectively.The obtained nanocomposites with a high relative fluorescence quantum yield（Q）exhibited superior fluorescent photoswitchable performance due to the effective photo-induced intermolecular energy transfer.The stability of photomerocyanine was also improved.
