In recent years,photochromic(PC)materials have garnered widespread interest due to their potential applications in next-generation optical storage devices and photocatalysis.These materials,which control luminescence ...In recent years,photochromic(PC)materials have garnered widespread interest due to their potential applications in next-generation optical storage devices and photocatalysis.These materials,which control luminescence intensity via PC reactions,are not only suitable for optical switches and information storage but also play a crucial role in enhancing catalytic efficiency in photocatalytic applications.However,quantifying the PC effect on performance in these applications is challenging,complicating the material design needed to meet performance specifications.This study reports on a multifunctional Na_(0.5)Bi_(4.5)Ti_(4)O_(15)(NBT)material that achieves adjustable photoluminescence(PL)and photocatalytic(PCA)performance through precise control of the PC reaction.Under alternating exposure to 405 nm light and thermal annealing,the Er/Yb co-doped NBT samples display remarkable photochromic(PC)behavior,capable of reversible color transitions between yellow and gray.After 30 s of 405 nm irradiation,strong energy transfer facilitates a high up-conversion(UC)luminescence contrast of 78.02%.Additionally,the PC reaction promotes the ideal separation of photoexcited carriers and significantly enhances the utilization of electron-hole pairs,nearly doubling the PCA efficiency of the NBT samples by 1.9 times.Furthermore,the luminescence contrast and PCA efficiency controlled by PC can be regulated through varying Er/Yb doping levels,maintaining consistent trends.This study provides theoretical and experimental foundations for the performance modulation of rare-earth-doped multifunctional photochromic materials.展开更多
The growing demand for the miniaturization and multifunctionality of optoelectronic devices has promoted the development of transparent ferroelectrics.However,it is difficult for the superior multiple optical properti...The growing demand for the miniaturization and multifunctionality of optoelectronic devices has promoted the development of transparent ferroelectrics.However,it is difficult for the superior multiple optical properties of these materials to be compatible with the excellent ferroelectricity and piezoelectricity in transparent ceramics.Here,we successfully synthesized Bi/Eu codoped eco-friendly K0.5Na0.5NbO3transparent-ferroelectric ceramics with photo luminescence(PL)behavior,photochromic(PC)reactions and temperature-responsive PL.Based on the distinct optical properties of ceramics at different temperature ranges(room temperature and ultralow temperature),high utilization of multiple optical functions was realized.At room temperature,the PC behavior induced PL modulation contrast reaches 75.2%(at 592 nm),which can be applied in the optical information storage field.In the ultralow temperature range,the ceramics exhibit excellent sensitivity(with a maximum relative sensitivity of26.32%/K)via fluorescence intensity ratio technology and exhibit great application potential in noncontact optical temperature measurements.Additionally,the change in the PL intensity at different wavelengths(I_(614)/I_(592))can serve as a reliable indicator for detecting the occurrence of the phase transition from rhombohedral to orthorhombic at low temperature.This work provides a feasible paradigm for realizing the integration of ferroelectricity and multifarious optical properties in a single optoelectronic material.展开更多
WO2 and TiO2 colMds were synthesized by the hydrolysis technique and part of the TiO2 colloid was treated by means of the hydrothermal method. The photochromic performances of the resulting materials obtained via comb...WO2 and TiO2 colMds were synthesized by the hydrolysis technique and part of the TiO2 colloid was treated by means of the hydrothermal method. The photochromic performances of the resulting materials obtained via combining the WO3 colloid with the treated TiO2 colloid and the non-treated TiO2 colloid, respectively, are very different. The TiO2 colloid without hydrothermal treatment can effectively improve the photochromic performance of the WO3colloid. The TiO2 nanoparticles were investigated in detail by XRD, TEM, surface photovohage spectra（SPS） and field-induced surface photovoltage spectrometry（FISPS）. The photochromism mechanism of WO3 colloid is discussed.展开更多
A series of DL-serine covalently modified multinuclear lanthanide implanted arsenotungstates K_(2)[{Ln(H_(2)O)_(7)}_(2){As_(4)W_(44)O_(137)(OH)_(18)(H_(2)O)_(2)(DL-Ser)_(2)}{Ln_(2)(H_(2)O)_(5)(DL-Ser)}_(2)]·65H_(...A series of DL-serine covalently modified multinuclear lanthanide implanted arsenotungstates K_(2)[{Ln(H_(2)O)_(7)}_(2){As_(4)W_(44)O_(137)(OH)_(18)(H_(2)O)_(2)(DL-Ser)_(2)}{Ln_(2)(H_(2)O)_(5)(DL-Ser)}_(2)]·65H_(2)O(DL-Ser=DL-serine,Ln=La(1),Ce(2),Pr(3))are obtained.Crystal structure analysis shows that these compounds are isomorphic and contain the basic[{As_(4)W_(44)O_(137)(OH)_(18)(H_(2)O)_(2)(DL-Ser)_(2)}{Ln_(2)(H_(2)O)_(5)(DL-Ser)}_(2)]^(8–)polyoxoanion constituted by two{As_(2)W_(19)O_(59)(OH)_(8)(H_(2)O)}^(6–)subunits,a[W_(6)O_(2)_(3)(OH)_(2)(DL-Ser)_(2)]_(14)–fragment,and two embedded[Ln_(2)(H_(2)O)_(5)(DL-Ser)]^(5+)groups,which further build into one dimensional linear chainlike structure via two peripheral Ln^(3+)ions.Most remarkably,these compounds exhibit rapid photochromic behaviors,which changed color quickly from white(1),yellow(2),green(3)to blue(1),brown(2)and glaucous(3)in ten minutes under UV irradiation,and that the colors gradually recovered in the dark for approximately 22 h.展开更多
Polyoxometalates (POMs) are important inorganic photochromic materials to be potentially applied in photo-induced switch,energy storage,and even the detection of light.However,due to the limited sensitivity of POMs,it...Polyoxometalates (POMs) are important inorganic photochromic materials to be potentially applied in photo-induced switch,energy storage,and even the detection of light.However,due to the limited sensitivity of POMs,it is difficult to realize the photochromic response to weak visible light.In this paper,by the coordination of solvated Pb(Ⅱ),a new structure-defined chain-like polyoxomolybdate complex of[(Pb(DMF)_(4))^(3)(P_(2)Mo_(18)O_(62))_(2)]n(Pb_(3)Mo_(18) ,DMF=dimethylformamide) has been demonstrated by a facile solvent-diffusion approach.By virtue of interactions between Pb(DMF)_(4) and polyoxoanions,Pb_(3)Mo_(18) shows an ultrasensitive photochromic response to weak visible lights and forms the reduced’heteropoly blue’species through ligand-to-metal charge transfer (LMCT) process.A new mechanism is firstly proposed here that the 6s orbital lone electron pair on Pb(II) can effectively stabilize the generated hole of oxygen atoms as a result of O→Mo charge transfer.Through the proposed mechanism,the LMCT barrier is drastically lowered and allows the coloration to be occurred even upon weak visible light.Also,because the conductivity of Pb_(3)Mo_(18) enhances with the increase of reduction extent,its electrochemical impedance signals are proportionally response to irradiation intensity.Especially,for the first time,the polyoxomolybdate composite can be used to detect weak visible light,in which the optical signal can be converted into electrical signal output.Moreover,Pb_(3)Mo_(18) can be drip-coated on the surface of the screen printed chip electrode,which is facile to the detection of light by portable devices compatible with computers,mobile phones and other electronic equipment.This work not only highlights a new approach to the molecular design of photochromic POMs by the coordination of metal ions with the effect of inert electron pair,but also lays a foundation to extend the application of POMs as light signal sensors.展开更多
The interfacial behaviors of the non-typical amphiphilic compound p-methylphenylazocalix[4]arene 1 and p-chlorophenylazocalix[4]arene 2 at the air/water interface and photochromism in the Langmuir-Blodgett films were ...The interfacial behaviors of the non-typical amphiphilic compound p-methylphenylazocalix[4]arene 1 and p-chlorophenylazocalix[4]arene 2 at the air/water interface and photochromism in the Langmuir-Blodgett films were studied by surface pressure-area isotherm and UV-Vis spectra. The results indicate that they can form stable monolayers at the air / water interface although they have no hydrophobic alkyl chains, and their LB film underwent reversible trans-cis photoisomerization on UV and daylight illumination.展开更多
A new family of photochromic diarylethene compounds, 1-（2-cyano-l,5-dimethyl- 4-pyrryl）-2-[2-methyl-5-（3-pyridyl）-3-thienyl]perfluorocyclopentene （lo） having an unsymmetrical pyrryl and thienyl substituted hexaf...A new family of photochromic diarylethene compounds, 1-（2-cyano-l,5-dimethyl- 4-pyrryl）-2-[2-methyl-5-（3-pyridyl）-3-thienyl]perfluorocyclopentene （lo） having an unsymmetrical pyrryl and thienyl substituted hexafluorocyclopentene unit, was synthesized and its structure was determined by X-ray analysis. The crystal belongs to triclinic system, space group PI with a = 8.897（7）, b = 10.139（8）, c = 12.361（9） A, α = 85.222（7）, ρ = 75.439（7）, γ = 78.736（8）°, Z = 2, V= 1057.8（14） A3, D,.= 1.468 mg/m3, p = 0.220 mm-1, F（000） = 476, the final R = 0.0608 and wR = 0.1754 for 3199 observed reflections （1 〉20（/））. Interestingly, compound 1 exhibits good photochromic properties with alternate irradiation of UV light and visible light （〉 510 nm） to form two photoisomers in hexane solution and crystal phase.展开更多
With the rapid development of science and technology,the high-security-level anti-counterfeiting technique is essential for ensuring property or information security.In this work,we prepared micron NaYTiO_(4):Bi/Er(NY...With the rapid development of science and technology,the high-security-level anti-counterfeiting technique is essential for ensuring property or information security.In this work,we prepared micron NaYTiO_(4):Bi/Er(NYT:Bi/Er) phosphors with integrating up-conversion(UC) photoluminescence,downshifting(DS) emission,phosphorescence and photochromism(PC) performances for advanced multiple anti-counterfeiting application.Owing to the abundant energy levels of Er^(3+)ions,the UC and DS luminescence behaviors are anticipated.Specifically,the yellow-green emission of Er^(3+)ions can be observed upon 980 nm excitation,and the bright green emission is demonstrated under 281 or 254 nm excitation due to the energy transitions of Er^(3+)ions and the energy transfer process from Bi^(3+)to Er^(3+)ions.Besides,the introduction of Bi^(3+)ions generates defect levels in the matrix and thus leads to phosphorescence.Furthermore,the repeatable PC performance could be triggered by the 365 nm irradiation and vanished with 450 nm illumination or thermal stimulation.To verify the practical usability of NYT:Bi/Er phosphors on anti-counterfeiting applications,some experiments are designed and successfully executed.It is believed that the NYT:Bi/Er phosphors can be a promising candidate for high-security-level multiple anti-counterfeiting.展开更多
Two-photon ionization and recombination processes of an aromatic chromophore doped in polymer films werestudied and the features of these processes were discussed in relation to photofunctional polymers, An aromatic m...Two-photon ionization and recombination processes of an aromatic chromophore doped in polymer films werestudied and the features of these processes were discussed in relation to photofunctional polymers, An aromatic moleculehaving low ionization potential, e.g., N,N,N',N'-tetramethyl-p-phenylene diamine doped in poly(methyl methacrylate)(PMMA) film was easily photoionized by intense laser ligh excitation, giving a colored radical cation (photochromism) anda trapped electron in PMMA matrix. As a reversed process, the radical cation recombined with the trapped electron, showingdiscoloration and emitting luminescence, either isothermal luminescence (ITL), or thermoluminescence (TL). In this report,ITL and TL through the charge recombination process were studied and the luminescence was suggested as a mean of the read-out of photorecording.展开更多
A cadmium tetracyanoplatinate host clathrate,(MV)[Cd_(2){Pt(CN)_(4)}_(3)]·2(H_(2)O)(1),including a methylviologen dication (MV^(2+)) was synthesized,and the crystal structures,photochromic and photoluminescence p...A cadmium tetracyanoplatinate host clathrate,(MV)[Cd_(2){Pt(CN)_(4)}_(3)]·2(H_(2)O)(1),including a methylviologen dication (MV^(2+)) was synthesized,and the crystal structures,photochromic and photoluminescence properties were investigated.In 1,the alternatively parallel stacking between the MV^(2+)dications as electron acceptors in the channels and the electron donors[Pt1(CN)_(4)]^(2-) units in the host frameworks give a unique donor-acceptor (DA) system.Under UV irradiation,the electron transfer between MV^(2+) and[Pt(CN)_(4)]^(2-) ions generates MV^(·+)radicals with a photochromic behavior from pale-yellow to blue.This process occurs through single-crystal-to-single-crystal (SCSC) transformation and obvious structure variation of viologen cations is successfully observed.Moreover,the spectral overlap between the emission bands of 1 and the absorption around 623 nm for the MV^(·+) radicals leads to a modulation of the photoluminescence.展开更多
A series of inorganic-organic thin films based on uniformly dispersed nanoparticles of polyoxometalates （POM）entrapped in polyacrylamide （PAM） matrix were prepared by ultrasonic method with different irradiation t...A series of inorganic-organic thin films based on uniformly dispersed nanoparticles of polyoxometalates （POM）entrapped in polyacrylamide （PAM） matrix were prepared by ultrasonic method with different irradiation time.The microstructure, photochromic behavior and mechanism of the films were studied by transmission electron microscopy （TEM）, ultraviolet-visible spectra （UV-VIS） and Fourier transform-infrared spectroscopy （FT-IR）.The microstructure and photochromic properties of the hybrid thin films could be controlled by ultrasound.TEM image revealed that the average size of phosphotungstic acid （PWA） nanoparticles decreased from 20 to 10 nm with the ultrasound irradiation time from 30 to 60 min. After irradiated with ultraviolet light,the transparent films changed from colorless to blue and showed reversible photochromism. The hybrid film, with ultrasound irradiation for 60 min had higher photochromic efficiency and faster bleaching reaction than the one with ultrasound irradiation for 30 min. FT-IR spectra showed that the Keggin geometry of heteropolyoxometalate was still preserved inside the composites, and the interactions between polyanions and polymer matrix increased as the ultrasound time prolonged. It is suggested that the mechanism of the different photochromic properties for the inorganic-organic thin films is the variation of the microstructure and interfacial interactions induced by ultrasound.展开更多
Four rare earth inorganic-organic hybrid compounds based on Keggin-type polyoxometalate {SiW_(12)}with general formula [{RE(DMF)_(4)(H_(2)O)_4RE(DMF)_(6)}_(2){SiW_(12)O_(40)}_(3)](RE = La(1),Pr(2),Sm(3),Eu(4),DMF=N,N-...Four rare earth inorganic-organic hybrid compounds based on Keggin-type polyoxometalate {SiW_(12)}with general formula [{RE(DMF)_(4)(H_(2)O)_4RE(DMF)_(6)}_(2){SiW_(12)O_(40)}_(3)](RE = La(1),Pr(2),Sm(3),Eu(4),DMF=N,N-dimethylformamide) were synthesized by the conventional solution method.Structure analyses indicate that four compounds are isostructural and are all built from three [SiW_(12)O_(40)]^(4-) polyoxoanions and DMF ligands linked by RE^(3+).Compounds 1-4 are extremely sensitive to UV light and present excellent photochromic properties,in which the coloring and fading time of samples are both no more than 2 min,and the reversible coloring-fading process can be repeated for at least 10 cycles with little fatigue,suggesting that compounds 1-4 can be a series of fast-responsive and durable photochromic materials.Moreover,the solid-state photoluminescence spectra of compounds 3(Sm) and 4(Eu)display strong characteristic emissions of rare earth ions based on f-f transitions.Meanwhile,compound4(Eu) has a longer fluorescence lifetime up to 566.74 μs.Notably,co mpounds 3(Sm) and 4(Eu) exhibit the switchable luminescence behavior induced by photochromism,which allows them to be used as potential molecular switches.展开更多
A series of acrylic ester copolymers with viologen group as pendant were synthesizedthrough the reaction of MMA-EBA (Ethenyl bromoacetate) copolymer with 4-(4'-pyridyl)-N-alkyl (or arylalkyl) pyridiniums. These vi...A series of acrylic ester copolymers with viologen group as pendant were synthesizedthrough the reaction of MMA-EBA (Ethenyl bromoacetate) copolymer with 4-(4'-pyridyl)-N-alkyl (or arylalkyl) pyridiniums. These viologen copolymers can exchange their anionwith NH_4PF_6 in methanol to improve their solubility in organic solvents such as DMFand acetone. Compared with the corresponding low molecular viologens, these viologencopolymers have relatively lower color development rate under UV light and fade fasterin air due to less affinity to photo-reductant and deficiency of association between theircation radicals. Their photofatigue resistant ability is also slightly better than that of lowmolecular vinlogens.展开更多
It remains a big challenge to develop solid-state stimuli-responsive materials for time-dependent information encryption and inkless erasable printing with long retention times.Herein,a 2D Cu_(2)I_(2)-based MOF with p...It remains a big challenge to develop solid-state stimuli-responsive materials for time-dependent information encryption and inkless erasable printing with long retention times.Herein,a 2D Cu_(2)I_(2)-based MOF with photoresponsive spiropyran(SP)groups orderly installed on its skeleton is developed.The structural isomerization from SP to colored merocyanine(MC)form can be triggered by removing the CH_(3)CN vips.Besides,the degree of structural isomerization and the retention time can be adjusted by controlling the amount of CH_(3)CN vips,exhibiting dynamic photochromic behavior with multicolor states and tunable retention time.Based on these advantages,time-dependent information encryption is successfully achieved.Furthermore,the long retention time(>72 h)of the MC form under daylight conditions in the CH_(3)CN-removed Cu_(2)I_(2)-based MOF and good repeatability make it promising in various applications,such as temporary calendars,price-cards,billboards,and reusable identity cards.This work provides a novel design strategy to fabricate multi-functional MOF-based smart materials for challenging applications of time-dependent information encryption and inkless erasable printing.展开更多
The photochromism in CaS:Sm (from white to pink) was observed for the first time by exposing it to ultraviolet light. The experiments results show that the absorption intensity of Sm2+ in the range of 500 similar to 6...The photochromism in CaS:Sm (from white to pink) was observed for the first time by exposing it to ultraviolet light. The experiments results show that the absorption intensity of Sm2+ in the range of 500 similar to 600nm was strongly increased after irradiation. This reveals that there is the valence changing of Sm. If the sample was excited by visible light again, the pink color turned to white, indicating that CaS:Sm has potential application in the field of storage material.展开更多
The photochromism of a 36-armed liquid crystalline dendrimer D6 was briefly described in this paper. The molar absorption coefficient, photoisomerization and photo back-isomerization of D6 in solution were investigate...The photochromism of a 36-armed liquid crystalline dendrimer D6 was briefly described in this paper. The molar absorption coefficient, photoisomerization and photo back-isomerization of D6 in solution were investigated by UV/Vis absorption spectra. The results indicate that the photochromism and photo back-isomerization of D6 in chloroform （CHC13） and tetrahydrofuran （THF） solutions are in accordance with the ftrst order kinetics. The photochromism rate constants of D6 are 101 sI, it is 107 times larger than that of side-chain liquid crystalline polymers containing the same azobenzene moieties.展开更多
The title compound 2,2-dithiophene-naphthopyran （C21H14OS2, Mr = 346.44） was synthesized and characterized by IR,^1lH NMR, elemental analysis and single-crystal X-ray diffraction. It belongs to the monoclinic system...The title compound 2,2-dithiophene-naphthopyran （C21H14OS2, Mr = 346.44） was synthesized and characterized by IR,^1lH NMR, elemental analysis and single-crystal X-ray diffraction. It belongs to the monoclinic system, space group P21/n, with a = 8.2349（14）, b = 6.1964（11）, c = 32.458（5）A, β= 95.051（3）°, V= 1649.8（5）A^3, Z = 4, Dc = 1.395 g/cm^3,μ = 0.327 cm^-1, F（000） = 720, the final R = 0.0559 and wR = 0.1442 for 3370 observed reflections （I 〉 2σ（I））. X-ray analysis revealed that the interatomic distance of C（13）-O（1） is 1.456（3）A, longer than that of normal C-O bond （1.41 - 1.43 A） in a six-membered heterocycle. The UV-vis spectra of the title compound showed that it exhibits excellent photochromic property in polyester coating and solutions.展开更多
The crystal structure of fused photochromic diarylethene dimer, 1,4-bis-[4-(4-{2-(5-phenyl)-2-methyl-thiophen-3-yl]-3,3,4,4,5,5-hexafluoro-cyclopent-1-enyl}-5-methyl-thiophen-2-yl) buta-1,3-diyne(1 oo, C46 H23 F12 S4)...The crystal structure of fused photochromic diarylethene dimer, 1,4-bis-[4-(4-{2-(5-phenyl)-2-methyl-thiophen-3-yl]-3,3,4,4,5,5-hexafluoro-cyclopent-1-enyl}-5-methyl-thiophen-2-yl) buta-1,3-diyne(1 oo, C46 H23 F12 S4) was determined by single-crystal X-ray diffraction analysis. This crystal belongs to the triclinic system, space group P1 with a = 7.546(3), b = 8.869(3), c = 16.196(5), α = 98.000(4)°, β = 100.803(4)°, γ = 98.449(4)°, Z = 2, V = 1037.6(6) ?~3, Dc = 1.496 mg/m^3, μ = 0.317, F(000) = 474, the final R = 0.0428 and wR = 0.1199 for 4115 observed reflections(I > 2σ(I)). Further study demonstrated this compound underwent reversible photochromism with color-switching between colorlessness and green in crystalline state. Upon 365 nm irradiation, the diarylethene shows one step photochromism to form isomer 1 oc. When irradiated with 312 nm, the stepwise photocyclization reactions occurred in diarylethene dimer through the line of 1 oo to 1 oc to 1 cc.展开更多
The title compound, 2,2-bis（4-tertial butyl phenyl） naphthopyran, has been prepared and characterized by means of IR, ^1H NMR and elemental analysis, and its crystal structure was determined with X-ray diffraction i...The title compound, 2,2-bis（4-tertial butyl phenyl） naphthopyran, has been prepared and characterized by means of IR, ^1H NMR and elemental analysis, and its crystal structure was determined with X-ray diffraction in the ring-opened form after hydrolyzation. It belongs to monoclinic, space group P21/c, with a = 14.358（3）, b = 7.6725（15）, c = 24.470（5） А, β= 97.147（4）°, C_33H_36O2, Mr=464.62, V= 2674.8（9）А^3, Z = 4, Dc = 1.154 g/cm^3,μ= 0.070 mm^-1, F（000） = 1000, the final R = 0.0514 and wR = 0.1272 for 5444 observed reflections （I 〉 2σ（I））. X-ray analysis revealed that the C（13）-O（1） bond of the title compound cracks after UV irradiation, the six-membered heterocycles are destroyed, and zwitterionic intermediates come into being. The molecular structure in the ring-opened form is obtained after hydrolyzation. It is infrequent that the single-crystal structure is determined in a ring-opened form. A two-dimensional framework is formed by O-H…O and CAr-H…O hydrogen bonds. The UV-vis spectra show that the title compound exhibits excellent photochromic properties in solutions and polymers.展开更多
The title compound 2 （C30H27N3O, Mr = 445.55） has been synthesized and its structure was determined by X-ray crystallography method. The crystal is of monoclinic, space group P21/c with a = 17.520（15）, b = 8.640（...The title compound 2 （C30H27N3O, Mr = 445.55） has been synthesized and its structure was determined by X-ray crystallography method. The crystal is of monoclinic, space group P21/c with a = 17.520（15）, b = 8.640（7）, c = 15.439（13） A, β = 98.642（14）°, V = 2310（3） 3, Dc = 1.281 g/cm^3, μ = 0.780 mm^-1, F（000） = 944, Z = 4, the final R = 0.0671 and wR = 0.1790 for 1952 observed reflections with Ⅰ 〉 2σ（Ⅰ）. X-ray analysis revealed that the interatomic distance of C（20）O（1） is 1.464（4） , longer than that of the normal C-O bond （1.41～1.43 A） in the six-membered heterocycle, but this kind of change coincides with other spiro compounds. The six-membered heterocycle containing spiro Csp3-O is nonplanar. The UV-vis spectra of the title compound in polymer films showed that it exhibits excellent photochromic property.展开更多
基金Project supported by the Jiangsu Province Graduate Research and Innovation Program(KYCX24_0329)。
文摘In recent years,photochromic(PC)materials have garnered widespread interest due to their potential applications in next-generation optical storage devices and photocatalysis.These materials,which control luminescence intensity via PC reactions,are not only suitable for optical switches and information storage but also play a crucial role in enhancing catalytic efficiency in photocatalytic applications.However,quantifying the PC effect on performance in these applications is challenging,complicating the material design needed to meet performance specifications.This study reports on a multifunctional Na_(0.5)Bi_(4.5)Ti_(4)O_(15)(NBT)material that achieves adjustable photoluminescence(PL)and photocatalytic(PCA)performance through precise control of the PC reaction.Under alternating exposure to 405 nm light and thermal annealing,the Er/Yb co-doped NBT samples display remarkable photochromic(PC)behavior,capable of reversible color transitions between yellow and gray.After 30 s of 405 nm irradiation,strong energy transfer facilitates a high up-conversion(UC)luminescence contrast of 78.02%.Additionally,the PC reaction promotes the ideal separation of photoexcited carriers and significantly enhances the utilization of electron-hole pairs,nearly doubling the PCA efficiency of the NBT samples by 1.9 times.Furthermore,the luminescence contrast and PCA efficiency controlled by PC can be regulated through varying Er/Yb doping levels,maintaining consistent trends.This study provides theoretical and experimental foundations for the performance modulation of rare-earth-doped multifunctional photochromic materials.
基金Project supported by the National Natural Science Foundation of China(52072075,52102126,12104093)the Natural Science Foundation of Fujian Province(2021J05122,2021J05123,2022J01087,2022J01552,2023J01259)。
文摘The growing demand for the miniaturization and multifunctionality of optoelectronic devices has promoted the development of transparent ferroelectrics.However,it is difficult for the superior multiple optical properties of these materials to be compatible with the excellent ferroelectricity and piezoelectricity in transparent ceramics.Here,we successfully synthesized Bi/Eu codoped eco-friendly K0.5Na0.5NbO3transparent-ferroelectric ceramics with photo luminescence(PL)behavior,photochromic(PC)reactions and temperature-responsive PL.Based on the distinct optical properties of ceramics at different temperature ranges(room temperature and ultralow temperature),high utilization of multiple optical functions was realized.At room temperature,the PC behavior induced PL modulation contrast reaches 75.2%(at 592 nm),which can be applied in the optical information storage field.In the ultralow temperature range,the ceramics exhibit excellent sensitivity(with a maximum relative sensitivity of26.32%/K)via fluorescence intensity ratio technology and exhibit great application potential in noncontact optical temperature measurements.Additionally,the change in the PL intensity at different wavelengths(I_(614)/I_(592))can serve as a reliable indicator for detecting the occurrence of the phase transition from rhombohedral to orthorhombic at low temperature.This work provides a feasible paradigm for realizing the integration of ferroelectricity and multifarious optical properties in a single optoelectronic material.
文摘WO2 and TiO2 colMds were synthesized by the hydrolysis technique and part of the TiO2 colloid was treated by means of the hydrothermal method. The photochromic performances of the resulting materials obtained via combining the WO3 colloid with the treated TiO2 colloid and the non-treated TiO2 colloid, respectively, are very different. The TiO2 colloid without hydrothermal treatment can effectively improve the photochromic performance of the WO3colloid. The TiO2 nanoparticles were investigated in detail by XRD, TEM, surface photovohage spectra（SPS） and field-induced surface photovoltage spectrometry（FISPS）. The photochromism mechanism of WO3 colloid is discussed.
基金supported by the National Natural Science Foundation of China(No.222071043)the Major Project of Science and Technology,Education Department of Henan Province(No.20A150010)the 2021 Students Innovative Pilot Plan of Henan University(No.202110475079)。
文摘A series of DL-serine covalently modified multinuclear lanthanide implanted arsenotungstates K_(2)[{Ln(H_(2)O)_(7)}_(2){As_(4)W_(44)O_(137)(OH)_(18)(H_(2)O)_(2)(DL-Ser)_(2)}{Ln_(2)(H_(2)O)_(5)(DL-Ser)}_(2)]·65H_(2)O(DL-Ser=DL-serine,Ln=La(1),Ce(2),Pr(3))are obtained.Crystal structure analysis shows that these compounds are isomorphic and contain the basic[{As_(4)W_(44)O_(137)(OH)_(18)(H_(2)O)_(2)(DL-Ser)_(2)}{Ln_(2)(H_(2)O)_(5)(DL-Ser)}_(2)]^(8–)polyoxoanion constituted by two{As_(2)W_(19)O_(59)(OH)_(8)(H_(2)O)}^(6–)subunits,a[W_(6)O_(2)_(3)(OH)_(2)(DL-Ser)_(2)]_(14)–fragment,and two embedded[Ln_(2)(H_(2)O)_(5)(DL-Ser)]^(5+)groups,which further build into one dimensional linear chainlike structure via two peripheral Ln^(3+)ions.Most remarkably,these compounds exhibit rapid photochromic behaviors,which changed color quickly from white(1),yellow(2),green(3)to blue(1),brown(2)and glaucous(3)in ten minutes under UV irradiation,and that the colors gradually recovered in the dark for approximately 22 h.
基金the financial support from the National Natural Science Foundation of China (No. 21971085)the Natural Science Foundation of Shandong Province (No. ZR2019MB004)。
文摘Polyoxometalates (POMs) are important inorganic photochromic materials to be potentially applied in photo-induced switch,energy storage,and even the detection of light.However,due to the limited sensitivity of POMs,it is difficult to realize the photochromic response to weak visible light.In this paper,by the coordination of solvated Pb(Ⅱ),a new structure-defined chain-like polyoxomolybdate complex of[(Pb(DMF)_(4))^(3)(P_(2)Mo_(18)O_(62))_(2)]n(Pb_(3)Mo_(18) ,DMF=dimethylformamide) has been demonstrated by a facile solvent-diffusion approach.By virtue of interactions between Pb(DMF)_(4) and polyoxoanions,Pb_(3)Mo_(18) shows an ultrasensitive photochromic response to weak visible lights and forms the reduced’heteropoly blue’species through ligand-to-metal charge transfer (LMCT) process.A new mechanism is firstly proposed here that the 6s orbital lone electron pair on Pb(II) can effectively stabilize the generated hole of oxygen atoms as a result of O→Mo charge transfer.Through the proposed mechanism,the LMCT barrier is drastically lowered and allows the coloration to be occurred even upon weak visible light.Also,because the conductivity of Pb_(3)Mo_(18) enhances with the increase of reduction extent,its electrochemical impedance signals are proportionally response to irradiation intensity.Especially,for the first time,the polyoxomolybdate composite can be used to detect weak visible light,in which the optical signal can be converted into electrical signal output.Moreover,Pb_(3)Mo_(18) can be drip-coated on the surface of the screen printed chip electrode,which is facile to the detection of light by portable devices compatible with computers,mobile phones and other electronic equipment.This work not only highlights a new approach to the molecular design of photochromic POMs by the coordination of metal ions with the effect of inert electron pair,but also lays a foundation to extend the application of POMs as light signal sensors.
基金supported by the National Natural Science Foundation(Grant No.20372032)Jiangsu Province in China(Grant.No.BK2004085)
文摘The interfacial behaviors of the non-typical amphiphilic compound p-methylphenylazocalix[4]arene 1 and p-chlorophenylazocalix[4]arene 2 at the air/water interface and photochromism in the Langmuir-Blodgett films were studied by surface pressure-area isotherm and UV-Vis spectra. The results indicate that they can form stable monolayers at the air / water interface although they have no hydrophobic alkyl chains, and their LB film underwent reversible trans-cis photoisomerization on UV and daylight illumination.
基金Supported by the NNSFC(21262015,21162011)Science Funds of the Education Office of Jiangxi Province(GJJ11690,GJJ13577)
文摘A new family of photochromic diarylethene compounds, 1-（2-cyano-l,5-dimethyl- 4-pyrryl）-2-[2-methyl-5-（3-pyridyl）-3-thienyl]perfluorocyclopentene （lo） having an unsymmetrical pyrryl and thienyl substituted hexafluorocyclopentene unit, was synthesized and its structure was determined by X-ray analysis. The crystal belongs to triclinic system, space group PI with a = 8.897（7）, b = 10.139（8）, c = 12.361（9） A, α = 85.222（7）, ρ = 75.439（7）, γ = 78.736（8）°, Z = 2, V= 1057.8（14） A3, D,.= 1.468 mg/m3, p = 0.220 mm-1, F（000） = 476, the final R = 0.0608 and wR = 0.1754 for 3199 observed reflections （1 〉20（/））. Interestingly, compound 1 exhibits good photochromic properties with alternate irradiation of UV light and visible light （〉 510 nm） to form two photoisomers in hexane solution and crystal phase.
基金supported by the Introduced Innovative R&D Team Project of "The Pearl River Talent Recruitment Program"of Guangdong Province (No.2019ZT08C321)Guangdong Basic and Applied Basic Research Foundation (No.2019A1515110443)the National Natural Science Foundation of China (No.51872327)。
文摘With the rapid development of science and technology,the high-security-level anti-counterfeiting technique is essential for ensuring property or information security.In this work,we prepared micron NaYTiO_(4):Bi/Er(NYT:Bi/Er) phosphors with integrating up-conversion(UC) photoluminescence,downshifting(DS) emission,phosphorescence and photochromism(PC) performances for advanced multiple anti-counterfeiting application.Owing to the abundant energy levels of Er^(3+)ions,the UC and DS luminescence behaviors are anticipated.Specifically,the yellow-green emission of Er^(3+)ions can be observed upon 980 nm excitation,and the bright green emission is demonstrated under 281 or 254 nm excitation due to the energy transitions of Er^(3+)ions and the energy transfer process from Bi^(3+)to Er^(3+)ions.Besides,the introduction of Bi^(3+)ions generates defect levels in the matrix and thus leads to phosphorescence.Furthermore,the repeatable PC performance could be triggered by the 365 nm irradiation and vanished with 450 nm illumination or thermal stimulation.To verify the practical usability of NYT:Bi/Er phosphors on anti-counterfeiting applications,some experiments are designed and successfully executed.It is believed that the NYT:Bi/Er phosphors can be a promising candidate for high-security-level multiple anti-counterfeiting.
文摘Two-photon ionization and recombination processes of an aromatic chromophore doped in polymer films werestudied and the features of these processes were discussed in relation to photofunctional polymers, An aromatic moleculehaving low ionization potential, e.g., N,N,N',N'-tetramethyl-p-phenylene diamine doped in poly(methyl methacrylate)(PMMA) film was easily photoionized by intense laser ligh excitation, giving a colored radical cation (photochromism) anda trapped electron in PMMA matrix. As a reversed process, the radical cation recombined with the trapped electron, showingdiscoloration and emitting luminescence, either isothermal luminescence (ITL), or thermoluminescence (TL). In this report,ITL and TL through the charge recombination process were studied and the luminescence was suggested as a mean of the read-out of photorecording.
文摘A cadmium tetracyanoplatinate host clathrate,(MV)[Cd_(2){Pt(CN)_(4)}_(3)]·2(H_(2)O)(1),including a methylviologen dication (MV^(2+)) was synthesized,and the crystal structures,photochromic and photoluminescence properties were investigated.In 1,the alternatively parallel stacking between the MV^(2+)dications as electron acceptors in the channels and the electron donors[Pt1(CN)_(4)]^(2-) units in the host frameworks give a unique donor-acceptor (DA) system.Under UV irradiation,the electron transfer between MV^(2+) and[Pt(CN)_(4)]^(2-) ions generates MV^(·+)radicals with a photochromic behavior from pale-yellow to blue.This process occurs through single-crystal-to-single-crystal (SCSC) transformation and obvious structure variation of viologen cations is successfully observed.Moreover,the spectral overlap between the emission bands of 1 and the absorption around 623 nm for the MV^(·+) radicals leads to a modulation of the photoluminescence.
文摘A series of inorganic-organic thin films based on uniformly dispersed nanoparticles of polyoxometalates （POM）entrapped in polyacrylamide （PAM） matrix were prepared by ultrasonic method with different irradiation time.The microstructure, photochromic behavior and mechanism of the films were studied by transmission electron microscopy （TEM）, ultraviolet-visible spectra （UV-VIS） and Fourier transform-infrared spectroscopy （FT-IR）.The microstructure and photochromic properties of the hybrid thin films could be controlled by ultrasound.TEM image revealed that the average size of phosphotungstic acid （PWA） nanoparticles decreased from 20 to 10 nm with the ultrasound irradiation time from 30 to 60 min. After irradiated with ultraviolet light,the transparent films changed from colorless to blue and showed reversible photochromism. The hybrid film, with ultrasound irradiation for 60 min had higher photochromic efficiency and faster bleaching reaction than the one with ultrasound irradiation for 30 min. FT-IR spectra showed that the Keggin geometry of heteropolyoxometalate was still preserved inside the composites, and the interactions between polyanions and polymer matrix increased as the ultrasound time prolonged. It is suggested that the mechanism of the different photochromic properties for the inorganic-organic thin films is the variation of the microstructure and interfacial interactions induced by ultrasound.
基金Project supported by the National Natural Science Foundation of China(22172022,21872021,21671033,21901135)。
文摘Four rare earth inorganic-organic hybrid compounds based on Keggin-type polyoxometalate {SiW_(12)}with general formula [{RE(DMF)_(4)(H_(2)O)_4RE(DMF)_(6)}_(2){SiW_(12)O_(40)}_(3)](RE = La(1),Pr(2),Sm(3),Eu(4),DMF=N,N-dimethylformamide) were synthesized by the conventional solution method.Structure analyses indicate that four compounds are isostructural and are all built from three [SiW_(12)O_(40)]^(4-) polyoxoanions and DMF ligands linked by RE^(3+).Compounds 1-4 are extremely sensitive to UV light and present excellent photochromic properties,in which the coloring and fading time of samples are both no more than 2 min,and the reversible coloring-fading process can be repeated for at least 10 cycles with little fatigue,suggesting that compounds 1-4 can be a series of fast-responsive and durable photochromic materials.Moreover,the solid-state photoluminescence spectra of compounds 3(Sm) and 4(Eu)display strong characteristic emissions of rare earth ions based on f-f transitions.Meanwhile,compound4(Eu) has a longer fluorescence lifetime up to 566.74 μs.Notably,co mpounds 3(Sm) and 4(Eu) exhibit the switchable luminescence behavior induced by photochromism,which allows them to be used as potential molecular switches.
基金This work is supported by the National Natural Science Foundation of China.
文摘A series of acrylic ester copolymers with viologen group as pendant were synthesizedthrough the reaction of MMA-EBA (Ethenyl bromoacetate) copolymer with 4-(4'-pyridyl)-N-alkyl (or arylalkyl) pyridiniums. These viologen copolymers can exchange their anionwith NH_4PF_6 in methanol to improve their solubility in organic solvents such as DMFand acetone. Compared with the corresponding low molecular viologens, these viologencopolymers have relatively lower color development rate under UV light and fade fasterin air due to less affinity to photo-reductant and deficiency of association between theircation radicals. Their photofatigue resistant ability is also slightly better than that of lowmolecular vinlogens.
基金supported by the National Natural Science Foundation of China(Nos.21825106,92061201,22105175)Postdoctoral Research Grant in Henan Province(No.202102001)。
文摘It remains a big challenge to develop solid-state stimuli-responsive materials for time-dependent information encryption and inkless erasable printing with long retention times.Herein,a 2D Cu_(2)I_(2)-based MOF with photoresponsive spiropyran(SP)groups orderly installed on its skeleton is developed.The structural isomerization from SP to colored merocyanine(MC)form can be triggered by removing the CH_(3)CN vips.Besides,the degree of structural isomerization and the retention time can be adjusted by controlling the amount of CH_(3)CN vips,exhibiting dynamic photochromic behavior with multicolor states and tunable retention time.Based on these advantages,time-dependent information encryption is successfully achieved.Furthermore,the long retention time(>72 h)of the MC form under daylight conditions in the CH_(3)CN-removed Cu_(2)I_(2)-based MOF and good repeatability make it promising in various applications,such as temporary calendars,price-cards,billboards,and reusable identity cards.This work provides a novel design strategy to fabricate multi-functional MOF-based smart materials for challenging applications of time-dependent information encryption and inkless erasable printing.
文摘The photochromism in CaS:Sm (from white to pink) was observed for the first time by exposing it to ultraviolet light. The experiments results show that the absorption intensity of Sm2+ in the range of 500 similar to 600nm was strongly increased after irradiation. This reveals that there is the valence changing of Sm. If the sample was excited by visible light again, the pink color turned to white, indicating that CaS:Sm has potential application in the field of storage material.
基金The authors thank the National Natural Science Foundation of China(No.29874020)for financial support.
文摘The photochromism of a 36-armed liquid crystalline dendrimer D6 was briefly described in this paper. The molar absorption coefficient, photoisomerization and photo back-isomerization of D6 in solution were investigated by UV/Vis absorption spectra. The results indicate that the photochromism and photo back-isomerization of D6 in chloroform （CHC13） and tetrahydrofuran （THF） solutions are in accordance with the ftrst order kinetics. The photochromism rate constants of D6 are 101 sI, it is 107 times larger than that of side-chain liquid crystalline polymers containing the same azobenzene moieties.
基金The work was supported by the National Natural Science Foundation of China (Nos 20602020 and 20490210)
文摘The title compound 2,2-dithiophene-naphthopyran （C21H14OS2, Mr = 346.44） was synthesized and characterized by IR,^1lH NMR, elemental analysis and single-crystal X-ray diffraction. It belongs to the monoclinic system, space group P21/n, with a = 8.2349（14）, b = 6.1964（11）, c = 32.458（5）A, β= 95.051（3）°, V= 1649.8（5）A^3, Z = 4, Dc = 1.395 g/cm^3,μ = 0.327 cm^-1, F（000） = 720, the final R = 0.0559 and wR = 0.1442 for 3370 observed reflections （I 〉 2σ（I））. X-ray analysis revealed that the interatomic distance of C（13）-O（1） is 1.456（3）A, longer than that of normal C-O bond （1.41 - 1.43 A） in a six-membered heterocycle. The UV-vis spectra of the title compound showed that it exhibits excellent photochromic property in polyester coating and solutions.
基金Supported by the National Natural Science Foundation of China(21701065)"5511" Science and Technology Innovation Talent Project of Jiangxi Province(20165BCB18015)+2 种基金the Project of Natural Science Foundation of Jiangxi Province(20171ACB20025,20171BAB203011)the Project of the Science Funds of Jiangxi Education Office(GJJ170659)the Project of Jiangxi Advantage Sci-Tech Innovative Team(20142BCB24012)
文摘The crystal structure of fused photochromic diarylethene dimer, 1,4-bis-[4-(4-{2-(5-phenyl)-2-methyl-thiophen-3-yl]-3,3,4,4,5,5-hexafluoro-cyclopent-1-enyl}-5-methyl-thiophen-2-yl) buta-1,3-diyne(1 oo, C46 H23 F12 S4) was determined by single-crystal X-ray diffraction analysis. This crystal belongs to the triclinic system, space group P1 with a = 7.546(3), b = 8.869(3), c = 16.196(5), α = 98.000(4)°, β = 100.803(4)°, γ = 98.449(4)°, Z = 2, V = 1037.6(6) ?~3, Dc = 1.496 mg/m^3, μ = 0.317, F(000) = 474, the final R = 0.0428 and wR = 0.1199 for 4115 observed reflections(I > 2σ(I)). Further study demonstrated this compound underwent reversible photochromism with color-switching between colorlessness and green in crystalline state. Upon 365 nm irradiation, the diarylethene shows one step photochromism to form isomer 1 oc. When irradiated with 312 nm, the stepwise photocyclization reactions occurred in diarylethene dimer through the line of 1 oo to 1 oc to 1 cc.
基金supported by the National Natural Science Foundation of China (Nos. 20602020 and 20490210)
文摘The title compound, 2,2-bis（4-tertial butyl phenyl） naphthopyran, has been prepared and characterized by means of IR, ^1H NMR and elemental analysis, and its crystal structure was determined with X-ray diffraction in the ring-opened form after hydrolyzation. It belongs to monoclinic, space group P21/c, with a = 14.358（3）, b = 7.6725（15）, c = 24.470（5） А, β= 97.147（4）°, C_33H_36O2, Mr=464.62, V= 2674.8（9）А^3, Z = 4, Dc = 1.154 g/cm^3,μ= 0.070 mm^-1, F（000） = 1000, the final R = 0.0514 and wR = 0.1272 for 5444 observed reflections （I 〉 2σ（I））. X-ray analysis revealed that the C（13）-O（1） bond of the title compound cracks after UV irradiation, the six-membered heterocycles are destroyed, and zwitterionic intermediates come into being. The molecular structure in the ring-opened form is obtained after hydrolyzation. It is infrequent that the single-crystal structure is determined in a ring-opened form. A two-dimensional framework is formed by O-H…O and CAr-H…O hydrogen bonds. The UV-vis spectra show that the title compound exhibits excellent photochromic properties in solutions and polymers.
基金The project was supported by the NNSFC (No. 20490210 and 20372039)
文摘The title compound 2 （C30H27N3O, Mr = 445.55） has been synthesized and its structure was determined by X-ray crystallography method. The crystal is of monoclinic, space group P21/c with a = 17.520（15）, b = 8.640（7）, c = 15.439（13） A, β = 98.642（14）°, V = 2310（3） 3, Dc = 1.281 g/cm^3, μ = 0.780 mm^-1, F（000） = 944, Z = 4, the final R = 0.0671 and wR = 0.1790 for 1952 observed reflections with Ⅰ 〉 2σ（Ⅰ）. X-ray analysis revealed that the interatomic distance of C（20）O（1） is 1.464（4） , longer than that of the normal C-O bond （1.41～1.43 A） in the six-membered heterocycle, but this kind of change coincides with other spiro compounds. The six-membered heterocycle containing spiro Csp3-O is nonplanar. The UV-vis spectra of the title compound in polymer films showed that it exhibits excellent photochromic property.
