Extensive multi-band afterglow data are available for GRB 980703. Especially,its radio afterglow was very bright and was monitored until more than 1000 days after the trigger time. Additionally,there is no obvious spe...Extensive multi-band afterglow data are available for GRB 980703. Especially,its radio afterglow was very bright and was monitored until more than 1000 days after the trigger time. Additionally,there is no obvious special feature,i.e.,no rebrightenings,no plateau,and no special steep decay or slow decay in the multi-band afterglow light curves. All these conditions make GRB 980703 a precious sample in gammaray burst research. Here we use the observational data of GRB 980703 to test the standard fireball model in depth. It is found that the model can give a satisfactory explanation to the multi-band and overall afterglow light curves. The beaming angle of GRB 980703 is derived as ～ 0.23 radian,and the circum-burst medium density is ～ 27 cm-3. The total isotropic equivalent kinetic energy of the ejecta is ～ 3.8 × 1052 ergs. A rest-frame extinction of AV ～ 2.5 mag in the host galaxy is also derived.展开更多
Organic afterglow materials hold significant potential for applications in information storage,anticounterfeiting,and biological imaging.However,studies on afterglow materials capable of ultra-wide range excitation an...Organic afterglow materials hold significant potential for applications in information storage,anticounterfeiting,and biological imaging.However,studies on afterglow materials capable of ultra-wide range excitation and emission simultaneously are limited.To enhance the practicality of strong emission single-component organic afterglow systems,overcoming the constraints of crystalline or other rigid environments is essential.We have developed solid-state dual-persistent thermally activated delayed fluorescence(TADF)and room temperature phosphorescence(RTP)emissions spanning yellow to red under visible light excitation,utilizing a single-molecule terminal group regulation strategy.The RTP lifetime extends from 4.19 ms to 399.70 ms.These afterglow materials exhibit an ultra-wide absorption range from 200 nm to 800 nm,rendering them capable of being excited by both sunlight simulator and nearinfrared radiation.The upconversion phosphorescence lifetime under 808 nm excitation reaches 13.72μs.The double persistent emission of these compounds is temperature-sensitive.Moreover,following grinding or heat treatment,accompanied by extensive afterglow color conversion due to planarization of excited state conformations and additional efficient kRIsc generation.In addition,the amorphous state post melt annealing facilitates the afterglow transition from yellow to green.Crucially,these compounds also maintain stable ultra-long afterglow emission in aqueous and acid-base environments.Overall,we have successfully developed a series of single-component intelligent luminescent materials that demonstrate significant benefits,including dual TADF and RTP emissions,adjustable afterglow lifetimes,a broad range of excitation and emission wavelengths,multi-modal luminescence not restricted to crystalline states,and robust afterglow performance in challenging environments,setting the stage for the practical deployment of afterglow materials in engineering applications,the upconversion afterglow emission also holds promising potential for applications in the field of biological imaging.展开更多
Carbon dots(CDs)are an emerging class of zero-dimensional carbon nano optical materials that are as promising candidates for various applications.Through the exploration of scientific researchers,the optical band gap ...Carbon dots(CDs)are an emerging class of zero-dimensional carbon nano optical materials that are as promising candidates for various applications.Through the exploration of scientific researchers,the optical band gap of CDs has been continuously regulated and red-shifted from the initial blue-violet light to longer wavelengths.In recent years,CDs with near-infrared(NIR)absorption/emission have been gradually reported.Because NIR light has deeper penetration and lower scattering and is invisible to the human eye,it has great application prospects in the fields of biological imaging and treatment,information encryption,optical communications,etc.Although there are a few reviews on deep red to NIR CDs,they only focus on the single biomedical direction.There is still a lack of comprehensive reviews focusing on NIR(≥700 nm)absorption and luminescent CDs and their multifunctional applications.Based on our research group’s findings on NIR CDs,this review summarizes recent advancements in their preparation strategies and applications,points out the current shortcomings and challenges,and anticipates future development trajectories.展开更多
The construction of triplet-to-singlet F?rster resonance energy transfer(TS-FRET)systems has significantly contributed to the advancement of high-performance optoelectronic materials,particularly in the development of...The construction of triplet-to-singlet F?rster resonance energy transfer(TS-FRET)systems has significantly contributed to the advancement of high-performance optoelectronic materials,particularly in the development of metal-free organic environmental afterglow materials.Despite these notable advancements,achieving highly efficient energy transfer between luminescent donor and acceptor molecules remains a formidable challenge.In this study,we present the utilization of cation-πinteractions as an effective strategy to enhance TS-FRET efficiency,with the ultimate objective of further advancing fiuorescence afterglow materials.Our results demonstrate that the cation-πinteraction in 1D supramolecular nanorods(1D-SNRs)enhances the dipole-dipole coupling,a crucial parameter for regulating TS-FRET between the triplet state phosphorescent donor and singlet state fiuorescent acceptor.As a result,we achieved an outstanding TS-FRET efficiency of up to 97%.Furthermore,the 1D-SNRs exhibit a long-lifetime afterglow property,which suggests their potential application as a cost-effective and secure medium for information encryption.Thus,our findings highlight the promising prospects of cation-πinteractions in enhancing TS-FRET efficiency and advancing the field of organic photo-functional materials.展开更多
In this paper,we developed low dose X-ray induced long afterglow phosphor Ca_(2)P_(2)O_(7):Pr^(3+),which shows excellent afterglow luminescence from ultraviolet C(UVC)to red region.The photoluminescent results show th...In this paper,we developed low dose X-ray induced long afterglow phosphor Ca_(2)P_(2)O_(7):Pr^(3+),which shows excellent afterglow luminescence from ultraviolet C(UVC)to red region.The photoluminescent results show that under 445.7 nm excitation,Ca_(1.995)P_(2)O_(7):0.5%Pr3+displays red emissions peaked at 598.3 and651.9 nm,corresponding to1D2-3H4and3P0-3F2transitions of Pr^(3+),respectively.Due to its pure red emission(CIE coordinates(0.59101,0.39926)),Ca_(1.995)P_(2)O_(7):0.5%Pr^(3+)can be regarded as a potential LED red phosphor.More importantly,Ca_(2)P_(2)O_(7):Pr^(3+)shows long afterglow luminescence from UVC to red region,which consists of four co ntinuous emissions with similar intensity including 260,359,466 and 598.3 nm.Since these afterglow continuous emissions are fitted to the absorption of most photodynamic therapy(PDT)agents,Ca_(2)P_(2)O_(7):Pr^(3+)can be regarded as excellent PDT agents.Furthermo re,30 s X-ray irradiation can induce 5400 s decay of Ca_(1.997)P_(2)O_(7):0.3%Pr^(3+),and its afterglow emission intensity still reaches 5×10^(4)cps after 5400 s decay.Even only 5 s X-ray irradiation also can produce 4.75×10^(4)cps afterglow emis sion after10 s decay.In addition,the repeat 980 nm laser irradiations can induce co ntinuous strong photo-stimulated(PSL)luminescent peaks,which can be utilized to conduct high efficiency PDT without another X-ray irradiation.The thermoluminesce nce results reveal that the existence of shallow(0.89 eV)and deep traps are responsible for the excellent X-ray induced long afterglow and PSL luminescence.All these results suggest that Ca_(2)P2O7:Pr^(3+)possesses great potential to be regarded as high efficiency PDT agents.展开更多
For the last few decades,there has been extensive research on the materials that persist to emit optical radiation long after any type of charging has stopped.Most of the established persistent luminescence(PersL)mate...For the last few decades,there has been extensive research on the materials that persist to emit optical radiation long after any type of charging has stopped.Most of the established persistent luminescence(PersL)materials emit light in the visible part of the spectrum;however,in recent years,there has been a growing interest in UV-emitting persistent phosphors in recent years.These materials have been tested for various applications,such as photocatalysis,sterilization,and anti-counterfeiting,among others.Here,we report on the X-ray and UV-activated UV-A long PersL of Ce^(3+)-doped Sr_(3)MgSi_(2)O_(8) material.We prepared samples with varied Ce^(3+)concentrations using solid-state reaction synthesis in an ambient atmosphere and conducted a thorough investigation using photoluminescence(PL),electron paramagnetic resonance(EPR),and thermally stimulated luminescence(TSL)spectroscopy methods.Our experiments show that the PersL signal of Ce^(3+)in the 300-450 nm range can be detected for at least 16 h when samples are irradiated with X-rays or UV.The TSL analysis reveals multiple discrete charge traps in the material with activation energies between 0.5 and 1.7 eV.Further EPR measurements confirm the presence of four paramagnetic centers.The thermal stability of these centers was analyzed,and it is established that one of these centers(g_(1)=2.0056,g_(2)=1.9981,and g_(3)=1.9926)gradually decays at room temperature,which is correlated with the PersL processes.展开更多
Multiband afterglow observations of gamma-ray bursts(GRBs)are important for studying the central engine.GRB 201223A is a GRB with prompt optical detection by GWAC.Here we report on the early optical afterglow of GRB 2...Multiband afterglow observations of gamma-ray bursts(GRBs)are important for studying the central engine.GRB 201223A is a GRB with prompt optical detection by GWAC.Here we report on the early optical afterglow of GRB 201223A detected by NEXT(only 2.8 minutes after the Swift/BAT trigger),which smoothly connects the prompt optical emission and the afterglow phase.Utilizing Amati diagrams and considering the detection of afterglow emission in the Swift u-band,we suggest a redshift range of 0.26–1.85.Based on our optical data and combined with early optical observation from GWAC and early X-ray data from Swift/XRT,a multiband fitting is performed using PyFRS,and we obtain the best afterglow parameters(assuming a redshift of z=1.0):=5.01+10/_(1.70)^(1.91)×^(54)erg,G=-426.58+_(138.18)/^(148.86),θj=-25.98+_(-10.54)^/(9.67)deg,=-n0=0.30+_(-0.26)^(+3.78)cm^(−3),=-p2.32+_(-0.01)/^(+0.01),εe=-3.31+_(-0.86)/^(+1.59)×10^(-5),εB=-3.47+_(-2.62)/^(+4.12)×10^(-1).The late-time X-ray shows a re-brightening,indicating late-time central engine activities.After comparing the leading two central engine models,i.e.,magnetar model and hyperaccreting black hole model,we find that the fallback accretion onto a newborn black hole provides a better explanation for the X-ray re-brightening with fallback accretion rate Mp≈2.76×10^(-9)M⊙s^(-1)and the total fallback accreted mass Mfb≈1.41×10^(−6)M⊙.展开更多
The low-dose X-ray induced long afterglow near infrared(NIR)luminescence from Cr^(3+)doped Zn_(1-x)Cd_(x)Ga_(2)O_(4)spinel solid solutions was investigated.The structure analysis shows the good formation of Zn_(1-x)Cd...The low-dose X-ray induced long afterglow near infrared(NIR)luminescence from Cr^(3+)doped Zn_(1-x)Cd_(x)Ga_(2)O_(4)spinel solid solutions was investigated.The structure analysis shows the good formation of Zn_(1-x)Cd_(x)Ga_(2)O_(4)spinel solid solutions,which possesses a cubic spinel structure with Fd3m space group.The formation of Zn_(1-x)Cd_(x)Ga_(2)O_(4)spinel solid solutions induces the obvious increase of long afterglow near infrared luminescence excited by low-dose X-ray,When the content of doped Cd^(2+)reaches 0.1,the low-dose X-ray induced long afterglow NIR luminescence is the maximum.More importantly,only 5 s Xray irradiation can induce more than 6 h NIR afterglow emission,of which the afterglow luminescent intensity is still 5 times stronger than the background intensity after 6 h.The thermoluminescent results show that under the 5 s exposure of X-ray,the trap density of Zn_(0.9)Cd_(0.1)Ga_(2)O_(4):Cr^(3+)is much higher than that of ZnGa_(2)O_(4):Cr^(3+).The replacement of Cd^(2+)ions with large radius at Zn^(2+)sites causes the increase of de fects and dislocations,which results in the obvious increase of trap co ncentrations.And the addition of high-z number elements Cd^(2+)would enhance the X-ray absorption of the solid solutions,which thus can be easily excited by low-dose X-ray.Zn_(0.9)Cd_(0.1)Ga_(2)O_(4):1%Cr^(3+)solid solution is a potential candidate of lowdose X-ray induced long afterglow luminescent materials.展开更多
The efficient production of high-quality scintillators with long radioluminescence afterglow is crucial for high-performance X-ray luminescence extension imaging.However,scaling-up the synthesis of ligand-free scintil...The efficient production of high-quality scintillators with long radioluminescence afterglow is crucial for high-performance X-ray luminescence extension imaging.However,scaling-up the synthesis of ligand-free scintillators to fabricate large-area X-ray imaging screens for industrial applications remains a challenge.In this study,we report an efficient method to synthesize ligand-free,lanthanide-doped microscintillators by a one-pot reaction via the concentrated hydrothermal method.The as-synthesized microscintillators exhibit prolonged persistent radioluminescence for up to 30 days after X-ray exposure and remain high stability in air or water for more than 18 months without deterioration.Monte Carlo simulations indicate that the size effect is responsible for the excellent afterglow performance of the microscintillators.We employ these high-quality lanthanide-doped microscintillators to fabricate a large-area X-ray imaging detector using a blade-coating method,a spatial resolution of 24.9 lp/mm for X-ray imaging.Our study offers a solution for scaling-up the synthesis of low-cost microscintillators for practical applications.展开更多
Organic color-tunable phosphorescent materials depend upon multiple emission centers to achieve colortunable phosphorescence with changes in excitation wavelength,temperature,time,and other external factors.Organic co...Organic color-tunable phosphorescent materials depend upon multiple emission centers to achieve colortunable phosphorescence with changes in excitation wavelength,temperature,time,and other external factors.Organic color-tunable phosphorescent materials are becoming increasingly popular due to their potential applications in anticounterfeiting,encryption and sensing.This brief review focuses on the formation of multiple emission centers in organic color-tunable phosphorescent materials and how to ensure that these multiple emission centers can simultaneously emit.In the future,materials with a large color tunable ranges,increased efficiency,and relatively long lives will be developed.展开更多
The non-grinding long afterglow material SrAl2O4：Eu^2＋ , Dy^3＋ was prepared by combustion method in home mierowave oven direetly, after dispersant, frother, eomburent, and mineralizer were added into the reacting s...The non-grinding long afterglow material SrAl2O4：Eu^2＋ , Dy^3＋ was prepared by combustion method in home mierowave oven direetly, after dispersant, frother, eomburent, and mineralizer were added into the reacting system. XRD analysis showed that the powders were nearly pure SrAl2O4 phase with few other phases, and the size of the grain was 41.1 nm. Fluoreseenee speetrum results indieated that there were 2 exeitation peaks loeated at 345 and 400 nm, and the emission peak loeated at 516 nm, afterglow lasted up to 30 min or more. The mierowave eombustion method has advantages of less time, low temperature and no grinding process, and the material made by the method has good luminescent property.展开更多
Near-infrared(NIR),particularly NIR-containing dual-/multimode afterglow,is very attractive in many fields of application,but it is still a great challenge to achieve such property of materials. Herein,we report a fac...Near-infrared(NIR),particularly NIR-containing dual-/multimode afterglow,is very attractive in many fields of application,but it is still a great challenge to achieve such property of materials. Herein,we report a facile method to prepare green and NIR dual-mode afterglow of carbon dots(CDs) through in situ embedding o-CDs(being prepared from o-phenylenediamine) into cyanuric acid(CA) matrix(named o-CDs@CA). Further studies reveal that the green and NIR afterglows of o-CDs@CA originate from thermal activated delayed fluorescence(TADF) and room temperature phosphorescence(RTP) of o-CDs,respectively. In addition,the formation of covalent bonds between o-CDs and CA,and the presence of multiple fixation and rigid e ects to the triplet states of o-CDs are confirmed to be critical for activating the observed dual-mode afterglow. Due to the shorter lifetime and insensitiveness to human vision of the NIR RTP of o-CDs@CA,it is completely covered by the green TADF during directly observing. The NIR RTP signal,however,can be readily captured if an optical filter(cut-o wavelength of 600 nm) being used. By utilizing these unique features,the applications of o-CDs@CA in anti-counterfeiting and information encryption have been demonstrated with great confidentiality. Finally,the as-developed method was confirmed to be applicable to many other kinds of CDs for achieving or enhancing their afterglow performances.展开更多
Nanosized long-persistent phosphors SrS：Eu^2＋, Dy^3＋ were prepared by the hydrothermal method.The samples were characterized by X-ray powder diffraction, transmission electron microscopy, and charge-coupled device ...Nanosized long-persistent phosphors SrS：Eu^2＋, Dy^3＋ were prepared by the hydrothermal method.The samples were characterized by X-ray powder diffraction, transmission electron microscopy, and charge-coupled device spectrometry.The persistence characteristic was studied using the decay curves.The results showed that the emission intensity decreased sharply with temperature increasing, although the particle size increased.The S2-vacancies caused by oxidization served as shallow traps, and Dy3＋ served as deep traps in SrS：Eu^2＋, Dy^3＋.The afterglow intensity of SrS：Eu^2＋, Dy^3＋ was higher than that of SrS：Eu2＋ prepared at the same temperature.However, the minimization span of initial afterglow with temperature for the former sample was larger than that for the latter.Binary-doped phosphor decayed more slowly than the singly doped one.The afterglow of SrS：Eu^2＋, Dy^3＋ decayed more quickly with the increase of sintering temperature.展开更多
The luminous polypropylene fiber based on long afterglow luminescent material Sr2MgSi2O7：Eu^2＋,Dy^3＋was prepared by melt-spinning process. Micro-morphology, phase composition, crystal structure, spectral features a...The luminous polypropylene fiber based on long afterglow luminescent material Sr2MgSi2O7：Eu^2＋,Dy^3＋was prepared by melt-spinning process. Micro-morphology, phase composition, crystal structure, spectral features and afterglow properties of the lu-minescent fiber were tested and analyzed. The results indicated that the fiber had independent superposition phase features of both Sr2MgSi2O7：Eu2＋,Dy3＋and polypropylene. The range of its excitation wavelength was located between 250-450 nm;therefore, the luminescent fiber could be excited by ultraviolet or visible light. It could emit blue light of 460 nm wavelength after excitation, which was caused by the 5d-4f transition of Eu^2＋ions within the host lattice. The initial luminescent intensity was more than 0.8 cd/m^2, and afterglow life lasted 7 h. The afterglow decay was composed of rapid-decaying and slow-decaying processes, and the decay charac-teristics depended on the depth and concentration of trap level in the Sr2MgSi2O7：Eu^2＋,Dy^3＋.展开更多
Calcium titanate doped with praseodymium was prepared through solid state reaction and it exhibited intense red emission at 612 nm. Phosphors were characterized for photoluminescence, thermo-luminescence and afterglow...Calcium titanate doped with praseodymium was prepared through solid state reaction and it exhibited intense red emission at 612 nm. Phosphors were characterized for photoluminescence, thermo-luminescence and afterglow emissions. Study of effects of rare earths on photoluminescence as well as afterglow intensity was reported. Presence of gadolinium enhanced luminescence. Presence of some monovalent ions enhanced both afterglow and photoluminescence emission. Thermo-luminescence glow curves were analyzed and ...展开更多
The long afterglow phosphor CaAl2O4： Eu^2＋, Nd^3＋ was prepared by the high temperature solid-state reaction method, and the influence of La^3＋ and Dy^3＋ on the properties of the long afterglow phosphor was studie...The long afterglow phosphor CaAl2O4： Eu^2＋, Nd^3＋ was prepared by the high temperature solid-state reaction method, and the influence of La^3＋ and Dy^3＋ on the properties of the long afterglow phosphor was studied by X-ray diffiaction （XRD）, photoluminescence （PL）, and thermoluminescence （TL）. The XRD pattem shows the host phase of CaAl2O4 is produced and no impurity phase appears. The peak wavelength of the phosphor does not vary with La^3＋ and Dy^3＋ doping. It implies that the crystal field, which affects the 5d electron states of Eu^2＋, is not changed dramatically after doping of La^3＋ and Dy^3＋. The TL spectra indicate that the phosphor doped with La^3＋ or Dy^3＋ produces different depths of trap energy level. In the mechanism of long afterglow luminescence, it is considered that La^3＋ or Dy^3＋ works as trap energy level. The decay time lies on the number of electrons in the trap energy level and the rate of the electrons returning to the excitation level.展开更多
With stable physical properties, the rare-earth silicate phosphor of MgSiO3：Mn2＋,Nd3＋ is one of the suitable luminescent materials used in preparing functional fibers. In order to promote the afterglow properties o...With stable physical properties, the rare-earth silicate phosphor of MgSiO3：Mn2＋,Nd3＋ is one of the suitable luminescent materials used in preparing functional fibers. In order to promote the afterglow properties of red-emitting phosphors, we prepared it by means of solid-state reaction, and the effect of manufacturing elements including H3BO3 and environmental factor of calcining temperature, type of flux on its luminescence property were investigated through evaluating their afterglow properties. The results showed that with the concentration of Nd3＋ increasing, the amounts of H3BO3 doping and calcining temperature, the afterglow time and initial brightness of the rare-earth silicate phosphor increased and then decreased gradually. The afterglow properties of different flux concentration were different from one to another as： H3BO3〉Na＋〉K＋〉No flux.展开更多
Blue-green luminescent BaAl2O4：Eu2＋,Dy3＋ phosphor powders were synthesized via combustion synthesis method assisted by microwave irradiation in air. The phosphors were characterized by X-ray diffraction （XRD）, sc...Blue-green luminescent BaAl2O4：Eu2＋,Dy3＋ phosphor powders were synthesized via combustion synthesis method assisted by microwave irradiation in air. The phosphors were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and fluorescence spectrophotometer. The XRD results revealed that when the concentration of urea was over 3 times higher than theoretical quantities, a BaAl2O4 single hexagonal phase was obtained. The SEM results revealed that the surface of the BaAl2O4：Eu2＋,Dy3＋ powder samples showed lots of voids and pores. The BaAl2O4：Eu2＋,Dy3＋ phosphors exhibited a broad emission band of main peak at 496 nm and a shoulder peak at 426 nm under excitation of 337 nm. The BaAl2O4：Eu2＋,Dy3＋ phosphors at the Eu2＋ concentration of 1 mol.% showed the strongest luminescent intensity. Long afterglow phosphorescence was observed in the dark with naked eyes after the removal of the excitation source.展开更多
Long afterglow photoluminescent materials Sr2MgSi2O7 doped with Eu2+, Dy3+ were prepared by sol-gel method. The synthesized samples were characterized by X-ray diffraction. The excitation spectrum, emission spectrum a...Long afterglow photoluminescent materials Sr2MgSi2O7 doped with Eu2+, Dy3+ were prepared by sol-gel method. The synthesized samples were characterized by X-ray diffraction. The excitation spectrum, emission spectrum and long decay curve were measured and analyzed. XRD pattern indicates that phosphor is with Sr2MgSi2O7 crystal structure. The wide range of excitation wavelength indicates that luminescent material can be excited by light from ultraviolet ray to visible light. The main peak of emission spectrum is located at 466 nm. Sample excited by visible light can emit bright blue light, and the afterglow time lasts more than 8 h.展开更多
Long persistent phosphors have received significant attention owing to their attractive photophysical properties.Here,we report a new long persistent phosphor exhibiting strong ultraviolet A(UVA)afterglow.The phosphor...Long persistent phosphors have received significant attention owing to their attractive photophysical properties.Here,we report a new long persistent phosphor exhibiting strong ultraviolet A(UVA)afterglow.The phosphors were synthesized by a solid-state reaction method.We find that the obtained phosphors demonstrate super long UVA-afterglow emissions after irradiation by X-ray source,and the afterglow can last more than 50 h.A wide range of experimental characterizations indicate that the Tb^3+doped fluoride elpasolite phosphors are defective and some fluoride ions are replaced by oxygen ions,which creates electron traps with suitable trap depths.Our results establish that Tb^3+can act as optical emitters in wide-bandgap hosts that can result in the UVA afterglow.This work enriches the bank of UV long persistent phosphors,and may stimulate more efforts for the design and synthesis of this kind of optical materials.展开更多
基金Supported by the National Natural Science Foundation of China (Grant Nos. 10625313 and 10973039)the National Basic Research Program of China (Grant No. 2009CB824800)a GRF Grant of Hong Kong Government (Grant No. HKU701109P)
文摘Extensive multi-band afterglow data are available for GRB 980703. Especially,its radio afterglow was very bright and was monitored until more than 1000 days after the trigger time. Additionally,there is no obvious special feature,i.e.,no rebrightenings,no plateau,and no special steep decay or slow decay in the multi-band afterglow light curves. All these conditions make GRB 980703 a precious sample in gammaray burst research. Here we use the observational data of GRB 980703 to test the standard fireball model in depth. It is found that the model can give a satisfactory explanation to the multi-band and overall afterglow light curves. The beaming angle of GRB 980703 is derived as ～ 0.23 radian,and the circum-burst medium density is ～ 27 cm-3. The total isotropic equivalent kinetic energy of the ejecta is ～ 3.8 × 1052 ergs. A rest-frame extinction of AV ～ 2.5 mag in the host galaxy is also derived.
基金financially supported by the National Natural Science Foundation of China(No.21871122)。
文摘Organic afterglow materials hold significant potential for applications in information storage,anticounterfeiting,and biological imaging.However,studies on afterglow materials capable of ultra-wide range excitation and emission simultaneously are limited.To enhance the practicality of strong emission single-component organic afterglow systems,overcoming the constraints of crystalline or other rigid environments is essential.We have developed solid-state dual-persistent thermally activated delayed fluorescence(TADF)and room temperature phosphorescence(RTP)emissions spanning yellow to red under visible light excitation,utilizing a single-molecule terminal group regulation strategy.The RTP lifetime extends from 4.19 ms to 399.70 ms.These afterglow materials exhibit an ultra-wide absorption range from 200 nm to 800 nm,rendering them capable of being excited by both sunlight simulator and nearinfrared radiation.The upconversion phosphorescence lifetime under 808 nm excitation reaches 13.72μs.The double persistent emission of these compounds is temperature-sensitive.Moreover,following grinding or heat treatment,accompanied by extensive afterglow color conversion due to planarization of excited state conformations and additional efficient kRIsc generation.In addition,the amorphous state post melt annealing facilitates the afterglow transition from yellow to green.Crucially,these compounds also maintain stable ultra-long afterglow emission in aqueous and acid-base environments.Overall,we have successfully developed a series of single-component intelligent luminescent materials that demonstrate significant benefits,including dual TADF and RTP emissions,adjustable afterglow lifetimes,a broad range of excitation and emission wavelengths,multi-modal luminescence not restricted to crystalline states,and robust afterglow performance in challenging environments,setting the stage for the practical deployment of afterglow materials in engineering applications,the upconversion afterglow emission also holds promising potential for applications in the field of biological imaging.
基金supported by the Science and Technology Development Fund of Macao SAR(Nos.0139/2022/A3,0007/2021/AKP,006/2022/ALC).
文摘Carbon dots(CDs)are an emerging class of zero-dimensional carbon nano optical materials that are as promising candidates for various applications.Through the exploration of scientific researchers,the optical band gap of CDs has been continuously regulated and red-shifted from the initial blue-violet light to longer wavelengths.In recent years,CDs with near-infrared(NIR)absorption/emission have been gradually reported.Because NIR light has deeper penetration and lower scattering and is invisible to the human eye,it has great application prospects in the fields of biological imaging and treatment,information encryption,optical communications,etc.Although there are a few reviews on deep red to NIR CDs,they only focus on the single biomedical direction.There is still a lack of comprehensive reviews focusing on NIR(≥700 nm)absorption and luminescent CDs and their multifunctional applications.Based on our research group’s findings on NIR CDs,this review summarizes recent advancements in their preparation strategies and applications,points out the current shortcomings and challenges,and anticipates future development trajectories.
基金financially supported by the National Natural Science Foundation of China(Nos.22071197,22022107)Key Research Program of Frontier Sciences,CAS(No.QYZDJ-SSW-SLH044)+2 种基金Key Research Program of the Chinese Academy of Sciences,(No.XDPB01)Fundamental Research Funds for the Central Universities(No.D5000230114)China Postdoctoral Science Foundation(No.2023M730951)。
文摘The construction of triplet-to-singlet F?rster resonance energy transfer(TS-FRET)systems has significantly contributed to the advancement of high-performance optoelectronic materials,particularly in the development of metal-free organic environmental afterglow materials.Despite these notable advancements,achieving highly efficient energy transfer between luminescent donor and acceptor molecules remains a formidable challenge.In this study,we present the utilization of cation-πinteractions as an effective strategy to enhance TS-FRET efficiency,with the ultimate objective of further advancing fiuorescence afterglow materials.Our results demonstrate that the cation-πinteraction in 1D supramolecular nanorods(1D-SNRs)enhances the dipole-dipole coupling,a crucial parameter for regulating TS-FRET between the triplet state phosphorescent donor and singlet state fiuorescent acceptor.As a result,we achieved an outstanding TS-FRET efficiency of up to 97%.Furthermore,the 1D-SNRs exhibit a long-lifetime afterglow property,which suggests their potential application as a cost-effective and secure medium for information encryption.Thus,our findings highlight the promising prospects of cation-πinteractions in enhancing TS-FRET efficiency and advancing the field of organic photo-functional materials.
基金Project supported by the fund of"Two-Hundred Talent"plan of Yantai Citythe National Natural Science Foundation of China(11974013)+1 种基金Natural Science Foundation of Fujian Province(2022J011270)the State Key Research Project of Shandong Natural Science Foundation(ZR2020KB019)。
文摘In this paper,we developed low dose X-ray induced long afterglow phosphor Ca_(2)P_(2)O_(7):Pr^(3+),which shows excellent afterglow luminescence from ultraviolet C(UVC)to red region.The photoluminescent results show that under 445.7 nm excitation,Ca_(1.995)P_(2)O_(7):0.5%Pr3+displays red emissions peaked at 598.3 and651.9 nm,corresponding to1D2-3H4and3P0-3F2transitions of Pr^(3+),respectively.Due to its pure red emission(CIE coordinates(0.59101,0.39926)),Ca_(1.995)P_(2)O_(7):0.5%Pr^(3+)can be regarded as a potential LED red phosphor.More importantly,Ca_(2)P_(2)O_(7):Pr^(3+)shows long afterglow luminescence from UVC to red region,which consists of four co ntinuous emissions with similar intensity including 260,359,466 and 598.3 nm.Since these afterglow continuous emissions are fitted to the absorption of most photodynamic therapy(PDT)agents,Ca_(2)P_(2)O_(7):Pr^(3+)can be regarded as excellent PDT agents.Furthermo re,30 s X-ray irradiation can induce 5400 s decay of Ca_(1.997)P_(2)O_(7):0.3%Pr^(3+),and its afterglow emission intensity still reaches 5×10^(4)cps after 5400 s decay.Even only 5 s X-ray irradiation also can produce 4.75×10^(4)cps afterglow emis sion after10 s decay.In addition,the repeat 980 nm laser irradiations can induce co ntinuous strong photo-stimulated(PSL)luminescent peaks,which can be utilized to conduct high efficiency PDT without another X-ray irradiation.The thermoluminesce nce results reveal that the existence of shallow(0.89 eV)and deep traps are responsible for the excellent X-ray induced long afterglow and PSL luminescence.All these results suggest that Ca_(2)P2O7:Pr^(3+)possesses great potential to be regarded as high efficiency PDT agents.
基金supported by the Latvian Council of Science,project"Defect engineering of novel UV-C persistent phosphor materials"(lzp-2021/1-0118)。
文摘For the last few decades,there has been extensive research on the materials that persist to emit optical radiation long after any type of charging has stopped.Most of the established persistent luminescence(PersL)materials emit light in the visible part of the spectrum;however,in recent years,there has been a growing interest in UV-emitting persistent phosphors in recent years.These materials have been tested for various applications,such as photocatalysis,sterilization,and anti-counterfeiting,among others.Here,we report on the X-ray and UV-activated UV-A long PersL of Ce^(3+)-doped Sr_(3)MgSi_(2)O_(8) material.We prepared samples with varied Ce^(3+)concentrations using solid-state reaction synthesis in an ambient atmosphere and conducted a thorough investigation using photoluminescence(PL),electron paramagnetic resonance(EPR),and thermally stimulated luminescence(TSL)spectroscopy methods.Our experiments show that the PersL signal of Ce^(3+)in the 300-450 nm range can be detected for at least 16 h when samples are irradiated with X-rays or UV.The TSL analysis reveals multiple discrete charge traps in the material with activation energies between 0.5 and 1.7 eV.Further EPR measurements confirm the presence of four paramagnetic centers.The thermal stability of these centers was analyzed,and it is established that one of these centers(g_(1)=2.0056,g_(2)=1.9981,and g_(3)=1.9926)gradually decays at room temperature,which is correlated with the PersL processes.
基金supported by the MINECO/FEDER through grant AyA2017-84089.7the science research grants from the China Manned Space Project with NO.CMSCSST-2021-A13CMS-CSST-2021-B11.W.H.Lei acknowledges support by the National Key R&D Program of China(No.2020YFC2201400)。
文摘Multiband afterglow observations of gamma-ray bursts(GRBs)are important for studying the central engine.GRB 201223A is a GRB with prompt optical detection by GWAC.Here we report on the early optical afterglow of GRB 201223A detected by NEXT(only 2.8 minutes after the Swift/BAT trigger),which smoothly connects the prompt optical emission and the afterglow phase.Utilizing Amati diagrams and considering the detection of afterglow emission in the Swift u-band,we suggest a redshift range of 0.26–1.85.Based on our optical data and combined with early optical observation from GWAC and early X-ray data from Swift/XRT,a multiband fitting is performed using PyFRS,and we obtain the best afterglow parameters(assuming a redshift of z=1.0):=5.01+10/_(1.70)^(1.91)×^(54)erg,G=-426.58+_(138.18)/^(148.86),θj=-25.98+_(-10.54)^/(9.67)deg,=-n0=0.30+_(-0.26)^(+3.78)cm^(−3),=-p2.32+_(-0.01)/^(+0.01),εe=-3.31+_(-0.86)/^(+1.59)×10^(-5),εB=-3.47+_(-2.62)/^(+4.12)×10^(-1).The late-time X-ray shows a re-brightening,indicating late-time central engine activities.After comparing the leading two central engine models,i.e.,magnetar model and hyperaccreting black hole model,we find that the fallback accretion onto a newborn black hole provides a better explanation for the X-ray re-brightening with fallback accretion rate Mp≈2.76×10^(-9)M⊙s^(-1)and the total fallback accreted mass Mfb≈1.41×10^(−6)M⊙.
基金Project supported by the State Key Research Project of Shandong Natural Science Foundation(ZR2020KB019)the fund of"Two-Hundred Talent"Plan of Yantai City+1 种基金the National Natural Science Foundation of China(11974013)the Natural Science Foundation of Fujian Province(2022J011270)。
文摘The low-dose X-ray induced long afterglow near infrared(NIR)luminescence from Cr^(3+)doped Zn_(1-x)Cd_(x)Ga_(2)O_(4)spinel solid solutions was investigated.The structure analysis shows the good formation of Zn_(1-x)Cd_(x)Ga_(2)O_(4)spinel solid solutions,which possesses a cubic spinel structure with Fd3m space group.The formation of Zn_(1-x)Cd_(x)Ga_(2)O_(4)spinel solid solutions induces the obvious increase of long afterglow near infrared luminescence excited by low-dose X-ray,When the content of doped Cd^(2+)reaches 0.1,the low-dose X-ray induced long afterglow NIR luminescence is the maximum.More importantly,only 5 s Xray irradiation can induce more than 6 h NIR afterglow emission,of which the afterglow luminescent intensity is still 5 times stronger than the background intensity after 6 h.The thermoluminescent results show that under the 5 s exposure of X-ray,the trap density of Zn_(0.9)Cd_(0.1)Ga_(2)O_(4):Cr^(3+)is much higher than that of ZnGa_(2)O_(4):Cr^(3+).The replacement of Cd^(2+)ions with large radius at Zn^(2+)sites causes the increase of de fects and dislocations,which results in the obvious increase of trap co ncentrations.And the addition of high-z number elements Cd^(2+)would enhance the X-ray absorption of the solid solutions,which thus can be easily excited by low-dose X-ray.Zn_(0.9)Cd_(0.1)Ga_(2)O_(4):1%Cr^(3+)solid solution is a potential candidate of lowdose X-ray induced long afterglow luminescent materials.
基金the National Key Research&Development Program of China(Nos.2020YFA0709900,2020YFA0210800)the National Natural Science Foundation of China(Nos.22027805,62134003,22104016)+1 种基金the Natural Science Foundation of Fujian Province(Nos.2022J01709,2023J01384)the Major Project of Science and Technology of Fujian Province(No.2020HZ06006)。
文摘The efficient production of high-quality scintillators with long radioluminescence afterglow is crucial for high-performance X-ray luminescence extension imaging.However,scaling-up the synthesis of ligand-free scintillators to fabricate large-area X-ray imaging screens for industrial applications remains a challenge.In this study,we report an efficient method to synthesize ligand-free,lanthanide-doped microscintillators by a one-pot reaction via the concentrated hydrothermal method.The as-synthesized microscintillators exhibit prolonged persistent radioluminescence for up to 30 days after X-ray exposure and remain high stability in air or water for more than 18 months without deterioration.Monte Carlo simulations indicate that the size effect is responsible for the excellent afterglow performance of the microscintillators.We employ these high-quality lanthanide-doped microscintillators to fabricate a large-area X-ray imaging detector using a blade-coating method,a spatial resolution of 24.9 lp/mm for X-ray imaging.Our study offers a solution for scaling-up the synthesis of low-cost microscintillators for practical applications.
基金financially supported by the Shandong Provincial Natural Science Foundation(Nos.ZR2019YQ19 and ZR2019BEM018)the Project of Shandong Province Higher Educational Science and Technology Program(No.2019KJA026)the National Natural Science Foundation of China(Nos.51403113 and 52072193)。
文摘Organic color-tunable phosphorescent materials depend upon multiple emission centers to achieve colortunable phosphorescence with changes in excitation wavelength,temperature,time,and other external factors.Organic color-tunable phosphorescent materials are becoming increasingly popular due to their potential applications in anticounterfeiting,encryption and sensing.This brief review focuses on the formation of multiple emission centers in organic color-tunable phosphorescent materials and how to ensure that these multiple emission centers can simultaneously emit.In the future,materials with a large color tunable ranges,increased efficiency,and relatively long lives will be developed.
基金Project supported by the National Natural Science Foundation of China (20476002)
文摘The non-grinding long afterglow material SrAl2O4：Eu^2＋ , Dy^3＋ was prepared by combustion method in home mierowave oven direetly, after dispersant, frother, eomburent, and mineralizer were added into the reacting system. XRD analysis showed that the powders were nearly pure SrAl2O4 phase with few other phases, and the size of the grain was 41.1 nm. Fluoreseenee speetrum results indieated that there were 2 exeitation peaks loeated at 345 and 400 nm, and the emission peak loeated at 516 nm, afterglow lasted up to 30 min or more. The mierowave eombustion method has advantages of less time, low temperature and no grinding process, and the material made by the method has good luminescent property.
基金the National Natural Science Foundation of China (52003284,51872300 and U1832110)the China Postdoctoral Science Foundation (BX20190338)S&T Innovation 2025 Major Special Program of Ningbo (2018B10054) for financially supporting this work。
文摘Near-infrared(NIR),particularly NIR-containing dual-/multimode afterglow,is very attractive in many fields of application,but it is still a great challenge to achieve such property of materials. Herein,we report a facile method to prepare green and NIR dual-mode afterglow of carbon dots(CDs) through in situ embedding o-CDs(being prepared from o-phenylenediamine) into cyanuric acid(CA) matrix(named o-CDs@CA). Further studies reveal that the green and NIR afterglows of o-CDs@CA originate from thermal activated delayed fluorescence(TADF) and room temperature phosphorescence(RTP) of o-CDs,respectively. In addition,the formation of covalent bonds between o-CDs and CA,and the presence of multiple fixation and rigid e ects to the triplet states of o-CDs are confirmed to be critical for activating the observed dual-mode afterglow. Due to the shorter lifetime and insensitiveness to human vision of the NIR RTP of o-CDs@CA,it is completely covered by the green TADF during directly observing. The NIR RTP signal,however,can be readily captured if an optical filter(cut-o wavelength of 600 nm) being used. By utilizing these unique features,the applications of o-CDs@CA in anti-counterfeiting and information encryption have been demonstrated with great confidentiality. Finally,the as-developed method was confirmed to be applicable to many other kinds of CDs for achieving or enhancing their afterglow performances.
基金supported by the National Natural Science Foundation of China (10774012 and 10434030)Beijing Jiaotong University Program (2007XM048, 2006XM038)
文摘Nanosized long-persistent phosphors SrS：Eu^2＋, Dy^3＋ were prepared by the hydrothermal method.The samples were characterized by X-ray powder diffraction, transmission electron microscopy, and charge-coupled device spectrometry.The persistence characteristic was studied using the decay curves.The results showed that the emission intensity decreased sharply with temperature increasing, although the particle size increased.The S2-vacancies caused by oxidization served as shallow traps, and Dy3＋ served as deep traps in SrS：Eu^2＋, Dy^3＋.The afterglow intensity of SrS：Eu^2＋, Dy^3＋ was higher than that of SrS：Eu2＋ prepared at the same temperature.However, the minimization span of initial afterglow with temperature for the former sample was larger than that for the latter.Binary-doped phosphor decayed more slowly than the singly doped one.The afterglow of SrS：Eu^2＋, Dy^3＋ decayed more quickly with the increase of sintering temperature.
基金supported by National Natural Science Foundation of China(21171074)Fundamental Research Funds for the Central Universities of China(JUSRP21003)the National Undergraduate Training Programs for Innovation(201310295046)
文摘The luminous polypropylene fiber based on long afterglow luminescent material Sr2MgSi2O7：Eu^2＋,Dy^3＋was prepared by melt-spinning process. Micro-morphology, phase composition, crystal structure, spectral features and afterglow properties of the lu-minescent fiber were tested and analyzed. The results indicated that the fiber had independent superposition phase features of both Sr2MgSi2O7：Eu2＋,Dy3＋and polypropylene. The range of its excitation wavelength was located between 250-450 nm;therefore, the luminescent fiber could be excited by ultraviolet or visible light. It could emit blue light of 460 nm wavelength after excitation, which was caused by the 5d-4f transition of Eu^2＋ions within the host lattice. The initial luminescent intensity was more than 0.8 cd/m^2, and afterglow life lasted 7 h. The afterglow decay was composed of rapid-decaying and slow-decaying processes, and the decay charac-teristics depended on the depth and concentration of trap level in the Sr2MgSi2O7：Eu^2＋,Dy^3＋.
文摘Calcium titanate doped with praseodymium was prepared through solid state reaction and it exhibited intense red emission at 612 nm. Phosphors were characterized for photoluminescence, thermo-luminescence and afterglow emissions. Study of effects of rare earths on photoluminescence as well as afterglow intensity was reported. Presence of gadolinium enhanced luminescence. Presence of some monovalent ions enhanced both afterglow and photoluminescence emission. Thermo-luminescence glow curves were analyzed and ...
基金the National Natu-ral Science Foundation of China (No. 50204002)the National High-Tech Research and Development Program of China (No. 2001AA324080)
文摘The long afterglow phosphor CaAl2O4： Eu^2＋, Nd^3＋ was prepared by the high temperature solid-state reaction method, and the influence of La^3＋ and Dy^3＋ on the properties of the long afterglow phosphor was studied by X-ray diffiaction （XRD）, photoluminescence （PL）, and thermoluminescence （TL）. The XRD pattem shows the host phase of CaAl2O4 is produced and no impurity phase appears. The peak wavelength of the phosphor does not vary with La^3＋ and Dy^3＋ doping. It implies that the crystal field, which affects the 5d electron states of Eu^2＋, is not changed dramatically after doping of La^3＋ and Dy^3＋. The TL spectra indicate that the phosphor doped with La^3＋ or Dy^3＋ produces different depths of trap energy level. In the mechanism of long afterglow luminescence, it is considered that La^3＋ or Dy^3＋ works as trap energy level. The decay time lies on the number of electrons in the trap energy level and the rate of the electrons returning to the excitation level.
基金Project supported by National Natural Science Foundation of China(21171074/B010201)
文摘With stable physical properties, the rare-earth silicate phosphor of MgSiO3：Mn2＋,Nd3＋ is one of the suitable luminescent materials used in preparing functional fibers. In order to promote the afterglow properties of red-emitting phosphors, we prepared it by means of solid-state reaction, and the effect of manufacturing elements including H3BO3 and environmental factor of calcining temperature, type of flux on its luminescence property were investigated through evaluating their afterglow properties. The results showed that with the concentration of Nd3＋ increasing, the amounts of H3BO3 doping and calcining temperature, the afterglow time and initial brightness of the rare-earth silicate phosphor increased and then decreased gradually. The afterglow properties of different flux concentration were different from one to another as： H3BO3〉Na＋〉K＋〉No flux.
基金supported by the National Natural Science Foundation of China (60477034)
文摘Blue-green luminescent BaAl2O4：Eu2＋,Dy3＋ phosphor powders were synthesized via combustion synthesis method assisted by microwave irradiation in air. The phosphors were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and fluorescence spectrophotometer. The XRD results revealed that when the concentration of urea was over 3 times higher than theoretical quantities, a BaAl2O4 single hexagonal phase was obtained. The SEM results revealed that the surface of the BaAl2O4：Eu2＋,Dy3＋ powder samples showed lots of voids and pores. The BaAl2O4：Eu2＋,Dy3＋ phosphors exhibited a broad emission band of main peak at 496 nm and a shoulder peak at 426 nm under excitation of 337 nm. The BaAl2O4：Eu2＋,Dy3＋ phosphors at the Eu2＋ concentration of 1 mol.% showed the strongest luminescent intensity. Long afterglow phosphorescence was observed in the dark with naked eyes after the removal of the excitation source.
文摘Long afterglow photoluminescent materials Sr2MgSi2O7 doped with Eu2+, Dy3+ were prepared by sol-gel method. The synthesized samples were characterized by X-ray diffraction. The excitation spectrum, emission spectrum and long decay curve were measured and analyzed. XRD pattern indicates that phosphor is with Sr2MgSi2O7 crystal structure. The wide range of excitation wavelength indicates that luminescent material can be excited by light from ultraviolet ray to visible light. The main peak of emission spectrum is located at 466 nm. Sample excited by visible light can emit bright blue light, and the afterglow time lasts more than 8 h.
基金supported by the National Natural Science Foundation of China(11574225,11874275)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)(61564007).
文摘Long persistent phosphors have received significant attention owing to their attractive photophysical properties.Here,we report a new long persistent phosphor exhibiting strong ultraviolet A(UVA)afterglow.The phosphors were synthesized by a solid-state reaction method.We find that the obtained phosphors demonstrate super long UVA-afterglow emissions after irradiation by X-ray source,and the afterglow can last more than 50 h.A wide range of experimental characterizations indicate that the Tb^3+doped fluoride elpasolite phosphors are defective and some fluoride ions are replaced by oxygen ions,which creates electron traps with suitable trap depths.Our results establish that Tb^3+can act as optical emitters in wide-bandgap hosts that can result in the UVA afterglow.This work enriches the bank of UV long persistent phosphors,and may stimulate more efforts for the design and synthesis of this kind of optical materials.
