The enhancement of the intensity of red upconversion(UC)emission has significant implications for biological applications.In KZnF_(3):Yb^(3+),Er^(3+)which inherently produces high-purity red emission,the introduction ...The enhancement of the intensity of red upconversion(UC)emission has significant implications for biological applications.In KZnF_(3):Yb^(3+),Er^(3+)which inherently produces high-purity red emission,the introduction of Fe^(3+)markedly improves the UC intensity by a factor of 13.The mechanism behind the enhanced UC red luminescence is deduced to originate from the Yb^(3+)-Fe^(3+)dimer,as determined by first principle calculation and analysis of UC luminescence properties.The thermometry performance,based on splitting peaks of red emission,demonstrated enhanced temperature sensitivity at lower ranges.Exploring the photothermal properties,it was observed that temperature exhibited a linear correlation with pump power under a 980 nm laser,achieving levels up to 48℃.This temperature range is ideal for applications in mild photothermal therapy(MPTT).This work elucidates the material’s potential in advanced biological applications,merging optical thermometry and photothermics,indicating its multifunctional utility.展开更多
4-Nonylphenol(NP)is a kind of estrogen belonging to the endocrine disrupter,widely used in various agricultural and industrial goods.However,extensive use of NP with direct release to environment poses high risks to b...4-Nonylphenol(NP)is a kind of estrogen belonging to the endocrine disrupter,widely used in various agricultural and industrial goods.However,extensive use of NP with direct release to environment poses high risks to both human health and ecosystems.Herein,for the first time,we developed near-infrared(NIR)responsive upconversion luminescence nanosensor for NP detection.The Förster resonance energy transfer based upconversion nanoparticles(UCNPs)-graphene oxide sensor offers highly selective and sensitive detection of NP in linear ranges of 5−200 ng/mL and 200−1000 ng/mL under 980 nm and 808 nm excitation,respectively,with LOD at 4.2 ng/mL.The sensors were successfully tested for NP detection in real liquid milk samples with excellent recovery results.The rare-earth fluoride based upconversion luminescence nanosensor with NIR excitation wavelength,holds promise for sensing food,environmental,and biological samples due to their high sensitivity,specific recognition,low LOD,negligible autofluorescence,along with the deep penetration of NIR excitation sources.展开更多
Very recently,upconversion luminescence(UCL)lifetime,as a powerful optical dimension,has attracted tremendous research interest due to its advantages of high information capacity and high photophysical stability.With ...Very recently,upconversion luminescence(UCL)lifetime,as a powerful optical dimension,has attracted tremendous research interest due to its advantages of high information capacity and high photophysical stability.With the implementation and emergence of endlessly fascinating UCL features,it is particularly meaningful to understand the photophysical mechanisms inside UCL materials to enable rational subdivision-level structure design,which is however currently far from sufficient.In this work,we take an ordinary upconversion nanoparticle as an example to prove that the UCL decay curves and corresponding lifetimes are indeed a collective response of the entire UCL system to excitations,that exhibits correlated,yet quite different properties from individual ions.A specially developed theoretical random walk model combined with an experimental lifetime control for Yb^(3+)/Er^(3+)UCL demonstrates that ene rgy diffusion principally alters the decay rate.Moreover,the different extent of the influence of energy diffusion on the emissions of ^(2)H_(11/2)/^(4)S_(3/2)(green)and ^(4)F_(9/2)(red)leads to an extremely uncommon crossover comparison of decay rates.This work provides new ideas for understanding decay dynamics and practical UCL lifetime manipulation methods.展开更多
Ultraviolet upconversion photoluminescence materials have great potential in various fields,but the improvement of the upconversion efficiency is challenging.Codoping of Li^(+)is considered as an effective strategy an...Ultraviolet upconversion photoluminescence materials have great potential in various fields,but the improvement of the upconversion efficiency is challenging.Codoping of Li^(+)is considered as an effective strategy and widely used to improve the photoluminescence properties of phosphors.In this paper,Li^(+)is introduced into a Y_(7)O_(6)F_(9):Pr^(3+),Gd^(3+)system.The effect of Li^(+)codoping on the phase purity,crystal structure,micro structure,downshifting and upconversion photo luminescence as well as the decay dynamic of the phosphors was studied.It is revealed that the overall photoluminescence efficiency and the energy transfer efficiency from pr^(3+)to Gd^(3+)are greatly promoted.The downshifting and upconversion photoluminescence increase by 2.58 and 10 times as 6 mol%of Li^(+)is codoped.The photo luminescence decay dynamic study shows that the ^(3)P_(0)state decays slower in the Li^(+)-containing phosphor than the Li^(+)-free one.The improvement of the photoluminescence properties is due to the increase of the crystallinity and the reduce of the quenching center.展开更多
Zinc phthalocyanines(ZnPc)are widely recognized as efficient triplet photosensitizers in photodynamic therapy and photocatalysis,owing to their intense absorption in the visible range and long triplet-state lifetimes....Zinc phthalocyanines(ZnPc)are widely recognized as efficient triplet photosensitizers in photodynamic therapy and photocatalysis,owing to their intense absorption in the visible range and long triplet-state lifetimes.However,their application in triplet-triplet annihilation(TTA)upconversion is lacking to date.In this study,we synthesized a new ZnPc photosensitizer,4I-ZnPc,and composed a TTA upconversion system using rubrene as the energy acceptor.Upon photoexcitation at 663 nm,yellow fluorescence from rubrene was observed in deoxygenated dichloromethane,demonstrating TTA upconversion with an anti-Stokes shift of 0.331 eV and a quantum yield of 1.82%(out of the 50%maximum).Using nanosecond transient absorption spectroscopy,we determined the triplet lifetime of 4I-ZnPc,the triplet-triplet energy transfer efficiency,and the fluorescence quantum yield.These measurements provide critical insights into the photophysical processes governing the TTA upconversion system.Our results highlight the potential advantages and limitations of ZnPc as a triplet photosensitizer for TTA upconversion.展开更多
Lanthanide-sensitized upconverting nanoparticles(UCNPs)are widely studied because of their unusual optical characteristics,such as large antenna-generated anti-Stokes shifts,high photostability,and narrow emission ban...Lanthanide-sensitized upconverting nanoparticles(UCNPs)are widely studied because of their unusual optical characteristics,such as large antenna-generated anti-Stokes shifts,high photostability,and narrow emission bandwidths,which can be harnessed for a variety of applications including bioimaging,sensing,information security and high-level anticounterfeiting.The diverse requirements of these applications typically require precise control over upconversion luminescence(UCL).Recently,the concept of energy migration upconversion has emerged as an effective approach to modulate UCL for various lanthanide ions.Moreover,it provides valuable insights into the fundamental comprehension of energy transfer mechanisms on the nanoscale,thereby contributing to the design of efficient lanthanide-sensitized UCNPs and their practical applications.Here we present a comprehensive overview of the latest developments in energy migration upconversion in lanthanide-sensitized nanoparticles for photon upconversion tuning,encompassing design strategies,mechanistic investigations and applications.Additionally,some future prospects in the field of energy migration upconversion are also discussed.展开更多
In this work,rare earth ions(REs)including Yb^(3+)/Er^(3+),Yb^(3+)/Ho^(3+)and Yb^(3+)/Tm^(3+)co-doped manganese oxyfluoride glasses were fabricated using melt quenching method.By fully utilizing the upconversion lumin...In this work,rare earth ions(REs)including Yb^(3+)/Er^(3+),Yb^(3+)/Ho^(3+)and Yb^(3+)/Tm^(3+)co-doped manganese oxyfluoride glasses were fabricated using melt quenching method.By fully utilizing the upconversion luminescence(UCL)of REs and regulating energy transfer between the different energy levels of RE ions and the4T1level of Mn^(2+),the output of UCL was regulated and even pure-red light can be achieved.Moreover,owing to the selective partitioning caused by phase-separation network structure in the oxyfluoride glass,the UCL intensity of glasses annealed for 72 h is significantly enhanced 58 times compared to the rapidly quenched samples.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
Lutetium oxide nanocrystals codoped with Tm3＋ and Yb3＋ were synthesized by the reverse-like co-precipitation method, using ammonium hydrogen carbonate as precipitant. Effects of the Tm3＋, Yb3＋ molar fractions and ...Lutetium oxide nanocrystals codoped with Tm3＋ and Yb3＋ were synthesized by the reverse-like co-precipitation method, using ammonium hydrogen carbonate as precipitant. Effects of the Tm3＋, Yb3＋ molar fractions and calcination temperature on the structural and upconversion luminescent properties of the Lu2O3 nanocrystals were investigated. The XRD results show that all the prepared nanocrystals can be readily indexed to pure cubic phase of Lu2O3 and indicate good crystallinity. The experimental results show that concentration quenching occurs when the mole fraction of Tm3＋ is above 0.2%. The optimal Tm3＋ and Yb3＋ doped molar fractions are 0.2% and 2%, respectively. The strong blue （490 nm） and the weak red （653 nm） emissions from the prepared nanocrystals were observed under 980 nm laser excitation, and attributed to the 1G4→3H6 and IG4→3F4 transitions of Tm3＋, respectively. Power-dependent study reveals that the 1G4 levels of Tm3＋ can be populated by three-step energy transfer process. The upconversion emission intensities of 490 nm and 653 nm increase gradually with the increase of calcination temperature. The enhancement of the upconversion luminescence is suggested to be the consequence of reducing number of OH- groups and the enlarged nanoerystal size.展开更多
Erbium-doped BaTiO3 films on LaNiO3/Si substrates were fabricated by sol-gel method. The crystalline structure, morphologies and upconversion （UC） luminescence properties of films were respectively investigated by X...Erbium-doped BaTiO3 films on LaNiO3/Si substrates were fabricated by sol-gel method. The crystalline structure, morphologies and upconversion （UC） luminescence properties of films were respectively investigated by X-ray diffraction （XRD）, atomic force microcopy （AFM） and photoluminescence （PL）. The results indicate that both of the microstructure and luminescence are found to be dependent on Er^3＋ substituting sites. The samples with A-site substitution have smaller lattice constants, larger grains and smoother surface than those with B-site substitution. The photoluminescence spectra show that both of the samples have two stronger green emission bands centered at 528 and 548 nm and a weak red emission band centered at 673 nm, which correspond to the relaxation of Er^3＋ from ^2H11/2, ^4S3/2, and ^4F9/2 levels to the ground level ^4I15/2, respectively. Compared with B-site doped films, A-site doped films have a stronger integrated intensity of green emissions and a weaker relative intensity of red emissions. The differences could be explained by the crystalline quality and cross relaxation （CR） process.展开更多
Rare earth doped upconversion nanoparticles can be considered as the spice of research in the field of luminescence nanomaterials due to their unique optical properties such as near-infrared excitation.Enormous works ...Rare earth doped upconversion nanoparticles can be considered as the spice of research in the field of luminescence nanomaterials due to their unique optical properties such as near-infrared excitation.Enormous works have been reported about biomedical applications of 980 nm excited and Yb^3+-sensitized upconversion nanoparticles.However,980 nm excitation wavelength overlaps with the absorption band of water molecules in the biological environment,leading to overheating effect that can induce thermal damages of normal cells and tissues.Recently,Nd^3+-sensitized upconversion nanoparticles which can be excited with 808 nm has been widely investigated as alternative nanoparticles that can surmount this issue of overheating effect.Even though Nd^3+-sensitized upconversion nanoparticles can reduce the overheating effect by 20 fold as compared to Yb^3+-sensitized counterpart,there are several factors that reduce the upconversion luminescence intensity.In this review article,photon energy harvesting and transferring mechanisms in Nd^3+,Yb^3+and emitter ions co-doped upconversion nanoparticles under 808 nm excitation are briefly discussed.Factors that affect upconversion luminescence intensity and quantum yield of Nd^3+-sensitized upconversion nanoparticles are also addressed.Besides,some of the important strategies that have been recently utilized to boost upconversion luminescence intensity of Nd^3+sensitized upco nversion nanoparticles are tho roughly summarized.Lastly,the future challenges in the area and our perspectives are in sight.展开更多
Investigation on the bright and stable upconversion(UC)phosphors with multicolor emissions is fundamental and significant for the frontier applications of display and tempe rature probe.He re,dive rse emitting colors ...Investigation on the bright and stable upconversion(UC)phosphors with multicolor emissions is fundamental and significant for the frontier applications of display and tempe rature probe.He re,dive rse emitting colors with blue,cyan and yellowish green,which are caused by the energy transfer and crossrelaxation processes,are obtained by altering Er^3+,Tm^3+and Yb^3+concentrations in Er3+singly,Er^3+-Tm^3+-Yb^3+co-and tri-doped double perovskite La2ZnTiO6(LZT)phosphors synthesized by a simple solid-state reaction.In addition,excellent infrared emission at 801 nm located at"first biological windo w"is collected in Tm^3+-Yb^3+co-doped phosphors.Meanwhile,the temperature sensing properties based on the thermally coupled levels((^2H11/2)/(^4S3/2))of Er3+ions were analyzed from 298 to 573 K of LZT:0.15 Er^3+/0.10 Yb^3+phosphor,demonstrating that the maximal sensitivity value is about56×10^-4 K^-1 at 448 K.All these results imply that this kind of UC material has potential applications in display,bioimaging and optical device.展开更多
A new upconversion luminescence agent, 40CdF2·60BaF2·0.8ErO3, was synthesized and its fluorescent spectra were determined. This upconversion luminescence agent can emit five upconversion fluorescent peaks sh...A new upconversion luminescence agent, 40CdF2·60BaF2·0.8ErO3, was synthesized and its fluorescent spectra were determined. This upconversion luminescence agent can emit five upconversion fluorescent peaks shown in the fluorescent spectra whose wavelengths are all below 387 nm under the excitation of 488 nm visible light. This upconversion luminescence agent was mixed into nano rutile TiO2 powder by ultrasonic and boiling dispersion and the novel doped nano TiO2 photocatalyst utilizing visible light was firstly prepared. The doped TiO2 powder was charactered by XRD and TEM and its photocatalytic activity was tested through the photocatalytic degradation of methyl orange as a model compound under the visible light irradiation emitted by six three basic color lamps. In order to compare the photocatalytic activities, the same experiment was carried out for undoped TiO2 powder. The degradation ratio of methyl orange in the presence of doped nano TiO2 powder reached 32.5% under visible light irradiation at 20 h which was obviously higher than the corresponding 1.64% in the presence of undoped nano TiO2 powder, which indicate the upconversion luminescence agent prepared as dopant can effectively turn visible lights to ultraviolet lights that are absorbed by nano TiO2 particles to produce the electron-cavity pairs. All the results show that the nano rutile TiO2 powder doped with upconversion luminescence agent is a promising photocatalyst using sunlight for treating the industry dye wastewater in great force.展开更多
Nanocrystal of upconversion （UC） phosphor Ho^3＋, Tm^3＋ , and Yb^3＋ co-doped NaYF4 was prepared by the hydrothermal method in the presence of the complexing agent EDTA. Under 980 nm diode laser excitation, the imp...Nanocrystal of upconversion （UC） phosphor Ho^3＋, Tm^3＋ , and Yb^3＋ co-doped NaYF4 was prepared by the hydrothermal method in the presence of the complexing agent EDTA. Under 980 nm diode laser excitation, the impact of different concentrations of Ho^3＋ ion on the UC luminescence intensity was discussed. The law of luminescence intensity versus pump power shows that the 474 nm blue emission, 538 nm green emission, and 642 nm red emission are all due to the two-photon process, while the 450 nm blue emission is a three-photon process. The UC mechanism and processes were also analyzed. The sample was characterized by transmission electron microscopy （TEM） and X-ray diffraction （XRD）. The result shows that Ho^3＋ ,Tm^3＋ , and Yb^3＋ co-doped NaYF4 prepared by the hydrothermal method exhibits a hexagonal nanocrystal.展开更多
Novel PEI-modified NaBiF4:Yb3+/Er3+upconversion nanoparticles(UCNPs)with hollow structure were prepared by a surface modification free one-step solvothermal method and applied as a luminescent probe to determinate wat...Novel PEI-modified NaBiF4:Yb3+/Er3+upconversion nanoparticles(UCNPs)with hollow structure were prepared by a surface modification free one-step solvothermal method and applied as a luminescent probe to determinate water content in organic solvents.XRD,SEM and HRTEM results demonstrate that the obtained PEI-NaBiF4:Yb3+/Er3+UCNPs are pure hexagonal phase with uniform size.The successful modification of PEI on the UCNPs surface was evidenced byζ-potential test,XPS and TG analysis.These synthesized UCNPs are disintegrated into smaller nanoparticles in the presence of water and thus result in a surface quenching effect,which show the features of 0-100%wide range water response in various organic solvents.The sensing performance towards real samples was validated by the water content determination in beer,rum and white spirit.Furthermore,the luminescence intensity variation of the PEI-modified NaBiF4:Yb3+/Er3+enable the test visualization and ease of portability.展开更多
Er^3＋/yb^3＋ codoped zincate BaGd2ZnO5 phosphors were synthesized via a traditional solid state reaction. The crystal structure and phase purity were checked by means of X-ray dfluence of Eiffraction （XRD）, and the...Er^3＋/yb^3＋ codoped zincate BaGd2ZnO5 phosphors were synthesized via a traditional solid state reaction. The crystal structure and phase purity were checked by means of X-ray dfluence of Eiffraction （XRD）, and the results showed that pure phase BaGd2ZnO5 phosphors with various Er^3＋/yb^3＋ concentrations were obtained. The Er^3＋ and Yb^3＋ doping concentrations on the green and red upconversion emissions was studied. It was found that both green and red upconversion emissions under 980 nm excitation were two-photon processes independent from the rare earth doping concentrations. However, the upconversion luminescence intensities greatly depended on the rare earth doping concentration. Furthermore, the population processes of upconversion luminescence and the quenching mechanisms were analyzed. The temperature-dependent green upconvcrsion luminescence was studied, and the temperature quenching process of two green upconversion emissions was modeled. The thermal quenching processes of the green upconversion emissions could be well explained by the model we proposed.展开更多
Y2O3： Er^3＋, Yb^3＋ nanoparticles were synthesized by a homogeneous precipitation method without and with different concentrations of EDTA 2Na. Upconversion luminescence spectra of the samples were studied under 980...Y2O3： Er^3＋, Yb^3＋ nanoparticles were synthesized by a homogeneous precipitation method without and with different concentrations of EDTA 2Na. Upconversion luminescence spectra of the samples were studied under 980 nm laser excitation. The results of XRD showed that the obtained Y2O3：Er^3＋,Yb^3＋ nanoparticles were of a cubic structure. The average crystallite sizes calculated were in the range of 28-40 nm. Green and red upconversion emission were observed, and attributed to ^2H11/2,^4S3/2→^4I15/2 and ^4F9/2→^4I15/2 transitions of the ion, respectively. The ratio of the intensity of green emission to that of red emission drastically changed with a change in the EDTA 2Na concentration. In the sample synthesized without EDTA, the relative intensity of the green emission was weaker than that of the red emission. The relative intensities of green emission increased with the increased amount of EDTA 2Na used. The possible upconversion luminescence mechanisms were discussed.展开更多
Upconversion nanoparticles(UCNPs)doped with lanthanides can convert near-infrared excitation into UV and visible emissions.Because of their relatively high emission efficiency,UCNPs are appealing materials for use in ...Upconversion nanoparticles(UCNPs)doped with lanthanides can convert near-infrared excitation into UV and visible emissions.Because of their relatively high emission efficiency,UCNPs are appealing materials for use in a variety of sectors.UCNPs are known for low auto-fluorescence,excellent chemical and thermal photo-stability,deep tissue penetration,exceptional biocompatibility,low toxicity,color purity,and ease of surface functionalization.In this review,we explain a few recent strategies to boost the efficiency and luminescence of upconversion nanoparticles and minimize quenching by fabricating them as core/shell,nanofibers,or heavily doped lanthanides.Applications of UCNPs in drug delivery,Photodynamic therapy(PDT),biosensors,bioimaging,and optogenetics are also discussed along with their mechanism of action.Our motivation for this review is to understand the working mechanism of UCNPs and their applications in various fields.展开更多
Photon upconversion has received substantial attention owing to its great promise in broad applications from bioimaging to other frontier fields like display,upconversion laser,information security and anticounterfeit...Photon upconversion has received substantial attention owing to its great promise in broad applications from bioimaging to other frontier fields like display,upconversion laser,information security and anticounterfeiting.A smart control and manipulation of the upconversion luminescence has always been a key topic,however,to date the most efficient mechanism for upconversion nanoparticles remains the energy transfer upconversion and recently reported energy migration mediated upconversion.Recently,we found that the interfacial energy transfer(IET)is also an efficient approach for enabling and tuning photon upconversion of lanthanide ions.Moreover,it can be used for the mechanistic understanding of the interionic interactions such as energy transfer and energy migration on the nanoscale.In this review,the recent advances of the research on the IET are summarized,the principles for designing IET process and typical examples are discussed together with its applications in both mechanistic research and frontier information security.The challenges and perspectives for future research are also commented.展开更多
The effect of glass network modifier R2O （R=Li, Na, K） on upconversion luminescence in Er3＋/yb3＋ co-doped NaYF4 oxyfluoride glass-ceramics was investigated. NaYF4 nanocrystals with different sizes were studied und...The effect of glass network modifier R2O （R=Li, Na, K） on upconversion luminescence in Er3＋/yb3＋ co-doped NaYF4 oxyfluoride glass-ceramics was investigated. NaYF4 nanocrystals with different sizes were studied under glass network modifier alkali mental oxide. The nanocrystals size in NaYF4 of Li2O modified samples was 11 nm, whereas in the Na20 and K2O modified sample, the crystal size was 25 and 43 nm, respectively. It was found that red, yellow and green upconversions were observed in SAL, SAN, SAK glass ceramics. The reported results would deepen the understanding of size effects on the lanthanide upcon- version in nanocrystals.展开更多
基金supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),"Qinglan Project"Young and Middle-aged Academic Leaders Program of Jiangsu Province,and the National Natural Science Foundation of China(General Program).
文摘The enhancement of the intensity of red upconversion(UC)emission has significant implications for biological applications.In KZnF_(3):Yb^(3+),Er^(3+)which inherently produces high-purity red emission,the introduction of Fe^(3+)markedly improves the UC intensity by a factor of 13.The mechanism behind the enhanced UC red luminescence is deduced to originate from the Yb^(3+)-Fe^(3+)dimer,as determined by first principle calculation and analysis of UC luminescence properties.The thermometry performance,based on splitting peaks of red emission,demonstrated enhanced temperature sensitivity at lower ranges.Exploring the photothermal properties,it was observed that temperature exhibited a linear correlation with pump power under a 980 nm laser,achieving levels up to 48℃.This temperature range is ideal for applications in mild photothermal therapy(MPTT).This work elucidates the material’s potential in advanced biological applications,merging optical thermometry and photothermics,indicating its multifunctional utility.
文摘4-Nonylphenol(NP)is a kind of estrogen belonging to the endocrine disrupter,widely used in various agricultural and industrial goods.However,extensive use of NP with direct release to environment poses high risks to both human health and ecosystems.Herein,for the first time,we developed near-infrared(NIR)responsive upconversion luminescence nanosensor for NP detection.The Förster resonance energy transfer based upconversion nanoparticles(UCNPs)-graphene oxide sensor offers highly selective and sensitive detection of NP in linear ranges of 5−200 ng/mL and 200−1000 ng/mL under 980 nm and 808 nm excitation,respectively,with LOD at 4.2 ng/mL.The sensors were successfully tested for NP detection in real liquid milk samples with excellent recovery results.The rare-earth fluoride based upconversion luminescence nanosensor with NIR excitation wavelength,holds promise for sensing food,environmental,and biological samples due to their high sensitivity,specific recognition,low LOD,negligible autofluorescence,along with the deep penetration of NIR excitation sources.
基金Project supported by the National Natural Science Foundation of China(62105235,62205035)the Scientific Research Project of Tianjin Education Commission(2022KJ060)+1 种基金Qinglan Project of Jiangsu Province of ChinaNatural Science Foundation of the Jiangsu Higher Education Institutions of China(22KJD350001)。
文摘Very recently,upconversion luminescence(UCL)lifetime,as a powerful optical dimension,has attracted tremendous research interest due to its advantages of high information capacity and high photophysical stability.With the implementation and emergence of endlessly fascinating UCL features,it is particularly meaningful to understand the photophysical mechanisms inside UCL materials to enable rational subdivision-level structure design,which is however currently far from sufficient.In this work,we take an ordinary upconversion nanoparticle as an example to prove that the UCL decay curves and corresponding lifetimes are indeed a collective response of the entire UCL system to excitations,that exhibits correlated,yet quite different properties from individual ions.A specially developed theoretical random walk model combined with an experimental lifetime control for Yb^(3+)/Er^(3+)UCL demonstrates that ene rgy diffusion principally alters the decay rate.Moreover,the different extent of the influence of energy diffusion on the emissions of ^(2)H_(11/2)/^(4)S_(3/2)(green)and ^(4)F_(9/2)(red)leads to an extremely uncommon crossover comparison of decay rates.This work provides new ideas for understanding decay dynamics and practical UCL lifetime manipulation methods.
基金supported by the National Natural Science Foundation of China(51701091,12004148,12104199,12204216)the Natural Science Foundation of Shandong Province(ZR2021QA057)+1 种基金the Shandong Province Science and Technology Small and Medium Sized Enterprise Innovation Ability Enhancement Project(2023TSGC0352)the Innovation Team of Higher Educational Science and Technology Program of Shandong Province(2019KJA025)。
文摘Ultraviolet upconversion photoluminescence materials have great potential in various fields,but the improvement of the upconversion efficiency is challenging.Codoping of Li^(+)is considered as an effective strategy and widely used to improve the photoluminescence properties of phosphors.In this paper,Li^(+)is introduced into a Y_(7)O_(6)F_(9):Pr^(3+),Gd^(3+)system.The effect of Li^(+)codoping on the phase purity,crystal structure,micro structure,downshifting and upconversion photo luminescence as well as the decay dynamic of the phosphors was studied.It is revealed that the overall photoluminescence efficiency and the energy transfer efficiency from pr^(3+)to Gd^(3+)are greatly promoted.The downshifting and upconversion photoluminescence increase by 2.58 and 10 times as 6 mol%of Li^(+)is codoped.The photo luminescence decay dynamic study shows that the ^(3)P_(0)state decays slower in the Li^(+)-containing phosphor than the Li^(+)-free one.The improvement of the photoluminescence properties is due to the increase of the crystallinity and the reduce of the quenching center.
基金supported by the National Natural Science Foundation of China(Nos.22473104 and 22403086)support of the China Postdoctoral Science Foundation(No.2023M733378).
文摘Zinc phthalocyanines(ZnPc)are widely recognized as efficient triplet photosensitizers in photodynamic therapy and photocatalysis,owing to their intense absorption in the visible range and long triplet-state lifetimes.However,their application in triplet-triplet annihilation(TTA)upconversion is lacking to date.In this study,we synthesized a new ZnPc photosensitizer,4I-ZnPc,and composed a TTA upconversion system using rubrene as the energy acceptor.Upon photoexcitation at 663 nm,yellow fluorescence from rubrene was observed in deoxygenated dichloromethane,demonstrating TTA upconversion with an anti-Stokes shift of 0.331 eV and a quantum yield of 1.82%(out of the 50%maximum).Using nanosecond transient absorption spectroscopy,we determined the triplet lifetime of 4I-ZnPc,the triplet-triplet energy transfer efficiency,and the fluorescence quantum yield.These measurements provide critical insights into the photophysical processes governing the TTA upconversion system.Our results highlight the potential advantages and limitations of ZnPc as a triplet photosensitizer for TTA upconversion.
基金supported by Senior Talent Fund of Jiangsu University(No.5501310021)China Postdoctoral Science Foundation(No.2023M741419)+1 种基金the Young Elite Scientist Sponsorship Program by ZJAST(No.G301310002)Research Fund for International Scientists(No.22350710187).
文摘Lanthanide-sensitized upconverting nanoparticles(UCNPs)are widely studied because of their unusual optical characteristics,such as large antenna-generated anti-Stokes shifts,high photostability,and narrow emission bandwidths,which can be harnessed for a variety of applications including bioimaging,sensing,information security and high-level anticounterfeiting.The diverse requirements of these applications typically require precise control over upconversion luminescence(UCL).Recently,the concept of energy migration upconversion has emerged as an effective approach to modulate UCL for various lanthanide ions.Moreover,it provides valuable insights into the fundamental comprehension of energy transfer mechanisms on the nanoscale,thereby contributing to the design of efficient lanthanide-sensitized UCNPs and their practical applications.Here we present a comprehensive overview of the latest developments in energy migration upconversion in lanthanide-sensitized nanoparticles for photon upconversion tuning,encompassing design strategies,mechanistic investigations and applications.Additionally,some future prospects in the field of energy migration upconversion are also discussed.
基金Project supported by National Natural Science Foundation of China(62305244,62374112,62105078)Shandong Province Natural Science Foundation(ZR2021QE060,ZR2021QF009)+1 种基金Young Elite Scientists Sponsorship Program by China Association for Science and Technology(2022QNRC001)Youth Science and Technology Innovation Team of Shandong Province Institution of Higher Learning(2022KJ258)。
文摘In this work,rare earth ions(REs)including Yb^(3+)/Er^(3+),Yb^(3+)/Ho^(3+)and Yb^(3+)/Tm^(3+)co-doped manganese oxyfluoride glasses were fabricated using melt quenching method.By fully utilizing the upconversion luminescence(UCL)of REs and regulating energy transfer between the different energy levels of RE ions and the4T1level of Mn^(2+),the output of UCL was regulated and even pure-red light can be achieved.Moreover,owing to the selective partitioning caused by phase-separation network structure in the oxyfluoride glass,the UCL intensity of glasses annealed for 72 h is significantly enhanced 58 times compared to the rapidly quenched samples.
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Foundation item: Projects (10704090,10774140,11047147)supported by the National Natural Science Foundation of ChinaProjects (KJ090514,KJTD201016)supported by the Natural Science Foundation of Chongqing Municipal Education Commission,China
文摘Lutetium oxide nanocrystals codoped with Tm3＋ and Yb3＋ were synthesized by the reverse-like co-precipitation method, using ammonium hydrogen carbonate as precipitant. Effects of the Tm3＋, Yb3＋ molar fractions and calcination temperature on the structural and upconversion luminescent properties of the Lu2O3 nanocrystals were investigated. The XRD results show that all the prepared nanocrystals can be readily indexed to pure cubic phase of Lu2O3 and indicate good crystallinity. The experimental results show that concentration quenching occurs when the mole fraction of Tm3＋ is above 0.2%. The optimal Tm3＋ and Yb3＋ doped molar fractions are 0.2% and 2%, respectively. The strong blue （490 nm） and the weak red （653 nm） emissions from the prepared nanocrystals were observed under 980 nm laser excitation, and attributed to the 1G4→3H6 and IG4→3F4 transitions of Tm3＋, respectively. Power-dependent study reveals that the 1G4 levels of Tm3＋ can be populated by three-step energy transfer process. The upconversion emission intensities of 490 nm and 653 nm increase gradually with the increase of calcination temperature. The enhancement of the upconversion luminescence is suggested to be the consequence of reducing number of OH- groups and the enlarged nanoerystal size.
基金Project (2009AA035002) supported by the High-tech Research and Development Program of China
文摘Erbium-doped BaTiO3 films on LaNiO3/Si substrates were fabricated by sol-gel method. The crystalline structure, morphologies and upconversion （UC） luminescence properties of films were respectively investigated by X-ray diffraction （XRD）, atomic force microcopy （AFM） and photoluminescence （PL）. The results indicate that both of the microstructure and luminescence are found to be dependent on Er^3＋ substituting sites. The samples with A-site substitution have smaller lattice constants, larger grains and smoother surface than those with B-site substitution. The photoluminescence spectra show that both of the samples have two stronger green emission bands centered at 528 and 548 nm and a weak red emission band centered at 673 nm, which correspond to the relaxation of Er^3＋ from ^2H11/2, ^4S3/2, and ^4F9/2 levels to the ground level ^4I15/2, respectively. Compared with B-site doped films, A-site doped films have a stronger integrated intensity of green emissions and a weaker relative intensity of red emissions. The differences could be explained by the crystalline quality and cross relaxation （CR） process.
基金Projects supported by the National Natural Science Foundation of China(21571125,51872183,51672171)National Key R&D Program of China(2016YFE0114800)
文摘Rare earth doped upconversion nanoparticles can be considered as the spice of research in the field of luminescence nanomaterials due to their unique optical properties such as near-infrared excitation.Enormous works have been reported about biomedical applications of 980 nm excited and Yb^3+-sensitized upconversion nanoparticles.However,980 nm excitation wavelength overlaps with the absorption band of water molecules in the biological environment,leading to overheating effect that can induce thermal damages of normal cells and tissues.Recently,Nd^3+-sensitized upconversion nanoparticles which can be excited with 808 nm has been widely investigated as alternative nanoparticles that can surmount this issue of overheating effect.Even though Nd^3+-sensitized upconversion nanoparticles can reduce the overheating effect by 20 fold as compared to Yb^3+-sensitized counterpart,there are several factors that reduce the upconversion luminescence intensity.In this review article,photon energy harvesting and transferring mechanisms in Nd^3+,Yb^3+and emitter ions co-doped upconversion nanoparticles under 808 nm excitation are briefly discussed.Factors that affect upconversion luminescence intensity and quantum yield of Nd^3+-sensitized upconversion nanoparticles are also addressed.Besides,some of the important strategies that have been recently utilized to boost upconversion luminescence intensity of Nd^3+sensitized upco nversion nanoparticles are tho roughly summarized.Lastly,the future challenges in the area and our perspectives are in sight.
基金supported by the National Natural Science Foundation of China(11464017,11864015)the Scientific Research Foundation for Universities from the Education Bureau of Jiangxi Province(GJJ170490)+1 种基金Foundation of Natural Science Funds for Distinguished Young Scholar of Jiangxi Province(20171BCB23064)the Science and Technology Major Project of Jiangxi Province(20165ABC28010).
文摘Investigation on the bright and stable upconversion(UC)phosphors with multicolor emissions is fundamental and significant for the frontier applications of display and tempe rature probe.He re,dive rse emitting colors with blue,cyan and yellowish green,which are caused by the energy transfer and crossrelaxation processes,are obtained by altering Er^3+,Tm^3+and Yb^3+concentrations in Er3+singly,Er^3+-Tm^3+-Yb^3+co-and tri-doped double perovskite La2ZnTiO6(LZT)phosphors synthesized by a simple solid-state reaction.In addition,excellent infrared emission at 801 nm located at"first biological windo w"is collected in Tm^3+-Yb^3+co-doped phosphors.Meanwhile,the temperature sensing properties based on the thermally coupled levels((^2H11/2)/(^4S3/2))of Er3+ions were analyzed from 298 to 573 K of LZT:0.15 Er^3+/0.10 Yb^3+phosphor,demonstrating that the maximal sensitivity value is about56×10^-4 K^-1 at 448 K.All these results imply that this kind of UC material has potential applications in display,bioimaging and optical device.
基金The National Natural Science Foundation of China (No.20371023)
文摘A new upconversion luminescence agent, 40CdF2·60BaF2·0.8ErO3, was synthesized and its fluorescent spectra were determined. This upconversion luminescence agent can emit five upconversion fluorescent peaks shown in the fluorescent spectra whose wavelengths are all below 387 nm under the excitation of 488 nm visible light. This upconversion luminescence agent was mixed into nano rutile TiO2 powder by ultrasonic and boiling dispersion and the novel doped nano TiO2 photocatalyst utilizing visible light was firstly prepared. The doped TiO2 powder was charactered by XRD and TEM and its photocatalytic activity was tested through the photocatalytic degradation of methyl orange as a model compound under the visible light irradiation emitted by six three basic color lamps. In order to compare the photocatalytic activities, the same experiment was carried out for undoped TiO2 powder. The degradation ratio of methyl orange in the presence of doped nano TiO2 powder reached 32.5% under visible light irradiation at 20 h which was obviously higher than the corresponding 1.64% in the presence of undoped nano TiO2 powder, which indicate the upconversion luminescence agent prepared as dopant can effectively turn visible lights to ultraviolet lights that are absorbed by nano TiO2 particles to produce the electron-cavity pairs. All the results show that the nano rutile TiO2 powder doped with upconversion luminescence agent is a promising photocatalyst using sunlight for treating the industry dye wastewater in great force.
基金Project supported bythe Key Laboratory of Rare Earth Chemistry and Physics ,ChangchunInstitute of Applied Chemistry ,Chinese Academy of Sciences (R020202K)
文摘Nanocrystal of upconversion （UC） phosphor Ho^3＋, Tm^3＋ , and Yb^3＋ co-doped NaYF4 was prepared by the hydrothermal method in the presence of the complexing agent EDTA. Under 980 nm diode laser excitation, the impact of different concentrations of Ho^3＋ ion on the UC luminescence intensity was discussed. The law of luminescence intensity versus pump power shows that the 474 nm blue emission, 538 nm green emission, and 642 nm red emission are all due to the two-photon process, while the 450 nm blue emission is a three-photon process. The UC mechanism and processes were also analyzed. The sample was characterized by transmission electron microscopy （TEM） and X-ray diffraction （XRD）. The result shows that Ho^3＋ ,Tm^3＋ , and Yb^3＋ co-doped NaYF4 prepared by the hydrothermal method exhibits a hexagonal nanocrystal.
基金Project supported by the National Natural Science Foundation of China(21804119,10804099)Key projects of Natural Science Foundation of Zhejiang Province(LZ18B050002).
文摘Novel PEI-modified NaBiF4:Yb3+/Er3+upconversion nanoparticles(UCNPs)with hollow structure were prepared by a surface modification free one-step solvothermal method and applied as a luminescent probe to determinate water content in organic solvents.XRD,SEM and HRTEM results demonstrate that the obtained PEI-NaBiF4:Yb3+/Er3+UCNPs are pure hexagonal phase with uniform size.The successful modification of PEI on the UCNPs surface was evidenced byζ-potential test,XPS and TG analysis.These synthesized UCNPs are disintegrated into smaller nanoparticles in the presence of water and thus result in a surface quenching effect,which show the features of 0-100%wide range water response in various organic solvents.The sensing performance towards real samples was validated by the water content determination in beer,rum and white spirit.Furthermore,the luminescence intensity variation of the PEI-modified NaBiF4:Yb3+/Er3+enable the test visualization and ease of portability.
基金Project supported by the National Natural Science Foundation of China(11104023,11104024,11374044)Fundamental Research Funds for the Central Universities(3132014087,3132014327,3132013100)the State Key Developmment Program for Basic Research of China(973 program,2012CB626801)
文摘Er^3＋/yb^3＋ codoped zincate BaGd2ZnO5 phosphors were synthesized via a traditional solid state reaction. The crystal structure and phase purity were checked by means of X-ray dfluence of Eiffraction （XRD）, and the results showed that pure phase BaGd2ZnO5 phosphors with various Er^3＋/yb^3＋ concentrations were obtained. The Er^3＋ and Yb^3＋ doping concentrations on the green and red upconversion emissions was studied. It was found that both green and red upconversion emissions under 980 nm excitation were two-photon processes independent from the rare earth doping concentrations. However, the upconversion luminescence intensities greatly depended on the rare earth doping concentration. Furthermore, the population processes of upconversion luminescence and the quenching mechanisms were analyzed. The temperature-dependent green upconvcrsion luminescence was studied, and the temperature quenching process of two green upconversion emissions was modeled. The thermal quenching processes of the green upconversion emissions could be well explained by the model we proposed.
基金the Foundation for the University by Educational Department of Liaoning (05L337)Key Laboratory of Rare Earth Chemistry and Physics, Chinese Academy of Sciences
文摘Y2O3： Er^3＋, Yb^3＋ nanoparticles were synthesized by a homogeneous precipitation method without and with different concentrations of EDTA 2Na. Upconversion luminescence spectra of the samples were studied under 980 nm laser excitation. The results of XRD showed that the obtained Y2O3：Er^3＋,Yb^3＋ nanoparticles were of a cubic structure. The average crystallite sizes calculated were in the range of 28-40 nm. Green and red upconversion emission were observed, and attributed to ^2H11/2,^4S3/2→^4I15/2 and ^4F9/2→^4I15/2 transitions of the ion, respectively. The ratio of the intensity of green emission to that of red emission drastically changed with a change in the EDTA 2Na concentration. In the sample synthesized without EDTA, the relative intensity of the green emission was weaker than that of the red emission. The relative intensities of green emission increased with the increased amount of EDTA 2Na used. The possible upconversion luminescence mechanisms were discussed.
基金SVKM's NMIMS University(PhD/20.08.2020)for providing fellowship to carry out research。
文摘Upconversion nanoparticles(UCNPs)doped with lanthanides can convert near-infrared excitation into UV and visible emissions.Because of their relatively high emission efficiency,UCNPs are appealing materials for use in a variety of sectors.UCNPs are known for low auto-fluorescence,excellent chemical and thermal photo-stability,deep tissue penetration,exceptional biocompatibility,low toxicity,color purity,and ease of surface functionalization.In this review,we explain a few recent strategies to boost the efficiency and luminescence of upconversion nanoparticles and minimize quenching by fabricating them as core/shell,nanofibers,or heavily doped lanthanides.Applications of UCNPs in drug delivery,Photodynamic therapy(PDT),biosensors,bioimaging,and optogenetics are also discussed along with their mechanism of action.Our motivation for this review is to understand the working mechanism of UCNPs and their applications in various fields.
基金Project supported by the National Natural Science Foundation of China(51702101,51972119,51472088)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01X137)。
文摘Photon upconversion has received substantial attention owing to its great promise in broad applications from bioimaging to other frontier fields like display,upconversion laser,information security and anticounterfeiting.A smart control and manipulation of the upconversion luminescence has always been a key topic,however,to date the most efficient mechanism for upconversion nanoparticles remains the energy transfer upconversion and recently reported energy migration mediated upconversion.Recently,we found that the interfacial energy transfer(IET)is also an efficient approach for enabling and tuning photon upconversion of lanthanide ions.Moreover,it can be used for the mechanistic understanding of the interionic interactions such as energy transfer and energy migration on the nanoscale.In this review,the recent advances of the research on the IET are summarized,the principles for designing IET process and typical examples are discussed together with its applications in both mechanistic research and frontier information security.The challenges and perspectives for future research are also commented.
基金supported by the National Natural Science Foundation of China(61368007,61265004,51272097)the Specialized Research Fund for the Doctoral Program of Higher Education of China(20125314120018)
文摘The effect of glass network modifier R2O （R=Li, Na, K） on upconversion luminescence in Er3＋/yb3＋ co-doped NaYF4 oxyfluoride glass-ceramics was investigated. NaYF4 nanocrystals with different sizes were studied under glass network modifier alkali mental oxide. The nanocrystals size in NaYF4 of Li2O modified samples was 11 nm, whereas in the Na20 and K2O modified sample, the crystal size was 25 and 43 nm, respectively. It was found that red, yellow and green upconversions were observed in SAL, SAN, SAK glass ceramics. The reported results would deepen the understanding of size effects on the lanthanide upcon- version in nanocrystals.
