Scintillator is a key material for the development of X-ray detectors,which has a promising application in medical imaging,security inspection and industrial non-injury detection.The majority of scintillators currentl...Scintillator is a key material for the development of X-ray detectors,which has a promising application in medical imaging,security inspection and industrial non-injury detection.The majority of scintillators currently used in imaging are real-time imaging scintillators,which can cause ionization radiation damage to biological subjects or detection equipment during the imaging process and require complex,highly sensitive detection systems.Therefore,exploring stable,environmentally friendly scintillator materials that can achieve delayed imaging is of significance in the field of imaging.Herein,we devel-oped an X-ray time-lapse imaging scintillator,Sr_(2)Al_(6)O_(11):Dy^(3+)phosphor,which generates stable traps by X-ray irradiation,thus endowing it with excellent persistent luminescence and information storage properties(>42 d).Moreover,traps constructed by X-ray can be repeatedly refilled(>40 times)under UV light and carriers are released in theform of mechanical or thermal excitation when refilling is complete.By constructing the traps in the phosphor during X-ray excitation and using it for repetitive imaging,the detection limit is 74.78 nGy/s,and the spatial imaging resolution is as high as 16 lp/mm.This discovery providesa new idea for the development oftime-delayed X-ray scintillator.展开更多
The relentless pursuit of advanced X-ray detection technologies has been significantly bolstered by the emergence of metal halides perovskites(MHPs)and their derivatives,which possess remarkable light yield and X-ray ...The relentless pursuit of advanced X-ray detection technologies has been significantly bolstered by the emergence of metal halides perovskites(MHPs)and their derivatives,which possess remarkable light yield and X-ray sensitivity.This comprehensive review delves into cutting-edge approaches for optimizing MHP scintillators performances by enhancing intrinsic physical properties and employing engineering radioluminescent(RL)light strategies,underscoring their potential for developing materials with superior high-resolution X-ray detection and imaging capabilities.We initially explore into recent research focused on strategies to effectively engineer the intrinsic physical properties of MHP scintillators,including light yield and response times.Additionally,we explore innovative engineering strategies involving stacked structures,waveguide effects,chiral circularly polarized luminescence,increased transparency,and the fabrication of flexile MHP scintillators,all of which effectively manage the RL light to achieve high-resolution and high-contrast X-ray imaging.Finally,we provide a roadmap for advancing next-generation MHP scintillators,highlighting their transformative potential in high-performance X-ray detection systems.展开更多
Photo-stimulated luminescence(PSL) is the process in which trapped charges are released by photons and produce luminescence through recombination. The variegated optical characteristics of photostimulated phosphors(PS...Photo-stimulated luminescence(PSL) is the process in which trapped charges are released by photons and produce luminescence through recombination. The variegated optical characteristics of photostimulated phosphors(PSPs) have drawn increasing attention and a large body of work encompassing mechanism and application of PSPs has been addressed. The optical data storage capacity resulting from abundant defect states enables PSPs to be applied to information storage. Moreover, PSPs provide potential application for anti-counterfeiting, as color changes due to the tunneling process. Recently, near infrared(NIR) light PSPs have been developed, exhibiting enormous potential for in vivo bio-imaging, as the stable and high noise-signal ratio characteristic of PSL. In this review, we devote to introducing the development and process of PSPs, and the challenge and future advance have also been demonstrated.展开更多
Optical thermometers have aroused considerable attention in recent years,and the increasing demand of sensitivity for practical application encourages the investigation on developing innovative non-contact optical the...Optical thermometers have aroused considerable attention in recent years,and the increasing demand of sensitivity for practical application encourages the investigation on developing innovative non-contact optical thermo metric materials with higher sensitivity and accuracy.Perovskite quantum dots(QDs)with excellent temperature-dependence optical properties,provide a feasible approach to realizing the detection of temperature change,however,their poor high temperature thermal stability and the facile realization to obtain the production remain a daunting challenge.Herein,growing Tb^(3+)-doped CsPbl_(3) QDs in situ in borosilicate glass is proposed,which ensures the phase stability,and high-efficiency florescence output of the all-inorganic perovskite as a temperature sensor.A higher absolute and relative temperature sensitivity(0.0398 K^(-1) and 7.12%/K,respectively),along with the visible color change from orange-red to yellow-green with the increase of temperature is accomplished.Notably,the repeatable florescence intensity of Tb^(3+)-doped CsPbl_(3) QDs under high temperature enables their temperature sensing application.展开更多
A series of mono-dispersed hexagon NaGdF_4:Yb^(3+),Er^(3+)@NaGdF_4 core-shell nanoparticles with different shell thickness were synthesized via a co-precipitation method. Nanoparticles with high upconversion fluoresce...A series of mono-dispersed hexagon NaGdF_4:Yb^(3+),Er^(3+)@NaGdF_4 core-shell nanoparticles with different shell thickness were synthesized via a co-precipitation method. Nanoparticles with high upconversion fluorescent emissions result in large signal-to-noise ratio, which guarantees the accuracy of the sensitivity. Besides, the maximum sensitivity of these NPs as detection film increases first and then decreases with the shell thickness increasing. When the shell thickness is 2.3 nm(NaGdF_4-2), the maximum sensitivity(0.69959 ppm^(-1)) is reached. A large degree of overlap between the rhodamine B absorption band and the Er^(3+) green emission bands ensures that the NaGdF_4:Yb^(3+),Er^(3+)@NaGdF_4 nanoparticles can be used as fluorescent probe to detect the concentration of rhodamine B based on fluorescent intensity ratio technology. The linear relationship between the rhodamine B concentration and the intensity ratio(R) of green and red emission intensity(I_(S+H) and I_F) were studied systematically. The result shows that the maximum sensitivity can be obtained in low concentration rhodamine B(<4 ppm), which is lower than the reported minimum detection concentration. Thus, the ultra-high sensitivity detection by NaGdF_4:Yb^(3+),Er^(3+)@NaGdF_4 core-shell upconversion nanoparticles in low concentration can be realized,which provides promising applications in bio-detection filed.展开更多
A green long persistent luminescence（LPL） phosphor Ca3Ga4O9：Tb3＋/Zn2＋ was prepared. Ca3 Ga4 O9 matrix exhibits blue self-activated LPL due to the creation of intrinsic traps. When Tb3＋ is doped, the photolumines...A green long persistent luminescence（LPL） phosphor Ca3Ga4O9：Tb3＋/Zn2＋ was prepared. Ca3 Ga4 O9 matrix exhibits blue self-activated LPL due to the creation of intrinsic traps. When Tb3＋ is doped, the photoluminescence（PL） and LPL colors change from blue to green with their intensities significantly enhanced. The doping of Zn^（2＋） evidently improves the PL and LPL performances of the Ca3Ga4O9 matrix and Ca3Ga4O9：Tb^（3＋）. The thermoluminescence（TL） spectra show that a successive trap distribution is formed by multiple intrinsic traps with different depths in the Ca3 Ga4 O9 matrix, and the incorporation of Tb^（3＋） and Zn^（2＋） effectively increases the densities of these intrinsic traps. The existence of a successive trap distribution makes the Ca3 Ga4 O9：Tb^（3＋）/Zn^（2＋） phosphor exhibit thermally stable PL and LPL, It is indicated that this phosphor shows great promise for the application such as high-temperature LPL phosphor.展开更多
Near infrared to near infrared(NIR-NIR)photo-stimulated persistent luminescence(PSPL)has shown excellent potential in high-resolution bioimaging for deep tissues.However,the PSPL in NIR-Ⅱregion(900-1700 nm)is still l...Near infrared to near infrared(NIR-NIR)photo-stimulated persistent luminescence(PSPL)has shown excellent potential in high-resolution bioimaging for deep tissues.However,the PSPL in NIR-Ⅱregion(900-1700 nm)is still lacking.In this work,Ca_(2)Ga_(2)GeO_(7):Yb^(3+),Tb^(3+)(CGGYT)phosphor with unique lowdimensional crystal structure was synthesized by high-temperature solid-state reaction.Thanks to the carriers transferring from deep traps to shallow ones induced by low energy light,the 978 nm PSPL originating from ^(2)F_(5/2) to ^(2)F_(7/2) transition of Yb^(3+)induced by multimode stimulating(980 nm or WLED)is successfully realized after pre-excited by UV lamp.The NIR PSPL of the specimen can be repeatedly stimulated after placed in dark for 12 h.Moreover,the results indicate that codoping with Tb^(3+)can significantly enhance the NIR-ⅡPSPL owing to the quantum cutting persistent energy transfer(QC PET)from Tb^(3+)to Yb^(3+).Our study points to a new direction for the future development of multimode PSPL materials for bioimaging or multimode optical storage applications.展开更多
Red emitting phosphors play a significant role in accelerating the improvement of illumination quality for white light emitting diodes(WLEDs).In this work,by using solid-state reaction method,an efficient novel Ba_(2)...Red emitting phosphors play a significant role in accelerating the improvement of illumination quality for white light emitting diodes(WLEDs).In this work,by using solid-state reaction method,an efficient novel Ba_(2)LuNbO_(6):Eu^(3+)phosphor with double-perovskite structure was successfully prepared.Here,a series of Ba_(2)LuNbO_(6):Eu^(3+)red phosphors can be efficiently pumped by the near-ultraviolet(UV)light and then present high-brightness at orange emission(598 nm,~5D_(0)→~7 F_(1))and red emission(610 nm,~5D_(0)→~7 F_(2)).The ratio values of 610 to 598 nm in Ba_(2)LuNbO_(6):Eu^(3+)phosphors exceed 1 when the content of Eu^(3+)is larger than 0.4 mol,because the occupation of Eu^(3+)ions is changed from Lu^(3+)ions with symmetric sites to Ba^(2+)ions with asymmetric sites.Besides,the optimized concentration of Eu^(3+)at the~5D_(0)→~7 F_(2)transitions is obtained when x=1,indicating that there is non-concentration quenching in Ba_(2)LuNbO_(6):Eu^(3+)phosphors.Moreover,the CIE chromaticity coordinates of Ba_(2)LuNbO_(6):Eu^(3+)was calculated to be(0.587,0.361),the color purity was calculated to be 72.26%and internal quenching efficiency(IQE)was measured to be 67%.Finally,the thermal stability of Ba_(2)LuNbO_(6):Eu^(3+)phosphors was also studied.Our work demonstrates that the novel double-perovskite red-emitting Ba_(2)LuNbO_(6):Eu^(3+)phosphors are prospective red emitting elements for WLEDs applications.展开更多
Low-dimensional halide perovskites have become the most promising candidates for X-ray imaging,yet the issues of the poor chemical stability of hybrid halide perovskite,the high poisonousness of lead halides and the r...Low-dimensional halide perovskites have become the most promising candidates for X-ray imaging,yet the issues of the poor chemical stability of hybrid halide perovskite,the high poisonousness of lead halides and the relatively low detectivity of the lead-free halide perovskites which seriously restrain its commercialization.Here,we developed a solution inverse temperature crystal growth(ITCG)method to bring-up high quality Cs_(3)Cu_(2)I_(5)crystals with large size of centimeter order,in which the oleic acid(OA)is introduced as an antioxidative ligand to inhibit the oxidation of cuprous ions effieiently,as well as to decelerate the crystallization rate remarkalby.Based on these fine crystals,the vapor deposition technique is empolyed to prepare high quality Cs_(3)Cu_(2)I_(5)films for efficient X-ray imaging.Smooth surface morphology,high light yields and short decay time endow the Cs_(3)Cu_(2)I_(5)films with strong radioluminescence,high resolution(12 lp/mm),low detection limits(53 nGyair/s)and desirable stability.Subsequently,the Cs_(3)Cu_(2)I_(5)films have been applied to the practical radiography which exhibit superior X-ray imaging performance.Our work provides a paradigm to fabricate nonpoisonous and chemically stable inorganic halide perovskite for X-ray imaging.展开更多
Mechano-luminescence(ML) has been found diverse applications such as stress sensing,3-D signature,energy harvesting,and anti-counterfeiting,due to the unique properties of the corresponding ML phosphors performing in-...Mechano-luminescence(ML) has been found diverse applications such as stress sensing,3-D signature,energy harvesting,and anti-counterfeiting,due to the unique properties of the corresponding ML phosphors performing in-situ and real-time response to mechanical stimulus.Trap-controlled ML materials realize reproducible,quantitative mechano-optical conversion resulting from the released carriers for the trap-mediated charge storage and release.Herein,modulating traps matters the controllable ML behavior for their promising applications.In this work,a deep trap distributed ranging from 0.9 to 1,3 eV is realized consecutively for the introduction of Sm^(3+)ions into LaGaO_(3) matrix,which contributes to the red emission at 600 nm under mechanical stimuli.Moreover,tunable ML emission modulated from 600to 545 nm is successfully achieved for the codopant of Tb^(3+)ions.It is unambiguously indicated that the released carriers from the trap sharing rather than an additional constructed trap contribute to the modulated ML color.Accordingly,multi-mode anti-counterfeiting and encryption are achieved with the as-explored Sm^(3+),Tb^(3+)co-activated ML phosphor.展开更多
Lithium metal has been considered one of the most promising anodes for next-generation rechargeable batteries,but its practical application is largely hindered by the uncontrollable dendrite growth and infinite volume...Lithium metal has been considered one of the most promising anodes for next-generation rechargeable batteries,but its practical application is largely hindered by the uncontrollable dendrite growth and infinite volume change.Here,inspired by superior catalytic effects of single-atom catalysts,carbon-supported single atomic Co with asymmetric N,O-coordination(Co-N/O)is developed for Li metal battery.Experimental results and theoretical calculations indicate that single atomic Co atoms with asymmetric N,O-coordination present enhanced binding ability toward Li in comparison with N-coordinated atomic Co site and isolated O site,enabling uniform Li plating/stripping.Moreover,the asymmetric N,O-coordination around Co atoms induces co-activation effects,lowering the energy barriers toward Li^(+)to Li^(0)conversion and largely promoting the deposition kinetics.When used as a Li deposition host,the Co-N/O achieves a high average coulombic efficiency of 98.6%at a current density of 1 mA cm^(-2)and a capacity of 2 mAh cm^(-2),long cycling life of 2000 h in symmetrical cells,and excellent rate performance(voltage hysteresis of 23 mV at 8 mA cm^(-2)).This work provides a comprehensive understanding of single atomic metals with asymmetric heteroatom coordination in the design of Li metal anode.展开更多
Ultralong organic phosphorescence(UOP)materials have garnered significant interest for applications in advanced optical recording and information encryption.However,it remains a formidable challenge achieving manipula...Ultralong organic phosphorescence(UOP)materials have garnered significant interest for applications in advanced optical recording and information encryption.However,it remains a formidable challenge achieving manipulated phosphorescence due to the limited color channels and poorly populated triplet energy levels.Herein,we report a novel multiresponsive organic phosphorescence material,in which the phosphorescence color can be dynamically tuned with stimuli such as radiation duration,concentration,excitation wavelength,time,and temperature.The material is based on the confined 7H-benzo[c]carbazole(BCz)molecules in the polymermatrix,which is achieved through the size-dependent cluster-triggered emission(CTE)mechanism.The BCz molecules form isolated molecules and different-sized clusters in the matrix,resulting in multiple luminescent centers with different energy levels and phosphorescence lifetimes.Throughmatrix confinement effects,the activation states of the monomers and multiple clusters could be precisely modulated,resulting in temperature-controlled tunable orange-to-green variations.Furthermore,the multiresponsive properties of the material have been used in both civil and military applications through sophisticated mathematical modeling.This work potentially proposes a guiding strategy for the development of multiresponsive UOP materials based on CTE molecules.展开更多
Real-time stress sensing based on mechanoluminescence materials has been widely studied for structural health monitoring of bridges,buildings,high-pressure vessels,and other infrastructure surfaces.However,this approa...Real-time stress sensing based on mechanoluminescence materials has been widely studied for structural health monitoring of bridges,buildings,high-pressure vessels,and other infrastructure surfaces.However,this approach is difficult to detect the stress information of closed mechanical structures.Here,we propose a delayed stress memory strategy to record the stress information of closed mechanical structure by the flexible film composed with CaAl_(2)O_(4):Eu^(2+),Sm^(3+)phosphor.After the force is applied,the optical information on the film can be read out by the near-infrared laser after a period of time without real-time monitoring,and the stress distribution information of bearings and gears in the engine can be obtained.Furthermore,the regulation of trap depth from 0.662 to 1.042 eV allows the captured carriers to remain in the traps for a long time without being released as long persistent luminescence,which is beneficial to the delayed stress memory.Therefore,this work promotes the application prospect of mechanoluminescence materials in stress sensing,and provides a new idea to record the stress information of closed mechanical structures.展开更多
A thermal simulation experiment of diagenesis,hydrocarbon generation and evolution of the organic matter-rich shale was carried out to investigate formation and evolution of organic pores under the constraint from imm...A thermal simulation experiment of diagenesis,hydrocarbon generation and evolution of the organic matter-rich shale was carried out to investigate formation and evolution of organic pores under the constraint from immature,low mature,mature,high mature to overmature geological conditions.The argon ion polishingefield emission scanning electron microscope was used to analyze microscopic features of original samples and simulated samples of various evolution stages.Results showed organic pores could be formed during hydrocarbon generation from biochemical and hypothermal processes in the immature and low mature stages,and the shale shallow-buried depth might be favorable for preservation of organic pores;the generation and evolution of organic pores were of heterogeneity,and the maturity was not a decisive factor which controlled formation and development of organic pores,while the difference in physiochemical structure of organic matter played an important role in formation and evolution of organic pores;the organic pore development was obviously related with the retained oil,and the organic pores formed in the oil generation stage were easily filled by pyrolysis asphalt;organic contraction fractures/organic marginal pores might be important storage spaces for shale gas occurrence,and their development was mainly controlled by the physiochemical structure and evolution degree of organic matters when the chemical adsorbed organic matter was converted into the physical adsorbed organic matter and the free organic matter.展开更多
In-situ observation of the growth and decomposition processes is significantly important for guiding the fabrication of upconversion nanocrystals(UCNCs)with high performance.However,the high crystallization energy and...In-situ observation of the growth and decomposition processes is significantly important for guiding the fabrication of upconversion nanocrystals(UCNCs)with high performance.However,the high crystallization energy and rapid nucleation rate of the corresponding crystals make real-time observation still a huge challenge.Herein,the in-situ nucleation-growth-degradation processes of the UCNCs are investigated by employing tailored metastable intermediates,which possess a slowing-down nucleation rate under electron beam irradiation.The non-classical nucleation processes of the UCNCs,containing the coalescence of clusters and the subsequent crystallization,are demonstrated.Moreover,the Ostwald ripening and oriented attachment processes,which determine the particle size and morphology,are unambiguously recorded.Furthermore,the degrading process of the UCNCs is observed to be triggered by surface defects.Our work provides an insight into the real-time evolution dynamics of the UCNCs,which further sheds light on the fabrication of nano-sized up-conversion phosphors.展开更多
基金the National Natural Science Foundation of China(12364044)Yunnan Major Scientific and Technological Projects(202202AG050004,202202AG050016,202302AQ370003)+1 种基金the International Joint Innovation Platform of Yunnan Province(202203AP140004)the Outstanding Youth Project of Yunnan Province Applied Basic Research Project(202401AV070012).
文摘Scintillator is a key material for the development of X-ray detectors,which has a promising application in medical imaging,security inspection and industrial non-injury detection.The majority of scintillators currently used in imaging are real-time imaging scintillators,which can cause ionization radiation damage to biological subjects or detection equipment during the imaging process and require complex,highly sensitive detection systems.Therefore,exploring stable,environmentally friendly scintillator materials that can achieve delayed imaging is of significance in the field of imaging.Herein,we devel-oped an X-ray time-lapse imaging scintillator,Sr_(2)Al_(6)O_(11):Dy^(3+)phosphor,which generates stable traps by X-ray irradiation,thus endowing it with excellent persistent luminescence and information storage properties(>42 d).Moreover,traps constructed by X-ray can be repeatedly refilled(>40 times)under UV light and carriers are released in theform of mechanical or thermal excitation when refilling is complete.By constructing the traps in the phosphor during X-ray excitation and using it for repetitive imaging,the detection limit is 74.78 nGy/s,and the spatial imaging resolution is as high as 16 lp/mm.This discovery providesa new idea for the development oftime-delayed X-ray scintillator.
基金supported by the National Nature Science Foundation of China(NSFC)(U2241236,1220041913,52473253)the National Key Research and Development Program of China(2022ZDZX0007)+1 种基金Fundamental Research Open Subject Grant Program of Yantai Advanced Materials and Green Manufacturing Laboratory of Shandong Province(AMGM2024F15)Yunnan Major Scientific and Technological Projects(202402AB080011).
文摘The relentless pursuit of advanced X-ray detection technologies has been significantly bolstered by the emergence of metal halides perovskites(MHPs)and their derivatives,which possess remarkable light yield and X-ray sensitivity.This comprehensive review delves into cutting-edge approaches for optimizing MHP scintillators performances by enhancing intrinsic physical properties and employing engineering radioluminescent(RL)light strategies,underscoring their potential for developing materials with superior high-resolution X-ray detection and imaging capabilities.We initially explore into recent research focused on strategies to effectively engineer the intrinsic physical properties of MHP scintillators,including light yield and response times.Additionally,we explore innovative engineering strategies involving stacked structures,waveguide effects,chiral circularly polarized luminescence,increased transparency,and the fabrication of flexile MHP scintillators,all of which effectively manage the RL light to achieve high-resolution and high-contrast X-ray imaging.Finally,we provide a roadmap for advancing next-generation MHP scintillators,highlighting their transformative potential in high-performance X-ray detection systems.
基金Project supported by the National Natural Science Foundation of China(61565009,11664022,11804038)the Foundation of Natural Science of Yunnan Province(2016FB088)+3 种基金the Reserve Talents Project of Yunnan Province(2017HB011)the Young Talents Support Program of Faculty of Materials Science and Engineering,Kunming University of Science and Technology(14078342)Chongqing Natural Science Foundation(cstc2017jcyjAX0418,cstc2018jcyjAX0569)Foundation of Chongqing University of Arts and Sciences(R2016DQ10)
文摘Photo-stimulated luminescence(PSL) is the process in which trapped charges are released by photons and produce luminescence through recombination. The variegated optical characteristics of photostimulated phosphors(PSPs) have drawn increasing attention and a large body of work encompassing mechanism and application of PSPs has been addressed. The optical data storage capacity resulting from abundant defect states enables PSPs to be applied to information storage. Moreover, PSPs provide potential application for anti-counterfeiting, as color changes due to the tunneling process. Recently, near infrared(NIR) light PSPs have been developed, exhibiting enormous potential for in vivo bio-imaging, as the stable and high noise-signal ratio characteristic of PSL. In this review, we devote to introducing the development and process of PSPs, and the challenge and future advance have also been demonstrated.
基金Project supported by the National Natural Science Foundation of China of China(11664022)the Reserve Talents Project of Yunnan Province(2017HB011)+1 种基金Yunnan Ten Thousand Talents Plan Young&Elite Talents Project(YNWR-QNBJ-2018-295,YNWR-QNBJ-2018-325)the Excellent Youth Project of Yunnan Province Applied Basic Research Project(2019FI001)。
文摘Optical thermometers have aroused considerable attention in recent years,and the increasing demand of sensitivity for practical application encourages the investigation on developing innovative non-contact optical thermo metric materials with higher sensitivity and accuracy.Perovskite quantum dots(QDs)with excellent temperature-dependence optical properties,provide a feasible approach to realizing the detection of temperature change,however,their poor high temperature thermal stability and the facile realization to obtain the production remain a daunting challenge.Herein,growing Tb^(3+)-doped CsPbl_(3) QDs in situ in borosilicate glass is proposed,which ensures the phase stability,and high-efficiency florescence output of the all-inorganic perovskite as a temperature sensor.A higher absolute and relative temperature sensitivity(0.0398 K^(-1) and 7.12%/K,respectively),along with the visible color change from orange-red to yellow-green with the increase of temperature is accomplished.Notably,the repeatable florescence intensity of Tb^(3+)-doped CsPbl_(3) QDs under high temperature enables their temperature sensing application.
基金supported by the National Natural Science Foundation of China(61565009,11664022)the Foundation of Natural Science of Yunnan Province(2016FB088)+2 种基金the Reserve Talents Project of Yunnan Province(2017HB011)the Young Talents Support Program of Faculty of Materials Science and Engineering,Kunming University of Science and Technology(14078342)Scientific and Technological Research Program of Chongqing Municipal Education Commission(KJ1711277)
文摘A series of mono-dispersed hexagon NaGdF_4:Yb^(3+),Er^(3+)@NaGdF_4 core-shell nanoparticles with different shell thickness were synthesized via a co-precipitation method. Nanoparticles with high upconversion fluorescent emissions result in large signal-to-noise ratio, which guarantees the accuracy of the sensitivity. Besides, the maximum sensitivity of these NPs as detection film increases first and then decreases with the shell thickness increasing. When the shell thickness is 2.3 nm(NaGdF_4-2), the maximum sensitivity(0.69959 ppm^(-1)) is reached. A large degree of overlap between the rhodamine B absorption band and the Er^(3+) green emission bands ensures that the NaGdF_4:Yb^(3+),Er^(3+)@NaGdF_4 nanoparticles can be used as fluorescent probe to detect the concentration of rhodamine B based on fluorescent intensity ratio technology. The linear relationship between the rhodamine B concentration and the intensity ratio(R) of green and red emission intensity(I_(S+H) and I_F) were studied systematically. The result shows that the maximum sensitivity can be obtained in low concentration rhodamine B(<4 ppm), which is lower than the reported minimum detection concentration. Thus, the ultra-high sensitivity detection by NaGdF_4:Yb^(3+),Er^(3+)@NaGdF_4 core-shell upconversion nanoparticles in low concentration can be realized,which provides promising applications in bio-detection filed.
基金supported by the National Natural Science Foundation of China(11774138)the Society Development Foundation of Yunnan Province(2016FA021)the Kunming University of Science and Technology(KKSY201632046)
文摘A green long persistent luminescence（LPL） phosphor Ca3Ga4O9：Tb3＋/Zn2＋ was prepared. Ca3 Ga4 O9 matrix exhibits blue self-activated LPL due to the creation of intrinsic traps. When Tb3＋ is doped, the photoluminescence（PL） and LPL colors change from blue to green with their intensities significantly enhanced. The doping of Zn^（2＋） evidently improves the PL and LPL performances of the Ca3Ga4O9 matrix and Ca3Ga4O9：Tb^（3＋）. The thermoluminescence（TL） spectra show that a successive trap distribution is formed by multiple intrinsic traps with different depths in the Ca3 Ga4 O9 matrix, and the incorporation of Tb^（3＋） and Zn^（2＋） effectively increases the densities of these intrinsic traps. The existence of a successive trap distribution makes the Ca3 Ga4 O9：Tb^（3＋）/Zn^（2＋） phosphor exhibit thermally stable PL and LPL, It is indicated that this phosphor shows great promise for the application such as high-temperature LPL phosphor.
基金Project supported by the National Natural Science Foundation of China-Yunnan Joint Fund(U1902222)the National Natural Science Foundation of China(11774138,11664022,51862020 and 11804255)the Natural Science Foundation of Yunnan Province(2019HC016)。
文摘Near infrared to near infrared(NIR-NIR)photo-stimulated persistent luminescence(PSPL)has shown excellent potential in high-resolution bioimaging for deep tissues.However,the PSPL in NIR-Ⅱregion(900-1700 nm)is still lacking.In this work,Ca_(2)Ga_(2)GeO_(7):Yb^(3+),Tb^(3+)(CGGYT)phosphor with unique lowdimensional crystal structure was synthesized by high-temperature solid-state reaction.Thanks to the carriers transferring from deep traps to shallow ones induced by low energy light,the 978 nm PSPL originating from ^(2)F_(5/2) to ^(2)F_(7/2) transition of Yb^(3+)induced by multimode stimulating(980 nm or WLED)is successfully realized after pre-excited by UV lamp.The NIR PSPL of the specimen can be repeatedly stimulated after placed in dark for 12 h.Moreover,the results indicate that codoping with Tb^(3+)can significantly enhance the NIR-ⅡPSPL owing to the quantum cutting persistent energy transfer(QC PET)from Tb^(3+)to Yb^(3+).Our study points to a new direction for the future development of multimode PSPL materials for bioimaging or multimode optical storage applications.
基金Project supported by the Excellent Youth Project of Yunnan Province Applied Basic Research Project(2019FI001)the National Natural Science Foundation of China(61775187,61965012,12064022)the Key Project of Yunnan Provincial Natural Science Foundation(202101AT070126)。
文摘Red emitting phosphors play a significant role in accelerating the improvement of illumination quality for white light emitting diodes(WLEDs).In this work,by using solid-state reaction method,an efficient novel Ba_(2)LuNbO_(6):Eu^(3+)phosphor with double-perovskite structure was successfully prepared.Here,a series of Ba_(2)LuNbO_(6):Eu^(3+)red phosphors can be efficiently pumped by the near-ultraviolet(UV)light and then present high-brightness at orange emission(598 nm,~5D_(0)→~7 F_(1))and red emission(610 nm,~5D_(0)→~7 F_(2)).The ratio values of 610 to 598 nm in Ba_(2)LuNbO_(6):Eu^(3+)phosphors exceed 1 when the content of Eu^(3+)is larger than 0.4 mol,because the occupation of Eu^(3+)ions is changed from Lu^(3+)ions with symmetric sites to Ba^(2+)ions with asymmetric sites.Besides,the optimized concentration of Eu^(3+)at the~5D_(0)→~7 F_(2)transitions is obtained when x=1,indicating that there is non-concentration quenching in Ba_(2)LuNbO_(6):Eu^(3+)phosphors.Moreover,the CIE chromaticity coordinates of Ba_(2)LuNbO_(6):Eu^(3+)was calculated to be(0.587,0.361),the color purity was calculated to be 72.26%and internal quenching efficiency(IQE)was measured to be 67%.Finally,the thermal stability of Ba_(2)LuNbO_(6):Eu^(3+)phosphors was also studied.Our work demonstrates that the novel double-perovskite red-emitting Ba_(2)LuNbO_(6):Eu^(3+)phosphors are prospective red emitting elements for WLEDs applications.
基金the financially support of the National Natural Science Foundation of China(12164051)the Joint Foundation of Provincial Science and Technology Department-Double First-class Construction of Yunnan University(2019FY003016)+4 种基金the Young Top Talent Project of Yunnan Province(YNWR-QNBJ-2018-229)the financially support by Yunnan Major Scientific and Technological Projects(202202AG050016)Advanced Analysis and Measurement Center of Yunnan University for the sample characterization service and the Postgraduate Research and Innovation Foundation of Yunnan University(2021Y036)the financially support of the National Natural Science Foundation of China(62064013)the Application Basic Research Project of Yunnan Province[2019FB130]。
文摘Low-dimensional halide perovskites have become the most promising candidates for X-ray imaging,yet the issues of the poor chemical stability of hybrid halide perovskite,the high poisonousness of lead halides and the relatively low detectivity of the lead-free halide perovskites which seriously restrain its commercialization.Here,we developed a solution inverse temperature crystal growth(ITCG)method to bring-up high quality Cs_(3)Cu_(2)I_(5)crystals with large size of centimeter order,in which the oleic acid(OA)is introduced as an antioxidative ligand to inhibit the oxidation of cuprous ions effieiently,as well as to decelerate the crystallization rate remarkalby.Based on these fine crystals,the vapor deposition technique is empolyed to prepare high quality Cs_(3)Cu_(2)I_(5)films for efficient X-ray imaging.Smooth surface morphology,high light yields and short decay time endow the Cs_(3)Cu_(2)I_(5)films with strong radioluminescence,high resolution(12 lp/mm),low detection limits(53 nGyair/s)and desirable stability.Subsequently,the Cs_(3)Cu_(2)I_(5)films have been applied to the practical radiography which exhibit superior X-ray imaging performance.Our work provides a paradigm to fabricate nonpoisonous and chemically stable inorganic halide perovskite for X-ray imaging.
基金Project supported by the Yunnan Provincial Natural Science Foundation (202101AT070126)the Research Start-up Fund of Chengdu University of Technology (10912-KYQD2020-08476)+1 种基金Fund of Hubei Key Laboratory of Plasma Chemistry,Advanced Materials (KF202103)Sichuan Natural Science Foundation (2022YFH0108,2022JDJQ0030)。
文摘Mechano-luminescence(ML) has been found diverse applications such as stress sensing,3-D signature,energy harvesting,and anti-counterfeiting,due to the unique properties of the corresponding ML phosphors performing in-situ and real-time response to mechanical stimulus.Trap-controlled ML materials realize reproducible,quantitative mechano-optical conversion resulting from the released carriers for the trap-mediated charge storage and release.Herein,modulating traps matters the controllable ML behavior for their promising applications.In this work,a deep trap distributed ranging from 0.9 to 1,3 eV is realized consecutively for the introduction of Sm^(3+)ions into LaGaO_(3) matrix,which contributes to the red emission at 600 nm under mechanical stimuli.Moreover,tunable ML emission modulated from 600to 545 nm is successfully achieved for the codopant of Tb^(3+)ions.It is unambiguously indicated that the released carriers from the trap sharing rather than an additional constructed trap contribute to the modulated ML color.Accordingly,multi-mode anti-counterfeiting and encryption are achieved with the as-explored Sm^(3+),Tb^(3+)co-activated ML phosphor.
基金supported by the Ministry of Education,Singapore,under its MOE tier2 grant MOE2019-T2-1-181.
文摘Lithium metal has been considered one of the most promising anodes for next-generation rechargeable batteries,but its practical application is largely hindered by the uncontrollable dendrite growth and infinite volume change.Here,inspired by superior catalytic effects of single-atom catalysts,carbon-supported single atomic Co with asymmetric N,O-coordination(Co-N/O)is developed for Li metal battery.Experimental results and theoretical calculations indicate that single atomic Co atoms with asymmetric N,O-coordination present enhanced binding ability toward Li in comparison with N-coordinated atomic Co site and isolated O site,enabling uniform Li plating/stripping.Moreover,the asymmetric N,O-coordination around Co atoms induces co-activation effects,lowering the energy barriers toward Li^(+)to Li^(0)conversion and largely promoting the deposition kinetics.When used as a Li deposition host,the Co-N/O achieves a high average coulombic efficiency of 98.6%at a current density of 1 mA cm^(-2)and a capacity of 2 mAh cm^(-2),long cycling life of 2000 h in symmetrical cells,and excellent rate performance(voltage hysteresis of 23 mV at 8 mA cm^(-2)).This work provides a comprehensive understanding of single atomic metals with asymmetric heteroatom coordination in the design of Li metal anode.
基金supported by the National Natural Science Foundation of China(NSFC)(U2241236,1220041913,52473253)the National Key Research and Development Program of China(2022ZDZX0007)+2 种基金Young Elite Scientists Sponsorship Program by CAST(2022QNRC001)Yunnan Major Scientific and Technological Projects(202402AB080011)the Science Fund of Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai(AMGM2024F15).
文摘Ultralong organic phosphorescence(UOP)materials have garnered significant interest for applications in advanced optical recording and information encryption.However,it remains a formidable challenge achieving manipulated phosphorescence due to the limited color channels and poorly populated triplet energy levels.Herein,we report a novel multiresponsive organic phosphorescence material,in which the phosphorescence color can be dynamically tuned with stimuli such as radiation duration,concentration,excitation wavelength,time,and temperature.The material is based on the confined 7H-benzo[c]carbazole(BCz)molecules in the polymermatrix,which is achieved through the size-dependent cluster-triggered emission(CTE)mechanism.The BCz molecules form isolated molecules and different-sized clusters in the matrix,resulting in multiple luminescent centers with different energy levels and phosphorescence lifetimes.Throughmatrix confinement effects,the activation states of the monomers and multiple clusters could be precisely modulated,resulting in temperature-controlled tunable orange-to-green variations.Furthermore,the multiresponsive properties of the material have been used in both civil and military applications through sophisticated mathematical modeling.This work potentially proposes a guiding strategy for the development of multiresponsive UOP materials based on CTE molecules.
基金This work was financially supported by the National Natural Science Foundation of China(No.61965012)Project of Yunnan Provincial Natural Science Foundation(Nos.202001AS070008,202101AT070126)+3 种基金Yunnan Ten Thousand Talents Plan Young&Elite Talents Project(No.YNWRQNBJ-2018-295)the Excellent Youth Project of Yunnan Province Applied Basic Research Project(No.2019FI001)Rare and Precious Metal Materials Genome Engineering Project of Yunnan Province(No.202002AB080001)Sichuan Natural Science Foundation(No.2022JDJQ0030).
文摘Real-time stress sensing based on mechanoluminescence materials has been widely studied for structural health monitoring of bridges,buildings,high-pressure vessels,and other infrastructure surfaces.However,this approach is difficult to detect the stress information of closed mechanical structures.Here,we propose a delayed stress memory strategy to record the stress information of closed mechanical structure by the flexible film composed with CaAl_(2)O_(4):Eu^(2+),Sm^(3+)phosphor.After the force is applied,the optical information on the film can be read out by the near-infrared laser after a period of time without real-time monitoring,and the stress distribution information of bearings and gears in the engine can be obtained.Furthermore,the regulation of trap depth from 0.662 to 1.042 eV allows the captured carriers to remain in the traps for a long time without being released as long persistent luminescence,which is beneficial to the delayed stress memory.Therefore,this work promotes the application prospect of mechanoluminescence materials in stress sensing,and provides a new idea to record the stress information of closed mechanical structures.
基金supported by the National Science and Technology Major Project of China(No.2017ZX05036002-004,No.2017ZX05005001-003)National Natural Science Foundation of China(No.U1663202,No.41690133)Sinopec Science and Technology Research Project(P14040).
文摘A thermal simulation experiment of diagenesis,hydrocarbon generation and evolution of the organic matter-rich shale was carried out to investigate formation and evolution of organic pores under the constraint from immature,low mature,mature,high mature to overmature geological conditions.The argon ion polishingefield emission scanning electron microscope was used to analyze microscopic features of original samples and simulated samples of various evolution stages.Results showed organic pores could be formed during hydrocarbon generation from biochemical and hypothermal processes in the immature and low mature stages,and the shale shallow-buried depth might be favorable for preservation of organic pores;the generation and evolution of organic pores were of heterogeneity,and the maturity was not a decisive factor which controlled formation and development of organic pores,while the difference in physiochemical structure of organic matter played an important role in formation and evolution of organic pores;the organic pore development was obviously related with the retained oil,and the organic pores formed in the oil generation stage were easily filled by pyrolysis asphalt;organic contraction fractures/organic marginal pores might be important storage spaces for shale gas occurrence,and their development was mainly controlled by the physiochemical structure and evolution degree of organic matters when the chemical adsorbed organic matter was converted into the physical adsorbed organic matter and the free organic matter.
基金This work was financially supported by the National Natural Science Foundation of China(NSFC)(No.61965012)Science and Technology Major Project of Yunnan Province(No.202202AG050004)+5 种基金Technological Innovation Fund Project of Small and Medium-sized Enterprises of Yunnan Province(No.202104AP080068)Yunnan Provincial Natural Science Foundation(Nos.202001AS070008 and 202101AT070126)Yunnan Ten Thousand Talents Plan Young&Elite Talents Project(No.YNWR-QNBJ-2018-295)the Excellent Youth Project of Yunnan Province Applied Basic Research Project(No.2019FI001)Rare and Precious Metal Materials Genome Engineering Project of Yunnan Province(No.202002AB080001)Sichuan Natural Science Foundation(Nos.2022YFH0108 and 2022JDJQ0030).
文摘In-situ observation of the growth and decomposition processes is significantly important for guiding the fabrication of upconversion nanocrystals(UCNCs)with high performance.However,the high crystallization energy and rapid nucleation rate of the corresponding crystals make real-time observation still a huge challenge.Herein,the in-situ nucleation-growth-degradation processes of the UCNCs are investigated by employing tailored metastable intermediates,which possess a slowing-down nucleation rate under electron beam irradiation.The non-classical nucleation processes of the UCNCs,containing the coalescence of clusters and the subsequent crystallization,are demonstrated.Moreover,the Ostwald ripening and oriented attachment processes,which determine the particle size and morphology,are unambiguously recorded.Furthermore,the degrading process of the UCNCs is observed to be triggered by surface defects.Our work provides an insight into the real-time evolution dynamics of the UCNCs,which further sheds light on the fabrication of nano-sized up-conversion phosphors.
