Optical thermometry has attracted great attention because it enables accurate temperature measurement in harsh environments due to non-contact temperature measurement.Three-dimensional(3D)lead-free halide perovskites ...Optical thermometry has attracted great attention because it enables accurate temperature measurement in harsh environments due to non-contact temperature measurement.Three-dimensional(3D)lead-free halide perovskites have a great application potential in this field,due to its outstanding luminous properties and stability.In this work,the Sb^(3+)and Er^(3+)are introduced in Cs_(2)NaYCl_(6)double perovskites(DPs).The Sb^(3+)doping Cs_(2)NaYCl_(6)DPs exhibits bright blue emission from the Sb^(3+)activated self-trapped excitons(STEs) and Sb^(3+),Er^(3+)co-doped Cs_(2)NaYCl_(6)has efficient green emission with excellent photo luminescence quantum yields(PLQY) of 81.1% because of the presence of energy transfer from self-trapped excitons to Er^(3+)ions.Excitingly,the ratio between the fluorescence intensity at 524and 550 nm(FIR(I524 nm/I550 nm)) and the ratio between the fluorescence intensity at 524 and 456 nm(FIR(I524 nm/I456 nm)) both have a high correlation with temperature in the range of 298-473 K.The maximum of relative sensitivity values reach to 1.18%/K(I524 nm/I550 nm) and 1.19%/K(I524 nm/I456 nm) at298 K,respectively.The outstanding temperature sensitivity suggests that the Sb^(3+),Er^(3+)co-doped Cs_(2)NaYCl_(6)has enormous application potential in ratio metric optical thermometry.展开更多
To meet the high demands of modern technology for temperature sensors,Lu_(2)WO_(6):Sm^(3+)self-activated phosphors were selected to design four-mode optical thermometers.A comprehensive investigation was conducted on ...To meet the high demands of modern technology for temperature sensors,Lu_(2)WO_(6):Sm^(3+)self-activated phosphors were selected to design four-mode optical thermometers.A comprehensive investigation was conducted on the synthetic method,structural and luminescent characteristics,and energy transfer mechanism([WO6]6-→Sm^(3+)). Due to the different temperature responses of two emission centers([WO6]6-and Sm^(3+)),the temperature sensing capability of Lu_(2)WO_(6):Sm^(3+)phosphors was studied.Fluorescence intensity(FI),fluorescence intensity ratio(FIR),Commission Internationale de L'Eclairage coordinates and excitation intensity ratio are the four modes for temperature sensing,and their maximum relative sensitivities are 2.62%/K(350 K),2.06%/K(320 K),0.67%/K(329 K) and 2.42%/K(303 K),respectively.Furthermore,within 303-483 K temperature range,the relative sensitivities based on FI and FIR are bigger than 1.67%/K and 1.16%/K,respectively.Our findings suggest that Lu_(2)WO_(6):Sm^(3+)phosphors with four temperature measurement modes might be applied in multi-mode self-calibration optical thermometers.展开更多
Er^(3+)-Yb^(3+)-Li^+:Gd_2(MoO_4)_3 and Er^(3+)-Yb^(3+)-Zn^(2+):Gd_2(MoO_4)_3 nanophosphors,synthesized by chemical co-precipitation technique were characterized through XRD,FESEM,dynamic light scattering(DLS),diffuse ...Er^(3+)-Yb^(3+)-Li^+:Gd_2(MoO_4)_3 and Er^(3+)-Yb^(3+)-Zn^(2+):Gd_2(MoO_4)_3 nanophosphors,synthesized by chemical co-precipitation technique were characterized through XRD,FESEM,dynamic light scattering(DLS),diffuse reflectance,photoluminescence,photometric and decay time analysis.The enhancement of about~28,~149 and~351 times in the green upconversion emission band is observed for the optimized Er^(3+)-Yb^(3+),Er^(3+)-Yb^(3+)-Li^+and Er^(3+)-Yb^(3+)-Zn^(2+):Gd_2(MoO_4)_3 nanophosphors in comparison to the singly Er^(3+)doped nanophosphors.The electric dipole-dipole interaction is found to be responsible for the concentration quenching.The temperature dependent behaviour of the two green thermally coupled levels of the Er^(3+)ions based on the fluorescence intensity ratio technique was studied.The maximum sensor sensitivity~38.7×10^(-3)K^(-1)at 473 K for optimized Er^(3+)-Yb^(3+)-Zn^(2+)codoped Gd_2(MoO_4)_3 nanophosphors is reported with maximum population redistribution ability~88%among the~2H_(11/2)and~4S_(3/2)levels.展开更多
In order to meet the needs of new materials gradually developing towards miniaturization,integration,and light weight,multifunctional BaNb_(2)O_(6):Yb^(3+)/Er^(3+)/Tm^(3+)transparent glass-ceramics were success-fully ...In order to meet the needs of new materials gradually developing towards miniaturization,integration,and light weight,multifunctional BaNb_(2)O_(6):Yb^(3+)/Er^(3+)/Tm^(3+)transparent glass-ceramics were success-fully prepared by melt quenching and controllable crystallization.Its structure,luminescence,and en-ergy transmission were studied.Using the opposite temperature dependence of the Tm^(3+)emission band and the corresponding large energy level gap,a maximum relative sensitivity of 2.3%K^(-1)based on thermal coupling levels(TCLs)is obtained in a wide temperature range(298-673 K).The multi-ratio optical thermometry based on TCLs and non-TCLs is successfully realized by using the different emission bands of double emission centers,which makes it possible for self-reference optical temperature measurement modes.In addition,the transparent glass-ceramic exhibits excellent electrical properties under 700 kV cm^(-1)electric field:high discharge energy density(W_(d)=0.99 J cm^(-3)),huge instantaneous power density(225.3 MW cm^(-3)),and ultra-fast discharge rate(T_(0.9)≤15.8 ns).The prepared glass-ceramic is expected to be a new type of lead-free multifunctional photoelectric material for temperature sensors and transparent electronic devices.展开更多
Optical thermometry as an important local temperature-sensing technique,has received increasing attention in scientific and industrial areas.However,it is still a big challenge to develop luminescent materials with se...Optical thermometry as an important local temperature-sensing technique,has received increasing attention in scientific and industrial areas.However,it is still a big challenge to develop luminescent materials with self-activated dual-wavelength emissions toward high-sensitivity optical thermometers.Herein,a novel ratiometric thermometric strategy of Bi^(3+)-activated dual-wavelength emission band was realized in the same lattice position with two local electronic states of La_(3)Sb_(1-x)Ta_xO_(7):Bi^(3+)(0≤x≤1.0)materials based on the different temperature-dependent emission behaviors,benefiting from the highlysensitive and regulable emission to the coordination environment of Bi^(3+).The structural and spectral results demonstrate that the emission tremendously shifted from green to blue with 68 nm and the intensity was enhanced 2.6 times.Especially,the visual dual-wavelength emitting from two emission centers was presented by increasing the Ta^(5+)substitution concentration to 20%or 25%,mainly originating from the two local electronic states around the Bi^(3+)emission center.Significantly,the dual-wavelength with different thermal-quenching performance provided high-temperature sensitivity and good discrimination signals for optical thermometry in the range between 303 and 493 K.The maximum relative sensitivity reached 2.64%/K(La_(3)Sb_(0.8)Ta_(0.2)O_(7):0.04Bi^(3+)@383 K)and 1.91%/K(La_(3)Sb_(0.75)Ta_(0.25)O_(7):0.04Bi^(3+)@388 K).This work reveals a rational design strategy of different local electronic states around the singledoping multiple emission centers towards practical applications,such as luminescence thermometry and white LED lighting.展开更多
K_(0.5)Na_(0.5)NbO_(3)(KNN)-based ceramics,with high Curie temperatures and good ferroelectric performance,show promising potential as functional materials.In this study,the incorporation of CaTiO_(3)(CT)into KNN-base...K_(0.5)Na_(0.5)NbO_(3)(KNN)-based ceramics,with high Curie temperatures and good ferroelectric performance,show promising potential as functional materials.In this study,the incorporation of CaTiO_(3)(CT)into KNN-based ceramics resulted in a high density,submicrometer grain size,and pseudocubic phase,which collectively contributed to an impressive infrared transmittance of 78%at 1336 nm,as well as enhanced relaxor ferroelectric properties.A slim P–E loop and well-defined polar nanoregions(PNRs)can be clearly observed in the samples when the CT content exceeds 0.175.Moreover,we demonstrate that ultrahigh sensitivity in temperature sensing can be achieved via Pr^(3+)-doped KNN–CT on the basis of the fluorescence intensity ratio(FIR)of the^(1)D_(2)–^(3)H_(4)emission to the^(3)P_(0)–^(3)H_(5)emission.The FIR increases by as much as 75-fold when the temperature increases from room temperature to 500 K,resulting in exceptional absolute sensitivity(S_(a)=0.139 K^(−1))and relative sensitivity(S_(r)=2.69%/K).This exceptional FIR performance is believed to be closely linked to the temperature-sensitive PNRs in KNN–CT,highlighting its significant potential for applications in optical temperature sensors.展开更多
Zero-dimensional metal halide perovskites have captured intense research interest owing to their unique optoelectronic properties.Particularly,metal halides with the ns^(2) electronic configuration are of great intere...Zero-dimensional metal halide perovskites have captured intense research interest owing to their unique optoelectronic properties.Particularly,metal halides with the ns^(2) electronic configuration are of great interest owing to the high-temperature sensitivity of their photoluminescence,which could be applied to remote optical thermometry(ROT).Herein,all-inorganic and lead-free halide perovskite Te^(4+)-doped Cs_(2)InCl_(5)·H_(2)O single crystals(SCs)were prepared through the hydrothermal method and showed a strong temperature dependence of photoluminescence lifetime.Upon Te^(4+) doping,the nonemissive Cs_(2)InCl_(5)·H_(2)O SC exhibits a bright orange emission at 660 nm with a wide full width at half maximum of 180 nm.The strong phonon-exciton coupling promotes the formation of self-trapped excitons in the soft lattice of the zero-dimensional Te^(4+)-doped Cs_(2)InCl_(5)·H_(2)O SC.The Te^(4+) ions with the 5 s^(2) electronic configuration endow the Te^(4+)-doped Cs_(2)InCl_(5)·H_(2)O SC with a strong temperaturedependent photoluminescence lifetime.This SC reaches a maximum specific sensitivity of 0.062 K^(-1) at 320 K,thereby showing the potential advantages of indium-based metal halide perovskites in ROT applications.展开更多
A series of Bi^(3+)/Eu^(3+)co-doped Ca_(2)Ta_(2)O_(7)(CTO:Bi^(3+)/Eu^(3+))phosphors were prepared by high-temperature solid-state method for dual-emission center optical thermometers and white light-emitting diode(WLE...A series of Bi^(3+)/Eu^(3+)co-doped Ca_(2)Ta_(2)O_(7)(CTO:Bi^(3+)/Eu^(3+))phosphors were prepared by high-temperature solid-state method for dual-emission center optical thermometers and white light-emitting diode(WLED)device.By modulating the doping ratio of Bi^(3+)/Eu^(3+)and utilizing the energy transfer from Bi^(3+)to Eu^(3+),the tunable color emission ranging from green to reddish-orange was realized.The designed CTO:0.04Bi^(3+)/Eu^(3+)optical thermometers exhibit signifcant thermochromism,superior stability,and repeatability,with maximum sensitivities of Sa=0.055 K^(−1)(at 510 K)and Sr=1.298%K^(−1)(at 480 K)within the temperature range of 300−510 K,owing to the diferent thermal quenching behaviors between Bi^(3+)and Eu^(3+)ions.These features indicate the potential application prospects of the prepared samples in visualized thermometer or hightemperature safety marking.Furthermore,leveraging the excellent zero-thermal-quenching performance,outstanding acid/alkali resistance,and color stability of CTO:0.04Bi^(3+)/0.16Eu^(3+)phosphor,a WLED device with a high Ra value of 95.3 has been realized through its combination with commercially available blue and green phosphors,thereby demonstrating the potential application of CTO:0.04Bi^(3+)/0.16Eu^(3+)in near-UV pumped WLED devices.展开更多
To develop efficient luminescence and optical thermometry materials for color display and non-contact temperature measurement,novel RE^(3+)(RE=Eu,Sm)doped self-activated Na_(2)LuMg_(2)V_(3)O_(12)phosphors were prepare...To develop efficient luminescence and optical thermometry materials for color display and non-contact temperature measurement,novel RE^(3+)(RE=Eu,Sm)doped self-activated Na_(2)LuMg_(2)V_(3)O_(12)phosphors were prepared by a typical solid-state reaction method.Their crystal structure,morphology,multi-color luminescence and temperature sensing properties were elaborately investigated.Under UV light excitation,an intense and broad green-yellow emission band from VO_(4)^(3-)group is observed in the Na_(2)LuMg_(2)V_(3)O_(12)matrix,indicating its potential application in solid state lighting.After the incorpo ration of Eu^(3+)and Sm^(3+)ions,efficient energy transfer(ET)from VO_(4)^(3-)group to Eu^(3+)/Sm^(3+)ions occurs and the emission color of the samples can be readily tuned among different color ranges.Besides,based on the change of luminescence intensity and lifetimes of VO_(4)^(3-)group in Na_(2)LuMg_(2)V_(3)O_(12):Eu^(3+)and Na_(2)LuMg_(2)V_(3)O_(12):Sm^(3+),the ET efficiency was analyzed and the mechanism is illustrated.Finally,large discrepancy between the thermal stability of VO_(4)^(3-)group and Eu^(3+)/Sm^(3+)ions is observed in the temperature-dependent emission spectra of Na_(2)LuMg_(2)V_(3)O_(12):Eu^(3+)and Na_(2)LuMg_(2)V_(3)O_(12):Sm^(3+).By taking advantage of the luminescence intensity ratio(LIR)between VO_(4)^(3-)group and Eu^(3+)/Sm^(3+)ions in Na_(2)LuMg_(2)V_(3)O_(12):0.01Eu^(3+)and Na_(2)LuMg_(2)V_(3)O_(12):0.07Sm^(3+),two new types of optical thermometry mediums were designed and their basic temperature sensing parameters were calculated.展开更多
A novel non-contact optical thermometer,qualified with high sensitivity and temperature resolution,is urgently needed for temperature measuring of micro devices,moving objects and specific severe environments.Hence,a ...A novel non-contact optical thermometer,qualified with high sensitivity and temperature resolution,is urgently needed for temperature measuring of micro devices,moving objects and specific severe environments.Hence,a series of dual-emitting La_(5)Si_(2)BO_(13):Ce^(3+),Eu^(2+)phosphors were synthesized.The two ions show diverse responses with the changing in temperature.The variational emissions of Ce^(3+)and Eu^(2+)can be converted to FIR(fluorescence intensity ratio)signals.The maximal absolute sensitivity Sa and relative sensitivity Sr reach up to 0.07526%/K and 3.2241%/K,respectively.It is worthy noting that the Sa and Sr possess the same variation tendency and both have high values in the low temperature region(293-373 K),showing the great temperature measuring property especially in low temperature region.The temperature sensing characteristics are superior to the results of most previous reports.The energy transfer(ET)process is certified to occur from Ce^(3+)to Eu^(2+)ions.These studies indicate that La_(5)Si_(2)BO_(13):Ce^(3+),Eu^(2+)phosphor could have a good prospect for optical thermometry.展开更多
YBO3：2 at.% Eu3＋ was prepared by the solid state reaction and its temperature dependent luminescence was investigated for possible applications in temperature sensing. Phase composition of this material was confirme...YBO3：2 at.% Eu3＋ was prepared by the solid state reaction and its temperature dependent luminescence was investigated for possible applications in temperature sensing. Phase composition of this material was confirmed by X-ray powder diffraction analysis and excitation and emission spectra were also provided. Under excitation of 355 nm, the fluorescence originating from 5D0 and 5D1 states varied as the temperature rose in a region from 333 to 773 K. The fluorescence intensity ratio （FIR） of SD0 and 5D1 was investigated which increased significantly with the rise of temperature. The maximal relative sensitivity in the whole temperature range was 1.8% K-1（at 333 K）. The results recommended YBO3：Eu3＋ as a new material of the FIR method for non-contact optical thermometry.展开更多
The Er3+doped double perovskite Ba_(2)CaWO_(6) crystal is a promising ratiometric thermometer based on the fluorescence intensity ratio(FIR) of transitions from ^(2)H_(11/2) and ^(4)S_(3/2) to the lowered ^(4)I_(15/2)...The Er3+doped double perovskite Ba_(2)CaWO_(6) crystal is a promising ratiometric thermometer based on the fluorescence intensity ratio(FIR) of transitions from ^(2)H_(11/2) and ^(4)S_(3/2) to the lowered ^(4)I_(15/2) level.However,the Ca^(2+) vacancy defect caused by the charge difference between rare-earth ions and the substituted alkaline-earth ions gives rise to the non-radiative probability and limits the thermal sensitivity.Here,the up-conversion luminescence and thermometric performance of Er^(3+),Yb^(3+) dopedBa_(2)CaWO_(6) are tuned by tri-doping with alkaline ions.The Ca^(2+) vacancy defect can be eliminated by the introduction of Na^(+),which occupies the Ca^(2+) site when it is doped into Ba_(2)CaWO_(6) with Er^(3+) and Yb^(3+).On the contrary,the doping of Cs^(+) into Ba_(2)CaWO_(6) with Er^(3+) and Yb^(3+) enhances the defect concentration because it occupies the site of Ba^(2+).Thus,the tri-doping of Na^(+) reduces the non-radiative probability and enhances the quantum efficiency of Er^(3+),leading to the improvement of the thermometric sensitivity of Ba_(2)CaWO_(6).As a result,we get an excellent thermometric Ba_(2)CaWO_(6):8%Yb^(3+),3.5%Er^(3+),6%Na^(+) powder with a luminescence lifetime of 515 μs and maximum thermal sensitivity(S_(r)) of 1.45%/K,which is more than three times higher than that of the BCWO:Er^(3+) powder.展开更多
Eu^(2+)/Sm^(3+)co-doped dual-emitting Sr_(4)La(PO_(4))_(3)O phosphors were synthesized through a convenient high temperature solid state reaction in reductive atmosphere.The structure,luminescence,energy transfer and ...Eu^(2+)/Sm^(3+)co-doped dual-emitting Sr_(4)La(PO_(4))_(3)O phosphors were synthesized through a convenient high temperature solid state reaction in reductive atmosphere.The structure,luminescence,energy transfer and temperature-dependent luminescence properties of Eu^(2+)/Sm^(3+)co-doped Sr_(4)La(PO_(4))_(3)O phosphors were researched and analyzed in detail.The blue emission of Eu^(2+)and the red emission of Sm^(3+)can work together as FIR signals.Based on the different response characteristics of these two ion emissions to temperature,Sr_(4)La(PO_(4))_(3)O:Eu^(2+)/Sm^(^(3+))phosphor achieves the relative sensitivity of0.48384%/K and a wide range of temperature measurements from room temperature to 573 K.The results reveal that the Sr_(4)La(PO_(4))_(3)O:Eu^(2+)/Sm^(3+)phosphor has application prospect in the field of high temperature optical thermometry.The energy transfer mechanism is proved to be the dipole-dipole interaction between Eu^(2+)and Sm^(3+)ions.展开更多
Nd^(3+)-doped tellurite glasses are promising materials for thermometers based on the fluorescence intensity ratio(FIR)technique.Nevertheless,at high Nd^(3+)concentrations,energy transfer(ET)processes such as optical ...Nd^(3+)-doped tellurite glasses are promising materials for thermometers based on the fluorescence intensity ratio(FIR)technique.Nevertheless,at high Nd^(3+)concentrations,energy transfer(ET)processes such as optical reabsorption and cross-relaxation can affect the Nd^(3+)emission,which has been little explored in the literature.Therefore,the present work investigated the use of Nd^(3+)-doped tellurite glass(samples doped with Nd^(3+)at 0.2 mol%,0.5 mol%,2.0 mol%,and 4.0 mol%)in fluorescence thermometers,in the temperature range from 299 to 371 K.The results indicate a strong dependence of the FIR parameters on the Nd^(3+)concentration,due to changes in the emission band profiles caused by optical reabsorption of the Nd^(3+)emissions and cross-relaxation processes.A decrease of the relative sensitivity of the ratio^(4)F_(5/2)→^(4)I_(9/2)/^(4)F_(3/2)→^(4)I_(9/2)is observed for samples doped with higher amounts of Nd^(3+).The maximum relative sensitivity at 299 K is 3.00%/K,which is the highest value among the reported Nd^(3+)ions.展开更多
In this research,a series of Sm^(3+) doped CsLu(WO_(4))_(2) phosphors was prepared via high temperature solid phase technique to design new red phosphors and optical thermometric materials.Their structures,morphology,...In this research,a series of Sm^(3+) doped CsLu(WO_(4))_(2) phosphors was prepared via high temperature solid phase technique to design new red phosphors and optical thermometric materials.Their structures,morphology,band gap and luminescence properties were characterized by X-ray diffraction,scanning electron microscopy,diffuse reflection and luminescence spectra,respectively.Under UV excitation,CsLu(WO_(4))_(2) gives rise to a blue broad emission band between 350 and 700 nm,which stems from the ^(3)T_(1u)→^(1)A_(1g) transition of WO_(6)^(6-) groups.When Sm^(3+) is introduced into CsLu(WO_(4))_(2),energy transfer between WO_(6)^(6-) groups and Sm^(3+) ions takes place in CsLu(WO_(4))_(2):Sm^(3+)phosphors,and color-tunable luminescence from blue to red is realized by controlling the Sm^(3+) doping concentration.The energy transfer efficiency between WO_(6)^(6-) groups and Sm^(3+) ons was analyzed,and the energy transfer mechanism was determined to be dipole-dipole interactions.According to the temperature-dependent luminescence spectra,WO_(6)^(6-)groups and Sm^(3+)ions exhibit large discrepancy in thermal quenching rates,and thus the temperature sensing properties of CsLu(WO_(4))_(2):Sm^(3+) in the temperature range of 283-403 K were analyzed.Based on the framework of fluorescence intensity ratio theory,the basic optical thermometry parameters including absolute and relative sensitivity of CsLu(WO_(4))_(2):Sm^(3+) we re calculated and the results show that it has great potential for application in optical thermometry.展开更多
The upconversion(UC)phosphors in the series(100-x-y-z)Y2O^(3+)xLa_(2)O^(3+)yYb_(2)O^(3+)zEr_(2)O_(3)with x=0,2,4,6,8,and 10;y=3;z=0.1 were prepared by a combustion method to know the effect of La^(3+)doping on UC emis...The upconversion(UC)phosphors in the series(100-x-y-z)Y2O^(3+)xLa_(2)O^(3+)yYb_(2)O^(3+)zEr_(2)O_(3)with x=0,2,4,6,8,and 10;y=3;z=0.1 were prepared by a combustion method to know the effect of La^(3+)doping on UC emission wavelengths and their intensities.The UC emission has been studied under the 980 nm(power 166 mW)and 932 nm(variable power)diode laser excitation.The phosphors show the green and red band emission pertaining to Er^(3+)ions.It has been observed that with a lower concentration of La^(3+)ions(up to 6 mol%),the emission intensity of both bands decreased,with the red band emission remaining dominant.However,as the doping concentration exceeded 6 mol%,the emission intensity of the green band increased significantly,leading to a switch from the red to green band emission at 10 mol%La^(3+)doping.The variation in the UC emission intensity with the pump power and temperature has been measured.The Er^(3+)and Yb^(3+)co-doped UC phosphor with 10 mol%La^(3+)doping can be used in optical thermometry with the maximum absolute sensitivity of 0.0543 K^(-1)at 303.15 K.The cubic crystal structure of prepared samples has been confirmed by a powder X-ray diffraction study.Doping of La^(3+)did not change the crystal structure,but the variation in lattice parameters was witnessed due to the modification of the crystal field by the La^(3+)ion.The absorbance of samples over the spectral range of 200 nm–1100 nm has been measured by the diffuse reflectance spectroscopy.All samples exhibited large band gaps.The morphology of particles has been studied by the scanning electron microscopy.Commission International de I’Eclairage(CIE)color coordinates have been determined.展开更多
基金Project supported by the National Natural Science Foundation of China (52262020)。
文摘Optical thermometry has attracted great attention because it enables accurate temperature measurement in harsh environments due to non-contact temperature measurement.Three-dimensional(3D)lead-free halide perovskites have a great application potential in this field,due to its outstanding luminous properties and stability.In this work,the Sb^(3+)and Er^(3+)are introduced in Cs_(2)NaYCl_(6)double perovskites(DPs).The Sb^(3+)doping Cs_(2)NaYCl_(6)DPs exhibits bright blue emission from the Sb^(3+)activated self-trapped excitons(STEs) and Sb^(3+),Er^(3+)co-doped Cs_(2)NaYCl_(6)has efficient green emission with excellent photo luminescence quantum yields(PLQY) of 81.1% because of the presence of energy transfer from self-trapped excitons to Er^(3+)ions.Excitingly,the ratio between the fluorescence intensity at 524and 550 nm(FIR(I524 nm/I550 nm)) and the ratio between the fluorescence intensity at 524 and 456 nm(FIR(I524 nm/I456 nm)) both have a high correlation with temperature in the range of 298-473 K.The maximum of relative sensitivity values reach to 1.18%/K(I524 nm/I550 nm) and 1.19%/K(I524 nm/I456 nm) at298 K,respectively.The outstanding temperature sensitivity suggests that the Sb^(3+),Er^(3+)co-doped Cs_(2)NaYCl_(6)has enormous application potential in ratio metric optical thermometry.
文摘To meet the high demands of modern technology for temperature sensors,Lu_(2)WO_(6):Sm^(3+)self-activated phosphors were selected to design four-mode optical thermometers.A comprehensive investigation was conducted on the synthetic method,structural and luminescent characteristics,and energy transfer mechanism([WO6]6-→Sm^(3+)). Due to the different temperature responses of two emission centers([WO6]6-and Sm^(3+)),the temperature sensing capability of Lu_(2)WO_(6):Sm^(3+)phosphors was studied.Fluorescence intensity(FI),fluorescence intensity ratio(FIR),Commission Internationale de L'Eclairage coordinates and excitation intensity ratio are the four modes for temperature sensing,and their maximum relative sensitivities are 2.62%/K(350 K),2.06%/K(320 K),0.67%/K(329 K) and 2.42%/K(303 K),respectively.Furthermore,within 303-483 K temperature range,the relative sensitivities based on FI and FIR are bigger than 1.67%/K and 1.16%/K,respectively.Our findings suggest that Lu_(2)WO_(6):Sm^(3+)phosphors with four temperature measurement modes might be applied in multi-mode self-calibration optical thermometers.
基金Project supported by Council of Scientific&Industrial Research(CSIR),New Delhi,India(03(1354)/16/EMR-II)
文摘Er^(3+)-Yb^(3+)-Li^+:Gd_2(MoO_4)_3 and Er^(3+)-Yb^(3+)-Zn^(2+):Gd_2(MoO_4)_3 nanophosphors,synthesized by chemical co-precipitation technique were characterized through XRD,FESEM,dynamic light scattering(DLS),diffuse reflectance,photoluminescence,photometric and decay time analysis.The enhancement of about~28,~149 and~351 times in the green upconversion emission band is observed for the optimized Er^(3+)-Yb^(3+),Er^(3+)-Yb^(3+)-Li^+and Er^(3+)-Yb^(3+)-Zn^(2+):Gd_2(MoO_4)_3 nanophosphors in comparison to the singly Er^(3+)doped nanophosphors.The electric dipole-dipole interaction is found to be responsible for the concentration quenching.The temperature dependent behaviour of the two green thermally coupled levels of the Er^(3+)ions based on the fluorescence intensity ratio technique was studied.The maximum sensor sensitivity~38.7×10^(-3)K^(-1)at 473 K for optimized Er^(3+)-Yb^(3+)-Zn^(2+)codoped Gd_2(MoO_4)_3 nanophosphors is reported with maximum population redistribution ability~88%among the~2H_(11/2)and~4S_(3/2)levels.
基金This work was financially supported by the National Natural Science Foundation of China(No.61865003)Project of Guangxi Key Laboratory of Information Materials(No.211009-Z).
文摘In order to meet the needs of new materials gradually developing towards miniaturization,integration,and light weight,multifunctional BaNb_(2)O_(6):Yb^(3+)/Er^(3+)/Tm^(3+)transparent glass-ceramics were success-fully prepared by melt quenching and controllable crystallization.Its structure,luminescence,and en-ergy transmission were studied.Using the opposite temperature dependence of the Tm^(3+)emission band and the corresponding large energy level gap,a maximum relative sensitivity of 2.3%K^(-1)based on thermal coupling levels(TCLs)is obtained in a wide temperature range(298-673 K).The multi-ratio optical thermometry based on TCLs and non-TCLs is successfully realized by using the different emission bands of double emission centers,which makes it possible for self-reference optical temperature measurement modes.In addition,the transparent glass-ceramic exhibits excellent electrical properties under 700 kV cm^(-1)electric field:high discharge energy density(W_(d)=0.99 J cm^(-3)),huge instantaneous power density(225.3 MW cm^(-3)),and ultra-fast discharge rate(T_(0.9)≤15.8 ns).The prepared glass-ceramic is expected to be a new type of lead-free multifunctional photoelectric material for temperature sensors and transparent electronic devices.
基金supported by the National Natural Science Foundation of China(Nos.52072101,51972088,52172205)the Fundamental Research Funds for the Provincial Universities of Zhejiang(No.GK229909299001-003)the Postgraduate Research Innovation Fund of Hangzhou Dianzi University(No.CXJJ2022032)。
文摘Optical thermometry as an important local temperature-sensing technique,has received increasing attention in scientific and industrial areas.However,it is still a big challenge to develop luminescent materials with self-activated dual-wavelength emissions toward high-sensitivity optical thermometers.Herein,a novel ratiometric thermometric strategy of Bi^(3+)-activated dual-wavelength emission band was realized in the same lattice position with two local electronic states of La_(3)Sb_(1-x)Ta_xO_(7):Bi^(3+)(0≤x≤1.0)materials based on the different temperature-dependent emission behaviors,benefiting from the highlysensitive and regulable emission to the coordination environment of Bi^(3+).The structural and spectral results demonstrate that the emission tremendously shifted from green to blue with 68 nm and the intensity was enhanced 2.6 times.Especially,the visual dual-wavelength emitting from two emission centers was presented by increasing the Ta^(5+)substitution concentration to 20%or 25%,mainly originating from the two local electronic states around the Bi^(3+)emission center.Significantly,the dual-wavelength with different thermal-quenching performance provided high-temperature sensitivity and good discrimination signals for optical thermometry in the range between 303 and 493 K.The maximum relative sensitivity reached 2.64%/K(La_(3)Sb_(0.8)Ta_(0.2)O_(7):0.04Bi^(3+)@383 K)and 1.91%/K(La_(3)Sb_(0.75)Ta_(0.25)O_(7):0.04Bi^(3+)@388 K).This work reveals a rational design strategy of different local electronic states around the singledoping multiple emission centers towards practical applications,such as luminescence thermometry and white LED lighting.
基金supported by the National Natural Science Foundation of China(No.52372104)the Guangdong Basic and Applied Research Foundation(No.2024A1515012377)the Key Discipline of Materials Science and Engineering,Bureau of Education of Guangzhou(No.202255464).
文摘K_(0.5)Na_(0.5)NbO_(3)(KNN)-based ceramics,with high Curie temperatures and good ferroelectric performance,show promising potential as functional materials.In this study,the incorporation of CaTiO_(3)(CT)into KNN-based ceramics resulted in a high density,submicrometer grain size,and pseudocubic phase,which collectively contributed to an impressive infrared transmittance of 78%at 1336 nm,as well as enhanced relaxor ferroelectric properties.A slim P–E loop and well-defined polar nanoregions(PNRs)can be clearly observed in the samples when the CT content exceeds 0.175.Moreover,we demonstrate that ultrahigh sensitivity in temperature sensing can be achieved via Pr^(3+)-doped KNN–CT on the basis of the fluorescence intensity ratio(FIR)of the^(1)D_(2)–^(3)H_(4)emission to the^(3)P_(0)–^(3)H_(5)emission.The FIR increases by as much as 75-fold when the temperature increases from room temperature to 500 K,resulting in exceptional absolute sensitivity(S_(a)=0.139 K^(−1))and relative sensitivity(S_(r)=2.69%/K).This exceptional FIR performance is believed to be closely linked to the temperature-sensitive PNRs in KNN–CT,highlighting its significant potential for applications in optical temperature sensors.
基金supported by the National Natural Science Foundation of China(U2001214)the Natural Science Foundation of Guangdong Province(2019B1515120050)the Fundamental Research Funds for the Central Universities。
文摘Zero-dimensional metal halide perovskites have captured intense research interest owing to their unique optoelectronic properties.Particularly,metal halides with the ns^(2) electronic configuration are of great interest owing to the high-temperature sensitivity of their photoluminescence,which could be applied to remote optical thermometry(ROT).Herein,all-inorganic and lead-free halide perovskite Te^(4+)-doped Cs_(2)InCl_(5)·H_(2)O single crystals(SCs)were prepared through the hydrothermal method and showed a strong temperature dependence of photoluminescence lifetime.Upon Te^(4+) doping,the nonemissive Cs_(2)InCl_(5)·H_(2)O SC exhibits a bright orange emission at 660 nm with a wide full width at half maximum of 180 nm.The strong phonon-exciton coupling promotes the formation of self-trapped excitons in the soft lattice of the zero-dimensional Te^(4+)-doped Cs_(2)InCl_(5)·H_(2)O SC.The Te^(4+) ions with the 5 s^(2) electronic configuration endow the Te^(4+)-doped Cs_(2)InCl_(5)·H_(2)O SC with a strong temperaturedependent photoluminescence lifetime.This SC reaches a maximum specific sensitivity of 0.062 K^(-1) at 320 K,thereby showing the potential advantages of indium-based metal halide perovskites in ROT applications.
基金the fnancial support of Innovative Research Team of Ningde Normal University(No.2023T03)the Natural Science Foundation of Fujian Province(No.2021J011149)Fujian Provincial Department of Education(No.JAT210469,JAT220282).
文摘A series of Bi^(3+)/Eu^(3+)co-doped Ca_(2)Ta_(2)O_(7)(CTO:Bi^(3+)/Eu^(3+))phosphors were prepared by high-temperature solid-state method for dual-emission center optical thermometers and white light-emitting diode(WLED)device.By modulating the doping ratio of Bi^(3+)/Eu^(3+)and utilizing the energy transfer from Bi^(3+)to Eu^(3+),the tunable color emission ranging from green to reddish-orange was realized.The designed CTO:0.04Bi^(3+)/Eu^(3+)optical thermometers exhibit signifcant thermochromism,superior stability,and repeatability,with maximum sensitivities of Sa=0.055 K^(−1)(at 510 K)and Sr=1.298%K^(−1)(at 480 K)within the temperature range of 300−510 K,owing to the diferent thermal quenching behaviors between Bi^(3+)and Eu^(3+)ions.These features indicate the potential application prospects of the prepared samples in visualized thermometer or hightemperature safety marking.Furthermore,leveraging the excellent zero-thermal-quenching performance,outstanding acid/alkali resistance,and color stability of CTO:0.04Bi^(3+)/0.16Eu^(3+)phosphor,a WLED device with a high Ra value of 95.3 has been realized through its combination with commercially available blue and green phosphors,thereby demonstrating the potential application of CTO:0.04Bi^(3+)/0.16Eu^(3+)in near-UV pumped WLED devices.
基金Project supported by Natural Science Foundation of Shandong Province(ZR2020KF017,ZR2020QE053,ZR2023QB261)the Natural Science Foundation of Anhui Province(2108085MB53)。
文摘To develop efficient luminescence and optical thermometry materials for color display and non-contact temperature measurement,novel RE^(3+)(RE=Eu,Sm)doped self-activated Na_(2)LuMg_(2)V_(3)O_(12)phosphors were prepared by a typical solid-state reaction method.Their crystal structure,morphology,multi-color luminescence and temperature sensing properties were elaborately investigated.Under UV light excitation,an intense and broad green-yellow emission band from VO_(4)^(3-)group is observed in the Na_(2)LuMg_(2)V_(3)O_(12)matrix,indicating its potential application in solid state lighting.After the incorpo ration of Eu^(3+)and Sm^(3+)ions,efficient energy transfer(ET)from VO_(4)^(3-)group to Eu^(3+)/Sm^(3+)ions occurs and the emission color of the samples can be readily tuned among different color ranges.Besides,based on the change of luminescence intensity and lifetimes of VO_(4)^(3-)group in Na_(2)LuMg_(2)V_(3)O_(12):Eu^(3+)and Na_(2)LuMg_(2)V_(3)O_(12):Sm^(3+),the ET efficiency was analyzed and the mechanism is illustrated.Finally,large discrepancy between the thermal stability of VO_(4)^(3-)group and Eu^(3+)/Sm^(3+)ions is observed in the temperature-dependent emission spectra of Na_(2)LuMg_(2)V_(3)O_(12):Eu^(3+)and Na_(2)LuMg_(2)V_(3)O_(12):Sm^(3+).By taking advantage of the luminescence intensity ratio(LIR)between VO_(4)^(3-)group and Eu^(3+)/Sm^(3+)ions in Na_(2)LuMg_(2)V_(3)O_(12):0.01Eu^(3+)and Na_(2)LuMg_(2)V_(3)O_(12):0.07Sm^(3+),two new types of optical thermometry mediums were designed and their basic temperature sensing parameters were calculated.
基金Project supported by Natural Science Foundation of Zhejiang Province,China(LY19E020005)Science and Technology Innovation Platform and Talent Plan of Zhejiang(2017R52037)。
文摘A novel non-contact optical thermometer,qualified with high sensitivity and temperature resolution,is urgently needed for temperature measuring of micro devices,moving objects and specific severe environments.Hence,a series of dual-emitting La_(5)Si_(2)BO_(13):Ce^(3+),Eu^(2+)phosphors were synthesized.The two ions show diverse responses with the changing in temperature.The variational emissions of Ce^(3+)and Eu^(2+)can be converted to FIR(fluorescence intensity ratio)signals.The maximal absolute sensitivity Sa and relative sensitivity Sr reach up to 0.07526%/K and 3.2241%/K,respectively.It is worthy noting that the Sa and Sr possess the same variation tendency and both have high values in the low temperature region(293-373 K),showing the great temperature measuring property especially in low temperature region.The temperature sensing characteristics are superior to the results of most previous reports.The energy transfer(ET)process is certified to occur from Ce^(3+)to Eu^(2+)ions.These studies indicate that La_(5)Si_(2)BO_(13):Ce^(3+),Eu^(2+)phosphor could have a good prospect for optical thermometry.
基金Project supported by the National Key Basic Research Program of China(2013CB921800)the National Natural Science Foundation of China(11374291,11204292,11274299 and 11311120047)the Fundamental Research Funds for the Central Universities(WK2030020021)
文摘YBO3：2 at.% Eu3＋ was prepared by the solid state reaction and its temperature dependent luminescence was investigated for possible applications in temperature sensing. Phase composition of this material was confirmed by X-ray powder diffraction analysis and excitation and emission spectra were also provided. Under excitation of 355 nm, the fluorescence originating from 5D0 and 5D1 states varied as the temperature rose in a region from 333 to 773 K. The fluorescence intensity ratio （FIR） of SD0 and 5D1 was investigated which increased significantly with the rise of temperature. The maximal relative sensitivity in the whole temperature range was 1.8% K-1（at 333 K）. The results recommended YBO3：Eu3＋ as a new material of the FIR method for non-contact optical thermometry.
基金Project supported by the National Natural Science Foundation of China (51972061,22109025,22171045,52072076)。
文摘The Er3+doped double perovskite Ba_(2)CaWO_(6) crystal is a promising ratiometric thermometer based on the fluorescence intensity ratio(FIR) of transitions from ^(2)H_(11/2) and ^(4)S_(3/2) to the lowered ^(4)I_(15/2) level.However,the Ca^(2+) vacancy defect caused by the charge difference between rare-earth ions and the substituted alkaline-earth ions gives rise to the non-radiative probability and limits the thermal sensitivity.Here,the up-conversion luminescence and thermometric performance of Er^(3+),Yb^(3+) dopedBa_(2)CaWO_(6) are tuned by tri-doping with alkaline ions.The Ca^(2+) vacancy defect can be eliminated by the introduction of Na^(+),which occupies the Ca^(2+) site when it is doped into Ba_(2)CaWO_(6) with Er^(3+) and Yb^(3+).On the contrary,the doping of Cs^(+) into Ba_(2)CaWO_(6) with Er^(3+) and Yb^(3+) enhances the defect concentration because it occupies the site of Ba^(2+).Thus,the tri-doping of Na^(+) reduces the non-radiative probability and enhances the quantum efficiency of Er^(3+),leading to the improvement of the thermometric sensitivity of Ba_(2)CaWO_(6).As a result,we get an excellent thermometric Ba_(2)CaWO_(6):8%Yb^(3+),3.5%Er^(3+),6%Na^(+) powder with a luminescence lifetime of 515 μs and maximum thermal sensitivity(S_(r)) of 1.45%/K,which is more than three times higher than that of the BCWO:Er^(3+) powder.
基金Project supported by Natural Science Foundation of Zhejiang Province,China(LY19E020005)Science and Technology Innovation Platform and Talent Plan of Zhejiang(2017R52037)。
文摘Eu^(2+)/Sm^(3+)co-doped dual-emitting Sr_(4)La(PO_(4))_(3)O phosphors were synthesized through a convenient high temperature solid state reaction in reductive atmosphere.The structure,luminescence,energy transfer and temperature-dependent luminescence properties of Eu^(2+)/Sm^(3+)co-doped Sr_(4)La(PO_(4))_(3)O phosphors were researched and analyzed in detail.The blue emission of Eu^(2+)and the red emission of Sm^(3+)can work together as FIR signals.Based on the different response characteristics of these two ion emissions to temperature,Sr_(4)La(PO_(4))_(3)O:Eu^(2+)/Sm^(^(3+))phosphor achieves the relative sensitivity of0.48384%/K and a wide range of temperature measurements from room temperature to 573 K.The results reveal that the Sr_(4)La(PO_(4))_(3)O:Eu^(2+)/Sm^(3+)phosphor has application prospect in the field of high temperature optical thermometry.The energy transfer mechanism is proved to be the dipole-dipole interaction between Eu^(2+)and Sm^(3+)ions.
基金Project supported by National Council for Scientific and Technological Development(CNPq)(#305067/2019-2,#303707/2022-4,#306452/2018-9)the Development of Education and Science and Technology of the State of Mato Grosso do Sul(FUNDECT)(#59/300.634/2016,#71/027.247/2022)。
文摘Nd^(3+)-doped tellurite glasses are promising materials for thermometers based on the fluorescence intensity ratio(FIR)technique.Nevertheless,at high Nd^(3+)concentrations,energy transfer(ET)processes such as optical reabsorption and cross-relaxation can affect the Nd^(3+)emission,which has been little explored in the literature.Therefore,the present work investigated the use of Nd^(3+)-doped tellurite glass(samples doped with Nd^(3+)at 0.2 mol%,0.5 mol%,2.0 mol%,and 4.0 mol%)in fluorescence thermometers,in the temperature range from 299 to 371 K.The results indicate a strong dependence of the FIR parameters on the Nd^(3+)concentration,due to changes in the emission band profiles caused by optical reabsorption of the Nd^(3+)emissions and cross-relaxation processes.A decrease of the relative sensitivity of the ratio^(4)F_(5/2)→^(4)I_(9/2)/^(4)F_(3/2)→^(4)I_(9/2)is observed for samples doped with higher amounts of Nd^(3+).The maximum relative sensitivity at 299 K is 3.00%/K,which is the highest value among the reported Nd^(3+)ions.
基金Project supported by the Natural Science Foundation (NSF)of Anhui Province (2108085MB53)the NSF for Distinguished Young Scholars of Anhui University (2022AH020087)University NSF of Anhui Province(KJ2020A0647)。
文摘In this research,a series of Sm^(3+) doped CsLu(WO_(4))_(2) phosphors was prepared via high temperature solid phase technique to design new red phosphors and optical thermometric materials.Their structures,morphology,band gap and luminescence properties were characterized by X-ray diffraction,scanning electron microscopy,diffuse reflection and luminescence spectra,respectively.Under UV excitation,CsLu(WO_(4))_(2) gives rise to a blue broad emission band between 350 and 700 nm,which stems from the ^(3)T_(1u)→^(1)A_(1g) transition of WO_(6)^(6-) groups.When Sm^(3+) is introduced into CsLu(WO_(4))_(2),energy transfer between WO_(6)^(6-) groups and Sm^(3+) ions takes place in CsLu(WO_(4))_(2):Sm^(3+)phosphors,and color-tunable luminescence from blue to red is realized by controlling the Sm^(3+) doping concentration.The energy transfer efficiency between WO_(6)^(6-) groups and Sm^(3+) ons was analyzed,and the energy transfer mechanism was determined to be dipole-dipole interactions.According to the temperature-dependent luminescence spectra,WO_(6)^(6-)groups and Sm^(3+)ions exhibit large discrepancy in thermal quenching rates,and thus the temperature sensing properties of CsLu(WO_(4))_(2):Sm^(3+) in the temperature range of 283-403 K were analyzed.Based on the framework of fluorescence intensity ratio theory,the basic optical thermometry parameters including absolute and relative sensitivity of CsLu(WO_(4))_(2):Sm^(3+) we re calculated and the results show that it has great potential for application in optical thermometry.
文摘The upconversion(UC)phosphors in the series(100-x-y-z)Y2O^(3+)xLa_(2)O^(3+)yYb_(2)O^(3+)zEr_(2)O_(3)with x=0,2,4,6,8,and 10;y=3;z=0.1 were prepared by a combustion method to know the effect of La^(3+)doping on UC emission wavelengths and their intensities.The UC emission has been studied under the 980 nm(power 166 mW)and 932 nm(variable power)diode laser excitation.The phosphors show the green and red band emission pertaining to Er^(3+)ions.It has been observed that with a lower concentration of La^(3+)ions(up to 6 mol%),the emission intensity of both bands decreased,with the red band emission remaining dominant.However,as the doping concentration exceeded 6 mol%,the emission intensity of the green band increased significantly,leading to a switch from the red to green band emission at 10 mol%La^(3+)doping.The variation in the UC emission intensity with the pump power and temperature has been measured.The Er^(3+)and Yb^(3+)co-doped UC phosphor with 10 mol%La^(3+)doping can be used in optical thermometry with the maximum absolute sensitivity of 0.0543 K^(-1)at 303.15 K.The cubic crystal structure of prepared samples has been confirmed by a powder X-ray diffraction study.Doping of La^(3+)did not change the crystal structure,but the variation in lattice parameters was witnessed due to the modification of the crystal field by the La^(3+)ion.The absorbance of samples over the spectral range of 200 nm–1100 nm has been measured by the diffuse reflectance spectroscopy.All samples exhibited large band gaps.The morphology of particles has been studied by the scanning electron microscopy.Commission International de I’Eclairage(CIE)color coordinates have been determined.
基金supported by the National Key Research and Development Program of China(2021YFE0105700)the National Natural Science Foundation of China(52302177 and 51972118)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01X137)。
