Lishiite,(Ca_(2)□)Sr_(3)(CO_(3))_(5),is a new mineral species from Shaxiongdong,Hubei Province,China.It mainly occours as conchoidal crystals and with combination of hexagonal prism and pyramid and is associated with...Lishiite,(Ca_(2)□)Sr_(3)(CO_(3))_(5),is a new mineral species from Shaxiongdong,Hubei Province,China.It mainly occours as conchoidal crystals and with combination of hexagonal prism and pyramid and is associated with calcite,K-feldspar,albite,aegirine,apatite,and ancylite-(Ce)(?)and strontianite etc.Lishiite is brittle with conchiform fracture and has a Mohs hardness of approximately 4 and none cleavages were observed.The Vickers microhardness(VHN10)is 197.42 kg/mm^(2)(range:166.88 kg/mm^(2) to 214.58 kg/mm^(2)),and the calculated density of lishiite is 3.696 g/cm3.Hand specimen of lishiite are yellow-brown.The empirical chemical formula of the lishiite is ^(A)(Ca_(1.18)Sr_(0.25)Na_(0.19□1.38))_(Σ3.00)^( B)[Sr_(2.17)(Ce_(0.42)La_(0.24)Nd_(0.09)Eu_(0.01))_(Σ0.76) Ba_(0.07)]_(Σ3.00)(C_(5.05)O_(15)).As a member of the burbankite group,the general formula of lishiite follows the general formula A_(3)B_(3)(CO_(3))_(5),where A=Na,Ca,or and B=Sr,Ba,REE,or Ca.Its crystal structure is hexagonal(space group P6_(3)mc)with unit cell parameters a=10.4898(5)Å,c=6.4167(5)Å,and V=611.47(6)Å^(3),characterized by layers of AO_(8) and BO_(10) polyhedra connected to[CO_(3)]^(3−)groups.The discovery of lishiite provides new insights into the evolutionary history of rare earth element(REE)carbonate deposit formation.展开更多
A set of germanate garnet phosphors containing Tb^(3+)and Eu^(3+)were adequately synthesized using the high-temperature solid-state technique.The structural properties,photoluminescence characteristics,fluorescence li...A set of germanate garnet phosphors containing Tb^(3+)and Eu^(3+)were adequately synthesized using the high-temperature solid-state technique.The structural properties,photoluminescence characteristics,fluorescence lifetimes,and temperature-sensing capabilities of the phosphors were thoroughly investigated.X-ray diffraction confirms the crystalline structure of the phosphors,while photoluminescence spectra reveal a colour shift attributed to the trans fer of energy from Tb^(3+)to Eu^(3+)as the concentration of Eu^(3+)increases.The phosphors excited by UV light display a transition in colour from green to yellow,and subsequently to red,which can be used as a colour tunable phosphor in white light-emitting diode(w-LED) applications.As a novel temperature sensing material,the maximum relative sensitivity of Ca_(3)Sc_(2)Ge_(3)O_(12):Tb^(3+),Eu^(3+)phosphor is 0.1044 K-1(298 K),highlighting its potential for applications in temperature sensing.展开更多
In this paper,we developed low dose X-ray induced long afterglow phosphor Ca_(2)P_(2)O_(7):Pr^(3+),which shows excellent afterglow luminescence from ultraviolet C(UVC)to red region.The photoluminescent results show th...In this paper,we developed low dose X-ray induced long afterglow phosphor Ca_(2)P_(2)O_(7):Pr^(3+),which shows excellent afterglow luminescence from ultraviolet C(UVC)to red region.The photoluminescent results show that under 445.7 nm excitation,Ca_(1.995)P_(2)O_(7):0.5%Pr3+displays red emissions peaked at 598.3 and651.9 nm,corresponding to1D2-3H4and3P0-3F2transitions of Pr^(3+),respectively.Due to its pure red emission(CIE coordinates(0.59101,0.39926)),Ca_(1.995)P_(2)O_(7):0.5%Pr^(3+)can be regarded as a potential LED red phosphor.More importantly,Ca_(2)P_(2)O_(7):Pr^(3+)shows long afterglow luminescence from UVC to red region,which consists of four co ntinuous emissions with similar intensity including 260,359,466 and 598.3 nm.Since these afterglow continuous emissions are fitted to the absorption of most photodynamic therapy(PDT)agents,Ca_(2)P_(2)O_(7):Pr^(3+)can be regarded as excellent PDT agents.Furthermo re,30 s X-ray irradiation can induce 5400 s decay of Ca_(1.997)P_(2)O_(7):0.3%Pr^(3+),and its afterglow emission intensity still reaches 5×10^(4)cps after 5400 s decay.Even only 5 s X-ray irradiation also can produce 4.75×10^(4)cps afterglow emis sion after10 s decay.In addition,the repeat 980 nm laser irradiations can induce co ntinuous strong photo-stimulated(PSL)luminescent peaks,which can be utilized to conduct high efficiency PDT without another X-ray irradiation.The thermoluminesce nce results reveal that the existence of shallow(0.89 eV)and deep traps are responsible for the excellent X-ray induced long afterglow and PSL luminescence.All these results suggest that Ca_(2)P2O7:Pr^(3+)possesses great potential to be regarded as high efficiency PDT agents.展开更多
In this study,a novel Ca_(2)GaTaO_(6):Sm^(3+)phosphor was developed using the conventional hightemperature solid-phase method.The phase structure and morphology test results of phosphor indicate that the Ca_(2)GaTaO_(...In this study,a novel Ca_(2)GaTaO_(6):Sm^(3+)phosphor was developed using the conventional hightemperature solid-phase method.The phase structure and morphology test results of phosphor indicate that the Ca_(2)GaTaO_(6):Sm^(3+)material was successfully synthesized and the Sm^(3+)ions were successfully doped into the host lattice.When utilizing 406 nm excitation,the Ca_(2)GaTaO_(6):Sm^(3+)phosphor has the strongest emission intensity at 599 nm and shows orange-red emission,which is mainly owing to the^(4)G_(5/2)→^(6)H_(7/2)jump of Sm^(3+)ions.For the performance of different concentrations of Sm^(3+)ions,3 mol%performs the best.At this time,concentration quenching occurs,which is most predominantly induced by dipole-dipole(d-d)interactions.In terms of thermal stability,the Ca_(2)GaTaO_(6):Sm^(3+)phosphor shows good properties,with the luminescence intensity at 423 K exhibiting 88.17%of that at 298 K.The white light-emitting diodes(WLEDs)devices prepared using Ca_(2)GaTaO_(6):Sm^(3+):0.03Sm^(3+)phosphor shows warm white light with excellent performance in terms of correlated color temperature and color rendering index(CCT=3642 K,CRI,Ra=93.5).In terms of anticounterfeit inks,the Ca_(2)GaTaO_(6):Sm^(3+)phosphor also shows good potential.These research results show that Ca_(2)GaTaO_(6):Sm^(3+)phosphors have great performance for application in WLEDs and anti-counterfeit inks.展开更多
Solid-state lighting is now developing toward high-power and super-brightness,but is largely limited by the lack of highly robust and efficient color conversion materials that can be survived from high-power or high-p...Solid-state lighting is now developing toward high-power and super-brightness,but is largely limited by the lack of highly robust and efficient color conversion materials that can be survived from high-power or high-power density excitation,typically the red-emitting ones.In this work,we fabricated highly effi-cient and pore-free Sr_(0.5)Ca_(0.5)AlSiN_(3)∶Eu^(2+)(SCASN)red-emitting ceramics by spark plasma sintering of fine phosphor powders.These fine phosphor powders were prepared by treating the commercial phosphors with high-energy ball-milling,centrifugation and acid washing,leading to a particle size of 2.55μm and an internal quantum efficiency as high as 74.0%under 450 nm excitation.The phosphor powders can be densified into SCASN ceramics without using sintering additives at a temperature as low as 1475℃,and the ceramics show an internal quantum efficiency of 75.3%,which is 50%higher than those ceram-ics fabricated with untreated commercial powders.When excited by a high-power blue LED at a current density of 4 A/mm^(2),the SCASN ceramics have a maximum luminous flux of 660 lm(i.e.,26 Mcd/m^(2)).The phosphor ceramics can also withstand a high laser power density of 15.7 W/mm^(2),and exhibit an output luminance of 188 Mcd/m^(2).This work provides a general method to prepare fine phosphor powders that enable to fabricate high efficiency phosphor ceramics used in high-power solid-state lighting.展开更多
Er^(3+)-and Tm^(3+)-doped Ca_(x)Sr_(2-x)Nb_(2)O_(7)(C_(x)S_(2-x)N,x=0.6,0.8,1,0,1.2,1,4) phosphors with layered pe rovskite structure were designed.These phosphors exhibit a dominant emission peak at 549 nm under980 n...Er^(3+)-and Tm^(3+)-doped Ca_(x)Sr_(2-x)Nb_(2)O_(7)(C_(x)S_(2-x)N,x=0.6,0.8,1,0,1.2,1,4) phosphors with layered pe rovskite structure were designed.These phosphors exhibit a dominant emission peak at 549 nm under980 nm laser excitation,attributed to the^(4)S_(3/2)→^(4)I_(15/2)transition.By increasing the content of Ca^(2+),the crystal field regulation of rare earth ions is realized and the luminescence enhancement is induced,which is manifested by the increase of^(2)H_(11/2),^(4)S_(3/2)→^(4)I_(15/2)emission.Furthermore,the temperature sensing sensitivities of C_(0.6)S_(1.4)N:Er,Tm and C_(0.6)S_(1.4)N:Er,Tm based on non-thermally coupled energy levels were studied.Finally,an anti-counterfeiting imprint was prepared using phosphors,which have high brightness and excellent photothermal stability.This work not only confirms that closer ionic radii substitution enables to increase the electronic density of states,improve the crystal field symmetry and enhance the luminescence,but also provides a promising phosphor system for temperature sensing and anti-counterfeiting applications,opening up new prospects in the optimization of the optical properties of phosphors.展开更多
Exploring high-performance broadband near-infrared(NIR)emitting materials is crucial for the development of NIR devices.In this study,Ca_(3)MgSn_(0.5)Zr_(0.5)Ge_(3)O_(12):Cr^(3+)and rare earth ion Pr^(3+)co-doped Ca_(...Exploring high-performance broadband near-infrared(NIR)emitting materials is crucial for the development of NIR devices.In this study,Ca_(3)MgSn_(0.5)Zr_(0.5)Ge_(3)O_(12):Cr^(3+)and rare earth ion Pr^(3+)co-doped Ca_(3)MgSn_(0.5)Zr_(0.5)Ge_(3)O_(12):Pr^(3+),Cr^(3+)phosphors were successfully synthesized.By utilizing time-resolved emission spectroscopy(TRES),photo luminescence(PL)spectra,and fluorescence decay curve,the Ca_(3)MgSn_(0.5)Zr_(0.5)Ge_(3)O_(12):Cr^(3+)phosphor is determined to exhibit a broadband emission(650-1150 nm)with a peak at 795 nm due to Cr^(3+)occupying multiple cationic sites,Ca_(3)MgSn_(0.5)Zr_(0.5)Ge_(3)O_(12):0.1Cr^(3+)has excellent thermal stability(86%@425 K),and co-doping Pr^(3+)ions into Ca_(3)MgSn_(0.5)Zr_(0.5)Ge_(3)O_(12):0.1Cr^(3+)obtains highly efficient NIR emission.The Ca_(3)MgSn_(0.5)Zr_(0.5)Ge_(3)O_(12):0.01 Pr^(3+),0.1 Cr^(3+)phosphor has quantum yield of 89.4%thanks to the energy transfer effect from Pr^(3+)to Cr^(3+).The fabricated NIR phosphorconverted light emitting diode(pc-LED)by integrating the blue chip with Ca_(3)MgSn_(0.5)Zr_(0.5)Ge_(3)O_(12):0.01 Pr^(3+),0.1Cr^(3+)has diverse applications including night vision,non-destructive testing,and medical imaging.展开更多
A novel Eu^(3+)-doped fluorapatite red phosphor Ca_(2)Y_(8)(BO_(4))_(2)(SiO_(4))_(4)F_(2)Eu^(3+)with pure phase was synthesized in this study.Density functional theory(DFT)calculation and diffuse reflection spectrum a...A novel Eu^(3+)-doped fluorapatite red phosphor Ca_(2)Y_(8)(BO_(4))_(2)(SiO_(4))_(4)F_(2)Eu^(3+)with pure phase was synthesized in this study.Density functional theory(DFT)calculation and diffuse reflection spectrum analysis reveal its potential as a matrix for phosphors excited by ultraviolet light.Eu^(3+)has a^(7)F_(0)→^(5)L_(6)transition at 394 nm,and the prepared phosphor exhibits a high emission intensity at 614 nm,which may be attributed to the^(5)D_(0)-^(7)F_(2)energy transition at the lower symmetry site of Eu^(3+).The optimal doping concentration of the phosphor is determined to be 11 mol%,with concentration quenching attributed to the exchange interaction mechanism.The overall color purity of the phosphor is up to 99.88%,with an internal quantum efficiency as high as 91.15%.Notably,Ca_(2)Y_(8)(BO_(4))_(2)(SiO_(4))_(4)F_(2):11 mol%Eu^(3+)(CYBSF:11 mol%Eu^(3+))phosphors exhibit good thermal stability,with a thermal quenching temperature(T1/2)of 552 K and the intensity of emission at 423 K still at 88.89%of that at 298 K.The activation energy of the phosphor is up to 0.30287 eV.Its comprehensive luminescence performance surpasses that of commercial red phosphor,making it suitable for near ultraviolet excited warm white light emitting diode(NUV-WLED)with a high color rendering index(Ra=82)and a correlated color temperature(CCT)of 4339 K.Moreover,the phosphor achieves latent fingerprint visualization and anti-counterfeiting ink on different material surfaces:glass,aluminum foil,plastic and paper.Overall,the fluorapatite CYBSF:11 mol%Eu^(3+)phosphor holds great potential for multimodal applications due to its high quantum efficiency and good thermal stability.展开更多
To separate the phosphorus-containing phase from steel slag,the effects of B_(2)O_(3)and Na_(2)B_(4)O_(7)on the enrichment of phosphorus-containing phases in Ca_(2)SiO_(4)–Ca_(3)(PO_(4))_(2)(C_(2)S–C_(3)P)solid solu...To separate the phosphorus-containing phase from steel slag,the effects of B_(2)O_(3)and Na_(2)B_(4)O_(7)on the enrichment of phosphorus-containing phases in Ca_(2)SiO_(4)–Ca_(3)(PO_(4))_(2)(C_(2)S–C_(3)P)solid solution were comparatively analyzed through theoretical calculations and experimental investigations.The results indicate that the optimum reaction temperature between B_(2)O_(3)and C_(2)S–C_(3)P is 800℃.The phase compositions of C_(2)S–C_(3)P equilibrium system with 5 wt.%B_(2)O_(3)at 800℃ included Ca_(3)(PO_(4))_(2),CaSiO_(3)and Ca11B_(2)Si_(4)O_(22),among which the content of Ca_(3)(PO_(4))_(2)was the highest.For C_(2)S–C_(3)P with 5 wt.%Na_(2)B_(4)O_(7)equilibrium system,Ca_(3)(PO_(4))_(2),CaSiO_(3),Ca11B_(2)Si_(4)O_(22)and Na_(2)Ca_(2)P_(2)O_(8)were independent at 390–690℃.Ca_(3)(PO_(4))_(2)and Ca_(2)SiO_(4)precipitated in the solid solution when the addition of B_(2)O_(3)was more than 6 wt.%,and the content of Ca_(3)(PO_(4))_(2)raised with the increase in the addition of B_(2)O_(3).The main phases in the C_(2)S–C_(3)P solid solution with Na_(2)B_(4)O_(7)were(Ca_(2)SiO_(4))0.05[Ca_(3)(PO_(4))_(2)],Ca_(2)SiO_(4)and Na_(3)Ca_(6)(PO_(4))_(5)at 650℃.And when the addition of Na_(2)B_(4)O_(7)exceeded 6 wt.%,the content of Na_(3)Ca_(6)(PO_(4))_(5)increased significantly.There was no precipitation of Ca_(3)(PO_(4))_(2)or boron-containing phase in the samples with Na_(2)B_(4)O_(7),but a small proportion of Ca_(3)(PO_(4))_(2)transformed into(Ca_(2)SiO_(4))0.05[Ca_(3)(PO_(4))_(2)],and Ca^(2+)was partially replaced by Na^(+)to generate Na_(3)Ca_(6)(PO_(4))_(5).As a result,the temperature for Na_(2)B_(4)O_(7)to enrich the phosphorus-containing phase in C_(2)S–C_(3)P solid solution was lower than that for B_(2)O_(3).However,the grade of the phosphorus-containing phase for Na_(2)B_(4)O_(7)was lower than that for B_(2)O_(3).展开更多
基金supported by the project China Geological Survey(DD202501026090)the National Key Research and Development Program of China(2024YFC2910102).
文摘Lishiite,(Ca_(2)□)Sr_(3)(CO_(3))_(5),is a new mineral species from Shaxiongdong,Hubei Province,China.It mainly occours as conchoidal crystals and with combination of hexagonal prism and pyramid and is associated with calcite,K-feldspar,albite,aegirine,apatite,and ancylite-(Ce)(?)and strontianite etc.Lishiite is brittle with conchiform fracture and has a Mohs hardness of approximately 4 and none cleavages were observed.The Vickers microhardness(VHN10)is 197.42 kg/mm^(2)(range:166.88 kg/mm^(2) to 214.58 kg/mm^(2)),and the calculated density of lishiite is 3.696 g/cm3.Hand specimen of lishiite are yellow-brown.The empirical chemical formula of the lishiite is ^(A)(Ca_(1.18)Sr_(0.25)Na_(0.19□1.38))_(Σ3.00)^( B)[Sr_(2.17)(Ce_(0.42)La_(0.24)Nd_(0.09)Eu_(0.01))_(Σ0.76) Ba_(0.07)]_(Σ3.00)(C_(5.05)O_(15)).As a member of the burbankite group,the general formula of lishiite follows the general formula A_(3)B_(3)(CO_(3))_(5),where A=Na,Ca,or and B=Sr,Ba,REE,or Ca.Its crystal structure is hexagonal(space group P6_(3)mc)with unit cell parameters a=10.4898(5)Å,c=6.4167(5)Å,and V=611.47(6)Å^(3),characterized by layers of AO_(8) and BO_(10) polyhedra connected to[CO_(3)]^(3−)groups.The discovery of lishiite provides new insights into the evolutionary history of rare earth element(REE)carbonate deposit formation.
基金Project supported by the National Natural Science Foundation of China (52274273)。
文摘A set of germanate garnet phosphors containing Tb^(3+)and Eu^(3+)were adequately synthesized using the high-temperature solid-state technique.The structural properties,photoluminescence characteristics,fluorescence lifetimes,and temperature-sensing capabilities of the phosphors were thoroughly investigated.X-ray diffraction confirms the crystalline structure of the phosphors,while photoluminescence spectra reveal a colour shift attributed to the trans fer of energy from Tb^(3+)to Eu^(3+)as the concentration of Eu^(3+)increases.The phosphors excited by UV light display a transition in colour from green to yellow,and subsequently to red,which can be used as a colour tunable phosphor in white light-emitting diode(w-LED) applications.As a novel temperature sensing material,the maximum relative sensitivity of Ca_(3)Sc_(2)Ge_(3)O_(12):Tb^(3+),Eu^(3+)phosphor is 0.1044 K-1(298 K),highlighting its potential for applications in temperature sensing.
基金Project supported by the fund of"Two-Hundred Talent"plan of Yantai Citythe National Natural Science Foundation of China(11974013)+1 种基金Natural Science Foundation of Fujian Province(2022J011270)the State Key Research Project of Shandong Natural Science Foundation(ZR2020KB019)。
文摘In this paper,we developed low dose X-ray induced long afterglow phosphor Ca_(2)P_(2)O_(7):Pr^(3+),which shows excellent afterglow luminescence from ultraviolet C(UVC)to red region.The photoluminescent results show that under 445.7 nm excitation,Ca_(1.995)P_(2)O_(7):0.5%Pr3+displays red emissions peaked at 598.3 and651.9 nm,corresponding to1D2-3H4and3P0-3F2transitions of Pr^(3+),respectively.Due to its pure red emission(CIE coordinates(0.59101,0.39926)),Ca_(1.995)P_(2)O_(7):0.5%Pr^(3+)can be regarded as a potential LED red phosphor.More importantly,Ca_(2)P_(2)O_(7):Pr^(3+)shows long afterglow luminescence from UVC to red region,which consists of four co ntinuous emissions with similar intensity including 260,359,466 and 598.3 nm.Since these afterglow continuous emissions are fitted to the absorption of most photodynamic therapy(PDT)agents,Ca_(2)P_(2)O_(7):Pr^(3+)can be regarded as excellent PDT agents.Furthermo re,30 s X-ray irradiation can induce 5400 s decay of Ca_(1.997)P_(2)O_(7):0.3%Pr^(3+),and its afterglow emission intensity still reaches 5×10^(4)cps after 5400 s decay.Even only 5 s X-ray irradiation also can produce 4.75×10^(4)cps afterglow emis sion after10 s decay.In addition,the repeat 980 nm laser irradiations can induce co ntinuous strong photo-stimulated(PSL)luminescent peaks,which can be utilized to conduct high efficiency PDT without another X-ray irradiation.The thermoluminesce nce results reveal that the existence of shallow(0.89 eV)and deep traps are responsible for the excellent X-ray induced long afterglow and PSL luminescence.All these results suggest that Ca_(2)P2O7:Pr^(3+)possesses great potential to be regarded as high efficiency PDT agents.
基金supported by Guizhou Provincial Basic Research Program(Natural Science)(Qian ke he ji chu-ZK2024 YiBan 095)。
文摘In this study,a novel Ca_(2)GaTaO_(6):Sm^(3+)phosphor was developed using the conventional hightemperature solid-phase method.The phase structure and morphology test results of phosphor indicate that the Ca_(2)GaTaO_(6):Sm^(3+)material was successfully synthesized and the Sm^(3+)ions were successfully doped into the host lattice.When utilizing 406 nm excitation,the Ca_(2)GaTaO_(6):Sm^(3+)phosphor has the strongest emission intensity at 599 nm and shows orange-red emission,which is mainly owing to the^(4)G_(5/2)→^(6)H_(7/2)jump of Sm^(3+)ions.For the performance of different concentrations of Sm^(3+)ions,3 mol%performs the best.At this time,concentration quenching occurs,which is most predominantly induced by dipole-dipole(d-d)interactions.In terms of thermal stability,the Ca_(2)GaTaO_(6):Sm^(3+)phosphor shows good properties,with the luminescence intensity at 423 K exhibiting 88.17%of that at 298 K.The white light-emitting diodes(WLEDs)devices prepared using Ca_(2)GaTaO_(6):Sm^(3+):0.03Sm^(3+)phosphor shows warm white light with excellent performance in terms of correlated color temperature and color rendering index(CCT=3642 K,CRI,Ra=93.5).In terms of anticounterfeit inks,the Ca_(2)GaTaO_(6):Sm^(3+)phosphor also shows good potential.These research results show that Ca_(2)GaTaO_(6):Sm^(3+)phosphors have great performance for application in WLEDs and anti-counterfeit inks.
基金supported by the National Key Research and Development Program(MOST,No.2022YFE0108800)the National Natural Science Foundation of China(Nos.52272165,U2005213 and 52172157)the Major Science and Technology Projects of Xiamen Science and Technology Bureau(No.3502Z20231018).
文摘Solid-state lighting is now developing toward high-power and super-brightness,but is largely limited by the lack of highly robust and efficient color conversion materials that can be survived from high-power or high-power density excitation,typically the red-emitting ones.In this work,we fabricated highly effi-cient and pore-free Sr_(0.5)Ca_(0.5)AlSiN_(3)∶Eu^(2+)(SCASN)red-emitting ceramics by spark plasma sintering of fine phosphor powders.These fine phosphor powders were prepared by treating the commercial phosphors with high-energy ball-milling,centrifugation and acid washing,leading to a particle size of 2.55μm and an internal quantum efficiency as high as 74.0%under 450 nm excitation.The phosphor powders can be densified into SCASN ceramics without using sintering additives at a temperature as low as 1475℃,and the ceramics show an internal quantum efficiency of 75.3%,which is 50%higher than those ceram-ics fabricated with untreated commercial powders.When excited by a high-power blue LED at a current density of 4 A/mm^(2),the SCASN ceramics have a maximum luminous flux of 660 lm(i.e.,26 Mcd/m^(2)).The phosphor ceramics can also withstand a high laser power density of 15.7 W/mm^(2),and exhibit an output luminance of 188 Mcd/m^(2).This work provides a general method to prepare fine phosphor powders that enable to fabricate high efficiency phosphor ceramics used in high-power solid-state lighting.
基金Project supported by the Science and Technology International Cooperation Project of Qinghai Province (2022-HZ-807)the Open Project Salt Lake Chemical Engineering Research Complex,Qinghai University (2023-DXSSZZ-04)。
文摘Er^(3+)-and Tm^(3+)-doped Ca_(x)Sr_(2-x)Nb_(2)O_(7)(C_(x)S_(2-x)N,x=0.6,0.8,1,0,1.2,1,4) phosphors with layered pe rovskite structure were designed.These phosphors exhibit a dominant emission peak at 549 nm under980 nm laser excitation,attributed to the^(4)S_(3/2)→^(4)I_(15/2)transition.By increasing the content of Ca^(2+),the crystal field regulation of rare earth ions is realized and the luminescence enhancement is induced,which is manifested by the increase of^(2)H_(11/2),^(4)S_(3/2)→^(4)I_(15/2)emission.Furthermore,the temperature sensing sensitivities of C_(0.6)S_(1.4)N:Er,Tm and C_(0.6)S_(1.4)N:Er,Tm based on non-thermally coupled energy levels were studied.Finally,an anti-counterfeiting imprint was prepared using phosphors,which have high brightness and excellent photothermal stability.This work not only confirms that closer ionic radii substitution enables to increase the electronic density of states,improve the crystal field symmetry and enhance the luminescence,but also provides a promising phosphor system for temperature sensing and anti-counterfeiting applications,opening up new prospects in the optimization of the optical properties of phosphors.
基金the National Natural Science Foundation of China(12374376)Natural Science Foundation of Shandong Province(ZR2021ZD10)Project of the Qilu Young Scholar Program of Shandong University.
文摘Exploring high-performance broadband near-infrared(NIR)emitting materials is crucial for the development of NIR devices.In this study,Ca_(3)MgSn_(0.5)Zr_(0.5)Ge_(3)O_(12):Cr^(3+)and rare earth ion Pr^(3+)co-doped Ca_(3)MgSn_(0.5)Zr_(0.5)Ge_(3)O_(12):Pr^(3+),Cr^(3+)phosphors were successfully synthesized.By utilizing time-resolved emission spectroscopy(TRES),photo luminescence(PL)spectra,and fluorescence decay curve,the Ca_(3)MgSn_(0.5)Zr_(0.5)Ge_(3)O_(12):Cr^(3+)phosphor is determined to exhibit a broadband emission(650-1150 nm)with a peak at 795 nm due to Cr^(3+)occupying multiple cationic sites,Ca_(3)MgSn_(0.5)Zr_(0.5)Ge_(3)O_(12):0.1Cr^(3+)has excellent thermal stability(86%@425 K),and co-doping Pr^(3+)ions into Ca_(3)MgSn_(0.5)Zr_(0.5)Ge_(3)O_(12):0.1Cr^(3+)obtains highly efficient NIR emission.The Ca_(3)MgSn_(0.5)Zr_(0.5)Ge_(3)O_(12):0.01 Pr^(3+),0.1 Cr^(3+)phosphor has quantum yield of 89.4%thanks to the energy transfer effect from Pr^(3+)to Cr^(3+).The fabricated NIR phosphorconverted light emitting diode(pc-LED)by integrating the blue chip with Ca_(3)MgSn_(0.5)Zr_(0.5)Ge_(3)O_(12):0.01 Pr^(3+),0.1Cr^(3+)has diverse applications including night vision,non-destructive testing,and medical imaging.
基金supported by the National Natural Science Foundation of China(52372013)Natural Science Foundation of Shanghai(22ZR1460600)。
文摘A novel Eu^(3+)-doped fluorapatite red phosphor Ca_(2)Y_(8)(BO_(4))_(2)(SiO_(4))_(4)F_(2)Eu^(3+)with pure phase was synthesized in this study.Density functional theory(DFT)calculation and diffuse reflection spectrum analysis reveal its potential as a matrix for phosphors excited by ultraviolet light.Eu^(3+)has a^(7)F_(0)→^(5)L_(6)transition at 394 nm,and the prepared phosphor exhibits a high emission intensity at 614 nm,which may be attributed to the^(5)D_(0)-^(7)F_(2)energy transition at the lower symmetry site of Eu^(3+).The optimal doping concentration of the phosphor is determined to be 11 mol%,with concentration quenching attributed to the exchange interaction mechanism.The overall color purity of the phosphor is up to 99.88%,with an internal quantum efficiency as high as 91.15%.Notably,Ca_(2)Y_(8)(BO_(4))_(2)(SiO_(4))_(4)F_(2):11 mol%Eu^(3+)(CYBSF:11 mol%Eu^(3+))phosphors exhibit good thermal stability,with a thermal quenching temperature(T1/2)of 552 K and the intensity of emission at 423 K still at 88.89%of that at 298 K.The activation energy of the phosphor is up to 0.30287 eV.Its comprehensive luminescence performance surpasses that of commercial red phosphor,making it suitable for near ultraviolet excited warm white light emitting diode(NUV-WLED)with a high color rendering index(Ra=82)and a correlated color temperature(CCT)of 4339 K.Moreover,the phosphor achieves latent fingerprint visualization and anti-counterfeiting ink on different material surfaces:glass,aluminum foil,plastic and paper.Overall,the fluorapatite CYBSF:11 mol%Eu^(3+)phosphor holds great potential for multimodal applications due to its high quantum efficiency and good thermal stability.
基金funding support from the National Key R&D Program of China(2020YFC1909105)the 2023 Basic Research Foundation Project for Universities in the Inner Mongolia Autonomous Region(2023RCTD006)+1 种基金the Major Science and Technology Project of Inner Mongolia Autonomous Region(2021ZD0016)the National Natural Science Foundation of China(51664044).
文摘To separate the phosphorus-containing phase from steel slag,the effects of B_(2)O_(3)and Na_(2)B_(4)O_(7)on the enrichment of phosphorus-containing phases in Ca_(2)SiO_(4)–Ca_(3)(PO_(4))_(2)(C_(2)S–C_(3)P)solid solution were comparatively analyzed through theoretical calculations and experimental investigations.The results indicate that the optimum reaction temperature between B_(2)O_(3)and C_(2)S–C_(3)P is 800℃.The phase compositions of C_(2)S–C_(3)P equilibrium system with 5 wt.%B_(2)O_(3)at 800℃ included Ca_(3)(PO_(4))_(2),CaSiO_(3)and Ca11B_(2)Si_(4)O_(22),among which the content of Ca_(3)(PO_(4))_(2)was the highest.For C_(2)S–C_(3)P with 5 wt.%Na_(2)B_(4)O_(7)equilibrium system,Ca_(3)(PO_(4))_(2),CaSiO_(3),Ca11B_(2)Si_(4)O_(22)and Na_(2)Ca_(2)P_(2)O_(8)were independent at 390–690℃.Ca_(3)(PO_(4))_(2)and Ca_(2)SiO_(4)precipitated in the solid solution when the addition of B_(2)O_(3)was more than 6 wt.%,and the content of Ca_(3)(PO_(4))_(2)raised with the increase in the addition of B_(2)O_(3).The main phases in the C_(2)S–C_(3)P solid solution with Na_(2)B_(4)O_(7)were(Ca_(2)SiO_(4))0.05[Ca_(3)(PO_(4))_(2)],Ca_(2)SiO_(4)and Na_(3)Ca_(6)(PO_(4))_(5)at 650℃.And when the addition of Na_(2)B_(4)O_(7)exceeded 6 wt.%,the content of Na_(3)Ca_(6)(PO_(4))_(5)increased significantly.There was no precipitation of Ca_(3)(PO_(4))_(2)or boron-containing phase in the samples with Na_(2)B_(4)O_(7),but a small proportion of Ca_(3)(PO_(4))_(2)transformed into(Ca_(2)SiO_(4))0.05[Ca_(3)(PO_(4))_(2)],and Ca^(2+)was partially replaced by Na^(+)to generate Na_(3)Ca_(6)(PO_(4))_(5).As a result,the temperature for Na_(2)B_(4)O_(7)to enrich the phosphorus-containing phase in C_(2)S–C_(3)P solid solution was lower than that for B_(2)O_(3).However,the grade of the phosphorus-containing phase for Na_(2)B_(4)O_(7)was lower than that for B_(2)O_(3).
