A series of novel luminescent materials, SrZnO2:M (M=Eu3+, or Eu3+ + Li+) have been synthesized by high-temperature solid-state reaction. The structure and luminescence properties of SrZnO2:Eu3+ phosphor were studied ...A series of novel luminescent materials, SrZnO2:M (M=Eu3+, or Eu3+ + Li+) have been synthesized by high-temperature solid-state reaction. The structure and luminescence properties of SrZnO2:Eu3+ phosphor were studied through XRD, photoluminescence and Raman spectroscopy. The excitation spectra show a broad intense band and a number of small peaks corresponding to the inner 4f-shell excitations of Eu3+ (the strongest one is at 395 nm for 7F0-5L6). After SrZnO2:Eu3+ phosphor was co-doped with Li+ ions, its charge transfer band extended to longer wavelengths. This resulted in increase of luminescent quantum efficiency of the sample. SrZnO2:Eu3+,Li+ phosphor can be efficiently excited by longer UV. From the fluorescence spectrum of SrZnO2:Eu3+ phosphor, apart from transition emissions of 5D0 → 7FJ (J=0~4), the transition emissions from 5D1 → 7FJ (J=0~2) have been observed. For the SrZnO2:Eu3+ phosphor, under excitation of UV, the dominant emission is at about 612 nm, due to the 5D0 → 7F2 hypersensitive transition. The incorporation of Li+ ions greatly enhanced the luminescence intensity and made emission peak from 5D0 → 7F2 transition red-shifted.展开更多
Eu3+-activated Gd2(MoO4)3 pseudo-pompon-like red-emitting phosphors were prepared by solid-state method. The structure, morphology, and luminescent properties of these powder samples were investigated by X-ray diffrac...Eu3+-activated Gd2(MoO4)3 pseudo-pompon-like red-emitting phosphors were prepared by solid-state method. The structure, morphology, and luminescent properties of these powder samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and fluorescent spectrophotometry, respectively. The as-obtained phosphors were single crystalline phase with orthorhombic unit cell. The particles of the powder samples had the length of 5-12 m and width of 3-7 m with flake shape and large surface area, which is suitable for manufacture of white LEDs. The phosphor could be efficiently excited by the incident light of 348-425 nm, well matched with the output wavelength of near-UV (In,Ga)N chip, and re-emitted an intense red light peaking at 615 nm. By combing this phosphor with a ~395 nm-emitting (In,Ga)N chip, a red LED was fabricated, so that the applicability of this novel phosphor to white LEDs was confirmed. It is considered to be an efficient red-emitting conversion phosphor for solid-state lighting based on (In,Ga)N LEDs.展开更多
With stable physical properties, the rare-earth silicate phosphor of MgSiO3：Mn2＋,Nd3＋ is one of the suitable luminescent materials used in preparing functional fibers. In order to promote the afterglow properties o...With stable physical properties, the rare-earth silicate phosphor of MgSiO3：Mn2＋,Nd3＋ is one of the suitable luminescent materials used in preparing functional fibers. In order to promote the afterglow properties of red-emitting phosphors, we prepared it by means of solid-state reaction, and the effect of manufacturing elements including H3BO3 and environmental factor of calcining temperature, type of flux on its luminescence property were investigated through evaluating their afterglow properties. The results showed that with the concentration of Nd3＋ increasing, the amounts of H3BO3 doping and calcining temperature, the afterglow time and initial brightness of the rare-earth silicate phosphor increased and then decreased gradually. The afterglow properties of different flux concentration were different from one to another as： H3BO3〉Na＋〉K＋〉No flux.展开更多
A red-emitting phosphor Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) with partial Al^(3+)/P^(5+) substitution on Si^(4+) was synthesized via a simple solid-state method,and the effects of the introduction of the M^(3+/5+)(M=Al,P)...A red-emitting phosphor Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) with partial Al^(3+)/P^(5+) substitution on Si^(4+) was synthesized via a simple solid-state method,and the effects of the introduction of the M^(3+/5+)(M=Al,P)ions on the crystal structure and photoluminescence performance of Ca_(2.91)Si_(2−x)M_(x)O_(7):0.09Eu^(3+) phosphors were investigated.The X-ray diffraction(XRD),energy-dispersive X-ray spectroscopy(EDS),and X-ray photoelectron spectroscopy(XPS)results revealed that the structure of Ca_(3)Si_(2)O_(7) remained the same after the introduction of Al^(3+) and P^(5+) ions.The characteristic emission of Eu^(3+)-doped Ca_(3)Si_(2−x)M_(x)O_(7) phosphors exhibited two main peaks at 617 nm(red)and 593 nm(orange)under excitation at 394 nm,which originated from the^(5)D_(0)→^(7)F_(2)and^(5)D_(0)→^(7)F_(1) electron transitions of Eu^(3+) ions.After the partial substitution of Al^(3+) and P^(5+),the red emission intensities of the Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) phosphors were significantly enhanced by 1.88-and 1.42-fold,respectively,which is attributed to the crystal-field effect around Eu^(3+).Meanwhile,the luminescence intensities of the Ca_(2.91)Si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+) and Ca_(2.91)Si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) phosphors at 210℃ were 79.36%and 77.53%of those at 30°C,respectively,indicating their excellent thermal stability.Moreover,the as-prepared Ca_(2.91)Si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+)and Ca_(2.91)Si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) red-emitting phosphors were combined with a near-ultraviolet chip of 395 nm to fabricate red-light-emitting diode(LED)and white(w)-LED devices with excellent chromaticity features.In summary,Al^(3+)/P^(5+)-substituted Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) can serve as red-emitting phosphors for applications in w-LEDs.展开更多
Novel red-emitting phosphors Sr2MgSi2O7：Eu3＋ were prepared by gel-combustion method assisted by microwave. The phase struc-ture and luminescent properties of as-synthesized phosphors were investigated by XRD and flu...Novel red-emitting phosphors Sr2MgSi2O7：Eu3＋ were prepared by gel-combustion method assisted by microwave. The phase struc-ture and luminescent properties of as-synthesized phosphors were investigated by XRD and fluorescence spectrophotometer, respectively. The results showed that the as-synthesized sample was Sr2MgSi2O7 with tetragonal crystal structure. The excitation spectrum of Sr2MgSi2O7：Eu3＋ was composed of two major parts： one was the broad band between 200 and 350 nm, which belonged to the charge transfer of Eu3＋-O2-; the other consisted of a series of sharp lines between 350 and 450 nm, ascribed to the f-f transition of Eu3＋. The emission spec-trum consisted of two emission peaks at 593 and 616 nm, which was attributed to 5D0→7F1 and 5D0→7F2 of Eu3＋, respectively. The concen-tration of Eu3＋ （x） had great effect on the emission intensity of Sr2-xMgSi2O7：Eu3＋x. When x varied in the range of 0.04-0.18, the intensity of emission peaks at 593 and 616 nm increased gradually with the concentration of Eu3＋ increasing. It was interesting that no concentration quenching occurred. Moreover, the luminescent intensity could be greatly enhanced with incorporation of charge compensator Li＋ ions.展开更多
At present,with the increasing application needs of phosphor-converted white light-emitting diode(wLED),the synthetic efficiency and thermal stability of phosphor become urgent problems.Herein,this research reports a ...At present,with the increasing application needs of phosphor-converted white light-emitting diode(wLED),the synthetic efficiency and thermal stability of phosphor become urgent problems.Herein,this research reports a microwave-assisted fast synthesis approach to obtain a Sm^(3+)-activated borotellurate Na_(2)Y_(2)TeO_(4)(BO_(3))_(2)(NYTB)red phosphor with high crystallinity,excellent thermostability,and low chromaticity shift.For the NYTB-based phosphor,in contrast to the conventional solid-state synthesis,the microwave-assisted synthesis method involves lower synthesis temperature and shorter processing time.Additionally,the concentration quenching mechanism was determined.The w-LED device packaged with the studied phosphor exhibits a near-standard white light with proper CCT and high Ra parameters.展开更多
In the interest of driving down the cost of DCM-type light emitting materials, we have found a new approach to prepare 2-（t-butyl）-6-methy1-4H-pyrone, which is cost effective and more amenable to large scale product...In the interest of driving down the cost of DCM-type light emitting materials, we have found a new approach to prepare 2-（t-butyl）-6-methy1-4H-pyrone, which is cost effective and more amenable to large scale production than the reported method. Furthermore, three new DCM-type dyes, N,N-bis-[p-（2-（4-dicyanomethylene-6-t-butyl-4H- pyran-2-yl）-vinyl）-phenyl]-4-t-butyl-aniline （BDCM-BA）, N,N-bis-[p-（2-（4-dicyanomethylene-6-t-butyl-4H-pyran- 2-yl）-vinyl）-phenyl]aniline （BDCM-A） and N,N-bis-[p-（2-（4-dicyanomethylene-6-t-butyl-4H-pyran-2-yl）-vinyl）- phenyl]-4-methoxyl-aniline （BDCM-MA） were synthesized in good yields using 2-（t-butyl）-6-methyl-4H-pyrone as starting material. They can be utilized in OLEDs as nondoped red emitting materials as the result of the restricted concentration quenching effect.展开更多
Novel red-emitting Eu3＋, Sm3＋ singly doped and co-doped Ca14Mg2（SiO4）8 phosphors were prepared by conventional solidstate reaction. Powder X-ray diffraction patterns were employed to confirm phase pttrity. Ca14Mg2...Novel red-emitting Eu3＋, Sm3＋ singly doped and co-doped Ca14Mg2（SiO4）8 phosphors were prepared by conventional solidstate reaction. Powder X-ray diffraction patterns were employed to confirm phase pttrity. Ca14Mg2（SiO4）8：Eu3＋ phosphors exhibited intense red emission under 394 nm excitation and Ca14Mg2（SiO4）8：Sm3＋ phosphors, excited at 405 nm, also showed strong red emitting at 602 nm. The concentration quenching mechanism of Cal4Mg2（SiOa）s：Eu3＋ was dipole-dipole interaction, while that of CalnMg2（SiOn）8：Sm3＋ was energy migration among nearest neighbor ions. The results indicated that Ca14Mg2（SiOn）8：Eu3＋ and Ca14Mg2（SiOn）s：Sm3＋ were promising red-emitting phosphors for WLEDs. Meanwhile, the effect of co-doping Sm3＋ ions on photoluminescence properties of CalaMg2（SiO4）s：Eu3＋ was studied and energy transfer from Sm3＋ to Eu3＋ was discovered in Eu3＋, Sm3＋ co-doped phosphors.展开更多
The photoluminescence properties of Eu2+-activated α’-Sr2SiO4 and α’-Ba2SiO4 with a high Eu2+ concentration were investigated. In the case of Sr2-xEuxSiO4, emission was shifted from 585 to 611 nm with increasing t...The photoluminescence properties of Eu2+-activated α’-Sr2SiO4 and α’-Ba2SiO4 with a high Eu2+ concentration were investigated. In the case of Sr2-xEuxSiO4, emission was shifted from 585 to 611 nm with increasing the total Eu2+ concentration (x) from 0.1 to 0.8. This trend was similar to that in Ba2-xEuxSiO4, where the emission was shifted from 513 to 545 nm. The large redshifts in both the excitation and emission spectra were discussed in terms of the Eu2+ occupancies on two kinds of M sites and their local structural changes (M: Sr and Ba).展开更多
A series of novel red-emitting BaLiZn_(3)(BO_(3))_(3):Eu^(3+)phosphors were synthesized through the high temperature solid state reaction method.The phase composition,crystal structure,morphology and photo luminescenc...A series of novel red-emitting BaLiZn_(3)(BO_(3))_(3):Eu^(3+)phosphors were synthesized through the high temperature solid state reaction method.The phase composition,crystal structure,morphology and photo luminescence property of the BaLiZn_(3)(BO_(3))_(3):Eu^(3+)samples were systematically investigated.The phosphor can be efficiently excited by the near ultraviolet light(NUV)of 396 nm and blue light of 466 nm,and give out red light emission at 618 nm corresponding to the electric dipole transition(^(5)D_(0)→^(7)E_(2)).The optimal doping concentration of Eu^(3+)ions in BaLiZn_(3)(BO_(3))_(3)is determined to be about 3 mol%,and the concentration-quenching phenomenon arise from the electric dipole-dipole interaction.The temperature dependent luminescence behavior of BaLiZn_(3)(BO_(3))_(3):0.03 Eu^(3+)phosphor exhibits its good thermal stability,and the activation energy for thermal quenching characteristics is calculated to be 0.1844 eV.The decay lifetime of the BaLiZn_(3)(BO_(3))_(3):0.03 Eu^(3+)is measured to be 1.88 ms.These results suggest that the BaLiZn_(3)(BO_(3))_(3):Eu^(3+)phosphors have the potential application as a red component in white light emitting diodes(WLEDs)with NUV or blue chips.展开更多
In this work, we presented a fluorescent probe(MCQ-DNBS) for selective and sensitive detection of biothiols based on a methylated chromenoquinoline(MCQ) derivative. Probe MCQ-DNBS was constructed by masking the OH gro...In this work, we presented a fluorescent probe(MCQ-DNBS) for selective and sensitive detection of biothiols based on a methylated chromenoquinoline(MCQ) derivative. Probe MCQ-DNBS was constructed by masking the OH group in MCQ with a common sensing unit, 2,4-dinitrobezensulfonate group(DNBS) for biothiols. Due to the photo-induced electron transfer(PET) process between MCQ and DNBS, this probe was weekly fluorescent. Upon the addition of biothiols(Cys, Hcy and GSH), this probe emitted a strong red fluorescence(λ_(em max)=613 nm) with a large Stokes shift(115 nm). In addition,fluorescence imaging of biothiols in living cells was successfully realized using MCQ-DNBS as a detector.展开更多
A series of Sr3Bi1-x（PO4）3： xSm^3＋phosphors were prepared by solid state method at 1250 ℃ for 4 h. X-ray diffraction （XRD） indicated that the sample was of a pure phase of Sr3Bi（PO4）3. The main excitation pea...A series of Sr3Bi1-x（PO4）3： xSm^3＋phosphors were prepared by solid state method at 1250 ℃ for 4 h. X-ray diffraction （XRD） indicated that the sample was of a pure phase of Sr3Bi（PO4）3. The main excitation peaks were located at 343 （6H5/2→4H9/2）, 360 （6H5/2→4D3/2）, 373 （6H5/2→6p7/2）, 400 （6H5/2→4F7/2）, 414 （6H5/2→6P5/2） and 467 nm （6H5/2→4113/2）. The main emission were located at 563 （4G5/2→6H5/2）, 599 （4G5/2→6H7/2）, 646 （4G5/2→6H9/2） and 708 nm （4G5/2→6H11/2）. The intensest emission was excited by 400 nm. We studied the effect of different doping concentrations of Sm3＋ activator on the luminescence properties and found that the luminescent intensity first increased with Sm3＋ concentration increasing, and then decreased. The luminescent intensity had the best value when x=0.04. The chromaticity coordinates of the sample Sr3Bi0.96（PO4）3：0.04Sm3＋ were （x=0.57, y=0.36）, and the lifetime was 2.12 ms.展开更多
文摘A series of novel luminescent materials, SrZnO2:M (M=Eu3+, or Eu3+ + Li+) have been synthesized by high-temperature solid-state reaction. The structure and luminescence properties of SrZnO2:Eu3+ phosphor were studied through XRD, photoluminescence and Raman spectroscopy. The excitation spectra show a broad intense band and a number of small peaks corresponding to the inner 4f-shell excitations of Eu3+ (the strongest one is at 395 nm for 7F0-5L6). After SrZnO2:Eu3+ phosphor was co-doped with Li+ ions, its charge transfer band extended to longer wavelengths. This resulted in increase of luminescent quantum efficiency of the sample. SrZnO2:Eu3+,Li+ phosphor can be efficiently excited by longer UV. From the fluorescence spectrum of SrZnO2:Eu3+ phosphor, apart from transition emissions of 5D0 → 7FJ (J=0~4), the transition emissions from 5D1 → 7FJ (J=0~2) have been observed. For the SrZnO2:Eu3+ phosphor, under excitation of UV, the dominant emission is at about 612 nm, due to the 5D0 → 7F2 hypersensitive transition. The incorporation of Li+ ions greatly enhanced the luminescence intensity and made emission peak from 5D0 → 7F2 transition red-shifted.
基金Project supported by the Natural Science Research Project of the Jiangsu Higher Education Institutions (08KJD150014)the QingLan Project of the Jiangsu Province (2008)the Basic Research Fund of Jiangsu Teachers University of Technology (KYY09031)
文摘Eu3+-activated Gd2(MoO4)3 pseudo-pompon-like red-emitting phosphors were prepared by solid-state method. The structure, morphology, and luminescent properties of these powder samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and fluorescent spectrophotometry, respectively. The as-obtained phosphors were single crystalline phase with orthorhombic unit cell. The particles of the powder samples had the length of 5-12 m and width of 3-7 m with flake shape and large surface area, which is suitable for manufacture of white LEDs. The phosphor could be efficiently excited by the incident light of 348-425 nm, well matched with the output wavelength of near-UV (In,Ga)N chip, and re-emitted an intense red light peaking at 615 nm. By combing this phosphor with a ~395 nm-emitting (In,Ga)N chip, a red LED was fabricated, so that the applicability of this novel phosphor to white LEDs was confirmed. It is considered to be an efficient red-emitting conversion phosphor for solid-state lighting based on (In,Ga)N LEDs.
基金Project supported by National Natural Science Foundation of China(21171074/B010201)
文摘With stable physical properties, the rare-earth silicate phosphor of MgSiO3：Mn2＋,Nd3＋ is one of the suitable luminescent materials used in preparing functional fibers. In order to promote the afterglow properties of red-emitting phosphors, we prepared it by means of solid-state reaction, and the effect of manufacturing elements including H3BO3 and environmental factor of calcining temperature, type of flux on its luminescence property were investigated through evaluating their afterglow properties. The results showed that with the concentration of Nd3＋ increasing, the amounts of H3BO3 doping and calcining temperature, the afterglow time and initial brightness of the rare-earth silicate phosphor increased and then decreased gradually. The afterglow properties of different flux concentration were different from one to another as： H3BO3〉Na＋〉K＋〉No flux.
基金This work was financially supported by the Department of Science and Technology of Sichuan Province(No.2020YJ0157).
文摘A red-emitting phosphor Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) with partial Al^(3+)/P^(5+) substitution on Si^(4+) was synthesized via a simple solid-state method,and the effects of the introduction of the M^(3+/5+)(M=Al,P)ions on the crystal structure and photoluminescence performance of Ca_(2.91)Si_(2−x)M_(x)O_(7):0.09Eu^(3+) phosphors were investigated.The X-ray diffraction(XRD),energy-dispersive X-ray spectroscopy(EDS),and X-ray photoelectron spectroscopy(XPS)results revealed that the structure of Ca_(3)Si_(2)O_(7) remained the same after the introduction of Al^(3+) and P^(5+) ions.The characteristic emission of Eu^(3+)-doped Ca_(3)Si_(2−x)M_(x)O_(7) phosphors exhibited two main peaks at 617 nm(red)and 593 nm(orange)under excitation at 394 nm,which originated from the^(5)D_(0)→^(7)F_(2)and^(5)D_(0)→^(7)F_(1) electron transitions of Eu^(3+) ions.After the partial substitution of Al^(3+) and P^(5+),the red emission intensities of the Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) phosphors were significantly enhanced by 1.88-and 1.42-fold,respectively,which is attributed to the crystal-field effect around Eu^(3+).Meanwhile,the luminescence intensities of the Ca_(2.91)Si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+) and Ca_(2.91)Si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) phosphors at 210℃ were 79.36%and 77.53%of those at 30°C,respectively,indicating their excellent thermal stability.Moreover,the as-prepared Ca_(2.91)Si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+)and Ca_(2.91)Si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) red-emitting phosphors were combined with a near-ultraviolet chip of 395 nm to fabricate red-light-emitting diode(LED)and white(w)-LED devices with excellent chromaticity features.In summary,Al^(3+)/P^(5+)-substituted Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) can serve as red-emitting phosphors for applications in w-LEDs.
基金Project supported by the National Natural Science Foundation of China (20675023)
文摘Novel red-emitting phosphors Sr2MgSi2O7：Eu3＋ were prepared by gel-combustion method assisted by microwave. The phase struc-ture and luminescent properties of as-synthesized phosphors were investigated by XRD and fluorescence spectrophotometer, respectively. The results showed that the as-synthesized sample was Sr2MgSi2O7 with tetragonal crystal structure. The excitation spectrum of Sr2MgSi2O7：Eu3＋ was composed of two major parts： one was the broad band between 200 and 350 nm, which belonged to the charge transfer of Eu3＋-O2-; the other consisted of a series of sharp lines between 350 and 450 nm, ascribed to the f-f transition of Eu3＋. The emission spec-trum consisted of two emission peaks at 593 and 616 nm, which was attributed to 5D0→7F1 and 5D0→7F2 of Eu3＋, respectively. The concen-tration of Eu3＋ （x） had great effect on the emission intensity of Sr2-xMgSi2O7：Eu3＋x. When x varied in the range of 0.04-0.18, the intensity of emission peaks at 593 and 616 nm increased gradually with the concentration of Eu3＋ increasing. It was interesting that no concentration quenching occurred. Moreover, the luminescent intensity could be greatly enhanced with incorporation of charge compensator Li＋ ions.
基金Project supported by the National Natural Science Foundation of China(22165031,21761034)NationalUndergraduate Innovation and Entrepreneurship Foundation(202210673034)Scientific Research Foundation of Education Departmentof Yunnan province(2022Y001)。
文摘At present,with the increasing application needs of phosphor-converted white light-emitting diode(wLED),the synthetic efficiency and thermal stability of phosphor become urgent problems.Herein,this research reports a microwave-assisted fast synthesis approach to obtain a Sm^(3+)-activated borotellurate Na_(2)Y_(2)TeO_(4)(BO_(3))_(2)(NYTB)red phosphor with high crystallinity,excellent thermostability,and low chromaticity shift.For the NYTB-based phosphor,in contrast to the conventional solid-state synthesis,the microwave-assisted synthesis method involves lower synthesis temperature and shorter processing time.Additionally,the concentration quenching mechanism was determined.The w-LED device packaged with the studied phosphor exhibits a near-standard white light with proper CCT and high Ra parameters.
基金Project supported by the National Natural Science Foundation of China （Nos. 20272065 and 50125310）, 863 （No. 90101013）, 973 （Nos. 2002AA324080 and 2002CB613405） Program of China. Dedicated to Professor Xikui Jiang on the occasion of his 80th birthday.
文摘In the interest of driving down the cost of DCM-type light emitting materials, we have found a new approach to prepare 2-（t-butyl）-6-methy1-4H-pyrone, which is cost effective and more amenable to large scale production than the reported method. Furthermore, three new DCM-type dyes, N,N-bis-[p-（2-（4-dicyanomethylene-6-t-butyl-4H- pyran-2-yl）-vinyl）-phenyl]-4-t-butyl-aniline （BDCM-BA）, N,N-bis-[p-（2-（4-dicyanomethylene-6-t-butyl-4H-pyran- 2-yl）-vinyl）-phenyl]aniline （BDCM-A） and N,N-bis-[p-（2-（4-dicyanomethylene-6-t-butyl-4H-pyran-2-yl）-vinyl）- phenyl]-4-methoxyl-aniline （BDCM-MA） were synthesized in good yields using 2-（t-butyl）-6-methyl-4H-pyrone as starting material. They can be utilized in OLEDs as nondoped red emitting materials as the result of the restricted concentration quenching effect.
基金supported by the Hong Kong,Macao and Taiwan Science and Technology Cooperation Special Project of Ministry of Science and Technology of China(2014DFT10310)the National Basic Research Program of China(973 Program,2014CB643801)the National Natural Science Foundation of China(51402288,51102229,21401184)
文摘Novel red-emitting Eu3＋, Sm3＋ singly doped and co-doped Ca14Mg2（SiO4）8 phosphors were prepared by conventional solidstate reaction. Powder X-ray diffraction patterns were employed to confirm phase pttrity. Ca14Mg2（SiO4）8：Eu3＋ phosphors exhibited intense red emission under 394 nm excitation and Ca14Mg2（SiO4）8：Sm3＋ phosphors, excited at 405 nm, also showed strong red emitting at 602 nm. The concentration quenching mechanism of Cal4Mg2（SiOa）s：Eu3＋ was dipole-dipole interaction, while that of CalnMg2（SiOn）8：Sm3＋ was energy migration among nearest neighbor ions. The results indicated that Ca14Mg2（SiOn）8：Eu3＋ and Ca14Mg2（SiOn）s：Sm3＋ were promising red-emitting phosphors for WLEDs. Meanwhile, the effect of co-doping Sm3＋ ions on photoluminescence properties of CalaMg2（SiO4）s：Eu3＋ was studied and energy transfer from Sm3＋ to Eu3＋ was discovered in Eu3＋, Sm3＋ co-doped phosphors.
文摘The photoluminescence properties of Eu2+-activated α’-Sr2SiO4 and α’-Ba2SiO4 with a high Eu2+ concentration were investigated. In the case of Sr2-xEuxSiO4, emission was shifted from 585 to 611 nm with increasing the total Eu2+ concentration (x) from 0.1 to 0.8. This trend was similar to that in Ba2-xEuxSiO4, where the emission was shifted from 513 to 545 nm. The large redshifts in both the excitation and emission spectra were discussed in terms of the Eu2+ occupancies on two kinds of M sites and their local structural changes (M: Sr and Ba).
基金Project supported by the National Key R&D Program of China(2019YFA0709101)National Natural Science Foundation of China(52072364,51902305)the Fund for Creative Research Groups(21221061)。
文摘A series of novel red-emitting BaLiZn_(3)(BO_(3))_(3):Eu^(3+)phosphors were synthesized through the high temperature solid state reaction method.The phase composition,crystal structure,morphology and photo luminescence property of the BaLiZn_(3)(BO_(3))_(3):Eu^(3+)samples were systematically investigated.The phosphor can be efficiently excited by the near ultraviolet light(NUV)of 396 nm and blue light of 466 nm,and give out red light emission at 618 nm corresponding to the electric dipole transition(^(5)D_(0)→^(7)E_(2)).The optimal doping concentration of Eu^(3+)ions in BaLiZn_(3)(BO_(3))_(3)is determined to be about 3 mol%,and the concentration-quenching phenomenon arise from the electric dipole-dipole interaction.The temperature dependent luminescence behavior of BaLiZn_(3)(BO_(3))_(3):0.03 Eu^(3+)phosphor exhibits its good thermal stability,and the activation energy for thermal quenching characteristics is calculated to be 0.1844 eV.The decay lifetime of the BaLiZn_(3)(BO_(3))_(3):0.03 Eu^(3+)is measured to be 1.88 ms.These results suggest that the BaLiZn_(3)(BO_(3))_(3):Eu^(3+)phosphors have the potential application as a red component in white light emitting diodes(WLEDs)with NUV or blue chips.
基金supported by the National Natural Science Foundation of China (No.U1608222)Special Fund for Agroscientific Research in the Public Interest of China(No.201503108)+1 种基金Fundamental Research Funds for the Central Universities of Central South University (No. 2018zzts109)the State Key Laboratory of Chemo/Biosensing and Chemometrics (No. 2016005)
文摘In this work, we presented a fluorescent probe(MCQ-DNBS) for selective and sensitive detection of biothiols based on a methylated chromenoquinoline(MCQ) derivative. Probe MCQ-DNBS was constructed by masking the OH group in MCQ with a common sensing unit, 2,4-dinitrobezensulfonate group(DNBS) for biothiols. Due to the photo-induced electron transfer(PET) process between MCQ and DNBS, this probe was weekly fluorescent. Upon the addition of biothiols(Cys, Hcy and GSH), this probe emitted a strong red fluorescence(λ_(em max)=613 nm) with a large Stokes shift(115 nm). In addition,fluorescence imaging of biothiols in living cells was successfully realized using MCQ-DNBS as a detector.
基金Project supported by Natural Science Foundation of Hebei Province (F2009000217)
文摘A series of Sr3Bi1-x（PO4）3： xSm^3＋phosphors were prepared by solid state method at 1250 ℃ for 4 h. X-ray diffraction （XRD） indicated that the sample was of a pure phase of Sr3Bi（PO4）3. The main excitation peaks were located at 343 （6H5/2→4H9/2）, 360 （6H5/2→4D3/2）, 373 （6H5/2→6p7/2）, 400 （6H5/2→4F7/2）, 414 （6H5/2→6P5/2） and 467 nm （6H5/2→4113/2）. The main emission were located at 563 （4G5/2→6H5/2）, 599 （4G5/2→6H7/2）, 646 （4G5/2→6H9/2） and 708 nm （4G5/2→6H11/2）. The intensest emission was excited by 400 nm. We studied the effect of different doping concentrations of Sm3＋ activator on the luminescence properties and found that the luminescent intensity first increased with Sm3＋ concentration increasing, and then decreased. The luminescent intensity had the best value when x=0.04. The chromaticity coordinates of the sample Sr3Bi0.96（PO4）3：0.04Sm3＋ were （x=0.57, y=0.36）, and the lifetime was 2.12 ms.
