Y_(3)Al_(2)Ga_(3)O_(12):Ce^(3+),Cr^(3+)(YAGG:Ce^(3+),Cr^(3+)),as a persistent luminescent material,has advantages of high initial luminescence intensity and long persistent time,which is promising in persistent lumine...Y_(3)Al_(2)Ga_(3)O_(12):Ce^(3+),Cr^(3+)(YAGG:Ce^(3+),Cr^(3+)),as a persistent luminescent material,has advantages of high initial luminescence intensity and long persistent time,which is promising in persistent luminescent material applications.At present,YAGG:Ce^(3+),Cr^(3+)powders exhibit good persistent performance,but their persistent performance of ceramics still needs to be further improved to meet the new requirements.In this work,(Y_(0.998)Ce_(0.002))_(3)(Al_(1-x)Cr_(x))_(2)Ga_(3)O_(12) ceramics with different Cr^(3+)doping concentrations were prepared by solid-state reaction,including air pre-sintering,hot isostatic pressing(HIP)post-treatment and air annealing,to investigate the effects of Cr^(3+)doping concentration on the microstructure,optical properties and persistent performance of the ceramics.The results showed that as the doping concentration of Cr^(3+)increased from 0.025%to 0.2%(in atom),no significant effect of Cr^(3+)concentration on the morphology of pre-sintered ceramics or HIP post-treatment ceramics was observed,but the in-line transmittance gradually increased while the persistent performance gradually decreased.Among them,YAGG:Ce^(3+),Cr^(3+)ceramics doped with 0.025%Cr^(3+)showed the strongest initial luminescence intensity exceeding 6055 mcd/m^(2) and a persistent time of 1030 min after air pre-sintering combined with HIP post-treatment and air annealing.By optimizing the Cr^(3+)doping concentration and the fabrication process,the persistent luminescence(PersL)performance of the YAGG:Ce^(3+),Cr^(3+)ceramics was obviously improved.展开更多
采用高温固相法制备了SrZrSi_(2)O_(7):Ce^(3+),Mn^(2+)荧光粉。通过X射线衍射(X-ray Power Diffractometer,XRD)、激发和发射光谱及电子显微分析对材料的分子结构、显微形貌、发光特性和能量传递机理进行了研究。结果表明,荧光粉的主...采用高温固相法制备了SrZrSi_(2)O_(7):Ce^(3+),Mn^(2+)荧光粉。通过X射线衍射(X-ray Power Diffractometer,XRD)、激发和发射光谱及电子显微分析对材料的分子结构、显微形貌、发光特性和能量传递机理进行了研究。结果表明,荧光粉的主晶相是单斜晶系的SrZrSi_(2)O_(7),Ce^(3+)离子和Mn^(2+)离子占据一部分Sr^(2+)离子的晶体学格位。在296 nm激发下,可以观察到来自Ce^(3+)离子的蓝光发射峰,归属于Ce^(3+)离子的5d→4f能级跃迁。在544 nm处,有来自Mn^(2+)离子的绿光发射峰,归因于Mn^(2+)离子的^(4)T_(1)(4G)-^(6)A_(1)(6S)自旋禁止跃迁,表明发生了从Ce^(3+)离子到Mn^(2+)离子的能量传递过程,为设计蓝光到绿光之间可控制备的新型荧光粉提供了理论和实验的信息。展开更多
The utilization of phosphors that achieve full-spectrum lighting has emerged as a prevailing trend in the advancement of white light-emitting diode(WLED)lighting.In this study,we successfully prepared a novel green ph...The utilization of phosphors that achieve full-spectrum lighting has emerged as a prevailing trend in the advancement of white light-emitting diode(WLED)lighting.In this study,we successfully prepared a novel green phosphor Ba_(2)Sc_(2)((BO_(3))_(2)B_(2)O_(5)):Ce^(3+)(BSBO:Ce^(3+))that can be utilized for full-spectrum lighting and low-temperature sensors.BSBO:Ce^(3+)exhibits a broad-band excitation spectrum centered at 410 nm,and a broad-band emission spectrum centered at 525 nm.The internal and external quantum efficiencies of BSBO:Ce^(3+)are 99%and 49%,respectively.The thermal stability of BSBO:Ce^(3+)can be improved by substituting partial Sc atoms with smaller cations.The thermal quenching mechanism of BSBO:Ce^(3+)and the lattice occupancy of Ce ions in BSBO are discussed in detail.Furthermore,by combining the green phosphor BSBO:Ce^(3+),the commercial blue phosphor and the red phosphor on a 405 nm chip,a white light source was obtained with a high average color rendering index(CRI)of 96.6,a low correlated color temperature(CCT)of 3988 K,and a high luminous efficacy of 88.0 Im/W.The lu-minous efficacy of the WLED exhibits negligible degradation during the 1000 h light aging experiment.What's more,an emission peak at 468 nm appears when excited at 352 nm and 80 K,however,the relative intensity of the peaks at 468 and 525 nm gradually weakens with increasing temperature,indicating the potential of this material as a low-temperature sensor.展开更多
The complex fluoride BaLiF3 and BaLiF3∶Ce3+ nanocrystals were synthesized in cetyltrimethylammonium bromide（CTAB）/2-octanol/water microemulsion systems.XRD analysis shows that the products were single phase and XPS...The complex fluoride BaLiF3 and BaLiF3∶Ce3+ nanocrystals were synthesized in cetyltrimethylammonium bromide（CTAB）/2-octanol/water microemulsion systems.XRD analysis shows that the products were single phase and XPS analysis shows the oxygen content was low.The result of ESEM confirms that the average size of the BaLiF3 nanocrystals was 28 nm in diameter.The emission peak of the BaLiF3∶Ce3+ nano-particles synthesized by microemulsion shows obvious blue shift in comparison with that of BaLiF3∶Ce3+ synthesized by the reaction at a high temperature and full width at half maximum（FWHM） of emission band was broaden.展开更多
在6种不同浓度的铈(C e3+)对0.1 m g.L-1的Cu2+毒害下,研究了菹草叶片中保护酶SOD、POD、CAT的活性,活性氧H2O2,膜脂过氧化产物M DA含量及叶绿素含量等的变化及影响.结果表明,在9~12 d之内,7.5 m g.L-1以下的C e3+可以增强SOD、CAT、PO...在6种不同浓度的铈(C e3+)对0.1 m g.L-1的Cu2+毒害下,研究了菹草叶片中保护酶SOD、POD、CAT的活性,活性氧H2O2,膜脂过氧化产物M DA含量及叶绿素含量等的变化及影响.结果表明,在9~12 d之内,7.5 m g.L-1以下的C e3+可以增强SOD、CAT、POD活性,降低M DA的含量,提高叶片中叶绿素和可溶性蛋白含量,从而减轻Cu2+对菹草植物体的伤害.而随着C e3+作用时间的延长和浓度的增大,C e3+的缓解作用不断减弱,C e3+和Cu2+产生协同效应,加重毒害.本实验结果认为,5~7.5 m g.L-1的C e3+缓解菹草叶片Cu2+毒害效果最好.展开更多
基金National Key R&D Program of China(2023YFB3506600)。
文摘Y_(3)Al_(2)Ga_(3)O_(12):Ce^(3+),Cr^(3+)(YAGG:Ce^(3+),Cr^(3+)),as a persistent luminescent material,has advantages of high initial luminescence intensity and long persistent time,which is promising in persistent luminescent material applications.At present,YAGG:Ce^(3+),Cr^(3+)powders exhibit good persistent performance,but their persistent performance of ceramics still needs to be further improved to meet the new requirements.In this work,(Y_(0.998)Ce_(0.002))_(3)(Al_(1-x)Cr_(x))_(2)Ga_(3)O_(12) ceramics with different Cr^(3+)doping concentrations were prepared by solid-state reaction,including air pre-sintering,hot isostatic pressing(HIP)post-treatment and air annealing,to investigate the effects of Cr^(3+)doping concentration on the microstructure,optical properties and persistent performance of the ceramics.The results showed that as the doping concentration of Cr^(3+)increased from 0.025%to 0.2%(in atom),no significant effect of Cr^(3+)concentration on the morphology of pre-sintered ceramics or HIP post-treatment ceramics was observed,but the in-line transmittance gradually increased while the persistent performance gradually decreased.Among them,YAGG:Ce^(3+),Cr^(3+)ceramics doped with 0.025%Cr^(3+)showed the strongest initial luminescence intensity exceeding 6055 mcd/m^(2) and a persistent time of 1030 min after air pre-sintering combined with HIP post-treatment and air annealing.By optimizing the Cr^(3+)doping concentration and the fabrication process,the persistent luminescence(PersL)performance of the YAGG:Ce^(3+),Cr^(3+)ceramics was obviously improved.
文摘采用高温固相法制备了SrZrSi_(2)O_(7):Ce^(3+),Mn^(2+)荧光粉。通过X射线衍射(X-ray Power Diffractometer,XRD)、激发和发射光谱及电子显微分析对材料的分子结构、显微形貌、发光特性和能量传递机理进行了研究。结果表明,荧光粉的主晶相是单斜晶系的SrZrSi_(2)O_(7),Ce^(3+)离子和Mn^(2+)离子占据一部分Sr^(2+)离子的晶体学格位。在296 nm激发下,可以观察到来自Ce^(3+)离子的蓝光发射峰,归属于Ce^(3+)离子的5d→4f能级跃迁。在544 nm处,有来自Mn^(2+)离子的绿光发射峰,归因于Mn^(2+)离子的^(4)T_(1)(4G)-^(6)A_(1)(6S)自旋禁止跃迁,表明发生了从Ce^(3+)离子到Mn^(2+)离子的能量传递过程,为设计蓝光到绿光之间可控制备的新型荧光粉提供了理论和实验的信息。
基金the National Natural Science Foundation of China(22003035,21963006,22073061)the Project of Shaanxi Province Youth Science and Technology New Star(2023KJXX-076)the National Training Program of Innovation and Entrepreneurship for Undergraduates(202314390018)。
文摘The utilization of phosphors that achieve full-spectrum lighting has emerged as a prevailing trend in the advancement of white light-emitting diode(WLED)lighting.In this study,we successfully prepared a novel green phosphor Ba_(2)Sc_(2)((BO_(3))_(2)B_(2)O_(5)):Ce^(3+)(BSBO:Ce^(3+))that can be utilized for full-spectrum lighting and low-temperature sensors.BSBO:Ce^(3+)exhibits a broad-band excitation spectrum centered at 410 nm,and a broad-band emission spectrum centered at 525 nm.The internal and external quantum efficiencies of BSBO:Ce^(3+)are 99%and 49%,respectively.The thermal stability of BSBO:Ce^(3+)can be improved by substituting partial Sc atoms with smaller cations.The thermal quenching mechanism of BSBO:Ce^(3+)and the lattice occupancy of Ce ions in BSBO are discussed in detail.Furthermore,by combining the green phosphor BSBO:Ce^(3+),the commercial blue phosphor and the red phosphor on a 405 nm chip,a white light source was obtained with a high average color rendering index(CRI)of 96.6,a low correlated color temperature(CCT)of 3988 K,and a high luminous efficacy of 88.0 Im/W.The lu-minous efficacy of the WLED exhibits negligible degradation during the 1000 h light aging experiment.What's more,an emission peak at 468 nm appears when excited at 352 nm and 80 K,however,the relative intensity of the peaks at 468 and 525 nm gradually weakens with increasing temperature,indicating the potential of this material as a low-temperature sensor.
文摘The complex fluoride BaLiF3 and BaLiF3∶Ce3+ nanocrystals were synthesized in cetyltrimethylammonium bromide（CTAB）/2-octanol/water microemulsion systems.XRD analysis shows that the products were single phase and XPS analysis shows the oxygen content was low.The result of ESEM confirms that the average size of the BaLiF3 nanocrystals was 28 nm in diameter.The emission peak of the BaLiF3∶Ce3+ nano-particles synthesized by microemulsion shows obvious blue shift in comparison with that of BaLiF3∶Ce3+ synthesized by the reaction at a high temperature and full width at half maximum（FWHM） of emission band was broaden.
