Sr~(2+)共掺杂YPO_4:Eu~(3+)发光材料的水热合成及其性能

采用水热法合成Sr~(2+)共掺杂YPO_4:Eu~(3+)发光材料,采用X射线衍射(XRD)和X射线荧光光谱对合成产物的物相结构和光学性能进行表征,对Sr~(2+)共掺杂浓度及反应体系p H值对合成样品的物相结构及发光性能的影响进行分析。结果表明,少量Sr~(2+)(≤15at%)共掺杂YPO_4:1at%Eu~(3+)均为纯相四方磷钇矿结构晶体,过量Sr~(2+)(≥20at%)共掺杂出现Sr_4P_2O_9杂相;p H值为6的反应体系可获得高结晶度的单一相Sr~(2+)、Eu~(3+)共掺杂YPO_4样品。X射线荧光光谱分析结果表明,采用水热法合成的YPO_4:1at%Eu~(3+),xat%Sr~(2+)样品可被396 nm的紫外光激发而发射出强烈的Eu~(3+)特征橙红色光,一定量的Sr~(2+)共掺杂能提高YPO_4:1 at%Eu~(3+)样品的发光性能,过量(10at%)的Sr~(2+)掺杂导致Eu~(3+)荧光猝灭。YPO_4:1at%Eu~(3+),10at%Sr~(2+)样品在396 nm紫外光激发下位于620 nm处的发射峰相对强度较YPO_4:1at%Eu~(3+)样品提高了72.6%。     

从废弃稀土荧光粉中再生Y_2O_3:Eu~(3+)红粉

浙江某照明公司回收的废弃稀土荧光粉中Y与Eu的含量分别为36.47%和6.22%。采用盐酸浸出、组合试剂除杂、稀土草酸沉淀及焙烧、水热法合成工艺从该废弃荧光粉中回收再生出Y_2O_3:Eu~(3+)红粉,并对所得Y_2O_3:Eu~(3+)样品的晶体结构、表面形貌及发光性能进行表征。结果表明,1在双氧水加入量为0.2 m L/g、盐酸浓度为4mol/L、浸出温度为60℃,浸出时间为4 h时,废弃荧光粉中Y、Eu的浸出率分别达99.56%、92.39%。2浸出液加氨水将p H终点调至4.5时,Al~(3+)、Fe~(3+)、Pb~(2+)、Zn~(2+)可除尽。3草酸沉淀试验中,在草酸浓度为100 g/L,沉淀时间为0.5 h,温度为60℃时,稀土纯度可达99.60%。4水热反应温度为180℃时制备的Y_2O_3:Eu~(3+)发光强度最高,其最大发射峰位于614 nm,对应着Eu~(3+)的5D0-7F2电偶极跃迁。SEM测试表明,Y_2O_3:Eu~(3+)荧光粉的形貌逐渐由球状转变为针管状,结晶度良好,长度分布均匀,微管长度平均为30μm,有轻微烧结团聚现象。     

C12A7:Yb3+/Eu3+多晶粉制备及上转换光学性能的研究

通过高温固相法制备不同Yb~(3+)和Eu~(3+)掺杂浓度的C12A7∶Yb~(3+)/Eu~(3+)多晶粉.利用X射线衍射、上转换荧光光谱和CIE色谱图研究了C12A7∶Yb~(3+)/Eu~(3+)多晶粉的晶体结构和荧光性能,结果表明:在波长980 nm激光激发下,C12A7∶Yb~(3+)/Eu~(3+)多晶粉分别于550 nm和663 nm处发射出上转换绿光和红光,它们分别来源于Eu~(3+)离子的~5D_0→~7F_0和~5D_0→~7F_3跃迁.结合上转换布局机制,分析了不同Yb~(3+)和Eu~(3+)掺杂浓度对C12A7∶Yb~(3+)/Eu~(3+)多晶粉光学性能的影响.分析CIE色度光谱,通过改变Yb~(3+)和Eu~(3+)离子掺杂浓度可以使C12A7∶Yb~(3+)/Eu~(3+)多晶粉的发光在黄绿光区域到绿色区域间调节.     

蓝光激发的Y_(3)Al_(2)Ga_(3)O_(12):Ce^(3+),Ge^(4+)绿色长余辉材料发光性能研究

采用高温固相法合成了新型Y_(3)Al_(2)Ga_(3)O_(12):Ce^(3+),Ge^(4+)绿色长余辉材料,并对其光致发光性能、余辉性能和光色热稳定性能进行了研究。结果表明:Y_(3)Al_(2)Ga_(3)O_(12):Ce^(3+),Ge^(4+)绿色长余辉材料在320—490 nm范围的宽带吸收与蓝光LED芯片相匹配,其发射光谱为位于450—650 nm范围的宽发射带,对应于Ce^(3+)的5d-4f跃迁;Y_(3)Al_(2)Ga_(3)O_(12):Ce^(3+),Ge^(4+)的内量子效率可以达到83.28%,τ80值约为12 s,远大于交流LED对于内量子效率>60%和τ80>0.4 ms的要求;在423 K前,Y_(3)Al_(2)Ga_(3)O_(12):Ce^(3+),Ge^(4+)具有良好的光色稳定性。以上结果表明,Y_(3)Al_(2)Ga_(3)O_(12):Ce^(3+),Ge^(4+)是一种潜在的能被蓝光激发的交流LED用绿色长余辉材料。     

Y2O3∶Er3+和Y2O3∶Er3+,Yb3+纳米粉体的制备及上转换发光性能的研究

利用硝酸盐和尿素作为原料通过均相共沉淀法合成了分散性良好的Y_2O_3:Er~(3+)和Y_2O_3:Er~(3+),Yb~(3+)球形纳米粉体,粒径大小分别为100～115 nm和110～145nm.X-射线衍射结果显示,所制备的掺杂粉体仍然保持了立方Y_2O_3的物相结构.在980nm激光的激发下,Y_2O_3:Er~(3+)样品的发光情况随着Er~(3+)离子浓度的增加,上转换红光的发射强度都先增加后减小,而绿光的强度则逐渐减小.究其原因是交叉弛豫2H_(11/2)+~4I_(13/2)→~4I_(9/2)+~4F_(9/2),~4F_(7/2)+~4I_(11/2)→~4F_(9/2)+~4F_(9/2),~2H_(11/2)+~4I_(15/2)→~4I_(9/2)+~4I_(13/2)和~4I_(13/2)+~4I_(11/2)→~4F_(9/2)+~4I_(15/2)的发生.Y_2O_3:Er~(3+),Yb~(3+)则且随着Yb~(3+)离子浓度的提高,上转换红、绿光的发射强度都增加,但上转换红光发射强度增加的幅度明显要大于上转换绿光发射强度增加的幅度.通过调整Yb"离子的掺杂浓度使其发光颜色在绿色、红色之间转变,其中单带红光上转换发光是由于在Yb~(3+)离子掺杂浓度较高时,Er~(3+)离子和Yb~(3+)离子之间发生了能量反向传递.     

Li~+、La~(3+)掺杂对尖晶石LiMn_2O_4的电化学性能影响

采用固相法制备了尖晶石LiMn_2O_4,将Li~+和La~(3+)复合掺入到主尖晶石相LiMn_2O_4中,研究了不同掺锂量和不同掺镧量对材料电化学性能的影响.利用XRD和SEM等对材料的物理性能进行了检测,结果表明掺杂锂、镧的材料具有尖晶石相,颗粒尺寸为7～8 μm.电性能测试结果显示材料具有良好的电化学性能.     

金属离子(Li~+、Al~(3+))掺杂SrWO_4∶Dy~(3+),Eu~(3+)白色荧光粉的制备及发光特性

通过掺杂具有价态补偿且离子半径较小的Li~+与Al~(3+)来改善SrWO_4∶Dy~(3+),Eu~(3+)荧光粉发光性能,制备出一种色温低且发光强度好的白光LED用荧光粉,采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、分光光度计对样品的物相结构、形貌及发光性能进行了表征及分析。结果表明,掺杂金属离子后的样品主晶相仍均为SrWO_4,微观结构主要为梭形结构,在391nm波长激发下,掺杂7.5%Al~(3+)荧光粉样品与未掺杂金属离子SrWO_4∶2.5%Dy~(3+),7.5%Eu~(3+)荧光粉相比发光强度及发光颜色有了很大改善,色坐标为(0.338,0.342),色温为4 337K,在619nm处发光强度与不掺杂金属离子样品相比提高了8倍,其次为SrWO_4∶2.5%Dy~(3+),7.5%Eu~(3+),7.5%Li~+样品,样品色坐标为(0.380,0.401),色温为4 867K,在619nm处发光强度与不掺杂金属离子样品相比提高了5倍,通过添加Li~+、Al~(3+)可以提高发光离子之间的能量传递作用,从而增加荧光粉发光颜色中红色成分,最终实现色坐标的红移,色温的降低。在低色温照明领域的研究中具有一定的研究意义。     

钙长石系尾矿微晶玻璃的制备及发光性能

以钼尾矿、铁尾矿和铜尾矿等为主要原料,采用烧结法制备了钙长石系微晶玻璃。采用X射线衍射仪(XRD)、差热扫描量热仪(DTA)表征了结构和性能,研究了Eu~(3+)在微晶玻璃中的发光性能。结果表明,采用一步法制备钙长石微晶玻璃:较佳熔制温度为1450℃,Eu_2O_3在掺杂浓度0.1%时荧光强度最好,当晶化温度到1050℃时荧光强度最强,Eu~(3+)的有效激发波长为415 nm,发射波长为591 nm的橙-红光。     

Gd_2O_2SO_4:Tb~(3+)纳米荧光粉的共沉淀合成及光致发光

以L-半胱氨酸为硫源,通过共沉淀法成功合成了Gd_2O_2SO_4∶Tb~(3+)纳米荧光粉。采用X射线衍射(XRD)、差热热重分析(DSC-TG)、傅里叶变换红外光谱仪(FTIR)、场发射扫描电子显微镜(FESEM)和光致发光(PL)光谱对产物的结构、形貌和发光性能进行表征。研究pH值、反应物的摩尔比和Tb~(3+)浓度对产物相组成、形貌和发光性能的影响。结果表明,当Gd~(3+)∶SO_4~(2-)=2∶3、pH=7.5时,合成的前驱体在800℃煅烧2h可获得单相Gd_2O_2SO_4纳米粉体。该粉体呈近球形,团聚较严重,平均粒径约为30nm。在230nm紫外光激发下,Gd_2O_2SO_4∶Tb~(3+)纳米荧光粉具有优异的发光性能,主发射峰位于544nm,归属于Tb~(3+)的~5 D_4→~7F_5跃迁。当Tb~(3+)浓度达到12%时,Gd_2O_2SO_4∶Tb~(3+)发光强度达到最大值。Gd_2O_2SO_4∶Tb~(3+)衰减过程符合双e指数衰减行为,对应的荧光寿命为τ1=0.177μs,τ2=0.119μs。     

Sr4Al14O25:Eu2+,Dy3+的制备与长余辉发光性能研究

采用高温固相反应制备稀土掺杂长余辉发光样品.原料配比按照化学式Sr4Al14O25:Eu20.+01,Dy03.+02准确称取,反应温度从1100℃逐渐升至1400℃,通过X射线衍射(XRD)图谱和扫描电子显微镜(SEM)照片,分析反应温度对产物物相和样品表面微观形貌的影响.在得到Sr4Al14O25:Eu2+,Dy3+单相发光材料基础上,研究了不同Eu2+掺杂浓度对发光体发射光谱的影响.通过对不同结构发光体的余辉衰减特性和热释光谱进行分析,得出不同结构发光体的余辉衰减快慢不同,是由于其基质中存在的陷阱能级深度不同,且陷阱能级越深,余辉时间越长.     

China rare earth market review

正November 21~30,2014Due to weak demand from downstream industries,transactions of rare earth in Chinese domestic market were inactive.It was difficult to sell any rare earth products except for dysprosium oxide and terbium oxide.Suppliers lost confidence in recent market.Demand for rare earth products was soft.Consumers continued to take a wait-and-see attitude.Rare earth export market remained slow.     

Current situation and future trend of China rare earth luminescent materialindustry(continued)

<正>Developing ecological lighting source The world is facing the big problem of energy shortage today and the contradiction between economy development and environmental protection is worsened.Therefore,people are more likely to choose an ecological light source that is more energy efficient and environmental friendly.The choice provides great opportunity for the development of rare earth optical material industry in China.The concept of green lighting positions rare earth luminescent material as a leading player in illumination market.The light source of both rare earth luminescent lamp and LED lamp is ecological and energy saving.This is why     

Galaxy Magnets achieved the net profit of 34.02 million yuan in the first six months of 2014

正Galaxy Magnet announced its financial results for the first half of 2014 on August 14.For the first six months ended on 30 June 2014,Galaxy Magnet achieved operation income of RMB 182.3 million,up8.40% over the same period of 2013,and the net profit attributable to the shareholders of the listed company of 34.02 million yuan,increasing 35.49% over the same period of last year.Stable performance increase was led by development of new customers and application market of magnets.     

Rare Earth Application in Steel in China

<正>China has rich rare earth resources.Output of rare earth and steel in China ranks the top first in the world.However,there is still certain distance between the steel produced in China and developed countries from the point of varieties and quality.China still has to import some types of steel.Improving the quality should be emphasiZed in future development of steel industry in China.Rare earth can be used to upgrade traditional steel     

稀散金属产业的观察与思考

分析了近年来国内外稀散金属产业的生产、应用、资源与市场状况.铟锡氧化物靶材、砷化镓晶片、锗红外材料、铼高温合金和硒在电解锰及玻璃的应用等已成为稀散金属的主要应用领域.稀散金属的产量快速增长达到历史高位而导致了市场的失衡.以GaInP_2/GaAs/Ge,CIGS和CdTe为代表的非硅系太阳能电池是稀散金属的新兴应用领域,将给稀散金属带来日益增长的需求.     

China rare earth market review

正November 1~10,2014Chinese rare earth market was still inactive.Demand for rare earth products was weak.Consumers took a wait-and-see attitude for lower price.As it was an off season for rare earth products,it was expected that prices of rare earth could continue turbulence at the bottom in short terms.Due to a sharp drop,demand for rare earth from downstream recovered.Affected by new energy vehicles,wind powder and energy-efficient appliances,production of rare earth permanent     

China rare earth market review

正August 1~10,2014 There was some good news in rare earth industry recently.Restructuring plans of rare earth groups led by Baotou IronSteel Group and Xiamen Tungsten Group respectively have been approved by MIIT.And rare earth storage policy,which had been expected for a very long time,has been launched officially.Pushed by the good news,rare earth price started to rebound since August 5.Price of didymium oxide and dysprosium oxide rose about 1% to 2%,averagely.About 10% of     

China rare earth market review

正July 1~10,2014Due to weak demand from downstream industry and slow transactions,rare earth market remained weak and price of rare earth products continued to decline.There was no sign of recovery in downstream market.The market of NdFeB magnetic materials and phosphor was depressed.Catalyst,     

New energy vehicle:an opportunity for rare earth magnets

<正>Extracted from Securities Guide 1.Popularity of new energy vehicles—an irresistible market trend1.1 Progress of new energy vehicles Chinese Premier Li Keqiang said recently on a visit to Xi'an BYD Autos that new energy vehicles,especially new energy bus,can lessen environment and noise pollution.He encouraged the use of new     

Brief news

正Corun invested another 50 million yuan in power battery for HEV Hunan Corun announced on 27 June that they had signed the cooperation agreement to jointly built Corun(Shaoxing)Autos Power Battery System Co.,Ltd.in Shaoxing Binhai New City.According to the announcement,total registered