La2O3：Sm发光粉的合成与发光性质的研究

以La2O3和Sm2O3为原料，用碳酸盐沉淀法制备了La2O3:Sm^3 发光粉，并分别用XRD，SEM和发光光谱及寿命进行了表征，La2O3晶相的形成温度为800℃，其发光强度随温度升高而增强，La2O3基质中Sm^3 的最佳掺杂浓度为1．5％（摩尔分数）。     

Li+,Zn2+共掺杂对Gd2O3:Eu3+纳米粉结构和发光性能的影响

采用燃烧法制备出Li^＋,Zn^2＋掺杂的Gd2O3：Eu^3＋纳米荧光粉,研究了掺杂离子对Gd2O3：Eu^3＋的结晶性能、晶粒形貌和光致发光特性的影响.以X射线衍射（XRD）、透射电子显微镜（TEM）、发射光谱和衰减时间谱等手段表征材料性能.结果表明,Li^＋,Zn^2＋掺杂可显著提高Gd2O3：Eu^3＋纳米粉在611 nm处的发光强度,最大可达到未掺杂时的2.5倍.发光增强的主要原因可归结为3个方面： （1）使晶粒由单斜相向更利于发光的立方相转变; （2）氧空位的敏化剂作用; （3）掺杂离子的助熔剂效应,使晶粒的结晶性能提高、粒径增大,从而降低表面态引起的发光猝灭.     

Er3+和Yb3+共掺杂La2Ti2O7纳米晶的上转换发光

采用溶胶-凝胶法制备了 Er3+单掺杂A2 Ti2O7(A=La,Y,Gd)和Er3+,Yb3+共掺杂的La2 Ti2O7纳米晶样品.用X射线衍射仪、扫描电子显微镜和紫外-可见-近红外光谱仪分别对样品的结构、形貌和光吸收性质进行了表征;测试了样品在980 nm激光激发下的室温上转换光谱.结果发现,样品都发出了很强的绿光(大约在525和549 nm)和红光(大约660 nm).通过研究这些基质的晶体结构对上转换发光的影响,发现La2 Ti2O7基质中Er3+离子的上转换发射最强.对La2 Ti2O7纳米晶的上转换发光研究表明,Yb3离子能够有效地敏化Er3离子的上转换发射.对上转换发光强度与泵浦功率的依赖分析,发现红光和绿光的发射均属于双光子吸收过程,最后讨论了Er3+和Yb3的上转换发光机制.     

Sm3+杂CaO-SiO2-B2O3发光玻璃的制备、表征及性质

用高温固相法合制备了以CaO-SiO2-B2O3为基质,Sm3+为激活离子的发光玻璃.对Sm3+的淬灭浓度、基质中的硼硅比例、其他稀土离子的敏化作用以及基质组成等因素对玻璃发光特性的影响进行了探讨,并用红外和X-衍射分析对样品的结构进行了表征.结果表明:当Sm3+掺杂的物质的量分数为1.2%,激发波长λ=404 nm时,玻璃体60CaO-20SiO2-20B2O3:1.2Sm3+的发光强度为4838 A.U.(λ=606 nm);这种发光玻璃具有将紫外及近紫外光转换为橙红色光的特点.少量的Eu3+的掺入,对玻璃体的发光起敏化作用;玻璃体中的组分CaO可被ZnO替代.     

La2O3∶Sm发光粉的合成与发光性质的研究

以La2O3和Sm2O3为原料, 用碳酸盐沉淀法制备了La2O3: Sm3+发光粉, 并分别用XRD, SEM 和发光光谱及寿命进行了表征. La2O3晶相的形成温度为800 ℃, 其发光强度随温度升高而增强. La2O3基质中Sm3+的最佳掺杂浓度为1.5%(摩尔分数).     

高掺杂Ce,Gd(Y_(3-x-y)Ce_xGd_y)Al_5O_(12)荧光粉的发光下降及温度猝灭特性

采用高温固相法分别合成了不同Ce浓度掺杂的和固定Ce浓度为0.06不同Gd浓度掺杂的Y3Al5O12(YAG)系列荧光粉,通过测量其激发、发射光谱、漫反射光谱、荧光寿命和变温发射光谱,研究了掺杂元素的浓度对荧光粉发光性能的影响以及荧光粉发光的温度猝灭性质。研究结果表明:荧光粉发光强度随着Ce3+掺杂浓度和Gd3+掺杂浓度的提高均呈下降趋势。分析发现,荧光粉发光强度下降并非主要由浓度猝灭所引起,而是由于高浓度掺杂下发生YAG基质与Ce3+对激发光的竞争吸收,导致Ce3+对激发光的吸收量减少,从而影响发光强度。温度实验表明,随着温度的升高,荧光粉发光强度下降。Ce含量的改变对YAG:Ce荧光粉的热猝灭性质影响较小,Gd的掺杂使荧光粉的发射波长向长波方向移动,同时热猝灭现象严重。     

Ga2O3薄膜的光致发光及激光烧蚀产物的分布

采用脉冲激光沉积技术在氧气氛中制备了Ga2O3薄膜。X射线衍射表明薄膜属于β单斜晶系,薄膜的颗粒在纳米量级;原子力显微镜显示随着氧气压强的增加,薄膜颗粒增大。测定了薄膜的光致发光,发现沉积时氧气压强的增加可以提高 纯Ga2O3薄膜的发光强度,且峰位红移。Ga2O3靶物质中掺杂少量的CeO2后所得到的薄膜,其发光强度可以明显地增加。此外,还利用发光光谱技术研究了由激光 烧蚀所产生的羽状物中Ga原子或离子的氧化反应。     

碱土金属离子(Mg2+,Ca2+,Ba2+)掺杂对长余辉荧光粉SrAl2O4:Eu2+,Dy3+发光性能的影响

采用高温固相法制备了碱土金属离子(Mg2 ,Ca2 ,Ba2 )掺杂的SrAl2O4:Eu2 ,Dy3 长余辉荧光粉.XRD谱分析表明,随着基质中掺人的碱土金属离子(Mg2 ,Ca2 ,Ba2 )浓度增加,基质晶格常数也随之发生变化.Mg2 ,Ca2 和Ba2 3种碱土离子在SrAl2O4中的固溶范围分别为40%,15%和30%.光谱分析则表明在固溶范围内随着掺杂Mg3 ,Ca2 和Ba2 浓度的增大,样品的发射峰值会在480～530 nm范围出现规律性移动.适当浓度的Mg2 ,Ba2 掺杂会不同程度地提高样品的发光强度,而Ca2 的掺杂则会降低发光强度.但是碱土金属离子(Mg2 ,Ca2 ,Ba2 )的掺杂并不能延长SrAl2O4:Eu2 ,Dy3 荧光粉的余辉时间.     

碱土金属离子（Mg^2＋，Ca^2＋，Ba^2＋）掺杂对长余辉荧光粉SrAl2O4：Eu^2＋，Dy^2＋发光性能的影响

采用高温固相法制备了碱土金属离子（Mg^2＋,Ca^2＋,Ba^2＋）掺杂的SrAl2O4：Eu^2＋,Dy^3＋长余辉荧光粉。XRD谱分析表明,随着基质中掺入的碱土金属离子（Mg^2＋,Ca^2＋,Ba^2＋）浓度增加,基质晶格常数也随之发生变化。Mg^2＋,Ca^2＋和Ba^2＋ 3种碱土离子在SrAl2O4中的固溶范围分别为40％,15％和30％。光谱分析则表明在固溶范围内随着掺杂Mg^2＋,Ca^2＋和Ba^2＋浓度的增大,样品的发射峰值会在480～530nm范围出现规律性移动。适当浓度的Mg^2＋,Ba^2＋掺杂会不同程度地提高样品的发光强度,而Ca^2＋的掺杂则会降低发光强度。但是碱土金属离子（Mg^2＋,Ca^2＋,Ba^2＋）的掺杂并不能延长SrAl2O4：Eu^2＋,Dy^3＋荧光粉的余辉时间。     

ZnO-P2O5:Tb3+玻璃的热释光研究

采用高温熔融法制备了ZnO-P2O5：Tb^3＋玻璃,并以热释光为手段,研究了基质组成、Tb^3＋掺杂浓度、熔制气氛、Tb^3＋与其他稀土离子共掺等因素对ZnO-P2O5：Tb^3＋玻璃的发光中心、陷阱浓度及陷阱能级分布的影响。结果表明：ZnO含量的增加,使得与Zn^2＋配位的氧空位的数量增多,导致50-150℃低温区对应的陷阱浓度增加;还原气氛下,Tb^3＋掺杂后,一方面形成发光中心使得热释光强度提高,另一方面,可能由于不等价取代基质中的Zn^2＋离子产生新的缺陷使得陷阱能级加深;空气气氛下,大部分Tb^3＋被氧化成Tb^4＋,发光中心浓度降低;Ce^3＋,Eu^3＋,Dy^3＋,Nd^3＋,Pr^3＋和Er^3＋与Tb^3＋共掺时,陷阱能级深度与陷阱中心的电荷密度发生了不同程度的变化。     

Upconversion and fluorescence spectral studies of Er3+/Yb3+-codoped Bi2Q3-GeO2-Ga2Q3-Na2O glasses

The absorption spectra and upconversion fluorescence spectra of Er3+/Yb3+-codoped natrium-gallium-germanium-bismuth glasses are measured and investigated. The intense green (533 and 549 nm) and red (672 nm) emission bands were simultaneously observed at room temperature. The quadratic dependence of the green and red emission on excitation power indicates that the two-photon absorption processes occur. The influence of Ga2C3 on upconversion intensity is investigated. The intensity of green emissions increases slowly with increasing Ga2O3 content, while the intensity of red emission increases significantly. The possible upconversion mechanisms for these glasses have also been discussed. The maximum phonon energy of the glasses determined based on the infrared (IR) spectral analysis is as low as 740 cm-1. The studies indicate that Bi2O3-GeO2-Ga2O3-Na2O glasses may be potential materials for developing upconversion optical devices.     

Er~(3 )/Yb~(3 )共掺杂AlF_3基氟化物玻璃材料的频率上转换

Er3 /Yb3 共掺杂的AlF3基氟化物玻璃材料ABCY的制备及其上转换荧光性质。样品的组分为 40AlF3 2 0BaF2 2 0CaF2 (2 0 2x 2y)YF3 xEr2 O3 yYb2 O3。在 95 0nm连续LD激发下 ,观察到该材料很强的绿色上转换发光 ,研究了该体系的上转换机理 ,认为Yb3 和Er3 之间的APTE效应是最主要的上转换途径。解释了红、绿色上转换荧光强度比值增大的现象 ,指出了可能的交叉弛豫过程。用公式y =a(x -x0 ) n 对上转换荧光强度与LD工作电流的关系进行拟合 ,得到的结果与理论值很好地一致。     

Preparation and up-conversion luminescence of hollow La2O3:Ln (Ln = Yb/Er, Yb/Ho) microspheres

Hollow La(2)O(3):Ln (Ln = Yb/Er, Yb/Ho) microspheres with up-conversion (UC) luminescence properties were successfully synthesized via a facile sacrificial template method by employing carbon spheres as hard templates followed by a subsequent heating process. The structure, morphology, formation process, and fluorescent properties are well investigated by various techniques. The results indicate that the hollow La(2)O(3):Ln microspheres can be well indexed to the hexagonal La(2)O(3) phase. The hollow La(2)O(3):Ln microspheres with uniform diameter of about 270 nm maintain the spherical morphology and good dispersion of the carbon spheres template. The shell of the hollow microspheres consists of numerous nanocrystals with the thickness of approximately 40 nm. Moreover, the possible formation mechanism of evolution from the carbon spheres to the amorphous precursor and to the final hollow La(2)O(3):Ln microspheres has also been proposed. The Yb/Er and Yb/Ho codoped La(2)O(3) hollow spheres exhibit bright up-conversion luminescence with different colors derived from different activators under the 980 nm NIR laser excitation. Furthermore, the doping concentration of the Yb(3+) is optimized under fixed concentration of Er(3+)/Ho(3+). This material may find potential applications in drug delivery, hydrogen and Li ion storage, and luminescent displays based on the uniform hollow structure, dimension, and UC luminescence properties.     

Study of upconversion fluorescence property of novel Er3+/Yb3+ co-doped tellurite glasses

Er3+/Yb3+ co-doped TeO2-B2O3-Nb2O5-ZnO (TBN) glasses were prepared. The absorption spectra and upconversion luminescence spectra of TBN glasses were measured and analyzed. The upconversion emission bands centered at 530, 546 and 658 nm were observed under the excitation at 975 nm, corresponding to the transitions of 2H11/2-->4I15/2, 4S3/2-->4I15/2 and 4F9/2-->4I15/2 respectively. The ratio of red emission to green emission increases with an increasing of Yb3+ ions concentration. According to the quadratic dependence on excitation power, the possible upconversion mechanisms and processes were discussed.     

Study of luminescence properties of novel Er3+ single-doped and Er3+/Yb3+ co-doped tellurite glasses

The novel Er(3+) single-doped and Er(3+)/Yb(3+) co-doped tellurite glasses were prepared. The effect of Yb(2)O(3) concentration on absorption spectra, emission spectra and upconversion spectra of glasses were measured and investigated. The emission intensity, fluorescence full width at half maximum (FWHM) and upconversion luminescence of Er(3+) go up with the increasing concentration of Yb(3+) ions. The maximum FWHM of (4)I(13/2) --> (4)I(15/2) transition of Er(3+) is approximate 77 nm for 1.41 x 10(21)ions/cm(3) concentration of Yb(3+)-doped glass. The visible upconversion emissions at about 532, 546 and 659 nm, corresponding to the (2)H(11/2) --> (4)I(15/2), (4)S(3/2) --> (4)I(15/2) and (4)F(9/2) --> (4)I(15/2) transitions of Er(3+), respectively, were simultaneously observed under the excitation at 970 nm. Subsequently, the possible upconversion mechanisms and important role of Yb(3+) on the green and red emissions were discussed and compared. The results demonstrate that this kind of tellurite glass may be a potentially useful material for developing potential amplifiers and upconversion optical devices.     

Effect of ZnX (X=F2 and Cl2) as modifier on luminescence properties of Ho3+/Yb3+ doped tellurite glasses

Optical absorption and photoluminescent properties of Ho(3+)/Yb(3+) co-doped tellurite and zinc halide tellurite glasses are investigated. The effect of zinc halides as modifier on the luminescence properties of above mentioned samples has been explored. Two intense upconversion emission bands centered at 546 ((5)F(4), (5)S(2)→(5)I(8)) and 660 ((5)F(5)→(5)I(8)) nm are observed when samples are excited by 976 nm radiation. Zinc halides act as quencher when 976 nm excitation source is used. The up and downconversion emission spectra are recorded with 532 nm excitation source also. In this case also, zinc halides do not show any improvement. The dependence of upconversion intensities on excitation power and temperature is discussed. The power dependence study shows a quadratic dependence of fluorescence intensity on the excitation power while decrement in emission intensity of different transitions at different rates is observed in temperature dependence study. The possible upconversion mechanisms are also discussed in order to understand the energy transfer between Yb(3+) and Ho(3+) ions.     

Yb:Er:Tm:LiTaO3的上转换发白光性能研究

980 nm脉冲激光激发下,首次通过高温固相法制备Yb(10%):Er(1%):Tm(1%):LiTaO3(摩尔分数)多晶粉并实现室温上转换白光.X射线粉末衍射测试结果表明,Yb:Er:Tm:LiTaO3中的掺杂离子并没有改变晶格结构,以取代的方式存在于钽酸锂晶格中.结合功率曲线测试结果和上转换机制研究发现,产生上转换蓝光的Tm3+离子1G4态的布居主要来自双光子同时吸收过程.而单光子上转换输出的红光,则由Tm3+和Er3+离子之间的交叉弛豫过程产生,即3F2/3(Tm3+)+4I15/2(Er3+)→3H6(Tm3+)+4I9/2(Er3+).上转换绿光来源于Yb/Er离子对的二次能量传递.     

Investigation of thermal stability and spectroscopic properties in Er3+/Yb3+-codoped TeO2-Li2O-B2O3-GeO2 glasses

The new Er3+/Yb3+ co-doped 70TeO2-5Li2O-(25-x)B2O3-xGeO2 (x = 0, 5, 10, 15 fand 20 mol.%) glasses were prepared. The thermal stability, absorption spectra, emission spectra and lifetime of the 4I(13/2) level of Er3+ ions were measured and studied. The FT-IR spectra were carried out in order to investigate the structure of local arrangements in glasses. It is found that the thermal stability, absorption cross-section of Yb3+, emission intensity and lifetime of the 4I(13/2) level of Er3+ increase with increasing GeO2 content in the glass composition, while the fluorescence width at half maximum (FWHM) at 1.5 um of Er3+ is about 70 nm. The obtained data suggest that this system glass can be used as a candidate host material for potential broadband optical amplifiers.     

纳米TiO2基质掺杂稀土离子Er3+和Yb3+的上转换发光特性

采用溶胶-凝胶法制备了掺杂稀土离子Er3 及Er3 /Yb3 的TiO2纳米晶体,考察了样品在980 nm激发光源作用下,不同的稀土离子掺杂量、不同的焙烧温度、不同的激发温度等对其上转换发光特性的影响,并对Er3 /Yb3 共掺杂的上转换发光机制进行了探讨.     

Photoluminescent Property Effect of Sc3+ on Er3+/y3+/yb3+ Doped Al2O3 Powders

The photoluminescence (PL) property effect of Sc3+ on the Er3+/Y3+/Yb3+ doped Al2O3 powders prepared by sol-gel method has been investigated. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) implied that the distribution of dopants (Er3+ , Y3+ , Yb3+ , Sc3+) was improved effectively with the rise of Sc3+ concentration. The Fourier transform infrared spectra (FTIR) results demonstrated that the ligand around the quenching center -OH and the population of -OH were altered by introducing different amounts of Sc3+ . The PL intensity centered at 1530 nm was increasingly improved with the rise of Sc3+ concentration, as well as the corresponding full widths at the half maximum (FWHM) and lifetime. The optimized PL intensity was 4.7 times higher than that non-Sc3+ doped sample for the Al2O3 powders codoped with 10mol% Sc3+ . This material can be promising candidates for optical fiber amplifier.