铋离子掺杂纳米Y_2O_3∶Eu~(3+)红色荧光粉的光学性能研究

采用水热法结合高温烧结处理制备Bi~(3+)掺杂Y_2O_3∶Eu~(3+)纳米荧光粉,并考察了掺杂Bi~(3+)对Y_2O_3∶Eu~(3+)荧光粉结构、紫外可见光吸收和发光性能的影响。X射线粉末衍射测试表明,Y_2O_3∶Eu~(3+)掺杂Bi~(3+)(摩尔分数3%)后保持纯立方相结构,纳米颗粒的平均粒径约为16.8nm。通过激发和发光光谱测试,讨论了Bi~(3+)对Eu~(3+)的敏化作用,发现Bi~(3+)离子能促进Y_2O_3∶Eu~(3+)于300~400nm的近紫外光吸收,再以能量转移的方式传给Eu~(3+)。因此,利用Bi~(3+)电荷迁移带的近紫外吸收,是实现近紫外光有效激发Y_2O_3∶Eu~(3+)荧光粉的一种重要途径。     

Tb3+/Gd3+/Ce3+/Sb3+和Eu3+/Bi3+/Sb3+共掺玻璃的发光性能研究

为了得到显色改善的绿色和红色发光玻璃,本文采用高温熔融技术制备了Tb~(3+)/Gd~(3+)/Ce~(3+)/Sb~(3+)和Eu~(3+)/Bi~(3+)/Sb~(3+)共掺杂的硼硅酸盐透明玻璃。通过对共掺样品紫外可见吸收光谱的分析和长波紫外激发下的激发光谱及荧光光谱的分析,研究了Tb~(3+)/Gd~(3+)/Ce~(3+)/Sb~(3+)和Eu~(3+)/Bi~(3+)/Sb~(3+)共掺杂离子在玻璃基质中的发光性能,结果表明,在高能紫外光激发下,Tb~(3+)/Gd~(3+)/Ce~(3+)/Sb~(3+)共掺杂样品发射典型纯正绿光荧光的能力较强,Eu~(3+)/Bi~(3+)/Sb~(3+)共掺杂样品发射红光荧光的能力较强。     

红色荧光粉Ba_3La_6(SiO_4)_6:Eu~(3+)的制备与发光性能

采用高温固相法合成了Eu~(3+)激活的Ba_3La_6(SiO_4)_6红色荧光粉并对其发光性质进行了研究。XRD谱显示,合成样品为纯相Ba_3La_6(SiO_4)_6晶体。样品的激发光谱由一系列宽谱组成,峰值分别位于300、364、384、395、416和466nm,其激发主峰位于395nm。在395nm激发下,荧光粉在619nm(~5D_0→~7F_2)处有很强的发射。研究了不同Eu~(3+)掺杂浓度对样品发射光谱的影响。结果显示,随Eu~(3+)掺杂量的增大,发光强度先增大后减小。Eu~(3+)掺杂摩尔分数为13%时,出现浓度淬灭,其浓度淬灭机理为电偶极-电偶极相互作用。研究了不同Bi~(3+)掺杂量对Ba_3La_6(SiO_4)_6:Eu~(3+)发射光谱及色坐标的影响。Bi~(3+)掺杂样品中存在Bi~(3+)→Eu~(3+)的能量传递。     

Bi~(3+)浓度对Y_2O_3基荧光粉发光性能的影响

采用高温固相法合成了Y_2O_3:x Bi~(3+)[x=0.05–1.00%(摩尔分数)]荧光粉,研究了Bi~(3+)掺杂浓度对荧光粉相组成、微观形貌及发光性能的影响。结果表明:Bi~(3+)掺杂量增加会引起Y_2O_3基质晶格膨胀和晶胞体积增大;荧光粉呈等轴状颗粒形貌,且随着Bi~(3+)掺杂量的增加,粒径逐渐从250 nm增加到600 nm。Y_2O_3:x Bi~(3+)荧光粉在波长为335 nm的紫外光激发下,其发射光谱由370、410和483 nm 3个宽带发射组成。370 nm紫外光发射和410 nm蓝光发射分别是由Bi~(3+)的S_6位点的~3A_u→~1A_g和~3E_u→~1A_g电子跃迁产生,483 nm蓝绿光发射是由C_2位点的~3B→~1A电子跃迁产生。当Bi~(3+)掺杂浓度为0.25%时,荧光粉发光性能最优;掺杂量大于0.25%时,由于Bi~(3+)间的偶极–偶极相互作用,产生浓度猝灭现象。所制备的Y_2O_3:0.25%Bi~(3+)荧光粉的色坐标为(0.159 2、0.218 1),显色指数Ra为69.27,表明这种蓝绿色荧光粉在白光LED领域具有良好应用前景。     

Tb~(3+)离子掺杂ZnO-P_2O_5玻璃的发光性能研究

通过高温固相法成功制备了Tb~(3+)离子掺杂的ZnO-P_2O_5玻璃,采用了激发发射光谱对其发光性能进行了研究,并采用了长余辉发光光谱对样品的长余辉性能进行了研究,此外本文还讨论了稀土离子(Dy,Eu,Nd,Ce,Er,Ho,Pr)与Tb~(3+)共掺杂对发光玻璃的影响并通过热释光谱进行分析,结果表明共掺杂使得热释峰的强度和位置发生变化。     

稀土离子(Gd~(3+),Ce~(3+)/Ce~(4+),Eu~(3+))对Tb~(3+)掺杂硅酸盐玻璃发光性能的影响

研究了(Gd3+,Ce3+/Ce4+,Eu3+)对Tb3+掺杂硅酸盐玻璃发光性能的影响.结果表明:Tb3+掺杂硅酸盐玻璃可以发出弱蓝光(400～460 mm)和较强的绿光(480～600mm).Gd3+对Tb3+的发光起敏化作用,可提高TB3+掺杂硅酸盐玻璃的发光强度.在空气中熔制的玻璃中Ce3+和Ce4+同时存在,Ce3+对Tb3+发光起敏化作用;而Ce4+对Tb3+发光起淬灭作用.由于Ce4+比例比较高,CeO2加入导致TB3+发光强度降低,同时也缩短了Tb3+发光余辉.加入Eu2O3时,Eu3+自身发光分散了激发Tb3+发光的能量,使Tb3+的特征发射强度降低.     

Cs_2NaBiCl_6:Mn~(2+)一种橙黄色全无机双钙钛矿荧光粉

采用液相合成法制备Cs_2Na Bi Cl_6:Mn~(2+)荧光粉,通过利用X射线衍射、荧光光谱对其结构及发光性能进行了研究。结果表明:随着Mn~(2+)的逐步引入,基质Cs_2Na Bi Cl_6中以Bi~(3+)为中心的局域激发强烈吸收近紫外光,Bi~(3+)向Mn~(2+)发生能量转移促进了原子d轨道之间的电子跃迁并导致了强烈的橙黄色光致发光。当锰铋摩尔比n(Mn)/n(Bi)达到0.7以后,由于浓度猝灭效应导致光致发光明显变弱,同时在发射谱中可以看到,在590 nm附近有1个宽的发射峰,为八面配位Mn~(2+)的~4T_1→~6A_1跃迁。激发谱包含了由Bi~(3+)的6s~2→6s~16p~1激发产生的356 nm的吸收峰。Cs_2Na Bi Cl_6:Mn~(2+)不含有毒元素,合成原料价格低廉,是一种具有潜在应用前景的新型橙黄色荧光材料。     

Er~(3+)/Ho~(3+)掺杂碲酸盐玻璃光谱性能和能量传递研究

采用熔融淬冷法制备了新型Er~(3+)/Ho~(3+)掺杂的多组分碲酸盐玻璃。测试了样品的吸收光谱、1.53μm发光光谱和上转换发射光谱,研究了980 nm激发下Er~(3+)/Ho~(3+)掺杂的碲酸盐玻璃的光谱性能和能量传递机理。结果表明:在Er~(3+)/Ho~(3+)掺杂碲酸盐玻璃中可以观察到明显的以525 nm,546 nm和659 nm为中心的绿色和红色发射。Ho~(3+)的共掺通过Er~(3+)与Ho~(3+)间存在良好的能量传递改善了上转换荧光强度,抑制了1.53μm的发光。在Ho_2O_3掺杂量为0.3mol%时Er~(3+)/Ho~(3+)共掺样品上转换发光达到最佳,可见Er~(3+)/Ho~(3+)掺杂的70TeO_2-13BaO-7La_2O_3-10GeO_2玻璃在光纤激光器上转换发光方面有潜在的应用前景。     

NaGd(MoO4)2∶Eu3+红色荧光粉的制备及发光性能研究

本文采用溶胶凝胶法,以钼酸铵、硝酸钠、氧化钆、氧化铕作为原料合成NaGd(MoO_4)_2:Eu~(3+)红色荧光粉。利用XRD对所合成的荧光粉进行结构分析,通过荧光光谱探究了样品的发光性能。结果表明:当退火温度为900℃,稀土离子Eu~(3+)的掺杂浓度为8%时所制备的荧光粉具有最佳的发光效果。     

铝铋离子掺杂对ZnO量子点荧光性能的影响研究

以二水合醋酸锌作为前驱体,无水乙醇作为溶剂,聚乙二醇(PEG-400)作为分散稳定剂,利用一种简单温和的方法制备Al~(3+)、Bi~(3+)掺杂氧化锌量子点,分别研究Al~(3+)、Bi~(3+)单掺,共掺对量子点荧光光谱性能的影响。结果表明:在紫外灯照射下,量子点颜色为绿色。在360 nm的激发下,ZnO量子点在524 nm附近有较的发射峰。随着掺杂离子用量的增加,ZnO量子点可见光区发射峰形状不变,单掺和共掺Al~(3+)、Bi~(3+)都使ZnO量子的荧光峰值减弱,但单掺Al~(3+)使荧光峰发生了红移。     

Size and shape controllable synthesis and luminescent properties of BaGdF5:Ce3+/Ln3+ (Ln = Sm, Dy, Eu, Tb) nano/submicrocrystals by a facile hydrothermal process

In this paper, we present a facile and environmentally-friendly hydrothermal process to synthesize BaGdF(5): 2.5 mol% Ce(3+)/2.5 mol% Ln(3+) (Ln = Sm, Dy, Eu and Tb) nano/submicroparticles. X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), as well as photoluminescence (PL) spectra are used to characterize the resulting samples. The size, shape, and composition of the products could be tuned just by varying the organic additives and the pH values of the initial reaction solutions. The morphologies for the products include nanospheres, submicrospheres, peanut-like particles, as well as the spindle-like and star-like aggregates. Moreover, the size of the samples can be tuned from 50 nm to 150 nm. Additionally, we systematically investigate the luminescence properties of different lanthanide ions in BaGdF(5) host. Under single-wavelength excitation at 260 nm, the samples doped with different lanthanide ions show intensive multicolor visible emissions depending on the doped Ln(3+) ions. The luminescence process can be attributed to the strong absorption of UV irradiation by Ce(3+) ions, followed by energy transfer to Gd(3+) ions, from which the energy is transferred to Ln(3+), resulting in the emission from the luminescent Ln(3+) centers. The Gd(3+) ions play an intermediate role in this process.     

溶胶—凝胶法合成发光玻璃陶瓷材料的研究

采用溶胶-凝胶法低温合成了CaO-SiO_2:Eu~(3+),Bi~(3+)发光玻璃陶瓷材料。研究了复杂体系中溶胶-凝胶转变过程,得到了pH值、含水量对胶凝时间、孔隙率、表观密度、比表面积的影响。利用小角X射线散射探讨了溶胶-凝胶转变过程中酸、碱催化的不同机理。通过X射线粉末衍射、红外光谱、热重及差热分析研究了由凝胶至发光晶体的转变过程。通过激发光谱和发光光谱的测试,讨论了材料的发光特性及Bi~(2+)对Eu~(3+)的敏化作用。     

Room temperature synthesis of hydrophilic Ln(3+)-doped KGdF4 (Ln = Ce, Eu, Tb, Dy) nanoparticles with controllable size: energy transfer, size-dependent and color-tunable luminescence properties

In this paper, we demonstrate a simple, template-free, reproducible and one-step synthesis of hydrophilic KGdF(4): Ln(3+) (Ln = Ce, Eu, Tb and Dy) nanoparticles (NPs) via a solution-based route at room temperature. X-Ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), photoluminescence (PL) and cathodoluminescence (CL) spectra are used to characterize the samples. The results indicate that the use of water-diethyleneglycol (DEG) solvent mixture as the reaction medium not only allows facile particle size control but also endows the as-prepared samples with good water-solubility. In particular, the mean size of NPs is monotonously reduced with the increase of DEG content, from 215 to 40 nm. The luminescence intensity and absolute quantum yields for KGdF(4): Ce(3+), Tb(3+) NPs increase remarkably with particle sizes ranging from 40 to 215 nm. Additionally, we systematically investigate the magnetic and luminescence properties of KGdF(4): Ln(3+) (Ln = Ce, Eu, Tb and Dy) NPs. They display paramagnetic and superparamagnetic properties with mass magnetic susceptibility values of 1.03 × 10(-4) emu g(-1)·Oe and 3.09 × 10(-3) emu g(-1)·Oe at 300 K and 2 K, respectively, and multicolor emissions due to the energy transfer (ET) process Ce(3+)→ Gd(3+)→ (Gd(3+))(n)→ Ln(3+), in which Gd(3+) ions play an intermediate role in this process. Representatively, it is shown that the energy transfer from Ce(3+) to Tb(3+) occurs mainly via the dipole-quadrupole interaction by comparison of the theoretical calculation and experimental results. This kind of magnetic/luminescent dual-function materials may have promising applications in multiple biolabels and MR imaging.     

Ca3MgSi2O8:RE(RE=Eu2+,Ce3+,Tb3+)的发光性能

采用高温固相法在还原气氛下合成了Ca3MgSi2O8:RE(RE=Eu2 ,Ce3 ,Tb3 )系列样品.用荧光光谱仪研究了样品掺杂Eu2 ,Ce3 ,Tb3 后的光谱性质.样品Ca3MgSi2O8:Ce3 在紫外光激发下呈蓝紫色发射;样品Ca3MgSi2O8:Eu2 在紫外光激发下则呈绿色发射.分别讨论了Ce3 ,Eu2 和Ce3 ,Tb3 共激活焦硅酸钙盐在紫外光激发下的光谱特性和其中存在的能量传递机理,发现Ce3 分别对Eu2 和Tb3 有敏化作用.     

Luminescence performance of yttrium-stabilized zirconia ceramics doped with Eu3+ ions fabricated by Spark Plasma Sintering technique

Yttrium stabilized zirconia (YSZ) ceramics doped with Eu³⁺ ions have been successfully fabricated by Spark Plasma Sintering (SPS) technique. The influence of the europium concentration and post-annealing process on the structural, optical, and luminescent properties of the ceramics has been studied. It is shown that an increase in the europium concentration from 0.1 to 3 wt% does not lead to significant changes in the transmission spectra. However, annealing in air atmosphere at temperature from 700 °C to 1300 °C significantly affects the transmission spectrum, as a possible consequenceofthe formation of oxygen vacancy defects. The analysis of the photoexcitation and photoluminescence spectra showed that the main excitation bands are determined by direct excitation of the ⁷F₀ ground state of Eu³⁺ions to the higher 4f energy levels with further radiation transitionsfrom these states. Moreover, the europium ion in the obtained ceramics occupy low-symmetry sites without inversion center.The luminescence decay kineticsare described by a doubleexponential function with decay time τ₁ ~ 20 ns and τ₂~ 90 ns for intrinsic emission centers and millisecond (τ ~ 1.4 ms) for Eu³⁺emission, for all investigated ceramics. The luminescence spectra in nanosecond time region are characteristic for yttrium-stabilized zirconia and are caused by oxygen vacancies in the presence of heavy cations (Y³⁺ and Eu³⁺).     

Ce3+ doped Lu3Al5O12 ceramics prepared by spark plasma sintering technology using micrometre powders: Microstructure,luminescence, and scintillation properties

Ce³⁺ doped Lu₃Al₅O₁₂ (Ce:LuAG) ceramics were fabricated by the solid-state reaction method through spark plasma sintering (SPS) from 1350 °C to 1700 °C for 5 min at a pressure of 50 MPa using micro powders. The average grain size of the SPSed ceramics gradually grew from 0.42 µm (1400 °C) to 1.55 µm (1700 °C), which is nearly one order of magnitude lower than that of vacuum sintered (VSed) Ce:LuAG ceramics (~24.6 µm). Characteristic Ce³⁺ emission peaking at around 510 nm appeared and 92% photoluminescence intensity of room temperature can be reserved at 200 °C revealing excellent thermal stability. The maximum radioluminescence intensity reached around 3 times of VSed Ce:LuAG ceramics and 7.8 times of BGO crystals. The maximum scintillation light yield under γ-ray (¹³⁷Cs) excitation reached 9634 pho/MeV @ 2 μs. It is concluded that SPS technology is a feasible way to develop Ce:LuAG ceramics and further optical enhancement can be expected.     

共沉淀法制备SrZrO3:Ce纳米粒子

以NH3.H2O和NH4HCO3混合溶液做复合沉淀剂,用共沉淀法制备了SrZrO3：Ce纳米粒子。用热重-差热分析和扫描电子显微镜、透射电子显微镜分析了前驱体的物相变化、粒子形貌,用荧光光度计分析了样品的激发和发射光谱。结果表明：当金属盐溶液的起始浓度为0.10mol/L,体系温度为0℃,滴定速率为3mL/min时,添加1.05×10-3mol.L十二烷基苯磺酸钠做分散剂,pH=11.0,在1000℃煅烧3h,合成出具有良好的分散性、粒径约40nm、近似球形的SrZrO3：Ce粒子。当Ce3＋掺杂摩尔分数为0.5%时,样品的相对发光强度最大,且激发光谱和发射光谱峰值分别对应247、487 nm和496 nm波长处。     

微乳液法制备纳米球形YAG:Ce3+荧光粉及其发光性能

采用反相微乳液法,以水/曲拉通X-100/正己醇/(环己烷 正己烷)为微乳体系,铝(Al)、钇(Y)和(Ce)的硝酸盐和氯化物作为起始反应物,氨水作为沉淀剂,成功制备了纳米球形铈掺杂钇铝石榴石(cerium doped yttrium aluminum garnet,YAG:Ce3 )荧光粉.实验表明:单相YAG可以在800℃合成,比周相反应法合成温度(1 500℃)大幅度降低.用失重-差热分析仪、Fourier变换红外光谱仪、X射线衍射仪、透射电镜、荧光分光光度计等对粉体特性进行了表征.结果表明:粉体颗粒粒径约为50nm,粒度分布均匀,球形度好,分散性好,粉体的激发光谱为双峰结构,主激发波长为469nm,发射波长为532nm,适用于白光发光二极管.