ZnO-B2O3∶Tb3+长余辉玻璃的发光性质

通过还原方法制备了Tb3+离子掺杂的硼酸锌玻璃,并观察到在254 nm紫外光激发后有明亮的绿色长余辉发光现象,余辉时间达6 h.通过激发与发射光谱、余辉光谱、余辉衰减曲线、热释光谱、热释光释出速率衰减曲线等得到的信息,研究了Tb3+离子掺杂的硼酸锌玻璃的发光性质.     

LiBa0.95-yBO3:0.05Tb3+,yBi3+荧光粉的制备及荧光性质

以硼酸和碳酸盐为原料,用高温固相法制备了可被（近）紫外光（369、254 nm）有效激发的Tb³⁺单掺杂LiBa_1-xBO₃：xTb³⁺（物质的量分数x=0.02、0.03、0.04、0.05、0.06、0.07）及Bi³⁺和Tb³⁺共掺杂LiBa_0.95-yBO₃：0.05Tb³⁺,yBi³⁺（物质的量分数y=0.02、0.03、0.04、0.05、0.06、0.07）的2个系列荧光粉,产物的结构和形貌分别用粉末X射线衍射（PXRD）和扫描电子显微镜进行表征。PXRD测定结果表明2个系列的产物均为纯相LiBaBO₃。通过对第一系列产物荧光光谱的测定,筛选出发光强度最好的产物,据此确定铽离子的最佳掺杂量;在此基础上制备出铋离子掺杂量不同的第二系列荧光粉。荧光光谱测定的实验结果表明,Tb³⁺/Bi³⁺共掺杂的荧光粉的发光强度好于Tb³⁺单掺杂的荧光粉,这说明Bi³⁺对Tb³⁺有敏化作用;而且随着Bi³⁺掺杂量的增加,产物的荧光强度表现出先增加后减小的趋势,当Bi³⁺的掺杂量y=0.03时,产物的荧光强度达到最大。Bi³⁺和Tb³⁺之间存在偶极-四极相互作用而进行能量传递。系列荧光粉的CIE坐标显示其发光颜色在一定程度上呈现出由绿色光到白光的渐变趋势。     

KMgF3∶Ce3+,Tb3+纳米粒子中Ce3+→Tb3+的发光及能量传递

利用微乳液方法,合成了铈、铽共掺杂的氟镁钾纳米粒子,研究了体系中Ce³⁺→Tb³⁺的发光特性以及它们之间的相互作用,结果表明KMgF₃∶Ce³⁺,Tb³⁺纳米粒子中存在Ce³⁺→Tb³⁺的能量传递过程,即Ce³⁺可以将吸收的能量直接传递给Tb³⁺离子,使得Tb³⁺的绿色发光强度大为增加。     

Cd3Al2Ge3O12: Mn2+磷光体的发光和长余辉性能

采用传统的高温固相法合成了Cd₃Al₂Ge₃O₁₂: Mn²⁺长余辉发光材料, 利用X射线粉末衍射仪、荧光光谱仪、热释光谱计量仪等手段对粉末样品进行了表征。研究了以Zr⁴⁺离子作为辅助激活剂离子, 对发光材料Cd₃Al₂Ge₃O₁₂: Mn²⁺余辉性能的影响。分析结果表明, 样品位于500~700 nm的黄光宽带发射峰源于Mn²⁺的⁴T₁(⁴G)→⁶A₁(⁶S)跃迁发射结果。并且观察到了由Cd₃Al₂Ge₃O₁₂基质向激活剂离子Mn²⁺的能量传递。共掺杂Zr⁴⁺离子后样品发射峰位没有明显变化, 但是余辉亮度衰减曲线表明适量的Zr⁴⁺离子掺杂可延长Cd₃Al₂Ge₃O₁₂: Mn²⁺的余辉时间。通过对热释光谱的分析, 解释了双掺杂荧光粉余辉性能增强的原因, Zr⁴⁺的掺杂在材料中引入了深度更为合适的缺陷陷阱, 可有效存储光能, 增强余辉的时间和强度。     

Cd3Al2Ge3O12:Mn2+磷光体的发光和长余辉性能

采用传统的高温固相法合成了Cd₃Al₂Ge₃O₁₂:Mn²⁺长余辉发光材料,利用X射线粉末衍射仪、荧光光谱仪、热释光谱计量仪等手段对粉末样品进行了表征。研究了以Zr⁴⁺离子作为辅助激活剂离子,对发光材料Cd₃Al₂Ge₃O₁₂:Mn²⁺余辉性能的影响。分析结果表明,样品位于500~700 nm的黄光宽带发射峰源于Mn²⁺的⁴T₁(⁴G)→⁶A₁(⁶S)跃迁发射结果。并且观察到了由Cd₃Al₂Ge₃O₁₂基质向激活剂离子Mn²⁺的能量传递。共掺杂Zr⁴⁺离子后样品发射峰位没有明显变化,但是余辉亮度衰减曲线表明适量的Zr⁴⁺离子掺杂可延长Cd₃Al₂Ge₃O₁₂:Mn²⁺的余辉时间。通过对热释光谱的分析,解释了双掺杂荧光粉余辉性能增强的原因,Zr⁴⁺的掺杂在材料中引入了深度更为合适的缺陷陷阱,可有效存储光能,增强余辉的时间和强度。     

Ca9Y(PO4)7:Ce3+,Tb3+纳米荧光粉的制备及发光性能

采用水热法制备出Ca₉Y（PO₄）₇：Ce³⁺,Tb³⁺纳米荧光粉,通过XRD、SEM和荧光光谱等对样品进行了分析,研究在Ca₉Y（PO₄）₇基质中引入Ce³⁺,Tb³⁺离子对发光性能的影响规律。研究发现因Tb³⁺离子自身能量交叉驰豫的存在,使得单掺Tb³⁺时,通过调节Tb³⁺离子的浓度可以实现对发光颜色的控制。同时研究了Ce³⁺-Tb³⁺之间的能量传递为电多极相互作用的偶极-四极机制,Ce³⁺-Tb³⁺之间最大的能量传递效率为55.6%。Ca₉Y（PO₄）₇：Ce³⁺,Tb³⁺的发光颜色可以通过激活离子之间的能量传递和共发射得到可控调节。SEM分析表明荧光粉颗粒尺寸在100 nm左右,分散性好。     

绿色荧光粉Ca3Y2Si3O12:Tb3+,Ce3+的制备及发光特性

采用高温固相法合成了绿色荧光粉Ca₃Y₂Si₃O₁₂:Tb³⁺.XRD检测结果显示,荧光粉主晶相为Ca₃Y₂Si₃O₁₂,属单斜晶系.荧光光谱分析表明：Ca₃Y₂Si₃O₁₂:Tb³⁺硅酸盐荧光粉可以被370 nm的近紫外光激发,发射绿光,主发射峰位于490 nm(⁵D₄→⁷F₆),544 nm(⁵D₄→⁷F₅),585 nm(⁵D₄→⁷F₄)和621 nm(⁵D₄→⁷F₃).用544 nm最强峰监测,得到主激发峰位于370 nm的激发光谱,此光谱覆盖了300~450 nm的波长范围.研究了煅烧条件、掺杂浓度及Ce³⁺共掺杂对荧光粉发光性能的影响：在1 400 ℃下经二次煅烧 6 h得到的样品的发光性能最佳,Tb³⁺离子的最佳掺杂浓度为20mol%,Ce³⁺离子共掺杂能够提高荧光粉的发光强度,其最佳掺杂量为4mol%,说明存在Ce³⁺→Tb³⁺的能量传递.     

Eu3+或Tb3+掺杂的KY2F7纳米球的制备与表征

利用简单的室温液相反应制备了KY₂F₇及镧系离子掺杂的KY₂F₇∶Eu³⁺和KY₂F₇∶Tb³⁺的纳米球，并利用XRD，TEM，SEM，XRF和荧光光谱对所制备的材料进行了表征。研究表明Eu³⁺或Tb³⁺离子已成功地掺杂在KY₂F₇纳米球中。掺杂     

发光颜色可调的白磷钙矿结构Ca8MgBi(PO4)7∶Ce3+，Tb3+荧光粉的制备、发光性能及能量传递

采用具有白磷钙矿结构的磷酸盐作为目标产物,通过高温固相法制备了发光颜色可调的 Ca₈MgBi(PO₄)₇∶Ce³⁺,Tb³⁺荧光粉。利用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)和荧光光谱等表征手段对其物相组成、微观形貌及发光性能进行了详细研究。结果表明：掺杂少量的 Ce³⁺、Tb³⁺并没有改变 Ca₈MgBi(PO₄)₇基质的晶体结构。荧光光谱和荧光寿命曲线确定了 Ce³⁺-Tb³⁺之间存在能量传递,其能量传递机制为四极-四极相互作用,能量传递效率可达 81%。固定 Ce³⁺浓度而逐渐增加 Tb³⁺的掺杂量时,系列Ca₈MgBi(PO₄)₇∶0.08Ce³⁺,yTb³⁺荧光粉的发光颜色可由蓝光调至绿光,从而实现发光颜色的可控化。     

Cd2Ge7O16中Tb的长余辉发光特性

本文研究了Cd₂Ge₇O₁₆∶Tb³⁺材料的发光及其长余辉性质。指出Tb³⁺的发光是该离子的 ⁵D₃- ⁷D_J、 ⁵D₄- ⁷D_J两种跃迁产生的；随着掺杂浓度的增加 ⁵D₄- ⁷D_J跃迁增强，发光颜色由蓝变绿。并把该材料的长余辉性质归结为基质结构中有电子陷阱和空穴陷阱。提出余辉机理模型。     

Tb3+在MO(M=Ca,Sr)中的长余辉发光

长余辉发光材料的研究与应用，已有近100年的历史，目前仍在许多领域中有着重要应用。此类材料与其他光致发光材料具有相同的发光性能．只是更注重其发光的衰减过程和热释光性能。如．ZnS：Cu作为黄绿色的长余辉发光材料，在1992年以前是余辉性能最好的长余辉发光材料，一直处于发光研究工作的中心。     

White-light-emitting long-lasting phosphorescence in Dy-doped SrSiO3

We report on a luminescent phenomenon in Dy³⁺-doped SrSiO₃ long-lasting phosphor. After irradiation by a 254-nm UV lamp for 5 min, the Dy³⁺-doped SrSiO₃ phosphor emits white light-emitting long-lasting phosphorescence for more than 1 h even after the irradiation source has been removed. Photoluminescence, long-lasting phosphorescence and thermoluminescence (TL) spectra are used to explain this phenomenon. Photoluminescence spectra reveal that the white light-emitting long-lasting phosphorescence originated from the two mixtures of Dy³⁺ characteristic luminescence, the 480-nm blue emission (⁴F_9/2→⁶H_15/2) and the 572-nm yellow emission (⁴F_9/2→⁶H_13/2). TL spectra shows that the introduction of Dy³⁺ ions into the SrSiO₃ host produces a highly dense trapping level at 377 K (0.59 eV), which is responsible for the long-lasting phosphorescence at room temperature. A possible mechanism of the long-lasting phosphorescence based on the experimental results is proposed. It is considered that the long-lasting phosphorescence is due to persistent energy transfer from the electron traps to the Dy³⁺ ions, which creates the persistent luminescence of Dy³⁺ to produce the white light-emitting long-lasting phosphorescence.     

Luminescent properties of Tb3+ and Gd3+ ions doped aluminosilicate oxyfluoride glasses

Tb³⁺ and Gd³⁺ ions doped lithium–barium–aluminosilicate oxyfluoride glasses have been prepared. The transmission, emission and excitation spectra were measured. It has been found that those Tb³⁺-doped lithium–barium–aluminosilicate oxyfluoride glasses exhibit good UV-excited luminescence. The luminescence intensity of Tb³⁺ ion increases for those (Tb³⁺, Gd³⁺)-codoped glasses. Energy transfer process from Gd³⁺ ion to Tb³⁺ ion is indicated.     

Preparation and luminescence properties of green-light-emitting afterglow phosphor Ca8Mg(SiO4)4Cl2:Eu2+

Green-light-emitting long-lasting phosphorescence phosphor, Eu²⁺ activated calcium magnesium chlorosilicate Ca₈Mg(SiO₄)₄Cl₂, has been prepared by a modified solid-state reaction method using Ca₂SiO₄:Eu²⁺ as a precursor. Its properties have been discussed and analyzed utilizing XRD, photoluminescence, excited-state decay curve and long-lasting phosphorescence decay curve. Upon UV light excitation, the emission spectrum of Ca₈Mg(SiO₄)₄Cl₂:Eu²⁺ phosphor is composed of two separate bands centered at 425 nm and 505 nm, respectively. Furthermore, after irradiation by a 320-nm UV light for 3 min, the 2% Eu²⁺-doped Ca₈Mg(SiO₄)₄Cl₂ phosphor emits intense green-light-emitting afterglow from the 4f⁶5d¹→4f⁷ transition of Eu²⁺, and its afterglow can be seen with the naked eye in the dark clearly for more than 3 h after removal of the excitation source. The disappearance of the high-energy 425 nm band in the afterglow emission spectrum is explained by its different crystallographic sites. The afterglow decay curve of the Eu²⁺-doped Ca₈Mg(SiO₄)₄Cl₂ phosphor contains a fast decay component and another slow decay one. The possible mechanism of this long-lasting phosphorescence phosphor is also discussed based on the experimental results.     

A new promising phosphor, Na3La2(BO3)3:Ln (Ln=Eu, Tb)

We present an efficient way to search a host for ultraviolet (UV) phosphor from UV nonlinear optical (NLO) materials. With the guidance, Na₃La₂(BO₃)₃ (NLBO), as a promising NLO material with a broad transparency range and high damage threshold, was adopted as a host material for the first time. The lanthanide ions (Tb³⁺ and Eu³⁺)-doped NLBO phosphors have been synthesized by solid-state reaction. Luminescent properties of the Ln-doped (Ln=Tb³⁺, Eu³⁺) sodium lanthanum borate were investigated under UV ray excitation. The emission spectrum was employed to probe the local environments of Eu³⁺ ions in NLBO crystal. For red phosphor, NLBO:Eu, the measured dominating emission peak was at 613 nm, which is attributed to ⁵D₀-⁷F₂ transition of Eu³⁺. The luminescence indicates that the local symmetry of Eu³⁺ in NLBO crystal lattice has no inversion center. Optimum Eu³⁺ concentration of NLBO:Eu³⁺ under UV excitation with 395 nm wavelength is about 30 mol%. The green phosphor, NLBO:Tb, showed bright green emission at 543 with 252 nm excited light. The measured concentration quenching curve demonstrated that the maximum concentration of Tb³⁺ in NLBO was about 20%. The luminescence mechanism of Ln-doped NLBO (Tb³⁺ and Eu³⁺) was analyzed. The relative high quenching concentration was also discussed.     

The role of excess Zn ions in improvement of red long lasting phosphorescence (LLP) performance of β-Zn3(PO4)2:Mn phosphor

Influences of excess Zn²⁺ ions and intrinsic defects on red (λ=616 nm) phosphorescence of β-Zn₃(PO₄)₂:Mn²⁺ are systematically investigated. It is clearly observed that red long lasting phosphorescence (LLP) properties of Mn²⁺, such as brightness and duration, are largely improved when excess Zn²⁺ ions are co-doped into the matrix. Photoluminescence (PL), LLP and thermoluminescence (TL) spectra indicate that Mn²⁺ ion acts as luminescent center whereas oxygen vacancy associated to Zn²⁺ ion plays a significant role in electron trap. The TL peak for oxygen vacancy is centered at 343 K, the depth of which is suitable for improvement in LLP performance of Mn²⁺ at room temperature. The possible mechanism for this phenomenon of red LLP of Mn²⁺ in β-Zn₃(PO₄)₂:Mn²⁺ with excess of Zn²⁺ is explained by means of a competitively trapping model.     

Mechanistic Insight into Energy-Transfer Dynamics and Color Tunability of Na4CaSi3O9:Tb3+,Eu3+ for Warm White LEDs

In this work, a latent energy-transfer process in traditional Eu³⁺,Tb³⁺-doped phosphors is proposed and a new class of Eu³⁺,Tb³⁺-doped Na₄CaSi₃O₉ (NCSO) phosphors is presented which is enabled by luminescence decay dynamics that optimize the electron-transfer energy process. Relative to other Eu³⁺,Tb³⁺-doped phosphors, the as-synthesized Eu³⁺,Tb³⁺-doped NCSO phosphors show improved large-scale tunable emission color from green to red upon UV excitation, controlled by the Tb³⁺/Eu³⁺ doping ratio. Detailed spectroscopic measurements in the vacuum ultraviolet (VUV)/UV/Vis region were used to determine the Eu³⁺–O²⁻ charge-transfer energy, 4f–5d transition energies, and the energies of 4f excited multiplets of Eu³⁺ and Tb³⁺ with different 4f^N electronic configurations. The Tb³⁺→Eu³⁺ energy-transfer pathway in the co-doped sample was systematically investigated, by employing luminescence decay dynamics analysis to elucidate the relevant energy-transfer mechanism in combination with the appropriate model simulation. To demonstrate their application potential, a prototype white-light-emitting diode (WLED) device was successfully fabricated by using the yellow luminescence NCSO:0.03Tb³⁺, 0.05Eu³⁺ phosphor with high thermal stability and a BaMgAl₁₀O₁₇:Eu²⁺ phosphor in combination with a near-UV chip. These findings open up a new avenue to realize and develop multifunctional high-performance phosphors by manipulating the energy-transfer process for practical applications.     

Sol-Gel Synthesis of Nd3+-Doped GeO2 Glasses and Their Optical Properties

Transparent Nd³⁺-doped GeO₂ bulk gels and glasses were prepared by the sol-gel method, and their thermal and spectroscopic properties including electron spin resonance (ESR), absorption, fluorescence and upconversion fluorescence spectra were investigated. Absorption spectra characteristic of Nd³⁺ ions were clearly observed. Under 805 nm laser excitation, the glass showed upconversion fluorescence at 362, 389, 421, 430, 470, 534, 600, and 662 nm at room temperature.     

Room Temperature Persistent Spectral Hole-Burning in Sol-Gel-Derived Glasses Doped with Eu3+ Ions

Persistent spectral hole burning was investigated for the Eu³⁺ ions-doped glasses prepared by a sol-gel method. For the glasses containing OH bonds, persistent spectral hole is burned by the laser-induced rearrangement of the OH bonds surrounding the Eu³⁺ ions, which is thermally unstable to erase up to 200 K. On the other hand, the Eu³⁺-doped Al₂O₃-SiO₂ glasses which are heated under H₂ gas or irradiated with X-ray exhibit room temperature PSHB. The depth of the burnt hole increases as the Al₂O₃ content increases. The hole-formation could be explained by a model of the excitation of the Eu³⁺ ions and subsequent electron transfer with the excited [Eu³⁺]^– or oxygen-defect centers in the Al—O bonds. The burnt holes are more stable compared with those burned by the rearrangement of the OH bonds.     

NaBaPOM4:Tb3+绿色荧光粉制备及其发光特性

采用高温固相法合成了NaBaPOM₄:Tb³⁺绿色荧光粉, 并研究了材料的发光性质. NaBaPOM₄:Tb³⁺材料呈多峰发射, 发射峰位于437、490、543、587和624 nm, 分别对应Tb³⁺的⁵D₃→⁷F₄和⁵D₄→⁷F_{J=6, 5, 4, 3}跃迁发射, 主峰为543 nm; 监测543 nm发射峰, 所得激发光谱由4f⁷5d¹宽带吸收(200-330 nm)和4f-4f 电子吸收(330-400 nm)组成, 主峰为380 nm. 研究了Tb³⁺掺杂浓度, 电荷补偿剂Li⁺、Na⁺、K⁺和Cl^-, 及敏化剂Ce³⁺对NaBaPOM₄:Tb³⁺材料发射强度的影响. 结果显示: 调节激活剂浓度、添加电荷补偿剂或敏化剂均可以在很大程度上提高材料的发射强度.