氟氧化物纳米相玻璃陶瓷Tb(0.7)Yb(5)∶FOV的合作下转换发光

报道了氟氧化物纳米相玻璃陶瓷Tb(0.7)Yb(5)∶FOV的红外量子剪裁研究,测量了从可见到红外的荧光发光光谱、激发谱、和荧光寿命,分析了{1([5 D4→7 F6](Tb3+),2([2 F7/2→2 F5/2] (Yb3+)}的红外量子剪裁现象,发现了487.0nm光激发5 D4能级和378.0nm光激发(5 D3,5 G6)能级的理论量子剪裁效率ηx％Yb依次分别为121.35％和136.27％.首次发现了一种新颖的合作(共协)下转换发光现象{2([(5 D3,5 G6)→5 D4](Tb3+),1([2 F7/2→2 F/2](Yb+)},即首次发现施主Tb3+离子释放两个小能量光子[(5 D3,5 G6)→5 D4]的能量,导致出现一个受主Yb3+的[2 F5/2→2 F7/2]的中等能量的光子.     

氟氧化物纳米相玻璃陶瓷Tb(0.7)Yb(5)∶FOV的合作下转换发光

报道了氟氧化物纳米相玻璃陶瓷Tb(0.7)Yb(5)∶FOV的红外量子剪裁研究,测量了从可见到红外的荧光发光光谱、激发谱、和荧光寿命,分析了{1([5 D4→7 F6](Tb3+),2([2 F7/2→2 F5/2] (Yb3+)}的红外量子剪裁现象,发现了487.0nm光激发5 D4能级和378.0nm光激发(5 D...     

氟氧化物纳米相玻璃陶瓷Tb(0.7)Yb(5):FOV的合作下转换发光

报道了氟氧化物纳米相玻璃陶瓷Tb(0.7)Yb(5)∶FOV的红外量子剪裁研究,测量了从可见到红外的荧光发光光谱、激发谱、和荧光寿命,分析了{1([5 D4→7 F6](Tb3+),2([2 F7/2→2 F5/2](Yb3+)}的红外量子剪裁现象,发现了487.0nm光激发5 D4能级和378.0nm光激发(5 D3,5 G6)能级的理论量子剪裁效率ηx%Yb依次分别为121.35%和136.27%。首次发现了一种新颖的合作(共协)下转换发光现象{2([(5 D3,5 G6)→5 D4](Tb3+),1([2 F7/2→2 F5/2](Yb3+)},即首次发现施主Tb3+离子释放两个小能量光子[(5 D3,5 G6)→5 D4]的能量,导致出现一个受主Yb3+的[2 F5/2→2 F7/2]的中等能量的光子。     

方波激发下Ho3+上转换绿色发光粉的激发机理

采用溶胶-凝胶法制备了BaGd2ZnO5:Yb3+,Ho3+的发光材料,测量了样品在不同激发密度下的上转换光发射光谱。用方波调制的971 nm LD激光激发样品得到上转换绿光发射的上升和衰减变化曲线,通过建立Ho3+离子5F4(5S2)和5I6能级及Yb3+离子2F5/2能级的速率方程,并利用速率方程对绿光的上升和衰减过程进行拟合,确定了Yb3+离子2F5/2能级寿命及Ho3+离子5F4(5S2)和5I6的能级寿命,并证实在Ho3+离子能级粒子数布居趋于稳定时,Yb3+→Ho3+的能量传递是Ho3+离子5F4(5S2)能级粒子的主要布居途径,而激发态吸收对粒子布居数的贡献较小。     

掺铒的纳米相氟氧化物玻璃陶瓷的多光子红外量子剪裁

研究了掺铒的纳米相氟氧化物玻璃陶瓷(Er(3):FOV)的红外量子剪裁现象,测量了红外和可见的Er(3):FOV的荧光光谱.结果发现光激发²H_11/2能级的⁴ I_13/2→⁴I_15/2荧光跃迁的近似量子剪裁效率已达约186.28%.计算了有关的无辐射弛豫速率、自发辐射速率和能量传递速率,分析了有关的能量传递动力学过程,发现     

钒酸钇的基质施主合作能量传递导致的镱离子的近红外量子剪裁发光

稀土材料的红外和可见量子剪裁对于寻找更好能量效率的发光材料来说都是一个激动人心的发展。发光效率的最大上限值能从100%提高到200%甚至更高。在第一代晶硅太阳能电池与第二代薄膜太阳能电池之后第三代的聚光太阳能电池已成为目前的重点发展方向。现在,利用稀土材料的近红外量子剪裁发光效应有可能较好的解决太阳光谱与太阳能电池光电响应之间存在的光谱失配的问题,因此有可能较大幅度的提高太阳能电池的发电效率,因而具有重要的意义与价值。研究了钒酸钇晶体基质中Yb3+离子的近红外量子剪裁发光现象,测量了从可见到红外的钒酸钇晶体的发光谱、激发谱与荧光寿命,测量发现钒酸钇晶体基质能带在约322.0nm光激发时能导致有效的从钒酸钇晶体基质到Yb3+离子的二级合作能量传递,进而导致了很强的Yb3+离子的985.5nm2 F5/2→2 F7/2的近红外量子剪裁发光,同时,钒酸钇晶体基质的位于430.0nm的发光强度大幅降低。测量发现:(A)Yb(1.5)∶YVO4晶体的430.0nm的荧光寿命值为τA=3.785μs;(B)YVO4晶体的430.0nm的荧光寿命值为τB=22.72μs;研究计算发现总的理论量子剪裁效率上限值为η1.5%Yb=183.3%。     

Yb3+/Ho3+/Tm3+共掺碲酸盐玻璃的上转换白光发射及其机理研究

采用高温熔融法分别制备了Yb3+/Ho3+,Yb3+/Tm3+和Yb3+/Ho3+/Tm3+共掺的碲酸盐玻璃。在980nm红外激光激发下,Yb3+/Ho3+/Tm3+共掺的玻璃样品显示了强的蓝光、绿光和红光发射,分别对应于Tm3+的1 G4→3 H6跃迁、Ho3+的5 F4(5 S2)→5I 8跃迁以及Ho3+的5 F5→5I 8和Tm3+的1 G4→3 F4跃迁。通过对比发现,Yb3+/Ho3+/Tm3+共掺样品中的红、绿光积分发射强度比值(3.95)明显大于Yb3+/Ho3+共掺样品(1.69),这是由于Ho3+和Tm3+间存在交叉弛豫过程3 H4(Tm3+)+5I 6(Ho3+)→3 F4(Tm3+)+5 F5(Ho3+)和3 F4(Tm3+)+5I 8(Ho3+)→3 H6(Tm3+)+5I 7(Ho3+)所致。在激发功率密度为8.2 W.cm-2时,Yb3+/Ho3+/Tm3+共掺样品的上转换发光色坐标值为x=0.345,y=0.338,非常接近于等能白光(x=0.333,y=0.333)。     

Yb3+敏化的Er3+/Ho3+共掺碲酸盐玻璃的上转换发光研究

用高温熔融法制备了系列Er3+/Yb3+共掺,Ho3+/Yb3+共掺,和Er3+/Yb3+/Ho3+三掺碲酸盐玻璃,在975 nm激光抽运下三种掺杂玻璃中都出现了较强的绿光和红光上转换.研究了Yb3+离子对Er3+和Ho3+离子上转换发光强度的影响以及Yb3+→Er3+,Yb3+→Ho3+能量传递效率.分析了碲酸盐玻璃中Yb3+直接敏化Er3+,Ho3+上转换发光机理.当Er3+和Ho3+浓度较低时,Er3+/Yb3+/Ho3+三掺玻璃的上转换强度随着Yb3+离子浓度的增加而增强,出现的548 nm绿光和660 nm红光主要是由于Er3+:4S3/2→4I15/2,Ho3+:5F4(5S2)→5I8和Er3+:4F9/2→4I15/2,Ho3+:5F5→5I8跃迁共同作用的结果.Er3+/Yb3+/Ho3+三掺碲酸盐玻璃的上转换机理受Er3+/Yb3+之间,Ho3+/Yb3+之间,Er3+/Ho3+之间三者共同相互作用影响,Er3+/Ho3+离子间存在的交叉弛豫过程可增加Ho3+离子在可见光范围的上转换强度.     

纳米相氟氧化物玻璃陶瓷中Er3+Yb3+离子对的量子剪裁发光造成的强的光谱调制

研究了纳米相氟氧化物玻璃陶瓷中Er3+Yb3+离子对的量子剪裁发光造成的强的光谱调制现象。测量了Er3+Yb3+双掺纳米相氟氧化物玻璃陶瓷的X射线衍射谱、表面形貌、激发光谱、吸收光谱、和发光光谱;而且也与Tb3+Yb3+双掺纳米相氟氧化物玻璃陶瓷的相对应的光谱参数进行了比较。发现378 nm光激发样品(A) Er(1%)Yb(8.0%)∶FOV和样品(B) Er(0.5%)Yb(3.0%)∶FOV所导致的652.0 nm红色发光强度为522 nm光激发时的680.85倍和303.80倍;我们还发现378 nm光激发所导致的样品(A) Er(1%)Yb(8.0%)∶FOV和样品(B) Er(0.5%)Yb(3.0%)∶FOV的 652.0 nm红色发光强度为样品(C) Er(0.5%)∶FOV 的491.05和184.12倍。我们还发现在378 nm光激发时的样品(A) Er(1%)Yb(8.0%)∶FOV和样品(B) Er(0.5%)Yb(3.0%)∶FOV的{978.0和1 012.0 nm}红外发光强度依次分别为样品(C) Er(0.5%)∶FOV 的{58.00和293.62}倍和{25.11和 67.50}倍。更进一步,对于652.0 nm波长发光的激发谱,发现(A) Er(1%)Yb(8.0%)∶FOV和(B) Er(0.5%)Yb(3.0%)∶FOV的378.5 nm激发谱峰强度是(C) Er(0.5%)∶FOV的大约606.02和199.83倍。同时,也发现样品(A) Er(1%)Yb(8.0%)∶FOV和样品(B) Er(0.5%)Yb(3.0%)∶FOV的一级量子剪裁红外1 012或978 nm发光强度为样品(D) Tb(0.7%)Yb(5.0%)∶FOV的二级量子剪裁红外976 nm发光强度的101.38和29.19倍。发现的该量子剪裁是目前所报道的最强的量子剪裁。因此,相信所发现的氟氧化物纳米玻璃陶瓷中Er3+Yb3+离子对的一级量子剪裁发光是强的可以作为量子剪裁层应用到提高晶硅太阳能电池的发电效率。研究结果也能加速对目前国际热点的下一代环保的光谱调制太阳能电池的探索。     

Er~(3+),Yb~(3+)共掺杂的NaYF_4荧光粉的制备及下转换发光研究

采用高温固相法合成了Er3+、Yb3+共掺杂的NaYF4荧光粉。XRD测量数据表明合成的样品为纯相。测量了样品的激发谱和发射谱,证明377 nm的紫外光通过量子剪裁的形式将能量传递给一个Yb3+,发射一个975 nm的红外光子,再从4F9/2能级跃迁到基态发射一个红外光子。测量了377 nm激发下,监测541 nm的发光寿命曲线,计算得到最大的量子效率为126.35%。通过监测Yb3+的975 nm的近红外发射,证明了Er3+的4F7/2和2H11/2能级通过下转换的形式将吸收的485 nm和519 nm的能量传递给Yb3+。这种将Er3+在可见光波段的多种光子能量传递给Yb3+发射975 nm的近红外光子的思想在以前的研究中从未被提出。     

Charge transfer excitation of the Nd3+, Sm3+, Dy3+, Ho3+, Er3+ and Tm3+ emission in CaGa2S4

The excitation spectra of the Nd³⁺, Sm³⁺, Dy³⁺, Ho³⁺, Er³⁺ and Tm³⁺ emission in the sodium-compensated CaGa₂S₄ host lattice, a sulfide with wide band gap, contain an intense band below the absorption edge. Comparison of the energy of its maximum with thermodynamic data and correlations to Jørgensen's refined spin-pairing theory predictions allow one to ascribe this band to a charge transfer transition ending onto 4f orbitals. The irregular variation within the rare earth series contrasts with the monotonic variation of the absorption edge in stoichiometric rare earth sulfides (e.g. NaLnS₂), associated with interband transitions.     

Emission analysis of RE3+ (Eu3+, Tb3+ & Ho3+): B2O3-BaO-LiF/AIF3 glasses

We report here the luminescence spectra of certain rare earth ions (Eu³⁺, Tb³⁺ & Ho³⁺) doped B₂O₃-BaO-LiF/AiF₃ based on the measurements of emission and decay curves of prominent emission transitions. For both the reference host glasses, FTIR, XRD, DTA-TG profiles have been recorded to understand their structural and thermal properties. Eu³⁺ doped glasses have shown five emission transitions of ⁵D₀ → ⁷F_{01,2,3 & 4} located at 580nm, 593nm, 615nm, 655nm and 704nm respectively with an excitation at λ_exci = 392 nm (⁷F₀ → ⁵L₆). Also under an UV source, these europium glasses have displayed a bright red emission from their surfaces. Tb³⁺ glasses have exhibited four emission bands of ⁵D₄ → ⁷F_6,5,4,3 at 491nm, 547nm, 588nm and 625nm respectively with an excitation at λ_exci = 376 nm (⁷F₆ → ⁵G₆). Intense green emission from the glass surfaces has been noticed upon exposure to the UV source. Prominently bluish-green emission has been noticed from the surfaces of the holmium glasses under an UV source and same emission transition (⁵F₄ → ⁵I₈) at 519 nm with an excitation at λ_exci = 389 nm (⁵I₈ − ⁵G₄) has also been obtained from their measured emission spectra. For all the prominent emissions of the rare earth glasses, decay curves have been measured to compute their lifetimes.     

FLUORESCENCE MECHANISMS OF Tm3+- AND Yb3+/Tm3+ DOPED AlF3-BASED FLUORIDE GLASS

A complete set of spectroscopic parameters, including Judd-Ofelt parameters, radiative transition probabilities, radiative lifetime, branching ratios and integrated absorption cross section, have been calculated for Tm³⁺- doped fluoroaluminate (AYF) glass, based on the measured absorption spectra. The mechanism of Tm³⁺→Tm³⁺ and Yb³⁺\Leftrightarrow Tm³⁺ energy transfers and fluorescence properties have been investigated in both Tm³⁺ single-doped and Yb³⁺/Tm³⁺ double-doped AYF glasses. The cross-relaxation process, ³F₄+³H₆→2³H₄, is proved, which makes the optimum Tm³⁺ concentration of 1.77μm fluorescence (³H₄→³H₆) much higher than 1.45μm fluorescence (³F₄→³3H₄) in Tm³⁺:AYF glasses. In Yb³⁺/Tm³⁺:AYF glasses, a stronger concentration quenching is found for the 476nm emission than that for the 797nm emission, and is discussed under the 970nm-excitation.     

Yb3+敏化的Er3+/Ho3+共掺碲酸盐玻璃的上转换发光研究

用高温熔融法制备了系列Er³⁺/Yb³⁺共掺，Ho³⁺/Yb³⁺共掺，和Er³⁺/Yb³⁺/Ho³⁺三掺碲酸盐玻璃，在975nm激光抽运下三种掺杂玻璃中都出现了较强的绿光和红光上转换.研究了Yb³⁺离子对Er³⁺和Ho³⁺离子上转换发光强度的影响以及Yb³⁺→Er关键词： 3+/Yb³⁺/Ho³⁺共掺')" href="#">Er³⁺/Yb³⁺/Ho³⁺共掺 碲酸盐玻璃 光谱性质 上转换     

Er3+及Er3+/Yb3+共掺铋酸盐玻璃光谱性质研究

制备了Er³⁺及Er³⁺/Yb³⁺共掺铋酸盐玻璃，测试了样品的吸收光谱、荧光光谱.应用Judd-Oflet理论计算了Er³⁺在铋酸盐玻璃中的光谱强度参数，分别为Ω₂=(5.47—2.92)×10^-20cm²，Ω₄=(2.16—1.22)×10^-20cm², 关键词： 3+')" href="#">Er³⁺ 铋酸盐玻璃 3+/Yb³⁺共掺')" href="#">Er³⁺/Yb³⁺共掺 光谱性质     

Er3+及Er3+/Yb3+掺杂ZrO2-Al2O3的制备及发光性质

采用共沉淀法制备了纳米晶ZrO₂-Al₂O₃∶Er³⁺发光粉体.所制备的粉体室温下具有Er3+离子特征荧光发射,主发射在绿光,其中位于547 nm、560 nm的绿光最强,并得出稀土离子与基质之间有能量传递.对不同煅烧温度下的样品研究表明:因不同温度下所制得的样品晶相不同.研究了纳米晶ZrO2-Al2O3∶Er3+及ZrO₂-Al₂O₃∶Er³⁺/Yb³⁺的上转换发光,并分析了上转换的跃迁机制.发现ZrO₂-Al₂O₃∶Er³⁺的绿光为双光子过程,而ZrO₂-Al₂O₃∶Er³⁺、Yb³⁺的上转换光谱中,红光和绿光也为双光子过程,而极弱的蓝光为三光子过程.讨论了Er³⁺的浓度猝灭现象.最适宜掺杂浓度的原子分数为2%（Er³⁺/Zr⁴⁺）.     

Tm3+/Yb3+/Er3+共掺氟氧硅酸盐玻璃的上转换发光特性

利用熔融法制备了Tm3+/Yb3+/Er3+共掺氟氧硅酸盐玻璃.在980nm LD激发下,研究了Tm3+离子和Er3+离子之间的能量传递和Tm3+离子的上转换荧光,分析了Tm3+离子的上转换机理,发现蓝色上转换荧光是三光子过程对应于1 G4→3 H6的跃迁,而红色上转换荧光是双光子过程对应于1 G4→3 F4的跃迁.比较不同掺杂摩尔分数的样品的荧光强度,发现Tm3+离子的最佳掺杂摩尔分数为0.2%.     

Ce3+/Tb3+/Sm3+共掺CaO-B2O3-SiO2玻璃的光学性能调控

采用高温熔融法制备了Ce³⁺/Tb³⁺/Sm³⁺掺杂的CaO-B₂O₃-SiO₂（CBS）发光玻璃。通过傅利叶红外光谱仪、荧光光谱仪表征了该系列发光玻璃的微观结构和发光性质,并对Ce³⁺到Tb³⁺、Ce³⁺到Sm³⁺之间的能量传递机制进行了研究。结果表明,在339,378,407 nm激发下,单掺Ce³⁺、Tb³⁺和Sm³⁺的CBS玻璃分别发射紫蓝光、绿光和红光,恰好符合混合合成白光的条件。Ce³⁺/Tb³⁺和Ce³⁺/Sm³⁺双掺CBS玻璃的发射光谱以及Ce³⁺衰减寿命的变化证实了Ce³⁺→Tb³⁺和Ce³⁺→Sm³⁺之间存在能量传递,随Tb³⁺和Sm³⁺浓度增加,Ce³⁺的寿命减小,且传递效率由5.4%和5.7%分别增加至24.0%和27.1%。调节3种稀土离子的掺杂浓度并选择合适的激发波长,实现了发光颜色可调,并最终获得白光发射。     

Diffusion-limited energy transfer from Tb3+ → Nd3+ and Tb3+ → Ho3+ in DMSO

The energy transfer phenomenon has been studied from Tb³⁺ → Nd³⁺ and Tb³⁺ → Ho³⁺ in DMSO. A diffusion limited dipole-dipole mechanism of energy transfer is suggested for both systems. At high acceptor concentrations, P_da depends linearly on C² consistent with the Fong and Diestler theory of energy transfer. However, at low acceptor concentrations the observations of time evolutions of Tb³⁺ luminescence decay following flash excitation has enabled us to examine diffusion limited energy transfer from Tb³⁺ to Nd³⁺ and Tb³⁺ to Ho³⁺ in DMSO.     

Vaaisible upconversion emission of Er3+-doped and Er3+/Yb3+-codoped LiInO2

Lithium-indium oxide is a high-density (5.9 g·cm⁻³), wide band-gap semiconductor with promising applications for scintillating detection of solar neutrinos as well as for efficient phosphorescence when doped with Er³⁺ or Sm³⁺ ions. In this report, we demonstrate visible upconversion emission of Er³⁺-doped LiInO₂ synthesized by a simple solid-state chemistry procedure and discuss mechanisms responsible for pumping the Er³⁺ ions to upper levels. Intense upconversion emission is observed in the green and red spectral regions under near-infrared excitation, and it is greatly enhanced by co-doping with Yb³⁺ ions. We also examined the upconversion intensity change as a function of temperature, and, consequently, possible applications of this material as a low-temperature sensor.