基于Er3+/Yb3+掺杂的上转换玻璃陶瓷材料的制备和性能

采用熔融-晶化法在ZnO-Al2 O3-SiO2系玻璃陶瓷的基础上,用GeO2取代部分SiO2成功制备出Er3+/Yb3+共掺ZnO-Al2 O3-GeO2-SiO2系玻璃陶瓷,并通过对样品的硬度及上转换荧光测试分析确定了GeO2的最佳取代量为7.5wt％.研究发现在980 nm波长光的激发下,样品产生了绿色(524 nm、546 nm)和红色(659 nm)上转换发光,且当Er3+/Yb3+掺杂比为2.5:6.5时样品上转换荧光强度最强.     

不同冷却方式对Er3+/Yb3+共掺BaF2粉末上转换发光效率的影响

采用液氮制冷和空冷两种冷却方式制备了不同烧结温度的系列相同配方Er3+/Yb3+共掺杂BaF2粉末.与同一烧结温度采用空冷制得的样品相比较,液氮制冷可将样品的上转换荧光强度提高20倍.各样品的XRD图谱表明,经两种方式冷却后样品的晶体结构没有明显区别,但采用液氮制冷制得样品的BaF2平均晶格常数a和样品中Yb2O3含量均较采用空冷制得样品的相应参数略有减小,由此可知液氮制冷有利于更多稀土离子替代基质材料中的Ba2+成为发光中心,提高了样品的上转换发光效率.     

Yb3+/Er3+共掺碲钨酸盐玻璃的能量传递与频率上转换发光

在970nm LD激发和Er^3 离子浓度几乎不变情况下,研究了Yb^3 ／Er^3 共掺碲钨酸盐玻璃中的能量传递和其上转换发光特性。结果表明：随掺Yb^3 浓度的增加,Yb^3 ／Er^3 间能量传递效率也增加,其值在0．52到0．60之间。在Yb^3 ／Er^3 共掺碲钨酸盐玻璃中观察到峰值分别位于533,547nm和668nm的上转换绿光和红光,它们分别来源于Er^3 离子^2H11/2→^4I15／2(533nm),^4S3／2→^4I15／2(547nm)和^4F9/2→^4I15／2(668nm)辐射跃迁。上转换红光和绿光均为双光子过程,且随Yb^3 离子掺杂浓度的增加,上转换红绿光强度和其强度比值Ic／Ig也增加,这被认为是与激发态Er^3 与激发态Yb^3 之间的能量传递过程有关。     

YVO4:Er3+/Yb3+纳米纤维的静电纺丝制备及表征

实验采用静电纺丝技术和高温煅烧法结合制备YVO_4∶Er~(3+)/Yb~(3+)纳米纤维,利用X-射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)对其物相结构、尺寸与形貌进行了基本的表征。并系统地研究了YVO_4∶Er~(3+)/Yb~(3+)纳米纤维的上转换发光性能。结果表明,YVO_4∶Er~(3+)/Yb~(3+)纳米纤维的红色发射与绿色发射,均随激光工作电流强度的增大而增大,都随着温度的升高呈现单调下降趋势。     

Er3+和Yb3+共掺锗硅酸盐玻璃的上转换发光性能

采用熔融-淬火法制备了基体为30SiO2-20GeO2-15Al2O3-5B2O3-30CaF2的Er3+和Yb3+共掺锗硅酸盐玻璃.采用X射线衍射仪、荧光光谱仪和热分析仪对样品进行了表征.结果表明:Er2O3含量从0.5％(摩尔分数,下同)增加到2.0％时,玻璃转变温度Tg和Tx-Tg(Tx为第一析晶温度)数值均有明显下降.Yb2O3含量从1.5％增加到4.5％时,玻璃上转换红光发光强度数量级由103提高到105,对其中1个样品在740℃热处理12h后发现,微晶化处理并未对Er的上转换发光产生有益影响.     

不同掺杂浓度的NaGdF4∶Ho3+,Tm3+,Yb3+发光粉的上转换发光

采用水热法制备了掺杂不同比例Ho3 +/Tmn3+和不同Ylb3+浓度的NaGdF4∶Ho3+,Tm3+,Yb3+上转换发光粉,对其结构和上转换发光性能进行了表征.XRD研究结果表明:所有的样品均为六方结构NaGdF4.980 nm红外光激发下,稀土掺杂的NaGdF4发光粉显示分别来自于Ho3+离子5S2,5F4(Ho)→5I8 (Ho)跃迁发射的绿光,5F5 (Ho)→5I8(Ho)跃迁发射的红光,5 S2,5 F4(Ho)→5I7(Ho)跃迁发射的近红外光;来自Tm3+离子1D2(Tm)→3F4(Tm)和1 G4(Tm)→3H6 (Tm)跃迁发射的蓝光,1 G4(Tm)→3 F4(Tm)跃迁发射的红光,3H4(Tm) →3 H6 (Tm)跃迁发射的红外光.研究了Ho3 +/Tm3比例和Yb3+浓度对发光粉上转换发光性能的影响,并讨论了体系的上转换发光机制.计算的发光粉色坐标显示:掺杂Ho3 +/Tm3+比例和Yb3+浓度的变化能调控样品上转换发光颜色.     

Sc3+/Tm3+/Yb3+共掺六方NaYF4纳米粒子的上转换发光特性

稀土Tm3+和敏化剂(Yb3+)共掺NaYF4是目前发现的Tm3+上转换发光效率最高的材料,但还不能满足实际应用.实验中采用Sc3+/Tm3+/Yb3+共掺Na(Y1-x-y,Tmx,Yby)F4研究不同掺量Sc3+对Tm3+上转换发光效率的影响.用X射线多晶衍射仪和透射电子显微镜分析水热法合成样品的物相结构和晶粒尺寸...     

金属离子掺杂对TiO_2:Yb~(3+)/Er~(3+)上转换材料发光性能的调控研究

稀土文章采用水热法合成掺杂不同金属离子的Ti O2:Yb3+/Er3+上转换发光材料。系统的探讨了不同的金属离子对Ti O2:Yb3+/Er3+发光材料发光性能、形貌以及晶型的影响。具体到通过荧光光谱数据分析离子价态、离子半径等对红、绿光性能的影响;通过SEM数据分析掺杂不同金属离子对应样品形貌的变化;通过XRD数据分析掺杂不同金属离子对应样品的晶型的变化。结果表明离子价态以及离子半径都会改变Ti O2:Yb3+/Er3+材料的发光性能,但与Ti O2:Yb3+/Er3+材料发光性能之间不存在线性关系;掺杂不同金属离子不会改变样品的形貌;掺杂不同金属离子得到了纯相的Ti O2:Yb3+/Er3+样品,且不改变样品的晶型。     

Temperature self-monitoring photothermal nano-particles of Er3+/Yb3+ Co-doped zircon-tetragonal BiVO4

Self-monitored photo-thermal therapy (PTT) still faces huge challenge in cancer treatment, which aims to realize the real-time temperature reading during the course of optical heating. Exploiting new-type photo-thermal therapeutic agent (PTA) with thermometric function is considered to be one of effective methods to fulfill self-monitored PTT. In this work, spindle-like zircon-tetragonal (z-t) phase BiVO₄:Yb³⁺/Er³⁺ up-conversion (UC) nano-particles as self-monitored PTAs were prepared through the combination of co-precipitation and hydrothermal method. Under 980 nm laser diode excitation, real-time thermometry was accomplished by monitoring thermo-responsive emission intensity ratio of Er³⁺ (²H_11/2/⁴S_3/2 → ⁴I_15/2) transitions. Meanwhile, the photo-thermal conversion effect associated with UC process was trigged via the non-radiative transition channels. Considering the balance between UC emission intensity and heat generation, the optimal sample composition was determined as BiVO₄:20%Yb³⁺/3%Er³⁺. Their maximum absolute sensitivity (S_a) reached 0.0125 K^-1 at 460 K as the thermometer and the ability of photo-thermal conversion up to 3.32 K cm²/W as PTAs. Their potential applications in controlled subcutaneous photo-thermal treatment were estimated through ex vivo experiments. Results provided a new choice for nano-materials to realize real-time temperature feedback in the single host material (z-t BiVO₄) during the course of PTT.     

Yb3+和Er3+共掺杂的NaY（WO4）2纳米晶的制备与发光性能

采用水热法制备出NaY(WO4):Yb3+,Er3+纳米发光粉。通过X射线衍射、扫描电子显微镜表征了制备的发光粉样品;研究了不同Yb/Er摩尔比对发光强度的影响。结果表明:Yb3+和Er3+共掺杂的NaY(WO4)2属于四方晶系,其粒径在30 nm左右,且分散均匀。当Yb/Er摩尔比为4:1时,NaY(WO4):Yb3+,Er3+发光粉样品的发射峰强度达到了最大值。用980nm激光对其进行激发,在室温下观察到了410、524、553和656nm的发射峰,分别对应于2H9/2→4I15/2,2H11/2→4I15/2,4S3/2→4I15/2和4F9/2→4I15/2的跃迁。根据激发功率与发光强度的关系得出410、524、553和656 nm发射峰均为双光子过程。     

Up-conversion luminescence and optical thermometry properties of transparent glass ceramics containing CaF2:Yb3+/Er3+ nanocrystals

A series of Yb³⁺/Er³⁺ codoped transparent oxyfluoride glass ceramics with various amounts of Yb³⁺ have been successfully fabricated and characterized. Under 980 nm laser prompting, the samples produce intense red, green and blue up-conversion emissions, and the emission intensities increase with Yb³⁺ concentration and heat treatment temperature. Before losing good transparency in the visible region, optimum emission intensities are obtained for the sample with 25 mol% of Yb³⁺ at a heat treatment temperature of 680 °C. A possible up-conversion mechanism is proposed from the dependence of emission intensities on pumping power. The fluorescence intensity ratio between the two thermally coupled levels ²H_11/2 versus ⁴S_3/2 was measured with the laser output power of 57 mW to avoid the possible laser induced heating effect. The fluorescence intensity ratio values in the temperature range from 295 K to 723 K can be well fitted with the equation: A exp (−∆E/k_BT), where A = 6.79 and ∆E=876 cm⁻¹. The relative temperature sensitivity at 300 K was evaluated to be 1.4% K⁻¹. All the results suggest that the Yb³⁺/Er³⁺ codoped CaF₂ glass ceramics is an efficient up-conversion material with potential in optical fiber temperature sensing.     

Effect of crystalline fraction on upconversion luminescence in Er3+/Yb3+ Co-doped NaYF4 oxyfluoride glass-ceramics

The crystalline fraction were adjusted MgO concentration and the corresponding effect on upconversion (UC) luminescence in Er³⁺/Yb³⁺ co-doped NaYF₄ oxyfluorode glass-ceramics was investigated. With increase of MgO and the content of Na₂O reduced, the internal network structure of the glass became compact, which made the size of NaYF₄ nanocrystals unchanged, while the average distance between the nanocrystals increased significantly. Crystal growth is limited with the glass network, keeping the crystal size not changed. SNM-1 glass ceramics samples show a predominant red up-conversion emission under near infrared excitation at 980 nm, while a predominant green emission is observed in the SNM-3 samples. In this paper, it was indicated that it changed the effect of glass network modifier MgO in the glass structure. The possible mechanism responsible for the color variation of UC in Er³⁺/Yb³⁺ co-doped was discussed.     

Tm~(3+)/Yb~(3+)共掺氟氧玻璃的光谱性质

制备了Tm3+/Yb3+共掺杂的20GaF3-15InF3-17CdF2-15ZnF2-10SnF2-3P2O5-(20-x-y)PbF2-xTmF3-yYbF3(x=0.2～2,y=1～4)系列玻璃。室温下,通过其吸收光谱,运用Judd-Ofelt理论计算了样品的强度参量Ωt(t=2,4,6)、自发辐射几率、荧光分支比和荧光寿命等光谱参数。研究发现,增加Tm3+掺入量对Ω2影响不大,Ω4、Ω6的值有增大的趋势。在980nm激发下的荧光光谱中,观察到5个上转换发射峰,其中发光较强的464nm的蓝光是三光子过程,650nm的红光和800nm的红外光是双光子过程,并讨论了其上转换发光机理和Tm3+、Yb3+掺杂浓度对发光强度的影响。     

Tailoring the Structure and Luminescence of Nanostructured Er3+ and Er3+/Yb3+‐Activated Hafnia‐Based Systems

Nanostructured Er³⁺‐ and Er³⁺/Yb³⁺‐activated hafnium oxide films and nanoparticles were prepared from a stable colloidal suspension and investigated by several techniques such as transmission electron microscopy, X‐ray diffraction, dynamic light scattering, atomic force microscopy, Fourier‐transform infrared spectroscopy, and photoluminescence. Low roughness and crack‐free films were deposited by dip‐coating and spin‐coating techniques on vitreous SiO₂ and Si substrates. Nanostructured particles were also synthesized. Remarkable structural and spectroscopic differences were observed for hafnium oxide‐based materials as a function of the Er³⁺ and Er³⁺/Yb³⁺ concentration. The ⁴I_13/2 → ⁴I_15/2 emission bandwidth and the lifetime of the ⁴I_13/2 metastable state of Er³⁺ was tailored through the rare‐earth concentration. The Er³⁺ emission in HfO₂ can be explored for photonic applications.