Spectroscopic properties of Er3+/Ho3+/Tm3+ doped α-SiAlON ceramics under 793 ​nm excitation

This paper reports the first demonstration of super broadband infrared downshifting emission extending from 1640 ​nm to 2200 ​nm with the full width at half maximum of ∼ 417 ​nm in lanthanides (Er³⁺, Ho³⁺, and Tm³⁺)-doped α-SiAlON ceramics upon 793 ​nm excitation. Using α-Si₃N₄ ceramic as a precursor the lanthanides-doped α-SiAlON ceramics were synthesized by the hot-press method. The lanthanides induced no significant secondary phases in the sintered α-SiAlON ceramics. Strong two-photon upconversion emission bands centered at 547, 671 and 694 ​nm have also been observed upon 793 ​nm excitation. The time-resolved measurements of the upconversion emissions confirm that the efficient energy transfer among the Er³⁺, Ho³⁺ and Tm³⁺ ions as well as the ground state absorption in Er³⁺ and Tm³⁺ are responsible for the observed spectroscopic properties.     

Ho~(3+)/Yb~(3+)和Er~(3+)/Yb~(3+)共掺氟氧化物玻璃的上转换发光

研究了Ho3+/Yb3+和Er3+/Yb3+共掺氟氧化物玻璃的上转换发光性质.结果表明,在980 nm近红外激光激发下,Ho3+/Yb3+和Er3+/Yb3+共掺样品都呈现了强烈的上转换红光和绿光发射.随着Ho3+和Er3+浓度的增加,红光和绿光的强度都先增大后减小,x≈0.1%时发光强度达到最大,而后逐渐减小,它们的最佳掺杂量分布在低浓度区域.上转换发光强度和激发光功率的关系表明上转换红光和绿光发射都是双光子的吸收过程.     

Gd_2O_3中掺杂Eu~(3+)和Yb~(3+)荧光粉的制备及荧光性能

采用溶胶-凝胶法制备了Gd2O3∶Eu3+,Gd2O3∶Yb3+与Gd2O3∶Eu3+,Yb3+荧光粉,对制备条件进行了研究,且进行了样品的物相表征.结果表明,Yb3+在高掺杂浓度下存在浓度猝灭,Eu3+可以通过共合作能量传递过程和交叉弛豫过程有效地将能量传递给临近的一对Yb3+离子.Gd2O3∶Eu3+,Yb3+在Eu3+的特征激发峰314 nm激发时,可以产生550~750 nm的Eu3+的特征发射和900~1100 nm的Yb3+近红外特征发射两个波段光谱.制备的Gd2O3∶Eu3+,Yb3+荧光粉可以将硅太阳能电池吸收较弱的300~550 nm的高能光子转换为两个响应较好的近红外光子.     

上转换材料LiLa(MoO4)2:Yb3+,Er3+(Tm3+)的制备及其光谱性质测定

采用溶胶-凝胶法制备了上转换材料LiLa(MoO4)2:Yb3+,Er3+(Tm3+),并对其进行了X射线衍射分析以及荧光光谱测定.在980 nm红外激光器激发下,LiLa(MoO4)2:Yb3+,Er3+发出波长为530 nm和550 nm的绿色可见光,而LiLa(MoO4)2:Yb3+,Tm3+发出波长为475 nm的蓝色可见光.对Yb3+/Er3+和Yb3+/Tm3+双掺体系的上转换发光机理进行了探讨,其中Er3+发出绿色上转换光的过程为双光子过程,而Tm3+发出蓝色上转换光的过程为三光子过程.     

Upconversion luminescence properties of Mn2+-doped NaYF4:Yb/Er nanoparticles

NaYF₄:Yb/Er upconversion nanoparticles doped with Mn²⁺ were synthesized by hydrothermal method. The upconversion photoluminescence measured by 975 nm continuous wave laser indicates that the as-synthesized samples generated green and red color emission with various intensity ratio ranging from 3.25 to 548.35, which is highly correlative to the dopant concentration of Mn²⁺. However, there is no red emission enhancement observed in Cu²⁺-doped NaYF₄:Yb/Er nanoparticles.     

Tm~(3+)/Yb~(3+)共掺新型氟氧化物玻璃上转换发光

在980nm近红外激光激发下,Tm3+/Yb3+共掺的新型氟氧化物玻璃呈现了强烈的上转换蓝光、红光和近红外光发射.随着Tm3+和Yb3+含量的增加,上转换蓝光和红光的强度都先增大后减小,它们的最佳掺杂物质的量分数分别为0.06%和3%.对上转换发光强度和激发光功率的关系进行了研究,研究表明上转换蓝光和红光发射都是三光子的吸收过程,近红外光的发射是两光子吸收过程.     

Dy3+/Eu3+共掺钒酸钇荧光粉的合成及发光性质研究

采用高温固相合成法制备了Y1-x VO4:Dy3+x和Y0.994-yVO4:Dy3+0.006,Eu3+y系列样品,通过XRD确定其晶体结构.研究其荧光性质发现,Dy3+在YVO4中可同时发射出483 nm(蓝光)和573 nm(黄光)荧光,分别归属于4F9/2→6H15/2和4F9/26H13/2的能级跃迁,且Dy...     

Yb3＋／Er3＋（Ho3＋）掺杂NaYF4与Y2O2S荧光粉的制备与上转换发光

比较研究了Yb／Er（Ho）共掺六方相NaYF4和Y2O2S在980nmLD泵浦下的上转换发光．研究结果表明,NaYF4：20％Yb,1％Er的发光明显强于NaYF4：20％Yb,1％Ho,而Y202S：6％Yb,0．25％Ho与Y202S：6％Yb,0．5％Er却呈现相近的总发射强度．分析认为,Yb／Er和Yb／Ho之间的不同能量传递机制是导致上述现象的主要因素．     

稀土掺杂CaF_2上转换白光研究

通过简单温和水热法合成Ca0.89Yb0.1Er0.01F2,Ca0.895Yb0.1Tm0.005F2及Ca0.885Yb0.1Er0.01Tm0.005F2白色粉末,并用X射线衍射仪和场发射扫描电镜对氩气保护下退火前后的粉末样品进行了结构和形貌表征。在980 nm连续半导体激光二极管激发下,用日立荧光光谱仪对退火后的粉末样品进行了上转换发射光谱表征。在980 nm激发下,Ca0.89Yb0.1Er0.01F2样品发出绿色和红色光(黄色光),Ca0.895Yb0.1Tm0.005F2样品发出蓝色光,Ca0.885Yb0.1Er0.01Tm0.005F2样品发出白色光。实验结果表明Ca0.885Yb0.1Er0.01Tm0.005F2是一种潜在的三维显示材料及白光光源材料。     

稀土掺杂CaF2上转换白光研究

通过简单温和水热法合成Ca0.89Yb0.1Er0.01,Ca0.895Yb0.1Tm0.005F2及Ca0.885Yb0.1Er0.01Tm0.005F2白色粉末,并用X射线衍射仪和场发射扫描电镜对氩气保护下退火前后的粉末样品进行了结构和形貌表征。在980nm连续半导体激光二极管激发下,用日立荧光光谱仪对退火后的粉末样品进行了上转换发射光谱表征。在980nm激发下,Ca0.89Yb0.1Er0.01F2样品发出绿色和红色光（黄色光）,Ca0.895Yb0.1Tm0.005F2样品发出蓝色光,Ca0.885Yb0.1Er0.01Tm0.005F2样品发出白色光。实验结果表明Ca0.885Yb0.1Er0.01Tm0.005F2是一种潜在的三维显示材料及白光光源材料。     

高发光强度上转换材料Y2O3 ∶Er,Yb纳米晶的制备

将反相乳液合成方法与水热处理方法相结合, 获得Y₂O₃ ∶Er,Yb纳米晶的前驱体, 经过一定温度灼烧, 获得了高发光强度的上转换Y₂O₃ ∶Er,Yb 纳米晶,经水热处理的纳米晶样品具有更好的晶体结构, 有利于激发电子在Er离子^{4F_9/2能级上的分布，进而导致红色发射强度极大地提高.}     

铒/镱掺杂多金属氧酸盐的制备及其近红外发光性研究

制备了高发射率的Keggin结构的铒镱共掺稀土多金属氧酸盐ZnPOM:Er3+,Yb3+,样品在室温980 nm激光激发下具有很强的位于1551nm的近红外发射,共掺样品中镱是铒有效的敏化剂,详细地探讨了镱铒间样品能量传递及近红外发光机理.     

白光发射稀土掺杂SrF2上转换荧光粉的研究

通过高温固相法合成了Sr_(0.89)Yb_(0.1)Er_(0.01)F_2和Sr_(0.8495)Yb_(0.15)Tm_(0.005)F_2高亮度上转换荧光粉.在980 nm激光激发下,Sr_(0.89)Yb_(0.1)Er_(0.01)F)2样品发出红色和绿色光(黄绿光),Sr0.8495Yb0.15Tm0.005F2样品发出蓝色光.二者发射的荧光强度均高于商用上转换荧光粉.将以上两种上转换荧光粉按一定比例混合后可以得到不同色温的白光发射荧光材料.该系列材料在防伪、三维显示及白光照明等领域具有潜在应用价值.     

Microstructure investigation and multicolor upconversion in Yb~(3+)/Ln~(3+)(Ln=Er/Tm/Ho) ions doped α-Sialon

Yb~(3+)/Ln~(3+)(Ln=Er/Tm/Ho)-α-sialon ceramics were fabricated by hot press sintering technique.Their microstructure and luminescent properties were studied by XRD,EDS,HRTEM and photoluminescence measurements.The results showed that the sintered ceramics consisted ofα-Sialon with a trace amount ofβ-Sialon phase.The frequency upconversion and downconversion properties of Yb~(3+)/Ln~(3+)(Ln=Er/Tm/Ho)-α-Sialon ceramics were investigated under 980 nm low-power excitation.The different concentrations of Yb~(3+)/Ln~(3+)(Ln=Er/Tm/Ho)produced multicolor emissions characteristics of each Ln~(3+)ion as a result of the energy transfer from Yb~(3+)to Er~(3+),Tm~(3+)and Ho~(3+)ions.The EDS spectra measurements and mappings showed that the Ln~(3+)ions were well incorporated in theα-Sialon matrix.Temporal evolution of the emission decay behavior has been investigated to understand the energy transfer mechanism.     

稀土Er3+/Yb3+/Ho3+掺杂能量上转换发光研究进展

介绍了基质材料的最新研究进展,以单掺或共掺的Er3 ,Yb3 ,Ho3 离子为例,详细的阐述了稀土离子的多种上转换机制,最后提出了今后的研究方向.     

Multi-color long-lasting phosphorescence of rare earth ions in CdSiO<Subscript>3</Subscript> matrix

A series of rare earth ions doped CdSiO3:RE^3 (RE=Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho,Er, Tin, Yb, Lu) multi-color long-lasting phosphorescence phosphors are prepared by the conventional hightemperature solid-state method. The results of XRD measurement indicate that the products fired under 1050~C for 3h have a good crystallization without any detectable amount of impurity phase. Rare earth ions doped CdSiO3 phosphors possess excellent Inmiuescence properties. When rare earth ions such as Y^3 , La^3 , Gd^3 , Lu^3 , Ce^3 , Nd^3 , Ho^3 , Er^3 ,Tm^3 and Yb^3 are introduced into the CdSiO3 host, one broadband centered at about 420 nm resulting from traps can be observed. In the case of other earth ions such as Pr^3 ,Sm^3 , Eu^3 , Tb^3 and Dy^3 , their characteristic line emitting as well as the -420 nm broadband luminescence can be obtained. The mixture of their characteristic line emitting with the -420 nm broadband Inminescence results in various afterglow color.     

Studies on the effects of pre-firing and sintering temperature on NSDC nanocomposite electrolytes

Solid oxide fuel cells (SOFCs) technology, with fuel flexibility, is one of the most promising power generation technology. However, the high operating temperature of SOFCs has hindered their commercial applications. As a crucial requirement to enhance its performance, SOFCs electrolytes should operate at a low temperature. Carbonate/ceria composites are developed as electrolytes for low operating temperature SOFCs, and a better understanding of the mechanism of its ionic conductivity serves this purpose. In this work, ceria-carbonate composite electrolyte, Na₂CO₃/samarium doped ceria (NSDC) were synthesized by the co-precipitation method. The synthesized electrolytes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV–Vis spectroscopy. The XRD and SEM results showed that the sintered NSDC nanocomposite comprised a single-phase dense electrolyte structure. The crystallite size of the NSDC nanocomposite was greatly affected by the different pre-firing temperatures and different sintering temperatures. Also, the ionic conductivity of the prepared NSDC nanocomposite electrolytes was strongly dependent on the pre-firing and sintering temperatures. The NSDC nanocomposite electrolytes were pre-fired at 950 ?°C and 650 ?°C and sintered at 1200 ?°C and 900 ?°C respectively, had ionic conductivity in H₂ and air high as 0.36 ?S/cm and 0.3 ?S/cm.     

Effect of alkali metal oxides on upconversion fluorescence properties of germanatetellurite glasses

Upconversion emissions of Yb^3 /Er^3 -codoped germanate-tellurite glasses have been investigated upon the excitation of 980 nm laser diode (LD). It is found that upconversion luminescence intensities significantly increase with the increasing size of alkali metal ions. Raman spectra show that the maximum phonon energies (MPE) of glass hosts are unchanged with the replacement of alkali metal oxides, indicating that MPE is not the reason for the increase of upconversion fluorescence intensities. The analysis of the non-radiative transition of Er^3 demonstrates that the decrease of the maximum energy phonon density is the main reason for the enhanced fluorescence intensities.     

Synthesis and luminescence properties of Ca2SiO4-based red phosphors with Sm3+ doping for white LEDs

Sm³⁺-activated Ca₂SiO₄ red phosphors were prepared by the conventional high-temperature solid-state reaction method, and the effects of sodium (Na⁺) and samarium (Sm³⁺) ions doping concentrations on their crystal structure and luminescent properties were investigated by X-ray diffraction (XRD) and fluorescent spectrofluorometer. XRD patterns demonstrate that a well-crystalline structure forms in the phosphors when they are treated by calcination at 1200°C for 4 h, and the excitation spectra exhibit good absorption in the range between 350 and 420 nm. Under the irradiation of 405 nm near-ultraviolet (NUV) light, the spectra of the phosphors show a main emission peak at 601 nm attributed to the ⁴G_5/2??⁶H_7/2 transition of Sm³⁺ ions, and its intensity is greatly influenced by the concentrations of Sm³⁺ and Na₂CO₃. When the concentrations of Sm³⁺ ions and Na₂CO₃ are 2mol% and 6mol%, respectively, the optimal emission intensity can be obtained. From strong absorption in the near ultraviolet zone, the Na_0.06Sm_0.02Ca_1.92SiO₄ phosphor is a promising red-emitting phosphor for white light emitting diodes (W-LEDs).     

上转换材料复合介孔TiO2晶须的可见光催化性能

用溶胶凝胶法制备上转换发光材料Y3Al5O12:Er。反射光谱、发射光谱表明:Y3Al5O12:Er在480 nm光的激发下,产生2个<387 nm的紫外光发射峰。将上转换材料介孔TiO2晶须复合成可见光催化剂,采用X线衍射仪(XRD)、场发射扫描电子显微镜(FESEM)以及低温N2吸附-脱附(BET)等对催化剂进行表征,通过光催化降解亚甲基蓝(MB),对催化剂的活性进行测试。结果表明:复合上转换材料的介孔TiO2晶须在可见光下能够有效降解MB,10%Y3Al5O12:Er的介孔TiO2晶须的MB降解率为73%。