Preparation and properties of CdSiO3: Mn2+, Tb3+ phosphor

CdSiO₃: Mn²⁺, Tb³⁺ long-lasting phosphor was prepared by the conventional high temperature solid-state method. Effects of the content of Mn²⁺ and Tb³⁺ on the luminescent properties of phosphor CdSiO₃: Mn²⁺, Tb³⁺ were investigated by means of photoluminescence (PL) spectra, the afterglow intensity decay curves and the thermoluminescence (TL) spectra. It was found that when the Mn²⁺ and Tb³⁺ dopant-concentrations were 0.4 mol% and 0.8 mol% of Cd²⁺ ions in CdSiO₃, respectively, the luminescence of phosphor prepared had better luminescent property and longer afterglow time. Role of Tb³⁺ co-doped into CdSiO₃: Mn²⁺ matrix was discussed in this paper.     

掺钆的铝酸锶铕镝磷光体的发光特性及晶相分析

采用高温固相法在弱还原气氛下制备了掺入Gd3+的SrAl2O4:Eu2+,Dy3+磷光体.研究了Gd3+对SrAl2O4:Eu2+,Dy3+磷光体的发光性能的影响.结果发现:引入Gd3+以后,对SrAl2O4基质的晶体结构基本上没有影响,也并未改变磷光体的发光光谱,却使磷光体的初始亮度显著提高,并使余辉时间延长.其余辉强度随时间的变化由最初的快衰减过程和随后的慢衰减过程组成,符合t-1.1的双曲线规律.并初步探讨了Gd3+的作用机制.     

铕—铽共掺杂的SrF2荧光体的光致发光性能

采用水热反应法合成了具有立方相结构的铕单掺杂、铽单掺杂、铕—铽共掺杂的氟化锶发光材料,采用粉末X-射线衍射(XRD)、荧光光谱(PL)等方法对合成的样品进行表征.结果表明,在Eu3+和Tb3+共掺杂的体系中存在电子转移现象,出现了Eu2+、Eu3+和Tb3+共存于同一基质共同发射的现象,在不同波长光的激发下得到的材料的...     

Ce3+/Pr3+: YAGG: A Long Persistent Phosphor Activated by Blue‐Light

The requirement of using ultraviolet light to stimulate afterglow luminescence has seriously restricted indoors/outdoors applications of most persistent materials developed hitherto. Herein, efficient blue‐light‐activated Ce³⁺, Pr³⁺: YAGG phosphors, showing optimized long‐persistent luminescence lasting for 1 h, were prepared and investigated in detail with the aid of X‐ray diffraction refinement, steady‐state/persistent photoluminescence spectra, room/low‐temperature persistent decay curves, and three‐dimensional thermo‐luminescence spectra. Notably, the afterglow properties were found highly dependent on the Ga content which greatly alters both the host band gap energy and the Ce³⁺: 5d level structure and thus is beneficial to the electrons' photoionization and trapping processes. Moreover, Pr³⁺ additive was found not only prolonged the afterglow lifetime of Ce³⁺ through improving concentration of carriers captured at the trap, but also served as the red‐emissive centers for color tuning. The persistent energy transfer from Ce³⁺ to Pr³⁺ was experimentally demonstrated for the first time.     

Multifunctional Gd2O3:Tm3+, Er3+, Nd3+ particles with luminescent and magnetic properties

Development of novel materials with advanced properties is one of the main research directions of chemistry. New substances are not only crucial for many current technological applications but also should satisfy the needs of tomorrow. Industry often requires reliable, economically effective methods that can provide high quality reproducible results. Here we propose an inexpensive synthesis method that is suitable for synthesis of many types of particles. In this work we focused on Gd₂O₃:Tm³⁺, Er³⁺, Nd³⁺ particles with luminescence and magnetic properties. Based on the analysis of morphology, structural and optical properties of particles prepared by the standard Pechini methods and its variations, we found that the method with K₂CO₃ as additive yields particles with smaller sizes (down to tens of nm), higher crystallinity, and up to 1.7 times increased luminescence intensity. We also demonstrate that the unique combination of the particles’ characteristics, for example, the intensity ratio of the luminescent bands corresponding to different REI and the mass susceptibility, strongly depends on the composition, synthesis method, and structure. The variety of the combination of the properties makes these particles a promising candidate for safety markers applications.     

Tunable color emission in LaScO3:Bi3+,Tb3+,Eu3+ phosphor

LaScO₃:xBi³⁺,yTb³⁺,zEu³⁺ (x = 0 − 0.04, y = 0 − 0.05, z = 0 − 0.05) phosphors were prepared via high-temperature solid-state reaction. Phase identification and crystal structures of the LaScO₃:xBi³⁺,yTb³⁺,zEu³⁺ phosphors were investigated by X-ray diffraction (XRD). Crystal structure of phosphors was analyzed by Rietveld refinement and transmission electron microscopy (TEM). The luminescent performance of these trichromatic phosphors is investigated by diffuse reflection spectra and photoluminescence. The phenomenon of energy transfer from Bi³⁺ and Tb³⁺ to Eu³⁺ in LaScO₃:xBi³⁺,yTb³⁺,zEu³⁺ phosphors was investigated. By changing the ratio of x, y, and z, trichromatic can be obtained in the LaScO₃ host, including red, green, and blue emission with peak centered at 613, 544, and 428 nm, respectively. Therefore, two kinds of white light-emitting phosphors were obtained, LaScO₃:0.02Bi³⁺,0.05Tb³⁺,zEu³⁺ and LaScO₃:0.02Bi³⁺,0.03Eu³⁺,yTb³⁺. The energy transfer was characterized by decay times of the LaScO₃:xBi³⁺, yTb³⁺, zEu³⁺ phosphors. Moreover absolute internal QY and CIE chromatic coordinates are shown. The potential optical thermometry application of LaScO₃:Bi³⁺,Eu³⁺ was based on the temperature sensitivity of the fluorescence intensity ratio (FIR). The maximum S_a and S_r are 0.118 K⁻¹ (at 473.15 K) and 0.795% K⁻¹ (at 448.15 K), respectively. Hence, the LaScO₃:Bi³⁺,Eu³⁺ phosphor is a good material for optical temperature sensing.     

Sr8Si4O12Cl8:Eu3+,M3+(M3+=Bi3+,Gd3+)中Eu3+的敏化发光

以Na2CO3为电荷补偿剂,采用高温固相法合成了碱土氯硅酸盐Sr8Si4O12Cl8:(Eu3 M3 )(M=Bi3 ,Gd3 )荧光材料.X射线衍射分析结果表明:合成的Sr8Si4O12Cl8:(Eu3 ,M3 )为纯四方相.Eu3 的发射主峰位于614 nm,为5D0→7F2的电偶极跃迁,表明Eu3 处于非中心对称格位,即取代Sr2 的位置.通过对其激发光谱和发射光谱研究,发现敏化剂Bi3 ,Gd3 的掺入对Eu3 的发射具有较强的敏化作用,当Bi3 和Gd3 的掺杂量(摩尔分数)分别为5.0%时,Eu3 的相对发光强度分别提高了29.4%和23.6%.     

Gd~(3+)和Zn~(2+)共掺杂二氧化钛介孔粉末的制备及光催化性能

采用溶胶-凝胶法制备了Gd3+和Zn2+共掺杂Ti O2粉末。研究了Gd3+和Zn2+掺杂对样品的相组成、表面形貌和光催化活性的影响;以亚甲基蓝为目标降解物评价了其光催化活性。结果表明:制备的样品为锐钛矿相并具有良好的介孔结构。Gd3+和Zn2+在抑制光生电子与空穴的复合起到不同的作用,Gd3+起到光生电子陷阱的作用,Zn2+可以在起到光生空穴陷阱的作用,Gd3+和Zn2+共同作用可以显著降低电子和空穴的复合速率,进而增大Ti O2的光催化活性。当Gd3+的掺杂量为0.5%、Zn2+的掺杂量为0.3%时,Ti O2粉末的光催化活性最高,经过40 min光催化降解亚甲基蓝溶液,降解率达到99.5%,比单掺杂0.5%Gd3+的Ti O2粉末降解率提高了11.5%,比单掺杂0.3%Zn2+的Ti O2粉末降解率提高了9.3%。     

Preparation and Application of Strong Near‐Infrared Emission Phosphor Sr3SiO5:Ce3+,Al3+,Nd3+

This work investigated the near‐infrared (NIR) emission properties of mCe³⁺, xNd³⁺ codoped Sr_3?m?x(Si_1?m?xAl_m+x)O₅ phosphors. Samples with various doping concentrations were synthesized by the high‐temperature solid‐state reaction. Al³⁺ ions have the ability to promote Ce³⁺ ions to enter into the Sr²⁺ sites and to improve the visible emission of Ce³⁺. Thus the NIR emission of Nd³⁺ is enhanced by the energy‐transfer process, which occurred from Ce³⁺ to Nd³⁺. The device based on these NIR emission phosphors is fabricated and combined with a commercial c‐Si solar cell for performance testing. Short‐circuit current density of the solar cell is increased by 7.7%. Results of this work suggest that the Sr_2.95Si_0.95Al_0.05O₅:0.025Ce³⁺, 0.025Nd³⁺ phosphors can be used as spectral convertors to improve the efficiency of c‐Si solar cell.     

Red,green and blue-violet emission coexistence in white-light-emitting Ca3SiO4Cl2:Bi3+, Li+, Eu2+, Eu3+ phosphor

A series of emission-tunable Ca₃SiO₄Cl₂:Bi³⁺, Li⁺, Euⁿ⁺(n =2, 3) (CSC:Bi³⁺, Li⁺, Euⁿ⁺) phosphors have been synthesized via sol-gel method. The X-ray diffraction results indicate that the as-synthesized phosphors crystallize in a low temperature phase with the space group of P21/c. Energy transfer from Bi³⁺ to Eu³⁺/Eu²⁺ exists in CSC:Bi³⁺, Li⁺, Euⁿ⁺ phosphors. Under the excitation of 327 or 365 nm, the Ca_2.98−ySiO₄Cl₂:0.01Bi³⁺, 0.01Li⁺, yEuⁿ⁺(y=0.0001–0.002) phosphors show an intense green emission band around 505 nm, while under the excitation of 264 nm, three emission bands centered around 396 nm (Bi³⁺), 505 nm (Eu²⁺) and 614 nm (Eu³⁺) are observed and tunable colors from blue-violet to green or white are achieved in these phosphors by varying the content of Eu. White-light emission with the color coordinate (0.312, 0.328) is obtained in Ca_2.978SiO₄Cl₂:0.01Bi³⁺, 0.01Li⁺, 0.002Euⁿ⁺(n =2, 3). Based on these results, the as-prepared CSC:Bi³⁺, Li⁺, Eu²⁺, Eu³⁺ phosphors can act as color-tunable and single-phase white emission phosphors for potential applications in UV-excited white LEDs.     

Tuning the luminescence properties of blue and far-red dual emitting Gd2MgTiO6: Bi3+, Cr3+ phosphor for LED plant lamp

Blue and far-red light play a key role in plant growth, so it is necessary to develop blue and far-red dual emitting phosphors. However, the match between phosphors and plant pigments is not satisfactory. In this work, we synthesized a series of blue and far-red dual emission Gd₂MgTiO₆: Bi³⁺, Cr³⁺ (GMTO: Bi³⁺, Cr³⁺) phosphors and discussed the luminescence performance. The blue emission at 430 nm is ascribed to ³P₁ → ¹S₀ transition of Bi³⁺ and the far-red emission is ascribed to ⁴T₂ → ⁴A₂ and ²E → ⁴A₂ transitions of Cr³⁺. Notably, because of the energy competition between Cr³⁺ ions and host materials, the luminescence tuning realized with the content of Cr³⁺ doping. In addition, an energy-transfer performance occurred from Bi³⁺ ions to Cr³⁺ ions and the photoluminescence intensity of Cr³⁺ can be enhanced by Bi³⁺. The pc-LEDs devices were synthesized by GMTO: Bi³⁺, Cr³⁺ phosphor, and ultraviolet (UV) chips. Finally, the emission of GMTO: Bi³⁺, Cr³⁺ phosphor matched well with the absorption spectra of plant pigments which indicated the potential applications in LED plant lamp.     

Nd3＋、Er3＋、Gd3＋和La3＋对超氧化物歧化酶活性的影响

通过研究Nd3＋、Er3＋、Gd3＋和La3＋稀土离子对枯草芽孢杆菌在生长过程中所产的超氧化物歧化酶活性的影响,来探讨稀土可能会导致生物体发生氧化损伤。利用改良的邻苯三酚自氧化法测定超氧化物歧化酶活性。结果表明：4种稀土离子对其细胞中超氧化物歧化酶活性均有抑制作用,且Nd3＋的抑制作用较其它3种稀土离子要强,故一定浓度的稀土离子很有可能会导致生物体发生氧化损伤。4种稀土离子的浓度不同影响有所不同,总的来说,稀土离子的浓度越大,对枯草杆菌抗氧化的抑制作用越明显,损伤毒性作用越强。     

Gd3＋对SrWO4：Dy3＋荧光粉发光性能的影响？

采用水热微乳液法合成了SrWO4：Dy3＋,Gd3＋系列发光材料。利用XRD、SEM和荧光测试对热处理后样品的结构、形貌和发光性能进行了表征。 XRD结果表明：SrWO4：Dy3＋,Gd3＋的结构属四方晶系。以365nm紫外光为激发源,测得SrWO4：0．05Dy3＋,0．05Gd3＋的发光光谱主要发光峰位于487nm、575nm处,分别对应于Dy3＋的4 F9/2→6 H15/2、6 H13/2跃迁,Gd3＋可以增强Dy3＋发光强度;当Gd3＋掺杂的摩尔分数大于2%时,出现了浓度猝灭现象。色坐标分析显示：荧光粉的色坐标随着掺杂离子Gd3＋的浓度加入量改变而发生变化。 x（Gd3＋）为1%的样品的色坐标为（0．332,0．311）,位于标准白光点的色坐标范围内。     

Synthesis and luminescence characterization of Pr3+, Gd3+ co-doped SrF2 transparent ceramics

Pr³⁺, Gd³⁺ co-doped SrF₂ transparent ceramic, as the potential material for visible luminescent applications, was prepared by hot-pressing of precursor nanopowders. The microstructure, phase compositions, and in-line transmittance, as well as the photoluminescence properties were investigated systematically. Highly optical quality Pr,Gd:SrF₂ transparent ceramic with nearly pore-free microstructure was obtained at 800°C for 1.5 hours. The average in-line transmittance of the x at.% Pr, 6 at.% Gd:SrF₂ (x = 0.2, 0.5, 1.0, 2.0) transparent ceramics reached to 87.3 % in the infrared region. The photoluminescence spectra presented intense visible light emissions under the excitation of 444 nm, the main intrinsic emission bands located at 483 and 605 nm, which were attributed to the transitions of Pr³⁺: ³P₀ → ³H₄ and ¹D₂ → ³H₄, respectively. With the co-doping of Gd³⁺ ions, the emission intensity of the Pr:SrF₂ transparent ceramic was greatly enhanced. All the emission bands of x at.% Pr, 6 at.% Gd:SrF₂ transparent ceramics exhibited the highest luminescence intensity with the 1.0 at.% Pr³⁺ doping concentrations, whereas the lifetimes decreased dramatically with the Pr³⁺ doping contents increasing from 0.2 to 2.0 at.% due to its intense concentration quenching effect. The 1 at.% Pr, 6 at.% Gd:SrF₂ transparent ceramic is a promising material for visible luminescent device applications.     

Bi3+激活的Sr2SiO4材料发光特性研究

采用溶胶-凝胶法制备了Sr2SiO4:Bi3+发光材料.X射线衍射谱显示其为纯相的Sr2SiO4晶体.测量了Sr2SiO4∶ Bi3+材料的激发与发射光谱,结果显示,材料的发射光谱为一单峰宽带,主峰位于441nm处;监测441nm发射峰,所得材料的激发光谱为一主峰位于376nm处的单峰宽带.研究了Bi3+掺杂浓度对Sr2SiO4∶ Bi3+材料发射光谱的影响,结果显示,随Bi3+掺杂浓度的增大,Sr2SiO4∶ Bi3+材料的发射光谱峰值强度表现出先增大后减小的趋势,在Bi3+掺杂物质的量浓度为3%时,可获得最大的峰值强度.加入电荷补偿剂Li+、Na+和K+,均提高了Sr2SiO4∶ Bi3+材料发射光谱峰值强度,其中以加入Li+的情况最明显.     

掺铽的铝酸锶铕镝磷光体的发光特性及晶相分析

采用高温固相法在弱还原气氛下制备了掺入Tb3 的SrAl2O4:Eu2 ,Dy3 磷光体.研究了Tb3 对SrAl2O4:Eu2 ,Dy3 磷光体的发光性能的影响.结果发现,引入Tb3 以后,对基质SrAl2O4的晶体结构基本上没有影响,也未改变磷光体的发光光谱,却使磷光体的初始亮度显著提高,并使余辉时间延长.其余辉强度随时间的变化由最初的快衰减过程和随后的慢衰减过程组成,符合t-1.1的双曲线规律.并初步探讨了Tb3 的作用机制.     

Heat-driven Tailored for Eliminating Nd3+ Re-clusters in Nd3+,Gd3+-codoped SrF2 Laser Ceramic

Transparent Nd³⁺,Gd³⁺-codoped SrF₂ laser ceramic was fabricated by a single-crystal ceramization (SCC) technique, and the fluorescence properties were also characterized. The results indicated that the SCC process would lead to reducing fluorescence properties of ceramic by re-clustering small amount of Nd³⁺ ions. In this study, the re-clustering of Nd³⁺ ions were addressed by a simple thermal drive-induced grains regrowth (TDIGR) treatment. The properties of the Nd³⁺,Gd³⁺-codoped SrF₂ laser ceramic undergo the TDIGR were improved and close to precursor Nd³⁺, Gd³⁺-codoped SrF₂ single crystal. Meanwhile, the transmittance of ceramic (T_{average@400-1400nm} ~ 92%) was hardly affected by the TDIGR treatment. Therefore, we have reasons to believe that the combination of SCC and TDIGR is a suitable approach to obtain high optical quality neodymium, buffer ion-codoped alkaline-earth fluoride (Nd³⁺,B³⁺-codoped MF₂) laser ceramics.     

Photostimulated and Long Persistent Luminescence Properties from Different Crystallographic Sites of β‐Sr2SiO4: Eu2+, R3+ (R = Tm,Gd)

Sintered ceramics of β‐Sr₂SiO₄: Eu²⁺, R³⁺(R=Tm, Gd) were prepared and their spectroscopic properties were evaluated. A large enhancement of green photostimulated luminescence (PSL) was observed from β‐Sr₂SiO₄:Eu²⁺ codoping with Tm³⁺ at a recognizable intensity level, and the most efficient PSL was obtained when the codoping concentration of Tm³⁺ was 0.002. It was proved that the introduction of Tm³⁺ created a large number of oxygen vacancies which serve as traps for electrons excited by UV irradiation. In addition, a distinguishable difference between the photoluminescence (PL) and PSL spectra of β‐Sr₂SiO₄: Eu²⁺, Tm³⁺ was observed, namely the PSL spectrum exhibits only a symmetric emission band peaked at about 540 nm while both 470 and 540 nm peaks were detected in the PL spectrum. It is safe to say that PSL only derives from one emission center of Eu2 in the crystallographic Sr2 sites, which could be ascribed to the different distribution of trap centers for two crystallographic Sr sites .     

Synthesis and Persistent Luminescence Mechanism of a Novel Orange Emitting Persistent Phosphor Sr5(BO3)3Cl:Eu2+

A series of Eu²⁺‐doped Sr₅(BO₃)₃Cl phosphors were prepared successfully using a conventional solid‐state reaction method. The luminescent properties were studied systematically by utilizing photoluminescence spectra, decay curves, persistent luminescence spectra, and thermoluminescence glow curves. Energy transfer from host to emission center Eu²⁺ was affirmed. The orange persistent luminescence emission was observed for the first time. The optimal doping concentration of Eu²⁺ for persistent luminescence was experimentally to be approximately 0.5% and the orange persistent luminescence duration can persist about 15 min. On the basis of the experimental results, a model was constructed and the relevant mechanism of persistent luminescence was illustrated in detail. Two different ways of trapping the charge carriers were also discussed.     

LED用的Gd2(MoO4)3:Eu3+红色荧光粉的制备和性能研究

本文利用液相沉积法合成白光LED用的Gd2(MoO4)3:Eu3+红色荧光粉,利用X射线衍射、荧光光谱以及扫描电镜进行系列表征,系统研究掺杂离子浓度、退火温度等条件对Gd2(MoO4)3:Eu3+荧光粉的发光性能影响。结果表明:当pH=7,退火温度为1100℃,Gd:Eu摩尔比例为1.8:0.2时,所合成的荧光粉为正交晶系的类白钨矿结构Gd2(MoO4)3化合物(20-0408),荧光粉在395 nm左右有高的激发效率,发射主峰位置位于615 nm是近紫外LED中一种比较有应用价值的红色荧光粉。