Ag Nanoparticles‐Enhanced Photoluminescence in LaPO4: Eu Three‐Dimensional Ordered Macroporous Films

The three‐dimensional ordered macroporous (3DOM) LaPO₄:Eu³⁺ films and Ag nanoparticles (NPs) were prepared via a template‐assisted process and sodium citrate reduction method, respectively. Composite systems consisting of 3DOM LaPO₄:Eu³⁺ films and Ag NPs were obtained by adding the Ag NPs into voids of 3DOM LaPO₄:Eu³⁺ films. The influence of Ag NPs on photoluminescence of 3DOM LaPO₄:Eu³⁺ was investigated. The results show that photoluminescence properties of 3DOM LaPO₄:Eu³⁺ films were enhanced after addition of Ag NPs, which was attributed to the local surface plasmons resonance effect of Ag NPs.     

有序大孔二氧化硅微球的制备研究

采用乳液聚合法合成了单分散改性聚苯乙烯（PS）乳胶粒,利用PS乳胶粒自组装制得胶体晶体（“蛋白石”）微球,通过溶胶-凝胶模板法制备了有序大孔SiO2（“反蛋白石”）微球,通过SEM对改性PS乳胶粒、胶体晶体微球和有序大孔SiO2微球表面形貌进行了表征。结果表明,改性PS乳胶粒呈单分散性,粒径为317 nm;胶体晶体微球表面PS乳胶粒排列有序;有序大孔SiO2微球表面呈有序多孔,其孔呈六边形,孔径分布均一,约为200 nm。     

Fabrication of Three-Dimensionally Ordered Macroporous TiO2 Films with Enhanced Photovoltaic Conversion Efficiency

Negative-charged polystyrene (PS) microspheres were prepared through a soap-free emulsion polymerization method using potassium persulfate as initiator. Three-dimensionally ordered macroporous TiO₂ films were fabricated using the high-quality PS colloidal crystals templates obtained via a horizontal deposition method. The as-prepared macroporous TiO₂ films were applied as the photoanodes in dye-sensitized solar cell (DSSC). The microstructure of the products were characterized by X-ray diffractometer, fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption–desorption analyzer. The results showed that the macroporous TiO₂ films replicated well the 3D ordered structure derived from PS colloidal crystal templates and revealed a relatively large specific surface area (69.99 m²/g), which could increase the capacity of TiO₂ film anode for absorbing dyes and scattering light. The photocurrent–voltage (I–V) characteristics of DSSC were measured by a digital source meter under simulated solar light. The results indicated that the introduction of an ordered macroporous TiO₂ interfacial layer increased the photovoltaic conversion efficiency, which was improved by 68 % from 3.61 to 6.08 %, as compared to a device using a bare P25 TiO₂ photoanode. Our results showed that the hierarchically ordered macroporous TiO₂ bilayer films photoanode for DSSC could be helpful to improve the photovoltaic conversion efficiency.     

AI2O3-SiO2:Tb3+发光材料的溶胶--凝胶合成及发光特性

采用溶胶－凝胶（sol-gel)法低温合成了Al2O3-SiO2:Tb^3 绿色发光材料，研究了Al2O3和SiO2配比，Tb^3 浓,烧结温度，烧结时间对光强度的影响，讨论了发光体的发光特性。     

Luminescence Properties and Energy Transfer of Ce3+,Tb3+‐Coactivatedβ‐SiAlON Phosphors

Using the solid‐state reaction method, Ce³⁺,Tb³⁺‐coactivated Si₅AlON₇ (Si_6?zAl_zO_zN_8?z, z = 1) phosphors were successfully synthesized. The obtained phosphors exhibit high absorption and strong excitation bands in the wavelength range of 240–440 nm, matching well with the light emitting‐diode (LED) chip. The ET from Ce³⁺ to Tb³⁺ ions in Si₅AlON₇:Ce³⁺,Tb³⁺ has been studied and demonstrated by the luminescence spectra and decay curves. Moreover, the phosphors show tunable emissions from blue to green by tuning the relative ratio of the Ce³⁺ to Tb³⁺ ions. Thermal quenching properties of Si₅AlON₇:Ce³⁺,Tb³⁺ had also been investigated and the quenching temperature is ~190°C. These results show that Si₅AlON₇:Ce³⁺,Tb³⁺ could be a promising candidate for a single‐phased color‐tunable phosphor applied in UV‐chip pumped LEDs.     

Synthesis of LaOF:Eu3+ Nanoparticles with Strong Luminescence Enhanced by Organic Ligands

LaOF:Eu³⁺ nanoparticles were successfully prepared by annealing LaF₃:Eu³⁺ nanocrytsals which were capped with SiO₂ shell. The SiO₂ shell effectively prohibited the growth of LaF₃:Eu³⁺ nanocrystals during the annealing process, and it was etched off after annealing to obtain the LaOF:Eu³⁺ nanoparticles. The LaOF:Eu³⁺ nanoparticles had a size comparable to the original LaF₃:Eu³⁺ nanoparticles. Inorganic–organic hybrid nanoparticles of LaF₃:Eu³⁺ and LaOF:Eu³⁺ nanoparticles with thenoyltrifluoroacetone (TTA) ligands were prepared. Strong luminescence as a result of the energy transfer from the TTA organic ligands to the LaF₃:Eu³⁺ and LaOF:Eu³⁺ nanoparticles was observed. The LaOF:Eu³⁺‐based hybrid nanoparticles exhibited stronger luminescence intensity and broader excitation spectral range than the LaF₃:Eu³⁺‐based hybrid nanoparticles. Effect of the content of TTA ligands on the luminescence of the LaOF:Eu³⁺ nanoparticles was investigated in detail.     

二氧化硅包覆CsPbI3纳米晶薄膜的制备

卤化钙钛矿型(ABX3)纳米材料是近几年兴起的光电新材料,由于全无机钙钛矿CsPbX3(X=Cl,Br,I)纳米晶体的稳定性差,严重阻碍了实际应用,但因其具有窄带隙,在太阳能电池领域有着重要的应用前景.本研究在CsPbI3纳米晶周围使硅酸四甲酯(TMOS)发生水解反应,形成CsPbI3@SiO2纳米晶体复合材料,促使甲苯悬浮液的稳定性显著提高,发光稳定性可增加到29 d.通过进一步以聚(苯乙烯-乙烯-丁二烯-苯乙烯)三嵌共聚物(SEBS)对复合材料进行包裹,得到具有良好透明性和可拉伸性的SEBS/CsPbI3@SiO2薄膜,在水中有保持24 h稳定荧光现象,在水中12 h能保持原有发光强度的53％,而未经二氧化硅包裹的SEBS/CsPbI3纳米晶薄膜在水中仅8 h就失去荧光.本研究不仅为CsPbX3的表面改性提供了一种新方法,有助于解决稳定性问题,而且以聚合物复合的薄膜具有可拉伸性,也可应用在柔性器件中,具有重要的应用价值.     

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.     

Tb3+掺杂钼酸盐玻璃陶瓷的制备及发光性能表征

采用熔融-晶化法制备了Tb3+掺杂的CaMoO4为主晶相的透明钼酸盐玻璃陶瓷。利用DSC、XRD、SEM确定了该体系玻璃样品的最佳热处理制度：715℃保温2.5 h;随着热处理时间的增加,玻璃陶瓷中的晶粒尺寸逐渐变大;利用UV-Vis-NIR得到样品玻璃陶瓷在可见光区的透过率可达80%;并利用荧光光谱讨论了在相同热处理条件下,不同Tb3+掺杂浓度对玻璃陶瓷样品发光性能的影响,研究表明Tb3+掺杂浓度为7.0mol%时样品的荧光强度最大。     

SiO_2复合纳米粒子的制备及其性能

用反相微乳液法制备SiO2复合纳米粒子,考察了温度、pH等条件对其光催化降解甲基橙的影响,并用高倍透射电镜对其结构形态进行表征。结果表明:在100mL质量浓度为20mg/L的甲基橙溶液中加入0.50g复合纳米粒子,353K强酸性条件下降解率可高达95%以上。提出了复合纳米粒子光催化降解机理,其中复合纳米粒子对甲基橙的吸附作用是光催化降解作用的前置步骤。电镜结果表明,复合纳米粒子各组分间分布均匀,粒径跨度较小,具有较好的催化性能。     

White‐emitting phosphor Ba2B2O5:Ce3+, Tb3+, Sm3+: Luminescence,energy transfer,and thermal stability

A series of Ba₂B₂O₅: RE (RE=Ce³⁺/Tb³⁺/Sm³⁺) phosphors were synthesized using high‐temperature solid‐state reaction. The X‐ray diffraction (XRD), luminescent properties, and decay lifetimes are utilized to characterize the properties of the phosphors. The obtained phosphors can emit blue, green, and orange‐red light when single‐doped Ce³⁺, Tb³⁺, and Sm³⁺. The energy can transfer from Ce³⁺ to Tb³⁺ and Tb³⁺ to Sm³⁺ in Ba₂B₂O₅, but not from Ce³⁺ to Sm³⁺ in Ce³⁺ and Sm³⁺ codoped in Ba₂B₂O₅. However, the energy can transfer from Ce³⁺ to Sm³⁺ through the bridge role of Tb³⁺. We obtain white emission based on energy transfer of Ce³⁺→Tb³⁺→Sm³⁺ ions. These results reveal that Ce³⁺/Tb³⁺/Sm³⁺ can interact with each other in Ba₂B₂O₅, and Ba₂B₂O₅ may be a potential candidate host for white‐light‐emitting phosphors.     

Preparation,characterization and photoluminescence properties of SiO2 and SiO2:Eu3+ submicron rods

SiO₂ and Eu³⁺-doped SiO₂ submicron rods were conveniently fabricated via a sol–gel process at room temperature. In this process, citric acid served as a unique structural modifier through hydrolysis of TEOS at alkaline condition to obtain the silica submicron rods. The morphology of the products was sensitive to the conditions, such as stirring, gelation time and the dropping speed of NH₄OH. By sampling the products at different reaction times, we discussed the formation and growing mechanism of SiO₂:Eu³⁺ submicron rods in detail. The weak interactions between ammonium citrate crystals and silica species may be the reasons of the rods formation. The obtained silica submicron rods were 5–6 μm in length and 650–750 nm in width and there was no obvious change after doping. Under UV light excitation, the undoped silica submicron rods exhibited blue emission, which may be associated with defect centers in the structures of the products. The Eu³⁺-doped silica submicron rods exhibited red emission, which was due to the 4f→4f transition of Eu³⁺. The effect of different doping concentrations of Eu³⁺ ions on the luminescence was investigated. The samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrum (FT-IR), Thermo-gravimetry Analysis (TGA), Scanning electron microscope (SEM), Transmission electron microscope (TEM), Energy-dispersive spectroscopy (EDS) and Photoluminescence spectrum.     

Synthesis,Crystal Structure,and Enhanced Luminescence of Garnet‐Type Ca3Ga2Ge3O12:Cr3+ by Codoping Bi3+

Garnet‐type compound Ca₃Ga₂Ge₃O₁₂ and Cr³⁺‐doped or Cr³⁺/Bi³⁺ codped Ca₃Ga₂Ge₃O₁₂ phosphors were prepared by a solid‐state reaction. The crystal structure of Ca₃Ga₂Ge₃O₁₂ host was studied by X‐ray diffraction (XRD) analysis and further determined by the Rietveld refinement. Near‐infrared (NIR) photoluminescence (PL) and long‐lasting phosphorescence (LLP) emission can be observed from the Cr³⁺‐doped Ca₃Ga₂Ge₃O₁₂ sample, and the enhanced NIR PL emission intensity and LLP decay time can be realized in Cr³⁺/Bi³⁺ codped samples. The optimum concentration of Cr³⁺ in Ca₃Ga₂Ge₃O₁₂ phosphor was about 6 mol%, and optimum Bi³⁺ concentration induced the energy‐transfer (ET) process between Bi³⁺ and Cr³⁺ ions was about 30 mol%. Under different excitation wavelength from 280 to 453 nm, all the samples exhibit a broadband emission peaking at 739 nm and the intensity of NIR emission increases owing to the ET behavior from Bi³⁺ to Cr³⁺ ions. The critical ET distance has been calculated by the concentration‐quenching method. The thermally stable luminescence properties were also studied and the introduction of Bi³⁺ can also improve the thermal stability of the NIR emission.     

Luminescence properties and energy transfer investigations of Sr2B2O5:Ce3+,Tb3+ phosphors

Ce³⁺ and Tb³⁺ co-doped Sr₂B₂O₅ phosphors were synthesized by the solid-state method. X-ray diffraction (XRD) was used to characterize the phase structure. The luminescent properties of Ce³⁺ and Tb³⁺ co-doped Sr₂B₂O₅ phosphors were investigated by using the photoluminescence emission, excitation spectra and reflectance spectra, respectively. The excitation spectra indicate that this phosphor can be effectively excited by near ultraviolet (n-UV) light of 317 nm. Under the excitation of 317 nm, Sr₂B₂O₅:Ce³⁺,Tb³⁺ phosphors exhibited blue emission corresponding to the f–d transition of Ce³⁺ ions and green emission bands corresponding to the f–f transition of Tb³⁺ ions, respectively. The Reflectance spectra of the Sr₂B₂O₅:Ce³⁺,Tb³⁺ phosphors are noted that combine with Ce³⁺ and Tb³⁺ ion absorptions. Effective energy transfer occurred from Ce³⁺ to Tb³⁺ in Sr₂B₂O₅ host due to the observed spectra overlap between the emission spectrum of Ce³⁺ ion and the excitation spectrum of Tb³⁺ ion. The energy transfer efficiency from Ce³⁺ ion to Tb³⁺ ion was also calculated to be 90%. The phosphor Sr₂B₂O₅:Ce³⁺,Tb³⁺ could be considered as one of double emission phosphor for n-UV excited white light emitting diodes.     

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.     

Near‐Net‐Shape Fabrication of Ti3SiC2‐based Ceramics by Three‐Dimensional Printing

This paper focuses on the preparation of near‐net‐shaped dense Ti₃SiC₂‐based materials via an indirect three‐dimensional printing (3D printing) and postreactive melt infiltration (RMI) processes. TiC preforms with bimodal pore size distribution were fabricated through 3D printing, followed by the infiltration of Si melt and Al–Si alloy (Al₄₀Si₆₀ and Al₇₀Si₃₀). Dense composites with density of ~4.1 g/cm³ were obtained after the infiltration. No volume shrinkage was obtained after the reactive infiltration with Al–Si alloy. The participation of Al during the infiltration process promoted the formation of Ti₃SiC₂. The as‐fabricated Ti₃SiC₂‐based materials showed enhanced mechanical and electromagnetic interference shielding properties.     

单分散GdxY2-xO3：Eu^3＋纳米颗粒的制备及其荧光性能

本文采用均相沉淀法制备了单分散GdxY2-xO3:Eu3 纳米颗粒,并利用SEM,TEM,XRD和荧光光谱对产品的形貌,晶体结构和荧光性能进行了表征.结果发现适量Gd3 的加入对Y2O3:Eu3 的发光具有显著的增强作用.同时达到最大荧光强度所需的价格较贵的Gd3 用量,也从燃烧法的80%大幅减少到20%.另外,本文还进一步研究了Eu3 浓度对纳米颗粒荧光性能的增强效果.     

Novel Broadband Excited and Linear Red‐Emitting Ba2Y(BO3)2Cl: Ce3+, Tb3+, Eu3+ Phosphor: Luminescence and Energy Transfer

A series of Ce³⁺, Tb³⁺, Eu³⁺ tri‐doped Ba₂Y(BO₃)₂Cl red‐emitting phosphor have been synthesized by solid‐state method. The Ce³⁺→Tb³⁺→Eu³⁺ energy‐transfer scheme has been proposed to realize the sensitization of Eu³⁺ ion emission by Ce³⁺ ions. Following this energy‐transfer model, near‐UV convertible Eu³⁺‐activated red phosphors have been obtained in Ba₂Y(BO₃)₂Cl: Ce³⁺, Tb³⁺, Eu³⁺ phosphors. Energy transfers from Ce³⁺ to Tb³⁺, and Tb³⁺ to Eu³⁺, as well as corresponding energy‐transfer efficiencies are investigated. The combination of narrow‐line red emission and near‐UV broadband excitation makes Ba₂Y(BO₃)₂Cl: Ce³⁺, Tb³⁺, Eu³⁺ as a novel and efficient red phosphor for NUV LED applications.     

SiO2荧光纳米粒子的制备及其分析应用

SiO2荧光纳米粒子由于具有良好的光学稳定性、化学活性、生物相容性、表面易功能化等特性,备受国内外研究者的关注。本文综述了目前SiO2荧光纳米粒子的主要制备方法 (反相微乳液法、Stber水解法)的原理及优缺点,并全面综述了SiO2荧光纳米粒子在生物工程、医药研究、环境检测、文物分析等方面的应用,最后对SiO2荧光纳米粒子的前景进行了展望。     

Preparation and characterization of a green emitting Li2Ca0.4Sr0.6SiO4:Tb3+ phosphor with afterglow behavior

A novel green emitting long afterglow phosphor Li₂Ca_0.4Sr_0.6SiO₄:Tb³⁺ was obtained via a high temperature solid-state reaction in air atmosphere. X-ray diffraction (XRD), photoluminescence spectroscope (PLS), long afterglow spectroscope (LAS) and thermal luminescence spectroscope (TLS) were performed to characterize the physical properties of the phosphors. Typical ⁵D₄-⁷F_j transitions of Tb³⁺ ions were detected by PL spectra, corresponding to CIE chromaticity coordinates of x =0.3456, y =0.5745. An optimal concentration of Tb³⁺ in the substrate was determined as 0.8 at%. The Li₂Ca_0.4Sr_0.6SiO₄ phosphors showed a typical afterglow behavior when the UV source was switched off. A typical triple exponential decay behavior was confirmed after fitting the experimental data. Thermal simulated luminescence study further indicated that the afterglow behavior of Li₂Ca_0.4Sr_0.6SiO₄:Tb³⁺ phosphors was generated by the recombination of electrons with the holes resulted from the doping of rare-earth ions (Tb³⁺) in Li₂Ca_0.4Sr_0.6SiO₄ host. The long afterglow luminescence mechanism of Li₂Ca_0.4Sr_0.6SiO₄:Tb³⁺ is illustrated and discussed in detail on the basis of experimental results.