TiO2空心微球在NaYF4∶Yb3+,Er3+/商业TiO2染料敏化太阳能电池中的应用

以TiCl₃为钛源,水热法制备高散射性能的锐钛矿TiO₂空心微球。以商业TiO₂(P25)/NaYF₄∶Yb~(³⁺),Er³⁺混合材料为底层薄膜,TiO₂空心微球为反射层组成双层结构光阳极薄膜,优化了太阳能电池性能。结果表明:新型结构的太阳能电池短路光电流(J_sc=16.81mA/cm²)、开路光电压(V_oc=0.78V)、填充因子(FF=0.66)和光电转化效率(η=8.65%),其光电转化效率与纯P25(6.70%)光阳极和P25/NaYF₄∶Yb³⁺,Er³⁺(7.35%)光阳极相比较分别提升了29%和18%。     

YVO4∶Eu3+,Bi3+红色荧光粉的水热合成及其荧光性能

以Y₂O₃、Eu₂O₃、Bi(NO₃)₃·H₂O、浓HNO₃、偏钒酸铵、氨水、无水乙醇和一缩二乙二醇为原料,采用聚乙烯吡咯烷酮(PVP)辅助水热法合成YVO₄: Eu³⁺, Bi³⁺纳米颗粒。使用X射线衍射(XRD)、扫描电镜(SEM)、红外光谱(IR)和荧光光谱(FL)等手段对产品进行了表征和分析。结果表明：合成的样品为YVO₄: Eu³⁺, Bi³⁺纳米颗粒,均具有四方晶相结构,其微结构随反应溶液的的pH值变化。YVO₄: Eu³⁺, Bi³⁺纳米颗粒在619 nm处有较强的红光发射(电偶极跃迁⁵D₀→⁷F₂),在594 nm有较弱的橙光发射(磁偶极跃迁⁵D₀→⁷F₁)。随着Eu/Bi比值的增大材料的荧光先增强后减弱,在Eu/Bi比值为5时样品的红光发射最强。溶液的pH值影响YVO₄: Eu³⁺, Bi³⁺纳米晶的发光强度,其中pH值为10时的样品其红光发射最强。并探讨了YVO₄: Eu³⁺, Bi³⁺纳米晶的发光机理。     

实验优化设计中频反应溅射Al2O3:Ce薄膜发光性质研究

为了得到最优发光的薄膜材料成分参数,采用均匀设计和二次通用旋转组合设计相结合的方法建立发光强度与薄膜中氧含量和Ce³⁺ 离子掺杂浓度的回归方程,并用遗传算法求其取最大值时的解。用中频反应磁控溅射技术制备了相应成分的Al₂O₃:Ce非晶薄膜。在320nm光激发下,获得了较理想的发射光谱,对薄膜发光机理分析表明:薄膜的光致发光来自于Ce³⁺ 离子的5d1激发态向基态4f1的两个劈裂能级的跃迁。发光强度强烈的依赖于薄膜的掺杂浓度和氧元素含量。XPS检测表明,Al₂O₃:Ce薄膜中存在Ce³⁺ 。Ce³⁺ 含量和薄膜的化学成分是通过X射线散射能谱(EDS)测量的。薄膜试样的晶体结构应用X射线衍射分析。     

脉冲激光沉积ZnSe:Cox纳米晶薄膜的微结构及光学性质研究

采用脉冲激光沉积技术在基片温度为800℃条件下制备了不同Co含量的ZnSe:Co_x(x=0.1,0.3,0.5)微晶薄膜。通过X射线衍射、原子力显微镜、X射线光电子能谱、红外透射光谱及光致发光光谱分析了薄膜的微结构及光学特性。结果表明：所制备的纳米晶薄膜结晶质量优秀,具有(111)择优取向,薄膜结晶质量、光谱透射率和光学带隙均随Co含量的增加而减小;薄膜在波长约700～850 nm处存在一吸收带,这源于Co²⁺在周围Se^2-构成的四面体晶场中⁴A₂(4F)→⁴T₁(4P)能级之间的跃迁;当Co掺入量x=0.5时,薄膜达到过掺杂状态,α-Co杂质相出现,薄膜红外光致发光谱大幅降低。     

Cr3+、In3+、Sb3+离子掺杂BiVO4电催化氧化水产过氧化氢

过氧化氢(H₂O₂)作为一种环境友好的化学品被广泛应用于多个领域。相对于传统的蒽醌法,基于双电子水氧化过程电催化制备H₂O₂具备反应过程简单、毒副产物少、可原位合成等优点。采用旋涂法制备掺杂不同浓度、不同种类金属离子(Cr³⁺、In³⁺、Sb³⁺)的钒酸铋(BiVO₄)薄膜,并系统探究其电催化氧化水产H₂O₂性能。实验结果表明,掺杂Cr³⁺可以提高BiVO₄的电流密度,其中3%Cr:BiVO₄在3.08 V vs RHE偏压下的电流密度约为29 mA/cm²;掺杂In³⁺和Sb³⁺可以提高BiVO₄对双电子水氧化反应的选择性。     

静电纺丝技术制备NiOZnTiO3TiO2同轴三层纳米电缆及其形成机制

采用静电纺丝技术, 通过改进实验装置, 在最佳的纺丝条件下制备了 [Ni(CH₃COO)₂+PVP]-[Zn(CH₃COO)₂+PVP]-[Ti(OC₄H₉)₄+CH₃COOH+PVP] 前驱体复合电缆, 在600℃下将其进行热处理, 制备出了NiO-ZnTiO₃-TiO₂同轴三层纳米电缆。采用热重-差热 (TG-DTA)、 X射线衍射(XRD)、 傅里叶变换红外光谱(FTIR)、 扫描电子显微镜(SEM)和透射电子显微镜(TEM)等分析技术对样品进行了表征。对NiO-ZnTiO₃-TiO₂ 同轴三层纳米电缆的形成机制进行了讨论。结果表明, 所得产物为NiO-ZnTiO₃-TiO₂同轴三层纳米电缆。芯层为NiO, 直径大约为(42.024±4.405) nm; 中间层为ZnTiO₃, 厚度大约为(55.385±7.681) nm; 壳层为TiO₂, 厚度大约为(70.747±7.373) nm。      

可见光波段稀土激光晶体的研究进展

可见光激光在数据存储、光通讯、激光显示、激光医疗、激光打印以及科学研究等领域具有非常重要的应用价值。随着蓝光LD泵浦源的商用化, 直接泵浦稀土离子掺杂激光晶体实现可见光激光输出吸引了人们极大的研究兴趣。目前, 可见光稀土离子主要集中在Pr ³⁺、Dy ³⁺、Tb ³⁺和Sm ³⁺等。其中, Pr ³⁺的研究较多, 发光波长涵盖面较广, 发射波段覆盖蓝光、绿光、红光、橙光; Dy ³⁺和Tb ³⁺因为能够发射黄光以填补Pr ³⁺的不足也吸引了广泛的研究; 此外, Sm ³⁺和Eu ³⁺也是典型的可见波段稀土发光离子。本文综述了近几年可见波段稀土离子掺杂激光晶体的研究现状, 主要以Pr ³⁺、Dy ³⁺、Tb ³⁺和Sm ³⁺掺杂YAlO₃ (YAP)、Mg : SrAl₁₂O₁₉ (SRA)等晶体为研究对象, 总结了一套适合Pr ³⁺掺杂材料的判据, 对晶体生长、结构、热学性能、偏振光谱性能和激光性能进行了系统的研究。     

WO3/BiVO4复合薄膜的制备及其光电化学性能

导电玻璃作为基底制备WO₃纳米片薄膜，通过改变旋涂BiVO₄次数，以WO₃纳米片薄膜为基底成功制得不同厚度的WO₃/BiVO₄复合薄膜样品。利用X射线衍射仪(XRD)和扫描电子显微镜(SEM)等分析方法对样品进行表征，并对WO₃/BiVO₄复合薄膜样品进行吸收光谱、光电流、光电催化和交流阻抗测试。结果表明：WO₃/BiVO₄复合薄膜样品的光电流密度和光电催化降解效率相较于单一WO₃纳米薄膜都得到了提高，具有更好的光电化学性能。且旋涂两次BiVO₄的WO₃/BiVO₄复合薄膜样品有最高的光电流密度值(1.79 mA/cm²)和光电催化降解效率(约为60.5%),比单一WO₃材料的光电流密度(1.30 mA/cm²)提高了27.4%,光电催化降...     

Confinement and antenna effect for ultrasmall Y2O3:Eu3+ nanocrystals supported by MOF with enhanced near-UV light absorption thereby enhanced luminescence and excellently multifunctional applications

A novel host-guest luminous system with enhanced near-UV light absorption thereby enhanced luminescence are designed based on the synergism of quantum confinement,spatial confinement,and antenna effect,where ultrasmall Y₂O₃:Eu³⁺nanocrystals are fixed inside MOF(Eu/Y-BTC)as supporting structure.The Eu/Y-BTC not only limits the size and leads to lattice distortion of Y₂O₃:Eu³⁺nanocrystals and controls the distance between nanocrystals,but also promotes the light absorption and emission.The significantly red-shifted and broadened charge transfer band of Y₂O₃:Eu³⁺/(Eu/Y-BTC)leads to the excellent applications of Y₂O₃:Eu³⁺in white light-emitting diodes(LEDs).Our results show that white light with superior color quality(CRI>90)and extremely high luminous efficacy(an LER of 335 lm/W)could be achieved using Y₂O₃:Eu³⁺/(Eu/Y-BTC)as red phosphor.The Y₂O₃:Eu³⁺/(Eu/Y-BTC)also improves the photoelectric performance of dye-sensitized solar cells(DSSCs),not only because Y₂O₃:Eu³⁺/(Eu/Y-BTC)has a large specific surface area and the adsorption amount of the dye is increased,but also because the valence band position of Y₂O₃:Eu³⁺/(Eu/Y-BTC)is 2.41 eV,which can provide an additional energy level between the TiO2 and dye,promoting electron transfer.For these advantageous features,the multifunctional Y₂O₃:Eu³⁺/(Eu/Y-BTC)composite product will open new avenues in white LEDs and DSSCs.     

Lu2(MoO4)3:Eu3+荧光粉的制备及热增强发光

采用固相法制备了Lu₂(MoO₄)₃:Eu³⁺系列红色荧光粉，利用X射线粉末衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)、能谱仪(EDS)和荧光光谱(PL)仪对制备荧光粉的结构、形貌、元素组成及光致发光性能进行表征与分析。实验结果表明Eu³⁺成功掺入基质晶格中并得到Lu₂(MoO₄)₃:Eu³⁺纯相样品，荧光粉颗粒大小在2μm左右。制备温度依赖样品光致发光结果表明1 000℃下制备Lu₂(MoO₄)₃:Eu³⁺样品发光性能最好。煅烧时间依赖样品光致发光结果表明1 000℃下煅烧时间为6 h时样品发光效果最好。反常于荧光粉发光热猝灭现象，Lu₂(MoO₄)₃:Eu³⁺样品在外界测试温度为250℃左右时出现热增强...     

Aqueous solution-based synthesis of rare earth-doped metal oxide thin films

Rare earth-doped TiO₂ thin films have been successfully formed on glass and Si wafer substrates from aqueous solution through equilibrium reaction between metal–fluoro complex and metal oxide, in which Ln³⁺–ethylenediaminetetraacetic acid (EDTA) complex (Ln: rare earth metal) was added into the reaction solution. Ln/Ti ratio and crystalline structure of the film could be controlled by varying the initial concentration of Ln³⁺–EDTA complex solution. The obtained Ln-doped films were densely-packed and had no cracks.     

Synthesis, structure and luminescent properties of Lu(PO3)3

A new structural type of rare earth metaphosphate, Lu(PO₃)₃, was prepared from high-temperature solution, of which the crystal structure was solved in S.G. of Cc (No.9) and Z = 4 with unit cell dimensions of a = 13.972(3) Å, b = 6.6710(13) Å, c = 9.958(2) Å and β = 127.36(3)°. In Lu(PO₃)₃, [LuO₆] octahedra connect with the non-bridging oxygens on (PO₃)_n infinite zigzag chains that extended along c-axis. The VUV and X-ray excited luminescent properties of undoped and Ln³⁺ (Ln = Ce, Eu, Tb) doped samples were examined, from which the optical band gap was estimated to be 8.3 eV. Besides, in the undoped sample a STE emission within 320–480 nm was observed, which probably be related to oxygen defects. However, in the Lu(PO₃)₃:Ce sample the Ce³⁺ emission was weak and STE emission was totally quenched under hard X-ray excitation.     

——————————CaSi2O2N2:Eu2+中空荧光纤维的制备及其发光性能研究

采用静电纺丝与气相还原氮化相结合的方式制备了用于白光LED的CaSi₂O₂N₂:Eu²⁺荧光纤维。通过调节纺丝溶液溶剂的配比, 得到了空心结构的Ca-Si-O-Eu纳米纤维和CaSi₂O₂N₂:Eu²⁺荧光纳米纤维。样品在微观上保持中空纤维结构, 宏观上也保持薄膜的状态。利用X射线衍射对样品物相结构进行分析, Ca-Si-O-Eu中空纤维在1300℃保温5 h后得到层状结构的CaSi₂O₂N₂, Eu²⁺离子的掺入没有改变CaSi₂O₂N₂的主晶相。在400 nm激发光照射下CaSi₂O₂N₂:Eu²⁺荧光纤维在550 nm附近具有一个宽发射峰, 对应着Eu²⁺离子4f⁶5d→4f⁷跃迁。与CaSi₂O₂N₂:Eu²⁺荧光粉或普通荧光纤维膜比较, 制备的中空荧光纤维膜有更高的发射光强度。     

Long lasting phosphorescence of Sr4Al14O25:Eu,Dy thin films by magnetron sputtering

This paper reports the preparation process and the long lasting phosphorescence of the Sr₄Al₁₄O₂₅:Eu²⁺,Dy³⁺ thin films obtained by magnetron sputtering. Phosphorescence was achieved by annealing the films in reducing atmosphere. Sr₄Al₁₄O₂₅ thin film was obtained when the films were treated at 1200 °C, while SrAl₂O₄ was generated as the intermediate phase during the annealing process. Sr₄Al₁₄O₂₅:Eu²⁺,Dy³⁺ film generated an emission at 485 nm, and SrAl₂O₄:Eu²⁺,Dy³⁺ film showed an emission peaking at 515 nm. Afterglow characteristics were observed for both films, and Sr₄Al₁₄O₂₅:Eu²⁺,Dy³⁺ film showed a better afterglow property than the SrAl₂O₄:Eu²⁺,Dy³⁺ film due to a deeper trap level and a higher trap concentration formed in the thin films.     

Study on UV excitation properties of Y2O3:Ln3+ (Ln = Eu3+ or Tb3+) luminescent nanomaterials

Y2O3:Ln3+ (Ln = Eu or Tb) nanocrystals with different Ln3+ doping concentrations and average sizes were prepared by chemical self-combustion. The corresponding bulk materials with various doping concentrations were obtained by annealing the nanomaterials at high temperature. The emission spectra, excitation spectra, and X-ray diffraction spectra were used in this study. It was found that the charge transfer band of Y2O3:Eu3+ red-shifted as particle size decreased, and the charge transfer band in the 5-nm particles obviously broadened toward the long wavelength. It was also found that the profile of excitation spectra corresponding to the 4f5d (4f8 --> 4f(7)5d1) transition changed a lot with the variation of the particle size. The dependence of the excitation spectra of Y2O3:Ln3+ on particle size was investigated.     

A CHEMICAL ROUTE FOR THE PREPARATION OF NANOSIZED RARE EARTH PEROVSKITE-TYPE OXIDES FOR ELECTROCERAMIC APPLICATIONS

This paper reviews the work performed by the authors on the preparation of LnTO₃ (Ln = rare earth elements, and T = transition metals) perovskite-type oxides by the thermal decomposition at low temperatures of the corresponding heteronuclear complexes. Bimetallic complexes in the series Ln[Fe(CN₆)]·nH₂O and Ln[Co(CN₆)] nH₂O, with Ln = from La through Yb, and trimetallic complexes in the series Ln¹_xLnnl-x[Co(CN₆)] nH₂O and Ln[FeyCo1-_y(CN₆)] nH₂O were prepared. The formation of the perovskite-type oxides by the thermal decomposition of the complexes has been studied by simultaneous thermogravimetric and differential thermal analysis (TG/DTA), x-ray fluorescence (XRF), Fourier transform infrared (FTTR) spectroscopy, x-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The composition and temperature limits of stability for the dimetallic and trimetallic perovskite-type oxides have been clarified. The major role played by the ionic radii of the Ln3⁺ and T3⁺ ions on the formation of the perovskite-type oxides has been identified. Homogeneous perovskite-type oxide powders with nanosized particles, which possess promising characteristics for their applications as functional ceramics, are easily synthesized with this method.     

Self-assembled peanut-like Ln3+ (Ln = Tb, Sm, Eu) doped NaLa(WO4)2: phase control and its relevance to luminescence modification

Ln3+ (Ln = Tb, Sm, Eu) doped NaLa(WO4)2 peanuts were successfully self-assembled by a facile EDTA assisted hydrothermal treatment. EDTA played critical roles in the phase and morphology control, which regulated the phase transformation from monoclinic La2(WO4)3 flowers to tetrahedral NaLa(WO4)2 peanuts. La2(WO4)3:Tb3+ exhibited two broad excitation bands at 280 and 340 nm, which are related to the normal and perturb sites of WO4(2-). However, the excitation band for NaLa(WO4)2:Tb3+ shifted to near ultraviolet region and showed only one broad excitation band originating from perturb sites. Under ultraviolet excitation, La2(WO4)3:Tb3+ displayed green light and NaLa(WO4)2:Tb3+ showed blue-green light consisting of WO4(2-) self-activated blue emission and the characteristic Tb3+ emission. It can be clearly seen that the blue emission of WO4(2-) was not sufficiently quenched in NaLa(WO4)2 as that in La2(WO4)3, because the distortions of crystalline lattice for NaLa(WO4)2 may alter the energy migration processes. When doping with Sm3+ and Eu3+, NaLa(WO4)2 peanuts exhibited white color emission which may find practical applications in solid state lighting devices.     

The luminescence of doped and undoped BaLn2(MoO4)4 (Ln = La,Gd)

The luminescence of nominally pure BaLn₂(MoO₄)₄ (Ln = La,Gd) is reported. Below 300 K molybdate emission is observed. The following activators were investigated: Eu³⁺, Tb³⁺, Pb²⁺ and Bi³⁺. The two lanthanide ions show their characteristic emission, the two s² configuration ions give an emission in which the host-lattice group as well as the activator is involved. The luminescence properties of these compositions are discussed and compared with those of related materials.     

ATP/CaF_2∶Ln~(3+)(Ln∶Eu,Tb,Ce/Tb)纳米粒子的制备及其荧光性能

采用两步法制备了三磷酸腺苷二钠(ATP)修饰的ATP/CaF_2∶Ln~(3+)(Ln∶Eu,Tb,Ce/Tb)纳米粒子。采用红外光谱(IR)、X-射线衍射分析(XRD)、透射电子显微镜(TEM)对所合成的纳米粒子进行结构表征,并通过荧光光谱(FS)研究了纳米粒子的荧光性能。结构研究结果表明,ATP成功地包覆在纳米粒子的表面,纳米粒子的晶相为CaF_2的立方结构,ATP/CaF_2∶Eu~(3+)、ATP/CaF_2∶Tb~(3+)、ATP/CaF_2∶Ce~(3+)/Tb~(3+)纳米粒子的平均粒径分别约为14nm、15nm、11nm。荧光性能研究表明,ATP/CaF_2∶Eu~(3+)、ATP/CaF_2∶Tb~(3+)纳米粒子基本不发射稀土离子的特征荧光,而发射出修饰剂ATP的荧光,由于Ce~(3+)对Tb~(3+)的敏化作用,ATP/CaF_2∶Ce~(3+)/Tb~(3+)纳米粒子发射出Tb~(3+)的特征荧光。