Ca_3La(BO_3)_3∶Tb~(3+)的合成与发光性质

高温固相反应法合成了Ca3La(BO3)3∶Tb3 光致发光材料。利用扫描电镜和激光衍射分析仪测定了样品的晶粒形貌及粒径大小分布,利用荧光分光光度计研究了Ca3La(BO3)3∶Tb3 的光致发光特性。确定了在Ca3La(BO3)3基质中Tb3 离子浓度对其发光强度的影响及其自身浓度猝灭机理;探讨了助熔剂L i2CO3、敏化剂Ce3 离子的加入对荧光粉发光强度的影响。     

(LaO)_3BO_3基质中Tb~(3+)的发光特性

在 2 54nm紫外光 (UV)激发下 ,研究了 (La O) 3 BO3 基质中 Tb3 + 的激发光谱、发射光谱、发光寿命与Tb3 +浓度的关系 ,并探讨了 Tb3 +的 5D3 → 7F4 跃迁发射的自身浓度猝灭机理。在阴极射线 (CR)激发下 ,研究了 (L a O) 3 BO3 :Tb3 + 的发光强度与 Tb3 + 浓度、加速电压及电流密度的关系。发现在 UV或 CR两种激发条件下 ,试样均能发出明亮的绿色荧光 ,有望成为一种有发展前途的绿粉     

Na3La2(BO3)3:Sm3+的合成及其光谱特性

本文采用固相反应法,合成了一系列掺Sm^3 的Na3La2(BO3)2[Na3(La1-xSmx)2(BO3)3]发光,X－射线粉末衍射数据分析表明它们属于正交晶系,空间群为Amm2,测量了红外光谱,荧光光谱,观察到在599nm,645nm处有较强的荧光发射,并研究了发光强度与Sm^3 离子浓度（x)的关系,确定了Sm^3 离子在Na3La2(BO3)3基质中发光的适宜浓度。     

Ba3Tb(BO3)3:Ce3+:一种白光LED用绿色荧光粉

采用高温固相法合成了Ba3Tb(BO3)3和Ba3Tb(BO3)3:Ce3+两种绿色荧光粉,并研究了材料的发光性质.Ba3Tb(BO3)2材料呈多峰发射,发射峰位于439,493,547,589和629 nm,分别对应Tb3+的5D3→7F4和5D4→7F1=6,5,4,3跃迁发射,主峰为547 nm;监测547 nm发射峰,所得激发光谱由4f75d1宽带吸收(200-330 nm)和4f4f电子吸收(330-400 nm)组成,主峰为380 nm.以Ce3+激活Ba3Tb(BO3)3,所得Ba3Tb(BO3)3:Ce3+与Ba3Tb(BO3),材料的发射光谱分布相同,但发射强度明显增强,说明Ce3+对Tb3+产生了很好的敏化作用;监测547 nm最强发射峰,所得激发光谱为宽带,主峰位于360 nm.改变H3BO3量,Ba3Tb(BO3)3:Ce3+材料的发射强度随之变化,当H3BO3过量15 wt%时,发射强度最大.上述研究结果表明Ba3Tb(BO3)3:Ce3+是一种很好的适于UV-LED管芯激发的白光LED用绿色荧光粉.     

白光LED用Ba3La（PO4）3∶Dy3+荧光粉的制备与发光性能

通过高温固相法合成了一系列Ba3La1-x(PO4)3∶xDy3+荧光粉材料。利用XRD测量样品的物相,结果显示样品为纯相Ba3La(PO4)3晶体。样品的激发光谱由一系列宽谱组成,峰值分别位于322,347,360,386,424,451 nm。在347 nm激发下,荧光粉在482 nm(4F9/2→6H15/2)和575 nm(4F9/2→6H13/2)处有很强的发射。研究了不同Dy3+掺杂浓度对样品发射光谱的影响,当Dy3+摩尔分数x=0.10时出现猝灭现象,浓度猝灭机理为电偶极-电偶极相互作用。确定了不同Dy3+掺杂浓度的Ba3La(PO4)3∶Dy3+的荧光寿命。Ba3La(PO4)3∶Dy3+荧光粉发射光谱的色坐标位于白光区域。     

LiM(M=Ca,Sr,Ba)BO_3∶Tb~(3+)材料光谱特性研究

采用固相法制备了绿色LiM(M=Ca,Sr,Ba)BO3:Tb3+发光材料.测量结果显示材料均可被紫外(350～410 nm)光激发,发射绿光.研究了Tb3+浓度对材料发射光谱的影响,结果显示,随Tb3+浓度的增大,发射光谱峰位未发生变化,但其强度呈现出先增大后减小的趋势,即:存在浓度猝灭效应.加入电荷补偿剂Li+,Na+和K+提高了LiM(M=Ca,Sr,Ba)BO3:Tb抖材料的发射强度.     

Ln(BO_3,PO_4)[Ln=La,Y]基质中Ce~(3+)、Tb~(3+)、Gd~(3+)的光谱

研究了硼磷酸镧和硼磷酸钇基质中Ce3 +、Tb3+、Gd3+的发射光谱和激发光谱。结果表明 :La(BO3,PO4 ) :Ce ,Tb体系中加入钆后 ,Ce3+的发射降低 ,Tb3+的发射增强 ;Y(BO3,PO4 ) :Ce ,Tb体系中加入钆后 ,Ce3+和Tb3 +的发射均增强 ,且前者增加的幅度高于后者。因此在La(BO3,PO4 ) :Ce ,Tb ,Gd体系中Gd3+离子起着能量传递中间体和敏化剂的作用 ;在Y(BO3,PO4 ) :Ce,Tb ,Gd体系中Gd3 +离子只起敏化剂作用 ,并且阻碍Ce3+→Tb3+的能量传递。与Y(BO3,PO4 ) :Ce,Tb ,Gd相比 ,La(BO3,PO4 ) :Ce,Tb ,Gd对紫外吸收强 ,2 5 4nm激发下发出的光绿色纯度高 ,强度大 ,更适合做荧光灯中的绿粉     

红色LiM(M=Ca,Sr,Ba)BO_3∶Re~(3+)(Re=Eu,Sm)发光材料的特性

采用固相法制备了红色LiM(M=Ca,Sr,Ba)BO3∶Re3+(Re=Eu,Sm)发光材料,研究了材料的发光性能。研究发现LiM(M=Ca,Sr,Ba)BO3∶Eu3+材料呈现多峰发射,最强发射分别位于610,615,613 nm处,分别监测这三个最强峰,所得激发光谱峰值位于369,400,470 nm。LiM(M=Ca,Sr,Ba)BO3∶Sm3+材料也呈多峰发射,分别对应Sm3+的4G5/2→6H5/2、4G5/2→6H7/2和4G5/2→6H9/2跃迁发射;分别监测602,599,597 nm三个最强发射峰,所得激发光谱峰值位于374,405 nm。研究了激活剂浓度对材料发射强度的影响,结果随激活剂浓度的增大,发射强度先增强后减弱,即,存在浓度猝灭效应。实验表明,加入电荷补偿剂Li+、Na+或K+均可提高LiM(M=Ca,Sr,Ba)BO3∶Re3+(Re=Eu,Sm)材料的发射强度。     

CaSnO3∶Tb3+绿色长余辉荧光粉的制备与发光性质的研究

采用高温固相法合成了CaSnO3∶Tb3+绿色长余辉荧光粉。利用X射线衍射分析了CaSnO3∶Tb3+物相结构。研究了Tb3+浓度对样品发光强度的影响,结果显示:随Tb3+浓度的增大,发射光谱强度先增大后减小,出现了浓度猝灭效应,Tb3+的最佳摩尔分数为0.3%。发射光谱由4个主要发射峰组成,峰中心分别位于492,546,588,623 nm处,以Tb3+的5D4→7F5(546 nm)跃迁发射为最强。对样品的温度特性进行了测量,通过对数据进行拟合得到样品的激活能为0.58 eV,陷阱深度为0.622 eV。最后,给出了CaSnO3∶Tb3+绿色长余辉荧光粉可能的余辉发光机理。     

Ca2SnO4∶Tb3+绿色荧光粉的制备及光致发光研究

采用高温固相法合成了Ca2 SnO4∶Tb3+绿色荧光粉.利用X射线衍射分析了Ca2 SnO4∶Tb3+物相的形成.测量了Ca2 SnO4∶Tb3+的激发和发射光谱,激发光谱由一个宽激发峰组成,研究了Tb3+浓度对样品激发光谱的影响,结果显示,随Tb3+浓度增大,宽带激发峰发生了红移.发射光谱由四个主要发射峰组成,峰值分别位于491,543,588和623 nm处,Tb3+以5 D4-7 F5(543 nm)跃迁发射最强,低掺杂浓度下,Tb3+的7 F6能级出现斯托克劈裂,劈裂峰(481 nm处)随Tb3+浓度增加,先增强然后减弱;在发光强度方面,随Tb3+浓度的增大呈现先增大后减小的趋势,当Tb3+摩尔浓度为9％时,发光强度最大,根据Dexter理论,确定了在Ca2 SnO4基质中Tb3+自身浓度猝灭机理.荧光寿命测试表明Tb3+在Ca2 SnO4基质中荧光衰减平均寿命为4.4 ms.     

Fine structure and isotope shift of the 3s4d 3 D-3s3p 3 P, 3s5d 3 D-3s3p 3 P and 3p 2 3 P-3s3p 3 P Transitions of MgI

Summary We report the measurements of the³ D(3s4d)-³ P(3s3p)³ D(3s5d)-³ P(3s3p), and³ P(3p ²)-³ P(3s3p) transition frequency of MgI, the fine-structure separation and isotope shift between²⁴Mg and²⁶Mg. The measurements have been performed in a metastable atomic beam; a good agreement is found for data already existing in the literature. The accuracy of the measurements reported in this paper is mainly limited by the Doppler broadening of theI ₂ transitions used as a reference and by the precision in the knowledge of the related wavelengths.     

The gas phase infrared band contours of s-triazine and s-triazine-d3: The fundamentals of C3N3H3 and C3N3D3 and some overtone and combination bands of C3N3H3

The systematic application of band contour techniques to account for most of the observed features of the ir spectra of s-triazine and s-triazine-d₃ have been made as well as a critique as to the limitations of such methods. The experimental and computer methods used to study the gas phase infrared band contours of s-triazine and s-triazine-d₃ are out-lined. Contours of the five E′ fundamentals of s-triazine have been recorded under moderate resolution and analyzed to give the Coriolis constants $\text{ζ}{}_{\mathrm{i}}{}^{\mathrm{z}}$, i = 6–10. The effects of l-resonance are very apparent for ν₈ and ν₉, in the form of holes in the Q branches of these bands. Under the highest resolution available, ν₆ and ν₁₀ also show l-resonance effects. Values of the l-doubling constants $\text{q}{}_{\mathrm{i}}{}^{\mathrm{(+)}}$ were obtained for these four fundamentals. One of the parallel A₂″ fundamentals of C₃H₃N₃ (ν₁₂) has also been studied. It lies close to ν₁₀(E′) and an A × E type of second-order Coriolis resonance may be the cause of the intensity enhancement observed in the inner wings of the ν₁₂ and ν₁₀ bands. Hot bands of the type (ν_i + nν₁₄ ? nν₁₄) have been observed in the contours of ν₈, ν₁₀, and ν₁₂. This is felt to be responsible for the large difference between our observed zeta sum (?1.30) and the theoretical sum (?1.00).The gas phase infrared band contours of the five E′ and 2A₂″ fundamentals of C₃N₃D₃ have also been recorded under moderate resolution. From P-R separations and by computer simulation of the contours, values of the Coriolis constants $\text{ζ}{}_{\mathrm{i}}{}^{\mathrm{z}}$ have been obtained for the E′ modes. The effects of l-resonance have been observed for ν₈(E′) and ν₁₀(E′) and values of the l-doubling constants $\text{q}{}_{\mathrm{i}}{}^{\mathrm{(+)}}$ have been estimated. An extensive series of hot bands of the type (ν₁₂ + nν₁₄ ? nν₁₄) has been observed in the contour of the ν₁₂ (A₂″) fundamental. The mass effect on the Coriolis constants has been discussed.Infrared band contours of the overtone 2ν₇ and seven degenerate E′ combination bands of C₃N₃H₃ have been recorded under moderate resolution. Analysis of these contours using the P-R separation method and computer simulation of the contours has given values of $\text{ζ}{}_{\mathrm{<mtext>eff</mtext>}}{}^{\mathrm{z}}$ for these bands. Fermi resonance between 2ν₇ and ν₆ has been analyzed. The importance of considering both the observed contour as well as the observed frequency when assigning higher tone bands is illustrated.     

LaGaO3:RE3+(RE3+=Eu3+,Ho3+)的光谱

本文用固态反应合成了钙钛矿型的LaGaO3和LaGaO3:RE3+(RE3+=Eu3+,Ho3+)荧光体,并观察了物相随不同的激活离子浓度的变化。测量了化合物在室温下的反射光谱,激发光谱和荧光光谱。研究了Eu3+的D0→7F2和Ho3+的5S2→5I8的荧光强度与激活离子浓度的关系,发现了浓度猝灭,并得到了最大荧光强度的浓度值。     

Dielectric investigations of solid solutions SrTiO3-KTaO3 and SrTiO3-KNbO3

The temperature dependences of the dielectric constant and dielectric hysteresis loops in ceramic samples of (1 ? x)SrTiO_3?x KNbO₃ and (1 ? x)SrTiO_3?x KTaO₃ (0 ≤ x ≤ 0.3) solid solutions prepared using different heat treatments have been investigated. Phase diagrams of the studied solid solutions have been constructed in the T-x coordinates. It has been shown that, after quenching of samples (spontaneous cooling at room temperature after long-term heating at the sintering temperature of the ceramic samples), the temperature of the induced phase transition increases because of the weakening of random electric fields associated with nonisovalent impurities due to their “frozen” nonequilibrium redistribution. For small concentrations x, strong dielectric relaxation is observed in the temperature range of 150–250 K. A model of relaxing centers, which is based on the local charge compensation of heterovalent impurities, has been proposed.     

Infrared spectra of matrix isolated BH3NH3, BD3ND3, and BH3ND3

The infrared spectra of ammonia-borane, BH₃NH₃, and two of its deuterated isotropic species, BD₃ND₃ and BH₃ND₃, isolated in argon matrix at liquid hydrogen temperature have been measured. Well resolved bands for these three isotopic species have been observed for all the fundamentals. A complete frequency assignment based on C₃v molecular symmetry has been made. A set of force constants have been calculated from the data for the two isotopes BH₃NH₃ and BD₃ND₃ using a valence force field. The agreement between experiment and frequencies calculated from these force constants for the mixed isotopic species, BH₃ND₃, substantiates the present assignment.     

Terahertz Vibrational Modes in CH3NH3PbI3 and CsPbI3 Perovskite Films

JETP Letters - Films of CH3NH3PbI3 organometallic perovskite, which is currently considered as a promising basic material for new-generation solar cells, as well as films containing CsPbI3...     

Modulated magnetic structures of ErPb3, HoPb3, ErTl3 and HoTl3

Neutron diffraction experiments have been carried out on the magnetically ordered phases of ErPb₃, HoPb₃, ErTl₃ and HoTl₃. The magnetic moments were found to be sinusoidally modulated with a propagation vector of (0, 0.2, 0.5) for the Pb-compounds and (0.38, 0.38, 0.16) for the Tl-compounds.Work supported by the Bundesministerium für Forschung und Technologie     

（LaO）3BO3中Eu^3＋和Sm^3＋的光致发光

研究了紫外光激发下，（ＬａＯ）３ＢＯ３基质中Ｅｕ＾３＋和Ｓｍ＾３＋的光谱性质，Ｅｕ＾３＋和Ｓｍ＾３＋的电荷迁移激发带及发光强度随组成和结构变化的规律性，并探讨了Ｅｕ＾３＋和Ｓｍ＾３＋自身浓度猝灭的机理。     

O_3 fast and simple treatment-enhanced p-doped in Spiro-MeOTAD for CH_3NH_3I vapor-assisted processed CH_3NH_3PbI_3 perovskite solar cells

We demonstrate a simple and fast post-deposition treatment with high process compatibility on the hole transport material(HTM) Spiro-MeOTAD in vapor-assisted solution processed methylammonium lead triiodide(CH_3NH_3PbI_3)-based solar cells. The prepared Co-doped p-type Spiro-MeOTAD films are treated by O_3 at room temperature for 5 min,10 min, and 20 min, respectively, prior to the deposition of the metal electrodes. Compared with the traditional oxidation of Spiro-MeOTAD films overnight in dry air, our fast O_3 treatment of HTM at room temperature only needs just 10 min,and a relative 40.3% increment in the power conversion efficiency is observed with respect to the result of without-treated perovskite solar cells. This improvement of efficiency is mainly attributed to the obvious increase of the fill factor and short-circuit current density, despite a slight decrease in the open-circuit voltage. Ultraviolet photoelectron spectroscopy(UPS) and Hall effect measurement method are employed in our study to determine the changes of properties after O_3 treatment in HTM. It is found that after the HTM is exposed to O_3, its p-type doping level is enhanced. The enhancement of conductivity and Hall mobility of the film, resulting from the improvement in p-doping level of HTM, leads to better performances of perovskite solar cells. Best power conversion efficiencies(PCEs) of 13.05% and 16.39% are achieved with most properly optimized HTM via CH_3NH_3I vapor-assisted method and traditional single-step method respectively.