Infrared vibrational Modes in Tl3SbS3, Tl3AsS3, and Tl3AsSe3 crystals

Reflectivity spectra of Tl₃SbS₃, Tl₃AsS₃, and Tl₃AsSe₃ crystals have been investigated in the wave number range 50–600 cm⁻¹ for the polarizations E∥c and E⟂c. The fundamental phonon parameters, the limiting dielectric constants ϵ_∞ and ϵ_S and the reflectivity spectra contours have been calculated by using classical dispersion relations for both E∥c and E⟂c configurations. The Szigeti effective charges and the relative ion charges of As, Tl, Sb, Se, S anions and cations have been calculated in dependence on the incident light polarization.     

The structures of three trimethylarsine-boron trihalide adducts: (CH3)3AsBCl3, (CH3)3AsBBr3, and (CH3)3AsBI3

An X-ray structure analysis of three trimethylarsine-boron trihalide adducts has been undertaken. Crystals of (CH₃)₃AsBCl₃ and (CH₃)₃AsBBr₃ are monoclinic with space groupP2₁/m (No. 11) withZ=2 while those of (CH₃)₃AsBI₃ are orthorhombic with space groupPnma (No. 62) withZ=4. For (CH₃)₃AsBCl₃,a=6.497(3) Å,b=10.735(3) Å,c=7.070(2) Å,=111.8(3)°,V=458.4(3) ų,R=0.0343. For (CH₃)₃AsBBr₃,a=6.672(4) Å,b=11.135(7) Å,c=7.199(4) Å,=111.5(1)°,V=497.7(5) ų,R=0.0434. For (CH₃)₃ÅsBI₃,a=13.113(7) Å,b=11.733(5) Å,c=7.387(3) Å,V=1136.5(5) ų,R=0.0329. The As-B bond lengths are 2.065(6), 2.04(1), and 2.03(1) Å, respectively, for the chloride, bromide, and iodide. These and other structural parameters are discussed with reference to previous predictions based on vibrational spectra and previous structural studies on the trimethyl-phosphine and trimethylamine adducts.     

Crystal and molecular structures of three trimethylamine-boron halide adducts: (CH3)3NBCl3, (CH3)3NBBr3, and (CH3)3NBI3

X-ray diffraction data from single crystals of the trimethylamine complexes of the three boron halides, BCl₃, BBr₃, and BI₃, lead to aP2₁/m monoclinic cell containing two molecules for each complex. The unit cell dimensions area = 6·68(1),b = 10·247(3),c = 6·502(6) Å, =116·2(1)° (chloro);a = 6·86(1),b = 10·612(4),c = 6·737(6) Å, = 115·8(1)° (bromo);a = 6·92(2),b = 10·86(1),c = 7·147(6) Å, = 93·9(1)° (iodo). The structures were solved by three-dimensional sharpened Patterson functions and show only the chloro and bromo compounds to be isomorphous. Refinement of 662,718 and 954 observed reflexions for the chloro, bromo and iodo complexes, respectively, using anisotropic thermal parameters yielded conventionalR factors of 0·045, 0·087 and 0·054.The molecules are shown to possess a B—N dative bond, a staggered conformation, and effective 3m (C _3v) symmetry. Average C—N bond lengths are 1·52(1) Å for all three complexes. Boronhalogen bond lengths average 1·864(4), 2·04(2) and 2·28(2) Å, while B—N bond distances are 1·609(6), 1·60(2) and 1·58(3) Å, respectively, for the chloro through iodo compounds. Bond angles are approximately tetrahedral with the C—N—C angle decreasing by several degrees in the Cl Br I series.Based in part on a dissertation submitted by Patty H. Clippard to the Rackham School of Graduate Studies of the University of Michigan, January 1969 in partial fulfillment of the requirements of the Ph.D. Degree.     

Second harmonic generation properties of Ca3(O3C3N3)2 ‐Sr3(O3C3N3)2 solid solutions

Solid solutions of the second harmonic generation (SHG) materials Ca₃(O₃C₃N₃)₂ (CCY) and Sr₃(O₃C₃N₃)₂ (SCY) were prepared via exothermic solid state metathesis reactions from appropriate amounts of the corresponding metal chlorides and potassium cyanate at 525 °C. The change in SHG intensity caused by the successive cation substitution is reported. Differential thermal analyses are used to explore the SCY–K(OCN) phase diagram as a medium for the growth of SCY crystals.     

Crystal Growth and Spectroscopic Characterisation of BiB3O6:RE3+ (RE3+ = Pr3+, Nd3+, Gd3+, Er3+, Tm3+)

Large single crystals of optical quality of BiB₃O₆:RE³⁺ (RE³⁺ = Pr³⁺, Nd³⁺, Gd³⁺, Er³⁺, Tm³⁺) were grown from nearly stoichiometric melts using the top‐seeding growth technique to dimensions up to 12 x 12 x 18 mm³. Absorption spectra were measured in the wavelength range from 10000 cm^‐1 to 30000 cm^‐1 with an absorption spectrometer to estimate the doping concentration of RE³⁺. For the determination of the phonon energies and the quenching behaviour of the host lattice IR and Raman spectra were recorded.     

Growth and characteristic of Sr3Tb(BO3)3 crystal

A new borate single crystal of Sr₃Tb(BO₃)₃ with dimension Ф20×25 mm² has been grown by the Czochralski method. The grown crystal was characterized by DTA–TGA, FTIR and X-ray powder diffraction analysis. The results showed the crystal with [BO₃]^3? is congruently melting at 1351.35 °C which belongs to hexagonal structure. The hardness of Sr₃Tb(BO₃)₃ crystal is 422.5 VDH, and is equal to 5.0 moh. The thermal expansion coefficients were determined to be 2.08×10^?5/°C along (1 0 0) direction and 7.43×10^?6/°C along (0 0 1) direction and the transmission spectrum was measured in 320–1800 nm at room temperature. The magnetic properties of the single crystal were studied which showed its paramagnetism and magnetic anisotropy. The specific Faraday rotation of single crystal was measured at room temperature in 532, 633, and 1064 nm wavelength. The Verdet constants and magneto-optical figures of merit were investigated. The primary emphasis is laid to explore a new magneto-optical material, all the magneto-optical properties of Sr₃Tb(BO₃)₃ are comparing to the ones of TGG.     

Growth and magnetic‐optical properties of Sr3Gd(BO3)3 and Sr3TbxGd1‐x(BO3)3 single crystals

Single crystals of Sr₃Gd(BO₃)₃ (SGB) and Sr₃Tb_xGd_1‐x(BO₃)₃ (TSGB) with dimension Ø 20 mm×20 mm have been grown by Czochralski method. The grown crystals were characterized by X‐ray powder diffraction analysis which showed the crystals belong to hexagonal structure with lattice parameters of a=b=1.254 nm, c=0.926 nm (SGB) and a=b=1.253 nm, c=0.925 nm (TSGB). In TSGB, x=17.7% was obtained by X‐ray fluorometry which showed the segregation coefficient of Tb is closed to 1. The transmission spectrum was measured, which indicated the crystals have high transmittance in 400‐1100 nm region. The Faraday rotation of single crystals at 532 nm wavelength was measured at room temperature. Finally, the Verdet constants were investigated, (SGB) V=17.9 degcm^‐1T^‐1 and (TSGB) V=21.3 degcm^‐1T^‐1. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Tb3+,Yb3+共掺杂LuBO3荧光粉的下转换发光

利用水热法成功合成了近红外量子剪裁荧光粉LuBO3∶15;Tb3+,x; Yb3+(x=0,1,2,4,8,12).通过X射线衍射(XRD)、光致发光谱(PL)、激发谱(PLE)和荧光寿命测试了合成物质的物相结构与发光性质.在286 nm(Tb3+∶7 F6→5D)紫外光激发下,观察到了Tb3∶5D4→7Fj(J=6,5,4,3)可见波段特征发射光和Yb3+:2F5/2→2F7/2的近红外光.研究了Yb3+浓度与激发发射光谱和荧光寿命之间的关系,表明Tb3+和Yb3+之间存在能量传递.当Tb3和Yb3+掺杂摩尔浓度分别为15;和2;时,近红外发射最强.计算得知,其最大下转换量子效率为160.74;.     

Photoacoustic Spectra of Pr3+, Nd3+, Gd3+ Acetate Complexes

The crystals of the complexes Pr(Ac)₃ · 4 H₂O, Nd(Ac)₃ · 4 H₂O, Gd(Ac)₃ · 4 H₂O were synthesized and their Pa spectra determined firstly. Their PA spectra and absorption are interpreted. The fluorescence properties of Pr³⁺, Nd³⁺, Gd³⁺ and the relaxation process models were studied by their PA spectra.     

Second harmonic generation in Na3Gd2(BO3)3 crystals

Na₃Gd₂(BO₃)₃ crystals with dimensions up to 22 × 20 × 5 mm³has been grown from NaBO₂ flux by the top‐seeded solution growth (TSSG) method for the first time. Differential scanning calorimetry (DSC) result shows that Na₃Gd₂(BO₃)₃ melts incongruently. The infrared spectrum indicates that Na₃Gd₂(BO₃)₃ contains characteristic triangular [BO₃]^3– groups responsible for the nonlinear optical effect. For the as‐grown crystal, the transmittance exceeds 80% in the wavelength range of 315 nm to 2670 nm, and the UV cutoff wavelength is 207 nm. The damage threshold is 0.47 GW cm^–2 at 1064 nm. Moreover, Na₃Gd₂(BO₃)₃ crystal exhibits an optical second harmonic generation effect which is 1.3 times as large as that of KH₂PO₄ (KDP). (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

3-Methyl-3a,4-Dihydro-3H-Thiochromeno[4,3-c]isoxazol

Abstract  The crystal structure of the title compound, C₁₁H₁₁NOS, was determined by an X-ray diffraction analysis. The compound crystallizes in the monoclinic space group P2₁/c with cell parameters a = 10.533(2) ?, b = 12.7826(19) ?, c = 7.6491(17) ?, β = 107.997(17)^°, V = 979.5(3) ?³ and Z = 4. The S containing heterocycle adopts a sofa conformation, whereas the 5-membered ring adopts an envelope conformation. The crystal packing is characterized by weak C–H···N contacts and π-stacking interactions. Graphical Abstract  The title compound, 3-methyl-3a,4-dihydro-3H-thiochromeno[4,3-c]isoxazol was synthesized by an 1,3 dipolar cycloaddition reaction and its crystal structure determined. Single crystal X-ray diffraction analysis reveals that the aromatic 6-membered ring is planar, whereas the ring containing the S atom adopts a sofa conformation and the 5-membered ring an envelope conformation. The methyl group is in an equatorial position.      

铒镱双掺的钒酸钇和铌酸锂晶体中的铒离子的上转换发光

利用J-O理论,计算了在铒、镱双掺的钒酸钇和铌酸锂晶体中的铒离子在室温下的晶场唯象参数Ωλ(λ=2,4,6)及辐射跃迁几率、无辐射跃迁几率和共振跃迁几率.考虑到铒、镱间的能量转移,写出了在这些晶体中的铒离子的速率方程.速率方程的解表明,在铒、镱双掺的钒酸钇晶体中的铒离子的550 nm的上转换发光,比它在铒、镱双掺的铌酸锂晶体中更为有效.这一理论结果与我们的实验观察结果一致.     

Nd3+:Na3La9O3(BO3)8晶体生长和光谱性能

采用顶部籽晶法生长Nd3+:Na3La9O3(BO3)8 晶体.在室温下测试了吸收光谱、发射光谱和荧光寿命.应用Judd-Ofelt理论评价了Nd3+:Na3La9O3(BO3)8晶体的光谱性能.812 nm处较宽的吸收峰适合AlGaAs LD泵浦的吸收.分别计算了Nd3+离子的唯象强度、谱线强度、辐射寿命、荧光分支比和荧光量子效率.     

Yb3+: Sr3Gd(BO3)3激光晶体的生长和光谱特性

采用提拉法(Czochralski)生长出了掺Yb3+的Sr3Gd(BO3)3晶体,晶体尺寸达到:25 mm×30 mm.测量了Yb3+: Sr3Gd(BO3)3晶体的吸收谱、荧光谱以及荧光寿命.Yb3+: Sr3Gd(BO3)3晶体在975 nm有一半峰宽为7 nm的强吸收峰,π谱的吸收跃迁截面σa=7.28×10-21 cm2,在1040 nm的发射跃迁截面σe=1.43×10-21 cm2.辐射寿命为1.46 ms, Yb3+浓度为13 at;时的荧光寿命f=2.14 ms,Yb3+浓度为0.5 at;时的荧光寿命f=1.21 ms.     

Study on the Sensitization of Ce3+ to Nd3+ in YAIO3

This paper presents the absorption spectra, excited spectra and fluorescence spectra of Nd: YAP, Ce: YAP and Nd, Ce: YAP. It is believed that there is an energy transfer from Ce³⁺ to Nd³⁺ and it is possible to improve the laser efficiency of Nd: YAP sensitized by Ce³⁺.     

Na3La2(BO3)3的晶体结构

以Na2CO3-H3BO3-NaF为助熔剂,使用顶部籽晶法生长出Na3La2(BO3)3透明单晶.测定了Na3La2(BO3)3的晶体结构,该晶体属正交晶系,空间群:mm2(No.38),晶胞参数为a＝0.51580(10)nm,b=1.1350(2)nm,c=0.73230(15)nm,α＝β＝γ＝90°,V＝0.42871(15)nm3,密度:.053g/cm3.晶体结构中的硼氧基团是平面的BO3基团,BO3基团相互独立,且与Na(1)O6、Na(2)O8、Na(3)O6和La(1)O9配位多面体连结形成三维网络骨架结构.讨论了Na3La2(BO3)3的晶体结构与倍频效应的关系.     

Na3La2(BO3)3晶体生长及光谱特性

本文以起始摩尔比为1:1的Na2CO3:H3BO3,并添加5;质量分数的NaF为助熔剂,用顶部籽晶法生长出φ35mm×5mm的透明Na3La2(BO3)3单晶.该晶体属正交晶系,空间群:Amm2,晶胞参数为a=0.51580(10)nm,b=1.1350(2)nm,c=0.73230(15)nm,α=β=γ=90°.测量了Na3La2(BO3)3晶体在室温下的透过光谱,紫外截止波长约为200nm.该晶体常温下稳定,不吸潮,但却易溶于稀酸.     

不同热处理氛围改善CH3NH3PbI3钙钛矿薄膜形貌和结晶

有机-无机金属卤素钙钛矿太阳能电池作为新一代光伏技术已经吸引到众多关注.近期研究表明,不管是在介空结构还是平面异质结结构的钙钛矿电池中,每次钙钛矿效率的重大突破都归因于钙钛矿薄膜质量的提高.钙钛矿太阳能电池与其他多晶薄膜太阳能电池相似,增加晶粒尺寸和减少晶界可以极大的增加器件效率.在本文中,钙钛矿薄膜形貌和结晶度在最优化的热处理过程可以得到极大的改善和提高.我们制备的高性能平面异质结钙结构钙钛矿太阳能电池,获得了17.81;的最高效率和17.44; ±0.5;的平均效率.