Synthesis,crystal structure and optical property of manganese (II) halides based on pyridine ionic liquids with high quantum yield

Transition Metal Chemistry - Two novel tetrahedral Mn (II) halide single-crystals [(C7H10N)2][MnCl4] (1) and [(C7H10N)2][MnBr4] (2), based on pyridine ionic liquids, have been successfully...     

Design of a coated thinly clad chalcogenide long-period fiber grating refractive index sensor based on dual-peak resonance near the phase matching turning point

A novel method for designing chalcogenide long-period fiber grating (LPFG) sensors based on the dual-peak resonance effect of the LPFG near the phase matching turning point (PMTP) is presented. Refractive index sensing in a high-refractive-index chalcogenide fiber is achieved with a coated thinly clad film. The dual-peak resonant characteristics near the PMTP and the refractive index sensing properties of the LPFG are analyzed first by the phase-matching condition of the LPFG. The effects of film parameters and cladding radius on the sensitivity of refractive index sensing are further discussed. The sensor is optimized by selecting the appropriate film parameters and cladding radius. Simulation results show that the ambient refractive index sensitivity of a dual-peak coated thinly clad chalcogenide LPFG at the PMTP can be 2400 nm/RIU, which is significantly higher than that of non-optimized gratings. It has great application potential in the field of chemical sensing and biosensors.     

Numerical analysis of the As2Se3 chalcogenide glass multi-ring photonic crystal fiber

A novel kind of As₂Se₃ chalcogenide glass multi-ring photonic crystal fiber is proposed. The characteristics of multi-ring photonic crystal fiber have been studied by the finite element method. Compared with another two kinds of single-core photonic crystal fibers, the multi-ring PCF can make the perfect combination of the effective mode area, the nonlinearity coefficient and multi-zero dispersion. It can achieve high power supercontinuum generation in middle infrared band; It also can be used in high-power pulsed laser fiber amplifier and high-power ultra-short pulse laser transmission in far infrared band.     

Eu2+掺杂KCaCl3晶体的生长及发光性能

通过坩埚下降法生长出不同物质的量分数Eu²⁺掺杂的KCa_1-xEu_xCl₃(x=0.005、0.01、0.02、0.03、0.05)单晶,并对晶体进行了X射线粉末衍射、热重、透过率、光致发光光谱、衰减时间、X射线激发发射光谱等测定。通过相图及结构分析,判断出该晶体为一致熔融化合物,并得出其为正交结构,晶胞参数为a=0.75604 nm,b=1.04823 nm,c=0.72657 nm,空间群为Pnma(62)。在紫外光的激发下,晶体在434 nm左右有一个宽的发射峰,对应于Eu²⁺的4f⁶5d¹→4f⁷跃迁;光致衰减时间1.473μs,晶体在X射线激发下的发光强度随Eu²⁺离子浓度增加而增强。     

Eu2+掺杂KCaCl3晶体的生长及发光性能

通过坩埚下降法生长出不同物质的量分数Eu²⁺掺杂的KCa_1-xEu_xCl₃（x=0.005、0.01、0.02、0.03、0.05）单晶,并对晶体进行了X射线粉末衍射、热重、透过率、光致发光光谱、衰减时间、X射线激发发射光谱等测定。通过相图及结构分析,判断出该晶体为一致熔融化合物,并得出其为正交结构,晶胞参数为a=0.756 04 nm,b=1.048 23 nm,c=0.726 57 nm,空间群为Pnma（62）。在紫外光的激发下,晶体在434 nm左右有一个宽的发射峰,对应于Eu²⁺的4f⁶5d¹→4f⁷跃迁;光致衰减时间1.473 μs,晶体在X射线激发下的发光强度随Eu²⁺离子浓度增加而增强。     

The optical,structural and thermal optimizations of Ge-As-Se-S-Te glasses

The optical, structural and thermal optimizations of Ge₃₃As₁₂Se₅₅ glass were the aim of this study. In this regards, Ge₃₃As₁₂Se₄₅M₁₀ (M = Se, Te, S and S_0.5Te_0.5) glasses were synthesized by conventional melt quenching technique in quartz ampule. The prepared samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The fundamental absorption edge for prepared samples was also analyzed in terms of the theory proposed by Davis and Mott. The addition of S and Te elements to melting batch has deleterious effects on optical properties of Ge₃₃As₁₂Se₅₅ glass. Mg and Al can act as gettering elements for reduction of the intensity of oxide absorption bands from FTIR spectra (without any effects on optical properties of Ge₃₃As₁₂Se₅₅ glass). The precipitation of GeSe phase, during crystallization process, has negligible effects on optical properties of Ge₃₃As₁₂Se₅₅ glass.     

Investigation of Er3+, Yb3+, Nd3+ doped yttrium calcium oxyborate for photon upconversion applications

In this work, investigation have been done on polycrystalline yttrium calcium oxyborate (YCa₄O(BO₃)₃) for the realization of existence of second harmonic generation and other photon upconversion processes as concurrent effect with the aid of Er, Yb, Nd trivalent lanthanide ions. Pure, Er:Yb co-doped and Er:Yb:Nd triply-doped YCa₄O(BO₃)₃ samples were prepared through solid state reaction and the phase identification has been done using powder X-ray diffraction spectral analysis. FTIR spectra show that the dopants increases the absorption of functional groups and modifies the lattice vibrational modes of YCa₄O(BO₃)₃. The spectral overlap of optical absorption bands of Er³⁺, Yb³⁺, Nd³⁺ ions in 840 nm–1070 nm region indicates the prospect of energy transfer between these ions. The photoluminescence spectrum of Er:Yb:Nd triply doped sample show good enhancement compared to pure and Er:Yb co-doped YCa₄O(BO₃)₃ samples. In the photon upconversion test carried out using 1064 nm Nd:YAG laser YCa₄O(BO₃)₃:Er:Yb:Nd sample produced green light with efficiency higher than the other two samples. Surface morphology of the samples was recorded using field emission scanning electron microscope and analysed. The elemental composition of the samples has been confirmed by energy dispersive X-ray spectral analysis.     

KCaCl3:Ce晶体的生长及发光性能

采用坩埚下降法生长出不同摩尔分数Ce³⁺(1%、2%、4%、6%、8%)掺杂的KCaCl₃:Ce单晶。晶体属于正交晶系,晶胞参数为a=0.756 0 nm,b=1.048 2 nm,c=0.726 6 nm。热重分析仪测得熔点为740 ℃,透过率测试显示晶体在可见光波段均具有较好光学透过率。对晶体的光致发光光谱、光致衰减时间、X射线激发发射光谱、透过率等光学性能进行了表征。光致发光光谱显示KCaCl₃:Ce晶体在358 nm和378 nm波长左右有宽的发射峰,符合Ce³⁺的5d₁→²F_5/2和5d₁→²F_7/2能级跃迁,通过拟合,KCaCl₃:Ce晶体的衰减时间在30 ns左右。晶体在X射线激发下均表现出优异的X射线发光性能。     

[(Epy)2][MnBr2I2]配合物的合成、晶体结构及发光性能

室温下,以N-乙基吡啶碘盐(Epy)I和四水溴化锰(MnBr₂·4H₂O)为原料合成了一种零维发光材料[(Epy)₂][MnBr₂I₂]。对该配合物进行元素含量分析、红外光谱、单晶X射线衍射、粉末X射线衍射、紫外可见吸收光谱、光致发光光谱及X射线激发发射光谱等测试。单晶X射线衍射结果表明:配合物为单斜晶系,C2/c空间群,中心离子Mn(Ⅱ)为四面体构型,晶胞参数为a=2.825 5(6) nm,b=0.839 71(17) nm,c=1.836 0(4) nm。在332 nm紫外光激发下,配合物发出528 nm的绿光,对应于四面体Mn(Ⅱ)配合物的⁴T₁(G)→⁶A₁特征辐射跃迁,荧光寿命为58.85 μs,荧光量子产率为58.29%。X射线激发光谱表明配合物发光强度较高,具有X射线荧光性能。