Bi2O3纳米晶玻璃三阶非线性光吸收性质的研究

利用溶胶凝胶法结合气氛控制方式合成了含Bi2O3纳米晶钠硼硅玻璃.利用X射线粉末衍射仪(XRD)、X射线光电子能谱(XPS)、透射电子显微镜(TEM)、X射线能量色散谱(EDX)、扫描模式透射电子显微镜(STEM)、高分辨透射电子显微镜(HRTEM)以及选区电子衍射(SAED)对掺杂在钠硼硅玻璃中Bi2O3纳米晶的形貌和微结构进行了表征,同时,利用飞秒开孔Z-scan技术详细地研究了Bi2O3纳米晶玻璃在800 nm处不同激发光强度下的三阶非线性光吸收性质.结果表明,在钠硼硅玻璃中形成了尺寸小于10 nm的Bi2O3单斜晶系纳米晶.随着激发光强度的增强,该玻璃的三阶非线性光吸收性质产生由饱和吸收向反饱和吸收的转变.进一步,计算得到的该玻璃三阶非线性极化率χ(3)的数量级范围在10-19~10-18m2/V2之间.这一结果说明该玻璃具有良好的非线性光学性能,并且在光限幅器等非线性光学领域具有潜在的应用价值.     

含Ag量子点钠硼硅玻璃的三阶非线性光学性质

以正硅酸乙酯、硼酸、金属钠为前驱体采用溶胶-凝胶法合成含Ag量子点的钠硼硅玻璃。X射线粉末衍射 (XRD) 分析Ag量子点具有立方相。通过透射电子显微镜 (TEM) 和高分辨透射电子显微镜 (HRTEM) 测定量子点的尺寸和分布, 结果显示在玻璃中量子点呈规则的球形, 并且尺寸在5~13 nm之间。紫外-可见(UV-Vis)吸收光谱仪得到Ag量子点的表面等离子体共振吸收峰大约在406 nm附近; 利用飞秒Z-scan 技术在800 nm波长处用飞秒钛宝石激光辐照对Ag量子点玻璃的非线性光学性质进行研究, 该玻璃的非线性折射率γ、非线性吸收系数β和三阶非线性极化率χ⁽³⁾分别为 –1.72×10^-17 m²/W、9.96×10^-11 m/W、1.01×10^-11 esu。     

掺杂CuCl钠硼硅玻璃的溶胶-凝胶方法制备及非线性光学性质

采用sol-gel方法以Na₂O-B₂O₃-SiO₂系统玻璃为基体,采用不同浓度的盐酸溶液为CuCl的先驱体溶剂,在500-600℃的温度范围内烧成了掺杂CuCl的钠硼硅玻璃,详细地研究了氯化亚铜的浓度及其先驱体溶剂对溶胶-凝胶及玻璃性质的影响,讨论了CuCl在钠硼硅干胶中的生成机制,研究了烧结条件对干胶转变成玻璃性质的影响,并研究了这种材料的光学性质,首次报道了掺杂CuCl的Na₂O-B₂O₃-SiO₂系统玻璃在1.33μm处的三阶非线性折射率,n₂=3.3×10^-20m²/W.     

AgIn合金量子点复合玻璃的制备及光学性质研究

采用溶胶-凝胶法结合气氛控制的技术制备了AgIn合金量子点掺杂钠硼硅基(NBS)玻璃。利用X射线粉末衍射仪(XRD)、X射线光电子能谱(XPS)、高分辨透射电子显微镜(HRTEM)以及选区电子衍射(SAED)对AgIn合金量子点在玻璃中的形貌和微结构进行了表征, 并利用荧光光谱仪对该玻璃的荧光性质进行了研究。结果表明, 在600℃热处理下钠硼硅玻璃中形成了尺寸分布在5 nm左右的均一的AgIn六方晶系量子点, 而且分布在玻璃中的AgIn量子点在435 nm附近存在一个荧光峰, 表明AgIn量子点掺杂NBS玻璃可以作为激光源、非线性介质和光子设备的候选玻璃。     

Er~(3+)掺杂透明微晶玻璃光谱性质的研究

通过高温熔融法和热处理制备了含有-γBi2WO6纳米晶的Er3+掺杂透明硼铋酸盐微晶玻璃.根据X射线粉末衍射结果和Scherrer公式计算得到-γBi2WO6晶粒大小约为15 nm.由于部分Er3+离子取代Bi3+进入-γBi2WO6纳米晶相中,使得Er3+离子在1.5μm的有效发射带宽由78 nm增加到85 nm,同时Er3+离子在4I13/2能级的荧光寿命由0.67 ms增加到1.43 ms.此外,与原始玻璃相比,在Er3+掺杂硼铋酸盐微晶玻璃中观察到强烈的绿光上转换发光,其上转换发光机制可以归为双光子过程.     

高三阶光学非线性Cd/CdS-SiO2复合薄膜的电化学–溶胶凝胶制备及表征

以硝酸镉、硫脲和正硅酸乙酯为前驱体, 采用电化学-溶胶凝胶法, 以ITO玻璃为基底制备了透明薄膜。扫描电子显微镜(SEM)表征表明薄膜为纳米束结构。X射线能谱(EDX)表征表明薄膜由Si、O、Cd、S元素组成, Cd/S(原子比)＞1。EDX表征结合循环伏安(CV)实验确定薄膜为Cd/CdS-SiO₂复合薄膜。Z扫描表征表明, 薄膜在1064 nm处表现出自散焦特性的非线性折射效应和饱和吸收特性的非线性吸收特性。薄膜的三阶非线性极化率(χ(3))较高, 达到了1.18×10^-14~1.39×10^-13 (m/V)², 表明薄膜具有优良的三阶光学非线性。分析认为薄膜中CdS的含量对薄膜的光学性非线性起主要作用。     

Tm3+掺杂Bi2O3-SiO2-PbO玻璃的～2μm发光光谱性质

用高温熔融法制备了Tm2O3摩尔掺杂浓度分别为0.1%、0.25%、0.5%、0.75%和1%的33Bi2O3-50SiO2-17PbO玻璃。采用DSC方法对该种玻璃的析晶性能进行研究,发现其Tx–Tg为138℃,说明该玻璃抗析晶性能良好。基于其吸收光谱,采用Judd-Ofelt理论计算了Tm3+离子的J-O参数和部分激发态能级的跃迁几率、荧光寿命和分支比等光谱参量。分析3F4能级寿命随掺杂浓度变化关系,发现产生自淬灭的临界浓度为3.54×1020ions/cm3。用McCumber理论计算在33Bi2O3-50SiO2-17PbO玻璃中Tm3+离子3F4→3H6能级跃迁的吸收截面和发射截面,最大吸收截面和最大受激发射截面分别为3.7×10-21和7.2×10-21cm2。研究结果表明33Bi2O3-50SiO2-17PbO玻璃具有较好的光谱性质,是一种实现~2μm激光的较理想玻璃基质。     

Bi2Te3纳米结构的制备、磁性掺杂和结构表征

通过液相法制备Bi2Te3纳米管,设计并优化了Co离子的掺磁方案。通过扫描电镜、透射电镜、X射线衍射、红外光谱和能量色散X射线光谱对制备的样品进行了结构表征。实验结果表明,液相法可制备出晶相良好的Bi2Te3纳米管、Co离子均匀掺杂的Bi2Te3纳米结构样品。     

Na2O-B2O3-SiO2玻璃的制备及其三阶非线性的研究

以正硅酸乙酯、硼酸和乙醇钠为先驱体,分别以无水乙醇、乙二醇甲醚和无水乙醇为溶剂,采用溶胶-凝胶结合气氛控制的方法制备了Na2O-B2O3-SiO2玻璃。通过热重-差热分析、红外光谱、X射线粉末衍射等手段对凝胶的热分解机制、玻璃的形成过程和物相结构进行了表征。结果表明,在600℃时制得了透亮密实的玻璃。采用紫外-可见吸收光谱和Z-扫描技术对获得的玻璃的光学特性进行了研究,结果表明该玻璃具有良好的光透过率,且其三阶非线性极化率为1.49×10-19 m2/V2。     

Cu2ZnSnS4纳米颗粒及其薄膜的制备与表征

采用热注入法,在油胺(OLA)中合成出Cu2ZnSnS4(CZTS)纳米颗粒,并在玻璃衬底上制备了薄膜,研究了不同合成温度对纳米颗粒生成的影响.通过X射线衍射仪、拉曼光谱仪、透射电子显微镜、扫描电子显微镜、紫外可见分光光度计对所得纳米晶材料的结构与成分、颗粒大小与形貌、光吸收谱进行了测试分析.研究结果表明:采用热注入法的最佳合成温度在260℃左右,该温度下生成的多晶CZTS纳米颗粒尺寸约10 nm,分散性良好,光学禁带宽度约1.5 eV.     

Microstructures and the third-order optical nonlinearities of semimetal Bi nanocrystals in the sodium borosilicate glass

The sodium borosilicate glass doped with semimetal Bi nanocrystals is prepared by employing both sol-gel and atmosphere control methods. Microstructures and the third-order optical nonlinearities of the glass are investigated by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), and Z-scan technique. The results show that semimetal Bi nanocrystals in hexagonal crystal system with spherical shape have formed uniformly in the glass, and the size of these nanocrystals is almost less than 40 nm. Furthermore, the third-order optical nonlinear refracitve index γ, absorption coefficient β, and susceptibility χ⁽³⁾ of the glass are determined to be 9.40 × 10⁻¹⁷ m²/W, 1.25 × 10⁻⁹ m/W, and 6.80 × 10⁻¹¹ esu, respectively.     

Structural,linear and third-order nonlinear optical properties of Cu nanocrystal in sodium borosilicate glass

Cu nanocrystals embedded in sodium borosilicate glass of varied Cu contents from 0.5 to 1.5 wt% have been successfully prepared through a sol–gel process. According to the results of X-ray diffraction (XRD) and the energy dispersive X-ray spectrometry (EDS), the metal Cu nanocrystals in cubic crystal system were well distributed inside glass matrix. Fourier Transform Infrared (FTIR) indicated the sodium borosilicate matrix had no major structural change for gels with different Cu contents. The optical absorption peaks due to the surface plasmon resonance of Cu particles were observed in the wavelength range of 550–600 nm. The absorption peak showed a red-shift trend with increasing Cu contents from 0.5 to 1.5 wt%. Transmission electron microscopy (TEM) revealed the existence of spherical Cu nanocrystals in the matrix. The diameter of Cu nanocrystals varied from 1 to 3.5 nm. Furthermore, the third-order nonlinear optical properties were investigated by Z-scan technique at 800 nm. Experimental results indicated the Cu nanocrystals have obvious positive refractive nonlinearities and reverse saturated absorption performance.     

Structure and luminescence properties of Eu/Tb codoped oxyfluoride glass ceramics containing Sr2GdF7 nanocrystals

Eu/Tb codoped transparent oxyfluoride borosilicate glass ceramics containing Sr₂GdF₇ nanocrystals were fabricated under a reductive atmosphere and the conversion of Eu³⁺ ions to Eu²⁺ ions was observed. The Sr₂GdF₇ nanocrystals with an average size of 32 nm were homogeneously precipitated in the oxyfluoride borosilicate glass matrix, which could be evidenced by X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy-dispersive X-ray (EDX) spectroscopy. The enhancement of photoluminescence emission intensity, reduction of the relative emission intensities between ⁵D₀ → ⁷F₂ and ⁵D₀ → ⁷F₁, and long fluorescence lifetimes of Eu²⁺, Eu³⁺, and Tb³⁺ ions revealed that more rare earth ions were partitioned into the low phonon energy environment Sr₂GdF₇ nanocrystals. Under ultraviolet excitation, pure and bright white light emission was obtained in the oxyfluoride borosilicate glass ceramic, which may be a potential blue, green and red-emitting phosphor for white LEDs.     

八面体形状的重钼酸钠纳米晶的制备及生长机制

采用热蒸发方法,以红外烧结炉为制备仪器,在玻璃衬底上制备了空心的八面体纳米晶。利用扫描电子显微镜、X射线衍射谱、透射电子显微镜及选区电子衍射分析产物的形貌、尺寸、成分及结构,并对纳米晶的形成机理进行了探讨分析。     

Preparation and characterization of perovskite LaFeO3 nanocrystals

Orthorhombic structure perovskite LaFeO₃ nanocrystals with size of 59 nm were prepared by glycine combustion method. The as-prepared LaFeO₃ nanocrystals were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high reaction transmission electron microscopy (HRTEM), energy dispersive X-ray spectrometer (EDS), scanning electron microscope (SEM), UV–Visible absorption spectroscopy, Laser Raman Spectroscopy (LRS) and Brunauer–Emmett–Teller (BET) nitrogen adsorption. The preparation process can be also applied to synthesize other complex oxides such as NdFeO₃, LaCoO₃ and LaNiO₃.     

纳米晶铁酸锌和铁酸镧的合成与表征

用硬脂酸凝胶法制备了尖晶石型ZnFe2O4和钙钛矿型LaFeO3纳米晶，通过热重差热（TG-DTA）、X射线粉末衍射（XRD）、透射电镜（TEM）和BET比表面吸附，对纳米粒子的组成、结构、形貌、粒径进行了分析和表征．     

Solution fabrication and photoelectrical properties of CuInS₂ nanocrystals on TiO₂ nanorod array

One-dimensional semiconductor architectures are receiving attention in preparing photovoltaic solar cells because of its superior charge transport as well as excellent light-harvesting efficiency. In this study, vertically aligned single-crystalline TiO(2) nanorods array was grown directly on transparent conductive glass (FTO), and then CuInS(2) nanocrystals were deposited on nanorods array by spin coating method to form TiO(2)/CuInS(2) heterostructure films. The resulting nanostructure assembly and composition was confirmed by field-emission scanning electron microscope (FESEM) , transmission electron microscopy (TEM), high-resolution TEM, and X-ray diffraction(XRD). Ultraviolet-visible absorption spectroscopy (UV-vis) data indicates that the absorbance of the nanocomposite film extended into the visible region compared with bare TiO(2) nanorod arrays. The surface photovoltage spectra (SPS) also showed a new and enhanced response region corresponding to the absorption spectrum. These results suggest that the novel CuInS(2) nanocrystals sensitized TiO(2) nanorod array on FTO photoelectrodes has a potential application in photovoltaic devices.