TiO 2 –ZnO binary heterojunctions with different molar ratios of TiO 2 to ZnO have been prepared via a two-step co-precipitation method, including the synthesis of TiO 2 nanoparticles (NPs) and then incorporating them into the ZnO matrix. Structural studies and elemental analysis have been carried out by a series of characterization techniques including X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and energy-dispersive X-ray spectrometer. The linear optical characteristics have been investigated using photoluminescence emission spectra at an excitation wavelength of 300 nm to estimate various energy states formed in crystalline structures. The optical nonlinearities of synthesized NPs have been tested by nanosecond laser pulse-based single-beam Z-scan technique. Closed-aperture and open-aperture Z-scan measurements have shown negative lens effects and reverse saturable absorption behaviours for as-synthesized composite nanostructures, respectively. The third-order susceptibilities of TiO 2 –ZnO nanocomposites have been estimated to be higher than that of pristine TiO 2 NPs with a maximum value of 4.8 × 10 −4 esu belonging to the sample with a 1:1 molar ratio of TiO 2 to ZnO.

中文翻译：

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TiO2–ZnO 纳米复合材料：合成、线性和非线性光学分析

已经通过两步共沉淀法制备了具有不同 TiO 2 与 ZnO 摩尔比的 TiO 2 -ZnO 二元异质结，包括合成 TiO 2 纳米颗粒 (NPs)，然后将它们结合到 ZnO 基质中。结构研究和元素分析已通过一系列表征技术进行，包括 X 射线衍射、场发射扫描电子显微镜、透射电子显微镜和能量色散 X 射线光谱仪。已使用激发波长为 300 nm 的光致发光发射光谱研究了线性光学特性，以估计晶体结构中形成的各种能态。已通过基于纳秒激光脉冲的单光束 Z 扫描技术测试了合成纳米颗粒的光学非线性。闭孔和开孔 Z 扫描测量分别显示出合成的复合纳米结构的负透镜效应和反饱和吸收行为。据估计，TiO 2 -ZnO 纳米复合材料的三阶磁化率高于原始 TiO 2 NPs，最大值为 4.8 × 10 -4 esu 属于样品，TiO 2 与 TiO 2 的摩尔比为 1:1氧化锌。