Zhang Ke-Xin, Yao Cheng-Bao, Wen Xing, Li Qiang-Hua, Sun Wen-Jun
Key Laboratory of Photonic and Electric Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University Harbin 150025 Heilongjiang Province China
RSC Adv. 2018 Jul 20;8(46):26133-26143. doi: 10.1039/c8ra03027h. eCollection 2018 Jul 19.
Silver (Ag) nanoparticle-decorated zinc oxide (ZnO) nanowires (Ag-ZnO) have been successfully synthesized by chemical vapour deposition and the magnetron sputtering method. Scanning electron microscopy images indicate that Ag nanoparticles are distributed uniformly on the surface of the ZnO nanowires. The results of room temperature photoluminescence (RTPL) reveal two major emission peaks for the Ag-ZnO nanowires, and the emission peaks in the visible region are stronger than those of the unmodified ZnO nanowires. The mechanism of RTPL and low temperature photoluminescence (LTPL) emission is discussed in detail. Nonlinear optical properties and ultrafast dynamics have been investigated using the -scan and two color pump-probe (TCPP) techniques, respectively. The nonlinear absorption properties in the nano-, pico- and femto-second regime have been analyzed using the singlet state three-level and four-level models, respectively. The samples show self-focusing nonlinearity and good two-photon absorption (TPA)-induced ground state saturation absorption as well as excited state reverse saturable absorption behavior. For the nanosecond and picosecond pulses, the reverse saturated absorption in the excited state mainly originates from the absorption at low excited states or deep levels; however, for the femtosecond pulse, it is caused by the absorption at high excited states. The TCPP results show that the ground state or deep level light bleaching (for nano- and pico-second regime) and TPA-induced excited-state absorption (for femtosecond regime) behaviors range from 470 nm to 620 nm. The remarkable nonlinear optical properties reveal that Ag-ZnO nanowires are potential nanocomposite materials for the development of nonlinear optical devices.
通过化学气相沉积和磁控溅射法成功合成了银（Ag）纳米颗粒修饰的氧化锌（ZnO）纳米线（Ag-ZnO）。扫描电子显微镜图像表明，Ag纳米颗粒均匀分布在ZnO纳米线表面。室温光致发光（RTPL）结果显示，Ag-ZnO纳米线有两个主要发射峰，且可见光区域的发射峰比未修饰的ZnO纳米线更强。详细讨论了RTPL和低温光致发光（LTPL）发射的机制。分别使用z扫描和双色泵浦-探测（TCPP）技术研究了非线性光学性质和超快动力学。分别使用单重态三能级和四能级模型分析了纳秒、皮秒和飞秒时间尺度下的非线性吸收特性。样品表现出自聚焦非线性、良好的双光子吸收（TPA）诱导的基态饱和吸收以及激发态反饱和吸收行为。对于纳秒和皮秒脉冲，激发态的反饱和吸收主要源于低激发态或深能级的吸收；然而，对于飞秒脉冲，它是由高激发态的吸收引起的。TCPP结果表明，基态或深能级光漂白（对于纳秒和皮秒时间尺度）以及TPA诱导的激发态吸收（对于飞秒时间尺度）行为发生在470 nm至620 nm范围内。显著的非线性光学性质表明，Ag-ZnO纳米线是开发非线性光学器件的潜在纳米复合材料。
