Time-resolved near-field spectroscopic study on photophysical processes at solid/liquid interface

固/液界面光物理过程的时间分辨近场光谱研究

基本信息

批准号：
16072217
负责人：
TAMAI Naoto
金额：
$ 16.83万
依托单位：
Kwansei Gakuin University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

1) Spectroscopic Properties of Semiconductor Nanostructures by Scanning Probe Microspectroscopy Non-linear optical properties such as two-photon absorption cross section and nonlinear refractive index of CdTe QDs were found to strongly depend on a size of QDs. The figure of merit was also found to increase with decreasing the size. The size dependence of nonlinear optical properties was analyzed by the theory derived by Sheik Bahae. CdTe nanowires synthesized from QDs was analyzed by time-resolved SPM, suggesting the heterogeneity of nanowires. In addition, the exciton annihilation of nanowires increased as compared with QDs because of the energy diffusion in nanowires. In previous experiments, blinking behavior was observed for single QD embedded by PVA and trehalose. We have found that the silica coating of a single CdTe QD dramatically suppress the blinking, suggesting that the environmental condition plays an important role for luminescence properties of single QD. Furthermore, CdS … More e nanorods and QDs were synthesized at low temperature and their physicochemical properties have been examined by SPM.2) Synthesis and Characterization of Ag Nanorods Silver nanorods were prepared by a seed-mediated growth approach with chemical reduction of Ag^+ in a detergent aqueous solution. Longitudinal and transverse modes of plasmon absorption have been clearly observed in this synthetic approach. Transient absorption dynamics indicates that the coherent acoustic vibration with oscillation period of 20 to 40 ps was originated from the heat release of nanorods that induces a periodic shift of plasmon absorption bands. By the analysis of acoustic vibration, the size of synthetic nanorods and the aspect ratio have been estimated.3) Highly-sensitive, Broadband Transient Absorption Microspectroscopy Detection wavelength region was expanded up to 1.6 μm by using InGaAs photodiode as a detector, which enables us to examine the dynamics of exciton delocalization or weak intermolecular interaction dynamics in small domains at interface with high sensitivity of △OD = 10^<-7> 〜 10^<-8>..Global-pump and local-probe geometry was also successful for transient absorption SNOM experiments. Less

1)通过强扫描探针显微光谱法研究半导体纳米结构的光谱特性发现CdTe QD的双光子吸收截面和非线性折射率等非线性光学特性取决于QD的尺寸。非线性光学特性的尺寸依赖性由 Sheik Bahae 导出的理论进行了分析。时间分辨 SPM，表明纳米线的异质性，此外，由于纳米线中的能量扩散，纳米线的激子湮灭增加。研究发现，单个 CdTe QD 的二氧化硅涂层显着抑制了闪烁，这表明环境条件对单个 QD 的发光性能起着重要作用。 CdS … More e 纳米棒和量子点在低温下合成，并通过 SPM 检查了它们的物理化学性质。2) 银纳米棒的合成和表征银纳米棒是通过种子介导的生长方法制备的，其中 Ag^+ 在在这种合成动力学方法中，可以清楚地观察到等离子体吸收的纵向和横向模式。瞬态吸收表明振荡周期为 20 的相干声振动。 40 ps 源自纳米棒的热释放，引起等离子体吸收带的周期性移动。通过声振动分析，估计了合成纳米棒的尺寸和纵横比。3）高灵敏度、宽带瞬态吸收显微光谱。使用InGaAs光电二极管作为检测器，检测波长范围扩大到1.6μm，这使我们能够检查激子离域动力学或弱分子间相互作用动力学。界面处的小域具有高灵敏度 △OD = 10^<-7> ~ 10^<-8>..全局泵浦和局部探针几何结构在吸收瞬态 SNOM 实验中也取得了成功。