IR-induced nonlinear optics in Ge-doped Bi12TiO20 large-sized nanocrystallites

Photoinduced non-linear optical effects in large-sized (up to 25 nm) nanocrystallites (NC) of Ge-doped Bi₁₂TiO₂₀ (BTO:Ge) incorporated within olygoether photopolymer matrix have been studied. Photoinduced second harmonic generation (PISHG) was measured. Nd:YAG pulsed laser (λ=1.06 μm) was used as a source of photoinducing light. As a fundamental light source for the SHG and two-photon absorption, Er:LiYF₄ laser (λ=2.065 μm) was used. We have found that with increasing IR pump power density, the output doubled frequency SHG signal (λ=1.03 μm) increases and achieves its maximum value at the pump power density about 0.45 GW/cm² and NC size about 12 nm.The values of second-order optical susceptibilities were almost 20% larger than for the pure BTO NC single crystals. With decreasing temperature below 60 K, the SHG signal increases achieving maximal value at LHeT.     

CdS/SiO2复合材料的低频Raman散射研究

对用溶胶凝胶法制备的ＣｄＳ／ＳｉＯ２复合材料进行低频Ｒａｍａｎ散射研究，结果表明可从其低频Ｒａｍａｎ散射峰位计算出ＣｄＳ微晶的粒径，两种不同的低频振动模式由激发光的两种偏振方向加以区分，低频Ｒａｍａｎ散射射的二级散射峰根据实验结果加以指认，所得平均粒径结果与透射电镜观察结果有较好的对应关系，复合材料吸收光谱吸收边蓝移与ＣｄＳ纳米子粒径之间存在着密切的关系，实验证明，样品吸收边能量与ＣｄＳ平均粒径的     

CdS nanocrystallites sensitized ZnO nanorods with plasmon enhanced photoelectrochemical performance

A sandwiched structure of CdS/Ag/ZnO nanorod photoanode exhibits greatly enhanced photoelectrochemical activity for solar hydrogen generation, due to synergistic effect of CdS nanocrystallites and plasmonic Ag nanoparticles for the enhanced optical absorption and the promoted charge carrier separation.     

Optically stimulated piezooptical effects in Cu-doped ZnO films

Photoinduced changes of the piezooptical effects were discovered in the ZnO crystalline films doped by Cu. The photoexcitation was performed by the Er³⁺ doped 10 ns glass laser at wavelength 1540 nm. The piezooptical effect was determined for the diagonal tensor component at 1150 nm. A nonlinear dependence of the output piezooptical response versus the photoinducing power density was established. The effect was completely reversible and disappears within the several second after the switching off of the photoinduced treatment. The possible explanation of the observed effect is given within a framework of the possible changes of Cu aggregates which is manifested through the changes of photoluminescence.     

Electronic structure of extended titanium carbide nanocrystallites

The electronic band structure and stability of extended nanocrystallites (NCs) of titanium monocarbide TiC were investigated by the electron density functional-tight binding (DFTB) technique. The stability of prismatic NCs increases with the number of atomic layers; the electronic spectrum of these compounds changes from semiconductor (for NC of minimal atomic size) to metallike type inherent in crystalline titanium carbide.     

Cooperative Processes in Nd3☎/Yb3☎ Co-Doped Yag Nanocrystallites

The cooperative processes in doubly doped Nd/Yb:YAG nanocrystallites were investigated. An extremely strong Yb^3? ion concentration influence on absorption intensities was noticed. An efficient Nd^3? → Yb^3? energy transfer in YAG nanocrystallites was found. However no back transfer was observed. The mechanisms of cooperative interactions between Nd^3? and Yb^3? ions in YAG nanocrystallites responsible for the observed concentration effects are discussed.     

花生酸单分子膜诱导PbS晶体取向生长的研究

以花生酸单分子膜为模板，诱导沉积了PbS半导体纳米粒子，粒径为30～50 nm.实验发现， 由于花生酸单分子膜的诱导作用， 使得PbS晶体在膜上发生取向生长，可以形成三角形、四边形和棒状的PbS纳米粒子.通过改变单分子膜的表面压，考察了表面压对PbS晶体取向生长的影响，结合透射电镜及电子衍射实验，对PbS晶体的生长机制进行了初步的分析和探讨.     

Synthesis and Characterization of Zirconia Nanocrystallites by Cationic Surfactant and Anionic Surfactant

1 INTRODUCTION Zirconia is a kind of metallic oxide with high mel- ting point. It is highly corrosion-resistant for acid fu- sant and neutral fusant, thus it can be used as refrac- tory material, and it can also be utilized as acid acy- loxy bi-functional catalystic material owing to hav- ing both acid and alkali surface centers[1]. Moreover, zirconia has superior ion-exchange capacity as well as chemical and mechanical stability, therefore, it can also be applied as a catalyst carrier. …     

Environmental Remediation Using Catalysis Driven Under Electromagnetic Irradiation

Photocatalytically reductive dehalogenation using nano-sized semiconductors such as ZnS and CdS nanocrystallites under respective UV ( > 300 nm) and visible light ( > 400 nm) irradiation is emphasized as a novel methodology for detoxification of halogenated organic compounds under mild conditions. Nano-sized ZnS and CdS can supply the compounds with photoexcited electrons of high reduction potentials. This photocatalytic dehalogenation is so selective that it gives no other products than the dehalogenated compounds. Microwave-assisted catalytic dehalogenation of halogenated organic compounds shows distinguished characteristics in rapid and complete detoxification, i.e., the selective heating and energy-saving when compared to conventional heating. Predominance of reductive dehalogenation performed in the above two systems is relieved in comparison with other reductive and oxidative techniques as detoxification methods.     

Nonlinear optical features of δ-BiB3O6/PVA polymer nanocomposites deposited on aluminum-doped zinc oxide substrates containing Ag nanoparticles

For the first time the Z-scan measurements and second harmonic generation of δ-BiB₃O₆:Pr³⁺ large-size nanocrystallites embedded into the polyvinyl alcohol (PVA) polymer matrices and deposited on AlZnO substrates decorated with Ag NP were studied. The comparison of the second and third order NLO is presented. The Z-scan measurements were done by 5 ns Nd:YAG laser and the second harmonic generation was measured using the 25 ns Nd:YAG laser with frequency repetition about 10 Hz. The measurements have shown that both second as well as third-order susceptibilities are sensitive to the sizes of the Ag NP deposited on the AlZnO substrate. The obtained results confirm a principal role of the Ag NP on the output nonlinear optical properties which may be a consequence of the contribution of the low-dimensional nano-trapping levels.