硅油两步脱水法可控制备纳米二氧化钛透镜

利用纳米粒子由下而上的组装来制备具有亚波长特征结构的新材料已成为操控并利用光的重要手段。本研究报道了一种新的纳米组装技术——即硅油两步脱水法, 该方法利用油水界面的流变性和限制效应, 实现了可批量、高重复性地将15 nm的二氧化钛(TiO₂)纳米粒子组装成具有高折射率、高透明度的光学材料, 并对其组装过程及机理进行了详细的分析。此外, 该方法还可实现TiO₂纳米粒子与其他纳米材料, 如金(Au)纳米粒子、Au纳米棒、Au纳米立方块或氧化石墨烯之间均匀的复合, 制备出TiO₂/Au或TiO₂/氧化石墨烯复合材料。其中, TiO₂纳米粒子的复合可使Au纳米粒子、Au纳米棒或Au纳米立方块的表面等离子体吸收峰产生显著的红移, 表明该组装法为未来制备功能性复合光电器件提供了有效的途径。

Controllable Preparation of Nano-TiO2 Lens by Silicon Oil Two-step Dehydration Method

Bottom-up assembly of nanoparticles into new materials with sub-wavelength features has become an important means to manipulate and utilize light. Here, we report a novel nano-assembly technology, named silicon oil two-step dehydration method. This method utilizes the rheological and confinement effects of the oil-water interface and enables the assembly of 15 nm titanium dioxide (TiO₂) nanoparticles into macroscopic hemispherical optical lenses with high refractive index and high transparency. The TiO₂ lens can be large-scale produced with this method. Moreover, the assembly process and mechanism are analyzed in details. In addition, this method can also achieve uniform composites of TiO₂ nanoparticles with other nanomaterials, such as gold (Au) nanoparticles, Au nanorods, Au nanocubes or graphene oxide, enabling the preparation of TiO₂/Au or TiO₂/graphene oxide composite devices. Among them, after the recombination of TiO₂ nanoparticles, the surface plasmon absorption peak of Au nanoparticles, Au nanorods or Au nanocubes have a significant red shift, indicating that this assembly method provides an effective way for the preparation of functional composite optoelectronic devices in the future.