Yanbo Ding

Two-dimensional SixGe1−x films with variable composition made via multilayer colloidal template-guided ionic liquid electrodeposition

The binary alloy system Si(x)Ge(1-x) provides a continuous series of materials with gradually varying properties. In this paper, we report on a fundamental basis a method to make large-area macroporous Si(x)Ge(1-x) films with variable Ge content by electrodeposition in an ionic liquid, with SiCl(4) and GeCl(4) as precursors. The chemical composition of the products can be modified by changing the molar ratio of the precursors. Periodical macroporous Si(x)Ge(1-x) was made by a multilayer polystyrene (PS) template assembled as face-centered cubic lattice. Two-dimensional (2-D) Si(x)Ge(1-x) bowl-like and fishing-net structures can be obtained by applying different deposition temperatures. The results highlight the potential applications, including photonic bandgap and battery materials, as well as ultra-thin gratings, due to the effect of modification of light and improved tunability of composition, although Si(x)Ge(1-x) made by our method is sensitive to oxidation by air.

Controllable synthesis of Cu2O petalody octahedral microcrystals and multi-patterned evolution.

The fabrication of cuprous oxide (Cu(2)O) with various morphologies has attracted extensive interest due to its applications in solar energy conversion, electrode materials, sensors, and catalysts. Herein, we report a facile controllable route for Cu(2)O microcrystals with various architectures via a hydrothermal method without using templates or surfactants. Six types of Cu(2)O microcrystals including petalody octahedral, concave truncated octahedron, truncated octahedron, octahedron, sphere-like, and sphere are obtained accompanying with Cu precipitation or urchin-like CuO particles due to the modifying of pH values. The petalody octahedral pattern of Cu(2)O is for the first time found here under the condition of pH 7-8. Additionally, possible growth mechanism for multi-patterned Cu(2)O and compositional evolution is discussed via preferential growths induced by selective absorption of acrylic acid and decomposition of lactic acid in the present reaction system. These experimental results prove a versatile and facile strategy for Cu(2)O microcrystals with special and complex architectures, which may highlights their potential applications due to the improved surface activity, catalytic, or photoelectric performance.

Two modes in macroporous Cu2O growth through template-assisted electrodeposition method

Macroporous materials with three dimensional pores and channels are anticipated to exhibit improved performance in numerous applications such as photonic band gap crystals, battery electrodes and gas sensors due to their special structure. In this work, macroporous Cu2O thin films were prepared by template-assisted electrodeposition method. The mechanism of electrodeposition infiltrating procedures indicated that the target architectures can basically maintain its original shape, and the fabrication of spherical-porous shaped Cu2O controlled by crystalline structures is firstly studied systematically. The morphology of macroporous material along the (1 1 1) direction demonstrated that the target architecture can copy both the crystalline structures and the colloidal crystal template. Moreover, models are set up to discuss the evolution of the morphology (the shapes of the pore mouths and pore walls), which indicated that the pore mouths and pore walls were deeply influenced by the deposition depth.

Synthesis of Silica Particles with Precisely Tailored Diameter

A modified seeded growth process of silica particles with a continuous addition of tetraethyl orthosilicate (TEOS) was presented to control the diameter of silica particles. The diameter of particles was monitored by dynamic light scattering to control the addition of TEOS. The increase in the diameter of the silica particles with time and the addition of TEOS was investigated. The diameter of silica seeds increased from 193 nm to 446 nm in 4 h. The final diameter of silica particles was tailored within the range of ±5 nm to the target diameter. Silica particles with diameter of 446 nm were synthesized and assembled into photonic crystals with a pseudo band gap centered at just 1000 nm. The feasibility and practicability of this modified seeded growth process was verified.

Studies on late formation of 3D ordered macroporous materials through colloidal crystal templates

Three-dimensional ordered macroporous (3DOM) materials are anticipated to exhibit improved performance in lots of applications due to their special structure. This paper presents the formation mechanism of 3DOM structure during the removal process of templates, which has not been systematically studied yet. Using polymer colloidal crystal template, 3DOM metallic materials were prepared by electrochemical deposition and dissolution. The results indicate that windows in inverse opals are formed because of the associated breaking of thin wall materials. There seems to be a critical thickness for the same wall materials. The existence of windows improved the formation of 3DOM structures during the removal process of templates.

3D Ordered Macroporous Ge/Al and Ge/Si Bilayer Films Made by Electrodeposition from Ionic Liquids

Abstract Three dimensionally ordered macroporous (3DOM) Ge/Al and Ge/Si bilayer films have been made via ordered polystyrene (PS) templates by electrodeposition from ionic liquids (IL), at room temperature. For this purpose, the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([EMIm]Tf2N) and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide ([Py1,4]Tf2N) with aluminium, germanium and silicon chlorides dissolved in were used as electrolytes. Self-assembled PS colloidal crystals were made by the vertical deposition method and used as templates. Germanium was chosen as the first layer, then after washing and drying Al and Si layers were deposited subsequently. SEM results verify that the 3DOM Ge/Al and Ge/Si have a different morphology, and EDX was used to analyze the composition of the samples. Novel 3DOM bilayer films made from reactive elements could have some potential as anode host material in future generation lithium ion batteries and can be regarded as the first step to make 3D ordered macroporous bilayer films.