材料科学
结晶度
无定形固体
电致变色
介孔材料
化学工程
小角X射线散射
薄膜
退火(玻璃)
纳米技术
结晶学
复合材料
有机化学
电极
散射
光学
催化作用
物理化学
工程类
化学
物理
作者
Torsten Brezesinski,Dina Fattakhova‐Rohlfing,Sébastien Sallard,Markus Antonietti,Bernd Smarsly
出处
期刊:Small
[Wiley]
日期:2006-08-29
卷期号:2 (10): 1203-1211
被引量:184
标识
DOI:10.1002/smll.200600176
摘要
Abstract WO 3 thin layers with nanometer‐scale periodicity were prepared by evaporation‐induced self‐assembly (EISA) using a novel amphiphilic block‐copolymer template (poly(ethylene‐co‐butylene)‐block‐poly(ethylene oxide)). The evolution of the mesoporous ordered network and the crystallinity of the framework were monitored by 2D‐SAXS, WAXS, SEM, XPS, and porosimetry. By annealing the films, the pore‐wall crystallinity is adjusted between fully amorphous and highly crystalline without mesostructural degradation. Thus, the crystalline‐film framework is composed of phase‐pure monoclinic WO 3 nanoparticles (12–14 nm in size). Furthermore, heat treatment transforms the originally spherical mesopores into ellipsoids, resulting in a unidirectionally shrunken, but still well‐defined and fully accessible bcc mesopore architecture. The influence of mesoporosity and crystallinity on electrochemical/electrochromic characteristics was addressed by monitoring electrochemical features and the absorption changes during Li insertion/extraction (repetitive potentiostatic cycling). Both the amorphous and crystalline mesoporous films possess electrochromic response times on the order of only seconds, which are attributable to the facilitated insertion of guest ions due to shortening of the diffusion path lengths. Also, the insertion/extraction reversibility of crystalline WO 3 layers with 3D mesoporosity is improved compared to amorphous ones and reaches values close to 100 %.
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