研究目的
To monitor the dissolution of electrochemically prepared mesoporous and microporous silicon particles in aqueous media using X-ray diffraction analysis, and to study the evolution of nanocrystal size distribution and the effect of biopolymer coating on stability.
研究成果
The dissolution of porous silicon nanoparticles in aqueous media leads to changes in nanocrystal size distribution, with micro-PSi showing an increase in average size due to polydispersity and the 'shrinking spheres' model, while meso-PSi shows a decrease. Biopolymer coating (dextran) can prevent degradation, indicating potential for biomedical applications such as drug delivery.
研究不足
The study is limited to specific types of porous silicon (micro-PSi and meso-PSi) and aqueous media; TEM could not accurately determine size distributions due to nanocrystal aggregation. The models used (e.g., Scherrer equation) have assumptions that may not hold for all distributions.
1：Experimental Design and Method Selection:
The study used X-ray diffraction (XRD) to analyze the dissolution of porous silicon nanoparticles (PSi NPs) in water and aqueous dextran solutions. A model of 'shrinking spheres' was employed to describe size distribution evolution.
2：Sample Selection and Data Sources:
Samples included microporous silicon (micro-PSi) and mesoporous silicon (meso-PSi) prepared by electrochemical etching of boron-doped silicon wafers. Suspensions were made in water or 10% dextran solution.
3：List of Experimental Equipment and Materials:
Equipment included a planetary mill (PULVERISETTE 7), X-ray diffractometer (RADIAN—DR2), and TEM for imaging. Materials included hydrofluoric acid, ethanol, dextran (30–40 kDa), silicon wafers, and ZrO2 balls.
4：Experimental Procedures and Operational Workflow:
PSi films were prepared by electrochemical etching, lifted from substrates, air-dried, ground into powders, suspended in water or dextran solution, and dried at various times. XRD measurements were performed with specific scan parameters.
5：Data Analysis Methods:
XRD peak profiles were analyzed using the Scherrer equation, pseudo-Voight function, and lognormal distribution models. Williamson-Hall plots were used to assess size-derived broadening.
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