Quantum size effect in TiO2 nanoparticles prepared by finely controlled metal assembly on dendrimer templates
Quantum size effect in TiO2 nanoparticles prepared by finely controlled metal assembly on dendrimer templates
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DOI：
10.1038/nnano.2008.2
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发表时间：
2008-02-01
影响因子：
38.3
通讯作者：
Yamamoto, Kimihisa
中科院分区：
文献类型：
--
作者：
Satoh, Norifusa;Nakashima, Toshio;Yamamoto, Kimihisa
使用树枝状聚合物模板来制备尺寸可控的金属基纳米颗粒引起了人们极大的兴趣。这些高度支化的大分子具有明确的结构，使它们能够结合金属离子以产生可转化为纳米颗粒的前体。我们描述了亚纳米尺寸控制的两个金红石型和金红石型的二氧化钛颗粒与苯基甲亚胺树枝状聚合物，导致样品具有非常窄的尺寸分布。这种微调是可能的，因为金属离子的数量和位置都可以在这些模板中精确控制。在颗粒中观察到量子尺寸效应，并且导带和价带之间的能隙随着颗粒尺寸的减小而呈现蓝移，并且取决于材料的晶体形式。利用半经验有效质量近似解释了带隙能量对这些因素的依赖关系。
The use of dendrimer templates to make metal-based nanoparticles of controlled size has attracted much interest. These highly branched macromolecules have well-defined structures that enable them to bind metal ions to generate precursors that can be converted into nanoparticles. We describe the sub-nanometre size control of both anatase and rutile forms of TiO2 particles with phenylazomethine dendrimers, leading to samples with very narrow size distributions. Such fine tuning is possible because both the number and location of metal ions can be precisely controlled in these templates. Quantum size effects are observed in the particles, and the energy gap between the conduction and valence bands exhibits a blueshift with decreasing particle size and is dependent on the crystal form of the material. The dependency of the bandgap energy on these factors is explained using a semi-empirical effective mass approximation.