Highly luminescent silicon nanocrystals with discrete optical transitions
Highly luminescent silicon nanocrystals with discrete optical transitions
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DOI：
10.1021/ja002956f
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发表时间：
2001-04-25
影响因子：
15
通讯作者：
Korgel, BA
中科院分区：
文献类型：
--
作者：
Holmes, JD;Ziegler, KJ;Korgel, BA
开发了一种新的合成方法，可在超临界流体中生产坚固的、高度结晶的有机单层钝化硅 (Si) 纳米晶体。通过在 500 ℃ 和 345 bar 的辛醇存在下热降解 Si 前体二苯基硅烷，可以获得大量直径为 15 至 40 埃的相对尺寸单分散的空间稳定的 Si 纳米晶体。辛醇通过醇盐键结合到硅纳米晶体表面，并通过烃链提供空间稳定性。由于量子限制效应，纳米晶体的吸光度和光致发光激发 (PLE) 光谱表现出光学特性从 1.2 eV 的体带隙能量发生显着蓝移。尽管颗粒尺寸极小，但稳定的硅团簇表现出高效的蓝色（15埃）或绿色（25 -40埃）带边光电发射，在室温下发光量子产率高达23％，并且电子结构特征主要是间接跃迁。最小的纳米晶体直径为 15 A，表现出离散的光学跃迁，这是具有窄尺寸分布的晶体纳米晶体的量子限制效应的特征。
A new synthetic method was developed to produce robust, highly crystalline, organic-monolayer passivated silicon (Si) nanocrystals in a supercritical fluid. By thermally degrading the Si precursor, diphenylsilane, in the presence of octanol at 500 degreesC and 345 bar, relatively size-monodisperse sterically stabilized Si nanocrystals ranging from 15 to 40 Angstrom in diameter could be obtained in significant quantities. Octanol binds to the Si nanocrystal surface through an alkoxide Linkage and provides steric stabilization through the hydrocarbon chain. The absorbance and photoluminescence excitation (PLE) spectra of the nanocrystals exhibit a significant blue shift in optical properties from the bulk band gap energy of 1.2 eV due to quantum confinement effects. The stable Si clusters show efficient blue (15 Angstrom) or green (25 -40 Angstrom) band-edge photoemission with luminescence quantum yields up to 23% at room temperature, and electronic structure characteristic of a predominantly indirect transition, despite the extremely small particle size. The smallest nanocrystals, 15 A in diameter, exhibit discrete optical transitions, characteristic of quantum confinement effects for crystalline nanocrystals with a narrow size distribution.