Size-Dependent Absolute Quantum Yields for Size-Separated Colloidally-Stable Silicon Nanocrystals
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- 作者：Melanie L. Mastronardi ; Florian Maier-Flaig ; Daniel Faulkner ; Eric J. Henderson ; Christian K眉bel ; Uli Lemmer ; Geoffrey A. Ozin
- 刊名：Nano Letters
- 出版年：2012
- 出版时间：January 11, 2012
- 年：2012
- 卷：12
- 期：1
- 页码：337-342
- 全文大小：347K
- 年卷期：v.12,no.1(January 11, 2012)
- ISSN：1530-6992
文摘
Size-selective precipitation was used to successfully separate colloidally stable allylbenzene-capped silicon nanocrystals into several visible emitting monodisperse fractions traversing the quantum size effect range of 1鈥? nm. This enabled the measurement of the absolute quantum yield and lifetime of photoluminescence of allylbenzene-capped silicon nanocrystals as a function of size. The absolute quantum yield and lifetime are found to monotonically decrease with decreasing nanocrystal size, which implies that nonradiative vibrational and surface defect effects overwhelm spatial confinement effects that favor radiative relaxation. Visible emission absolute quantum yields as high as 43% speak well for the development of 鈥済reen鈥?silicon nanocrystal color-tunable light emitting diodes that can potentially match the performance of their toxic heavy metal chalcogenide counterparts.