Size-Dependent Absolute Quantum Yields for Size-Separated Colloidally-Stable Silicon Nanocrystals

作者：Mastronardi Melanie L; Maier Flaig Florian; Faulkner Daniel; Henderson Eric J; Kuebel Christian; Lemmer Uli; Ozin Geoffrey A^*

来源：Nano Letters, 2012, 12(1): 337-342.

DOI：10.1021/nl2036194

• Silicon nanocrystals
• size-selective precipitation
• size-dependent absolute quantum yield
• photoluminescence
• lifetime

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 S 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 %26quot;green%26quot; silicon nanocrystal color-tunable light emitting diodes that can potentially match the performance of their toxic heavy metal chalcogenide counterparts.

• 出版日期2012-1