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Bright Silicon Nanocrystals from a Liquid Precursor: Quasi-Direct Recombination with High Quantum Yield.
ACS Nano ( IF 15.8 ) Pub Date : 2020-03-09 , DOI: 10.1021/acsnano.9b09614
Todd A Pringle 1 , Katharine I Hunter 2 , Alexandra Brumberg 3 , Kenneth J Anderson 4 , Jeffrey A Fagan 5 , Salim A Thomas 1 , Reed J Petersen 6 , Mahmud Sefannaser 6 , Yulun Han 4 , Samuel L Brown 1 , Dmitri S Kilin 4 , Richard D Schaller 3, 7 , Uwe R Kortshagen 2 , Philip Raymond Boudjouk 4 , Erik K Hobbie 1, 6, 8
Affiliation  

Silicon nanocrystals (SiNCs) with bright bandgap photoluminescence (PL) are of current interest for a range of potential applications, from solar windows to biomedical contrast agents. Here, we use the liquid precursor cyclohexasilane (Si6H12) for the plasma synthesis of colloidal SiNCs with exemplary core emission. Through size separation executed in an oxygen-shielded environment, we achieve PL quantum yields (QYs) approaching 70% while exposing intrinsic constraints on efficient core emission from smaller SiNCs. Time-resolved PL spectra of these fractions in response to femtosecond pulsed excitation reveal a zero-phonon radiative channel that anticorrelates with QY, which we model using advanced computational methods applied to a 2 nm SiNC. Our results offer additional insight into the photophysical interplay of the nanocrystal surface, quasi-direct recombination, and efficient SiNC core PL.

中文翻译:

来自液体前体的明亮硅纳米晶:具有高量子产率的准直接重组。

具有亮带隙光致发光(PL)的硅纳米晶体(SiNC)对于从太阳能窗口到生物医学造影剂的一系列潜在应用目前引起人们的关注。在这里,我们使用液态前体环六硅烷(Si6H12)进行胶体SiNC的等离子体合成,并具有示例性的核发射。通过在氧气屏蔽环境中进行尺寸分离,我们实现了接近70%的PL量子产率(QYs),同时暴露了来自较小SiNC的有效核发射的固有限制。这些级分的时间分辨PL光谱响应飞秒脉冲激发显示了与QY反相关的零声子辐射通道,我们使用应用于2 nm SiNC的先进计算方法对其进行建模。我们的结果提供了对纳米晶体表面光物理相互作用的更多了解,
更新日期:2020-03-09
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