Bright Silicon Nanocrystals from a Liquid Precursor: Quasi-Direct Recombination with High Quantum Yield
Bright Silicon Nanocrystals from a Liquid Precursor: Quasi-Direct Recombination with High Quantum Yield
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DOI：
10.1021/acsnano.9b09614
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发表时间：
2020-04-28
期刊：
影响因子：
17.1
通讯作者：
Hobbie, Erik K.
中科院分区：
文献类型：
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作者：
Pringle, Todd A.;Hunter, Katharine, I;Hobbie, Erik K.
具有亮带隙光致发光（PL）的硅纳米晶体（SiNCs）对于从太阳能窗到生物医学造影剂的一系列潜在应用是当前感兴趣的。在这里，我们使用的液体前体环己硅烷（Si 6 H12）的胶体SiNC的等离子体合成与示例性的核心发射。通过在氧气屏蔽环境中执行的尺寸分离，我们实现了PL量子产率（QY）接近70%，同时暴露了来自较小SiNC的有效核心发射的内在约束。这些分数响应飞秒脉冲激发的时间分辨PL光谱揭示了与QY相关的零声子辐射通道，我们使用先进的计算方法应用于2 nm SiNC模型。我们的研究结果提供了额外的洞察到的nano-physical相互作用的表面，准直接复合，和有效的SiNC核心PL。
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.