Pringle Todd A, Hunter Katharine I, Brumberg Alexandra, Anderson Kenneth J, Fagan Jeffrey A, Thomas Salim A, Petersen Reed J, Sefannaser Mahmud, Han Yulun, Brown Samuel L, Kilin Dmitri S, Schaller Richard D, Kortshagen Uwe R, Boudjouk Philip Raymond, Hobbie Erik K
Materials and Nanotechnology Program, North Dakota State University, Fargo, North Dakota 58108, United States.
Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States.
ACS Nano. 2020 Apr 28;14(4):3858-3867. doi: 10.1021/acsnano.9b09614. Epub 2020 Mar 18.
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 (SiH) 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.
具有明亮带隙光致发光（PL）的硅纳米晶体（SiNCs）目前在一系列潜在应用中受到关注，从太阳能窗户到生物医学造影剂。在这里，我们使用液体前驱体环己硅烷（SiH）通过等离子体合成具有典型核心发射的胶体SiNCs。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），同时揭示了较小SiNCs有效核心发射的内在限制。这些部分在飞秒脉冲激发下的时间分辨PL光谱揭示了一个与QY反相关的零声子辐射通道，我们使用应用于2纳米SiNC的先进计算方法对其进行建模。我们的结果为纳米晶体表面、准直接复合和高效SiNC核心PL的光物理相互作用提供了更多见解。
