Center for Advanced Solar Photophysics, C-PCS, Chemistry Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States.
Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108, United States.
J Am Chem Soc. 2017 Feb 15;139(6):2152-2155. doi: 10.1021/jacs.6b11945. Epub 2017 Jan 31.
We demonstrate controlled synthesis of discrete two-dimensional (2D) PbSe nanoplatelets (NPLs), with measurable photoluminescence, via oriented attachment directed by quantum dot (QD) surface chemistry. Halide passivation is critical to the growth of these (100) face-dominated NPLs, as corroborated by density functional theory studies. PbCl moieties attached to the (111) and (110) of small nanocrystals form interparticle bridges, aligning the QDs and leading to attachment. We find that a 2D bridging network is energetically favored over a 3D network, driving the formation of NPLs. Although PbI does not support bridging, its presence destabilizes the large (100) faces of NPLs, providing means for tuning NPL thickness. Spectroscopic analysis confirms the predicted role of thickness-dependent quantum confinement on the NPL band gap.
我们通过量子点（QD）表面化学导向的定向附着，展示了离散二维（2D）PbSe 纳米片（NPL）的可控合成，具有可测量的光致发光。卤化物钝化对于这些（100）面为主的 NPL 的生长至关重要，这一点得到了密度泛函理论研究的证实。附着在小纳米晶体的（111）和（110）上的 PbCl 部分形成了颗粒间桥，将 QD 对齐并导致附着。我们发现二维桥接网络在能量上优于三维网络，从而驱动 NPL 的形成。尽管 PbI 不支持桥接，但它的存在会使 NPL 的大（100）面不稳定，为调节 NPL 厚度提供了手段。光谱分析证实了厚度相关量子限制对 NPL 带隙的预测作用。
