Colloidal Synthesis Path to 2D Crystalline Quantum Dot Superlattices
Colloidal Synthesis Path to 2D Crystalline Quantum Dot Superlattices
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DOI：
10.1021/acsnano.0c07202
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发表时间：
2021-02-23
期刊：
影响因子：
17.1
通讯作者：
Alivisatos, A. Paul
中科院分区：
文献类型：
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作者：
Ondry, Justin C.;Philbin, John P.;Alivisatos, A. Paul
通过结合胶体晶体合成、自组装和溶液相外延生长技术，我们开发了一种制备单点厚原子附着量子点（QD）超晶格的通用方法，该超晶格具有高质量的平移和晶体取向顺序沿着，并且附着厚度具有最先进的均匀性。该过程开始于六棱柱形核/壳QD（例如，CdSe/CdS），随后是液体亚相自组装和超晶格在衬底上的固定化。另外的半导体材料的溶液相外延生长填充颗粒之间的空隙，导致QD-在-矩阵结构中。的量子点矩阵结构的光致发光发射光谱保留特性的0 D电子约束。重要的是，所得结构的退火消除了QD-QD无机桥中的不均匀性，我们的原子电子结构计算表明，否则会导致安德森型局域化。该过程的分段性质允许人们独立地调整QD核、壳、QD-QD距离和基质材料的尺寸和材料。这四个选择可以被调整以控制许多属性（量子限制的程度、量子耦合、能带对准等）。这取决于具体的应用。最后，可以在最终的基质中QD上进行阳离子交换反应，如本文所示，通过CdSe/CdS到HgSe/HgS的转化。
By combining colloidal nanocrystal synthesis, self-assembly, and solution phase epitaxial growth techniques, we developed a general method for preparing single dot thick atomically attached quantum dot (QD) superlattices with high-quality translational and crystallographic orientational order along with state-of-the-art uniformity in the attachment thickness. The procedure begins with colloidal synthesis of hexagonal prism shaped core/shell QDs (e.g., CdSe/CdS), followed by liquid subphase self-assembly and immobilization of superlattices on a substrate. Solution phase epitaxial growth of additional semiconductor material fills in the voids between the particles, resulting in a QD-in-matrix structure. The photoluminescence emission spectra of the QD-in-matrix structure retains characteristic 0D electronic confinement. Importantly, annealing of the resulting structures removes inhomogeneities in the QD-QD inorganic bridges, which our atomistic electronic structure calculations demonstrate would otherwise lead to Anderson-type localization. The piecewise nature of this procedure allows one to independently tune the size and material of the QD core, shell, QD-QD distance, and the matrix material. These four choices can be tuned to control many properties (degree of quantum confinement, quantum coupling, band alignments, etc.) depending on the specific applications. Finally, cation exchange reactions can be performed on the final QD-in-matrix, as demonstrated herein with a CdSe/CdS to HgSe/HgS conversion.