熵配体实现的理想CdSe / CdS核/壳纳米晶体及其核尺寸，壳厚度和配体依赖性光致发光性质,Journal of the American Chemical Society

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熵配体实现的理想CdSe / CdS核/壳纳米晶体及其核尺寸，壳厚度和配体依赖性光致发光性质
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2017-11-13 00:00:00 , DOI: 10.1021/jacs.7b07434
Jianhai Zhou ₁ , Meiyi Zhu ₁ , Renyang Meng ₁ , Haiyan Qin ₁ , Xiaogang Peng ₁

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这项工作探索了获得具有理想光致发光（PL）特性的胶体量子点（QD）的可能性，即，单指数PL衰减动力学，统一PL量子产率，整体PL光谱与单点水平相同，单点PL不闪烁和抗漂白。以CdSe / CdS核/壳量子点为模型系统，系统地研究了壳-外延，配体交换和核/壳量子点的形状转化，从而建立了可重复合成具有目标性质的量子点的策略。外延期间的关键合成参数是熵配体的应用，即具有不同烃链长度和/或结构的混合羧酸酯配体。人们发现，具有一定厚度的受控外延壳（CdS壳的约3–8个单层）对于达到理想的光致发光特性是必不可少的，并且核心QD的大小在确定光物理和光化学性质方面都起着至关重要的作用。核心/外壳QD的属性。核心量子点的形状的影响是不明显的，并且核心/壳量子点的形状仅在数量上影响光物理性质。表面配体（胺与羧酸盐）对于光化学性质（抗闪烁和抗漂白）很重要，但只要在外延过程中使用熵配体（具有可区分的烃链长度的混合羧酸盐配体），对光物理性质的影响就很小。化学环境（在聚合物或空气中），加上表面配体，

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Ideal CdSe/CdS Core/Shell Nanocrystals Enabled by Entropic Ligands and Their Core Size-, Shell Thickness-, and Ligand-Dependent Photoluminescence Properties

This work explored possibilities to obtain colloidal quantum dots (QDs) with ideal photoluminescence (PL) properties, i.e., monoexponential PL decay dynamics, unity PL quantum yield, ensemble PL spectrum identical to that at the single-dot level, single-dot PL nonblinking, and antibleaching. Using CdSe/CdS core/shell QDs as the model system, shell-epitaxy, ligand exchange, and shape conversion of the core/shell QDs were studied systematically to establish a strategy for reproducibly synthesizing QDs with the targeted properties. The key synthetic parameter during epitaxy was application of entropic ligands, i.e., mixed carboxylate ligands with different hydrocarbon chain length and/or structure. Well-controlled epitaxial shells with certain thickness (∼3–8 monolayers of the CdS shells) were found to be necessary to reach ideal photoluminescence properties, and the size of the core QDs was found to play a critical role in determining both photophysical and photochemical properties of the core/shell QDs. Effects of shape of the core QDs were unnoticeable, and shape of the core/shell QDs only affected photophysical properties quantitatively. Surface ligands, amines versus carboxylates, were important for photochemical properties (antiblinking and antibleaching) but barely affected photophysical properties as long as entropic ligands (mixed carboxylate ligands with distinguishable hydrocarbon chain lengths) were applied during epitaxy. Chemical environment (in polymer or in air), coupled with surface ligands, determined photochemical properties of the core/shell QDs with a given core size and shell thickness.

更新日期：2017-11-16

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