Wang Tinghui, Wang Zhe, Wang Shanling, Chen Xiaoqin, Luan Chaoran, Yu Kui
Engineering Research Center in Biomaterials, Sichuan University, 610065, Chengdu, Sichuan, P. R. China.
Analytical and Testing Center, Sichuan University, 610065, Chengdu, Sichuan, P. R. China.
Angew Chem Int Ed Engl. 2023 Oct 23;62(43):e202310234. doi: 10.1002/anie.202310234. Epub 2023 Sep 14.
The evolution of prenucleation clusters in the prenucleation stage of colloidal semiconductor quantum dots (QDs) has remained unexplored. With CdTe as a model system, we show that substances form and isomerize prior to the nucleation and growth of QDs. Called precursor compounds (PCs), the prenucleation clusters are relatively optically transparent and can transform to absorbing magic-size clusters (MSCs). When a prenucleation-stage sample at 25, 45, or 80 °C is dispersed in a mixture of cyclohexane (CH) and octylamine (OTA) at room temperature, either MSC-371, MSC-417, or MSC-448 evolves with absorption peaking at 371, 417, or 448 nm, respectively. We propose that PC-371 forms at 25 °C, and isomerizes to PC-417 at 45 °C and to PC-448 at 80 °C. The PCs and MSCs are quasi isomers. Relatively large and small amounts of OTA favor PC-371 and PC-448 in dispersion, respectively. The present findings suggest the existence of PC-to-PC isomerization in the QD prenucleation stage.
胶体半导体量子点（QD）成核前阶段预成核簇的演化一直未被探索。以碲化镉作为模型系统，我们表明物质在量子点的成核和生长之前就已形成并异构化。这些预成核簇被称为前体化合物（PC），它们相对光学透明，并且可以转变为具有吸收性的魔法尺寸簇（MSC）。当在25、45或80°C下处于成核前阶段的样品在室温下分散于环己烷（CH）和辛胺（OTA）的混合物中时，分别会形成吸收峰位于371、417或448 nm的MSC - 371、MSC - 417或MSC - 448。我们提出PC - 371在25°C时形成，在45°C时异构化为PC - 417，在80°C时异构化为PC - 448。PC和MSC是准异构体。相对大量和少量的OTA分别有利于分散体中的PC - 371和PC - 448。目前的研究结果表明在量子点成核前阶段存在PC到PC的异构化。
