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Thermally-Induced Isomerization of Prenucleation Clusters During the Prenucleation Stage of CdTe Quantum Dots |
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| Authors: | Tinghui Wang Zhe Wang Dr. Shanling Wang Xiaoqin Chen Dr. Chaoran Luan Prof. Kui Yu |
| Affiliation: | 1. Engineering Research Center in Biomaterials, Sichuan University, 610065 Chengdu, Sichuan, P. R. China These authors contributed equally to this work.;2. Analytical and Testing Center, Sichuan University, 610065 Chengdu, Sichuan, P. R. China;3. Engineering Research Center in Biomaterials, Sichuan University, 610065 Chengdu, Sichuan, P. R. China;4. Laboratory of Ethnopharmacology, Tissue-orientated Property of Chinese Medicine Key Laboratory of Sichuan Province, West China School of Medicine, West China Hospital, Sichuan University, 610065 Chengdu, Sichuan, P. R. China |
| Abstract: | 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. |
| Keywords: | Cadmium Telluride Magic-Size Cluster Precursor Compound Prenucleation Cluster Quantum Dot |