Luan Chaoran, Gökçinar Ömür Ö, Rowell Nelson, Kreouzis Theo, Han Shuo, Zhang Meng, Fan Hongsong, Yu Kui
Engineering Research Center in Biomaterials , Sichuan University , Chengdu 610065 , P. R. China.
National Research Council Canada , Ottawa , Ontario K1A 0R6 , Canada.
J Phys Chem Lett. 2018 Sep 20;9(18):5288-5295. doi: 10.1021/acs.jpclett.8b02334. Epub 2018 Aug 31.
There are two types of colloidal semiconductor nanocrystals (NCs) that exhibit band gap absorption that is relatively sharp compared to conventional quantum dots (QDs). One type displays an absorption doublet, while the other displays an absorption singlet. Here, we report the evolution of the two types of NCs at room temperature from a single CdTe sample extracted during the induction period (IP) prior to nucleation and growth of conventional QDs. The resulting NCs exhibit band gap absorption peaking at ∼371 nm and are magic-size clusters (MSCs), labeled as dMSC-371 and sMSC-371 for the doublet and singlet cases, respectively. We demonstrate that dMSC-371 (with another peak at ∼350 nm) evolves when the sample is incubated. When the sample is dispersed without incubation into a toluene and octylamine mixture, dMSC-371 or sMSC-371 grows depending on the amine amount. We propose that dMSC-371 and sMSC-371 are a pair of polymorphs (with identical CdTe core compositions). The present study brings insight into the formation relationship between dMSCs and sMSCs.
有两种胶体半导体纳米晶体（NCs），它们表现出与传统量子点（QDs）相比相对尖锐的带隙吸收。一种类型显示出吸收双峰，而另一种显示出吸收单峰。在这里，我们报告了在传统量子点成核和生长之前的诱导期（IP）期间从单个CdTe样品中提取的两种类型的纳米晶体在室温下的演变。所得的纳米晶体表现出在约371nm处达到峰值的带隙吸收，并且是魔尺寸团簇（MSCs），分别标记为dMSC - 371和sMSC - 371用于双峰和单峰情况。我们证明，当样品孵育时，dMSC - 371（在约350nm处有另一个峰）会发生演变。当样品未孵育就分散到甲苯和辛胺混合物中时，dMSC - 371或sMSC - 371会根据胺的量而生长。我们提出dMSC - 371和sMSC - 371是一对多晶型物（具有相同的CdTe核组成）。本研究深入了解了dMSC和sMSC之间的形成关系。
