†ITMO University, St. Petersburg, 197101, Russia.
‡School of Chemistry and CRANN, University of Dublin, Trinity College, Dublin 2, Ireland.
Nano Lett. 2015 May 13;15(5):2844-51. doi: 10.1021/nl504439w. Epub 2015 Apr 27.
A new class of chiral nanoparticles is of great interest not only for nanotechnology, but also for many other fields of scientific endeavor. Normally the chirality in semiconductor nanocrystals is induced by the initial presence of chiral ligands/stabilizer molecules. Here we report intrinsic chirality of ZnS coated CdSe quantum dots (QDs) and quantum rods (QRs) stabilized by achiral ligands. As-prepared ensembles of these nanocrystals have been found to be a racemic mixture of d- and l-nanocrystals which also includes a portion of nonchiral nanocrystals and so in total the solution does not show a circular dichroism (CD) signal. We have developed a new enantioselective phase transfer technique to separate chiral nanocrystals using an appropriate chiral ligand and obtain optically active ensembles of CdSe/ZnS QDs and QRs. After enantioselective phase transfer, the nanocrystals isolated in organic phase, still capped with achiral ligands, now display circular dichroism (CD). We propose that the intrinsic chirality of CdSe/ZnS nanocrystals is caused by the presence of naturally occurring chiral defects.
一类新的手性纳米粒子不仅引起了纳米技术领域的关注，也引起了许多其他科学研究领域的关注。通常情况下，半导体纳米晶体的手性是由初始存在的手性配体/稳定剂分子诱导的。在这里，我们报告了由非手性配体稳定的 ZnS 涂层 CdSe 量子点 (QD) 和量子棒 (QR) 的固有手性。已经发现这些纳米晶体的预组装体是 d-和 l-纳米晶体的外消旋混合物，其中还包括一部分非手性纳米晶体，因此溶液中没有圆二色性 (CD) 信号。我们开发了一种新的对映选择性相转移技术，使用合适的手性配体分离手性纳米晶体，并获得 CdSe/ZnS QD 和 QR 的光学活性组装体。对映选择性相转移后，仍然用非手性配体封端的纳米晶体在有机相中分离出来，现在显示出圆二色性 (CD)。我们提出 CdSe/ZnS 纳米晶体的固有手性是由天然存在的手性缺陷引起的。
