MUKHINA Maria St.Petersburg National Research University of Information Technologies, Mechanics and Optics

Circular Dichroism in Chiral Quantum Nanoplatelets

Co-authors MASLOV Vladimir, BARANOV Alexander, FEDOROV Anatoly, GUN’KO Yurii

Chiral nanocrystals are an emerging class of nanostructures that has attracted considerable attention, because chirality of the semiconductor nanocrystals can have a tremendous effect on the nanotechnology field. The key advantage of using artificial nanocrystals is an ability to manipulate the units of matter at the scale close to molecular one. If nanocrystal, whose sizes are comparable to the sizes of biomolecules and the pores of cell membranes, also possesses chirality, its «lock and key» interaction with biological objects may be possible. Inherent and induced chirality of CdSe quantum nanoplatelets have been investigated using a technique of circular dichroism (CD). It was shown that the nanoplatelets synthesized without using of any chiral reagents possess circular dichroism in their intrinsic condition. All of the nanoplatelets samples display circular dichroism with the same sign (L). The CD values can be enhanced up to 20 times by attachment of the chiral molecules of solubilizer. The attachment of the chiral solubilizer was obtained via a procedure of the phase transfer from chloroform to water assisted by the chiral molecules of cysteine. The degree of CD increasing depends on thickness of the nanoplatelets. Enhancement of the CD signal is less for thicker nanoplatelets. The nanoplatelets tend to roll up into tubes. We assume that the CD enhancement originate from tighter rolling-up of the nanoplatelets after the phase transfer from chloroform to water. It agrees with weaker CD enhancement observed in the case of thicker nanoplatelets. Because, the probability of rolling-up into a tube is less for thicker nanoplatelets.