title: Intrinsic Chirality of CdSe/ZnS Quantum Dots and Quantum Rods.
abstract: 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.
authors.affiliation: †ITMO University, St. Petersburg, 197101, Russia.
authors.forename: Maria V
authors.initials: MV
authors.lastname: Mukhina
authors.affiliation: †ITMO University, St. Petersburg, 197101, Russia.
authors.forename: Vladimir G
authors.initials: VG
authors.lastname: Maslov
authors.affiliation: †ITMO University, St. Petersburg, 197101, Russia.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Baranov
authors.affiliation: †ITMO University, St. Petersburg, 197101, Russia.
authors.forename: Anatoly V
authors.initials: AV
authors.lastname: Fedorov
authors.affiliation: †ITMO University, St. Petersburg, 197101, Russia.
authors.forename: Anna O
authors.initials: AO
authors.lastname: Orlova
authors.affiliation: ‡School of Chemistry and CRANN, University of Dublin, Trinity College, Dublin 2, Ireland.
authors.forename: Finn
authors.initials: F
authors.lastname: Purcell-Milton
authors.affiliation: ‡School of Chemistry and CRANN, University of Dublin, Trinity College, Dublin 2, Ireland.
authors.forename: Joseph
authors.initials: J
authors.lastname: Govan
authors.affiliation: †ITMO University, St. Petersburg, 197101, Russia.|‡School of Chemistry and CRANN, University of Dublin, Trinity College, Dublin 2, Ireland.
authors.forename: Yurii K
authors.initials: YK
authors.lastname: Gun'ko
keywords: Intrinsic chirality of nanocrystals; chiral defects; circular dichroism; screw dislocation; separation of nanocrystal enantiomers