Chiral nanostructures exhibiting different absorption of right- and left-handed circularly polarized light are of rapidly growing interest due to their potential applications in various fields. Here, we have studied the induction of chirality in atomically thin (0.6–1.2 nm thick) ZnSe and CdSe nanoplatelets grown by a colloidal method and coated with L-cysteine and N-acetyl-L-cysteine ligands. We conducted an analysis of the optical and chiroptical properties of atomically thin ZnSe and CdSe nanoplatelets, which was supplemented by a detailed analysis of the composition and coordination of ligands. Different signs of circular dichroism were shown for L-cysteine and N-acetyl-L-cysteine ligands, confirmed by different coordination of these ligands on the basal planes of nanoplatelets. A maximum value of the dissymmetry factor of (2–3) × 10−3 was found for N-acetyl-L-cysteine ligand in the case of the thinnest nanoplatelets.

Samples of inverted photonic-crystal films, containing planar and rolled-up (in the form of scrolls) CdSe nanocrystals, are studied. The transmission spectra of these structures are recorded. These spectra (along with the change in colour) confirm the incorporation of nanocrystals into the films. The photoluminescence decay dynamics is investigated. It is shown that the photonic-crystal matrix affects significantly the luminescence kinetics of nanostructures. The differences in the decay curves measured for nanocrystals in a photonic-crystal matrix and for their ensemble on a glass substrate are explained by the influence of the photonic-crystal stop band and the orientational effect of crystalline matrix, which orients anisotropic nanocrystals and prevents them from aggregation. The results obtained may be important for potential applications in optoelectronic devices.

In this work, the phonon spectra of atomically thin ZnSe nanoplatelets (NPLs) were studied using Raman and infrared spectroscopies. Atomically thin ZnSe NPLs were grown on the Si substrate covered with a 100 nm thick gold layer by the colloidal method in the temperature range of 100−170 °C. The triangular and rectangular NPLs with 2.5-and 4-monolayer thicknesses, respectively, were synthesized, as determined by atomic force microscopy (AFM) measurements. Longitudinal optical (LO) and transverse optical (TO) phonon modes in ZnSe NPLs were found at 198 and 252 cm −1 , respectively, and the surface optical phonon mode was observed at about 216 cm −1 . The LO and TO phonon modes revealed the opposite frequency shifts with increasing growth temperature. The effect was induced by the phonon confinement, and it confirmed the formation of NPLs of different thicknesses. Comparing the frequency positions of longitudinal and TO phonon modes confined in ZnSe NPLs with the data on the dispersion of optical phonons in bulk ZnSe, the thickness of the NPLs formed at a low temperature was derived as 0.567 nm, correlating well with the AFM results.