Optical features of nanoplatelets modified with chiral ligands

Optical Materials: X. 2026. Vol. 30. Article 100441.

A.M. Smirnov, Kurtina D. A., Saitov S. R., Fedyanin A. A., Mantsevich V. N., Musorin A. I., Kotova L. V., Zedomi T., Vasiliev R. B.

Chiral semiconductor nanostructures and nanoparticles are promising materials for applications in biological sensing, enantioselective separation, photonics, and spin-polarized devices. Here we performed a detailed analysis of optical properties of chiral CdSe nanoplatelets with thickness of 2 and 3 monolayers (ML) with Nacetyl-L-cysteine ligands. We studied the absorption spectra peculiarities, analyzed time-resolved photoluminescence and investigated circular and linear polarization of light passed the samples with different chirality. It was found that non-chiral nanoplatelets reveal the transformation of linear polarization into circular one due to the precence of birefringence. It was demonstrated that only one of the exciton resonances dominates in the polarization properties of chiral nanoplatelets. For chiral 2-ML-thick CdSe nanoplatelets the most pronounced chiral optical response corresponds to the heavy hole excitons and for 3-ML-thick CdSe nanoplatelets light hole excitons play the most important role. We performed complex analysis of the optical features of nanoplatelets modified by chiral ligands and combined for the first time to the best of our knowledge the polarization analysis with time resolved measurements. Moreover, we demonstrated an important role of birefringence in the semiconductor in addition to the presence of chiral ligands, which was not carefully separated before.

Keywords: exciton polariton, circular polarization, chirality, linear polarization, CdSe nanoplatelets