Work

Formation of CdSe/CdS/ZnS Quantum Dots Floating Monolayers on the NiCl2 Containing Subphase

Year: 2021

Type: article

Abstract: The development of low-defect self-organizing thin film materials is one of the most important directions of modern optoelectronics.For this purpose, the formation and stability of quantum dots (QDs) floating monolayers on the composition (pure water or NiCl 2 aqueous solutions) and temperature (19 and 25 °C) of subphase have been investigated.The studied quantum dots were CdSe/CdS/ZnS (core/shell/shell) stabilized by oleic acid.The data on -A isotherms, hysteresis, and stability of QDs floating monolayers were analyzed.It was found that the monolayer formed on the pure water subphase is more stable.It was established that the increase of NiCl 2 content in the aqueous subphase (from 1 to 5 mM) leads to the decrease of the gas phase region and the increase of the liquid and condensed phase regions on π-A isotherms.It was suggested that Ni 2+ cation interacts with the carboxylic groups of free (unbounded to QDs) oleic acid molecules.As a result, the density of floating layer and the compression module values increased.The highest compression modulus values of QDs floating monolayers were found for the 5 mM NiCl 2 containing subphase.On the basis of the studied floating layers, thin films were obtained on silicon substrates, and their surface was investigated by the AFM method.It was determined that the presence of NiCl 2 in the aqueous subphase leads to an increase in the thicknesses and hydrophobicity of the prepared thin films.The obtained data can be used at the formation of multicomponent thin film nanomaterials containing quantum dots.

Source: Liquid Crystals and their Application

DOI: 10.18083/lcappl.2021.4.74