Spatiotemporal analysis of structured Langmuir films formed from stabilised CdSe/CdS/ZnS quantum dots

Langmuir-Blodgett Films (LBFs) were studied using X-ray Diffraction (XRD), Raman Scattering (RS), Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDX), Transmission Electron Microscopy (TEM), High Resolution TEM (HRTEM), Electronic Data Processing (EDP), Atomic Force Microscopy (AFM), and ab-initio simulations. Unlike in the classical form of compression isotherms π(t), the transition to the time dependence Δπ(t) = π(t2) - π(t1) made it possible to reveal the “liquid–solid phase” transition starting from 500 s to 650 s, and nanofilm collapse after 1400 s as illustrated by Brewster images. According to AFM, HRTEM images, and XRD data, it is established that the formation of an LBF from CdSe/CdS/ZnS quantum dots is accompanied by a structural transition from sphalerite to dominant wurtzite close packing, which is in qualitative agreement with the results from combinatorial geometry and ab-initio calculations. The dominance of the wurtzite crystal structure was established by X-ray diffraction, HRTEM and RS methods.