Suchergebnisse

AbstractThe absorption spectra of various sizes of nanoparticles of copper (Cu), silver (Ag), and gold (Au) are theoretically investigated. The density functional theory (DFT), time‐dependent DFT (TDDFT), and real‐time TDDFT are used to demonstrate how size and shape affect their optical properties and how these are evolved as the number of atoms increases. For this reason, the focus was turned on almost spherical nanoparticles cut out from the corresponding crystal structure (called 0D), elongated ones (1D), and flattened ones (2D). The nature of the observed absorption peaks is further analyzed with the help of transition contribution maps and induced density plots which help us identify the emergence of probable plasmonic resonances as the size of the nanoparticles increases.

Nanocrystalline SnS powder has been prepared using tin chloride (SnCl2) as a tin ion source and sodium sulfide (Na2S) as a sulfur ion source with the help of ultrasound irradiation at room temperature. The as-synthesized SnS nanoparticles were quantitatively analyzed and characterized in terms of their morphological, structural and optical properties. The detailed structural and optical properties confirmed the orthorhombic SnS structure and a strongly blue shifted direct band gap (1.74 eV), for synthesized nanoparticles. The measured band gap energy of SnS nanoparticles is in a fairly good agreement with the results of theoretical calculations of exciton energy based on the potential morphing method (PMM) in the Hartree Fock approximation ; European Union 312123 ; Gobierno de Grecia D.237.002