Browsing by Author "Bozek, John"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Aerosol Synthesis and Gas-Phase Photoelectron Spectroscopy of Ag-Bi-I Nanosystems
    Danilović, Danijela; Božanić, Dušan; Dojčilović, Radovan; Vukmirović, Nenad; Sapkota, Pitambar; Vukašinović, Ivana; Đoković, Vladimir; Bozek, John; Nicolas, Christophe; Ptasinska, Sylwia; Milosavljević, Aleksandar
    We report on the aerosol generation of ligand-free silver iodobismuthate (Ag-Bi-I) nanoparticles (NPs) and on in situ investigation of their electronic structure using synchrotron radiation soft X-ray aerosol photoelectron spectroscopy (XAPS). The structural and morphological characterizations revealed the aerosol to be composed of spherical rudorffite Ag3BiI6 particles, approximately 100 nm in size. The XAPS showed well-resolved signals from all expected elements (Ag, Bi, and I) and allowed estimation of the NP work function to be about 4.5 eV. The ionization energy of Ag3BiI6 NPs was determined to be 6.1 eV that is in good agreement with our calculations based on a hybrid functional approach. The presented method of production of Ag3BiI6 aerosol can prove beneficial for the future development of Ag-Bi-I-based photovoltaic materials, since it allows the deposition of Ag-Bi-I particles on large surface areas of arbitrary shape and roughness.
  • No Thumbnail Available
    Item
    Electronic Properties of Free-Standing Surfactant-Capped Lead Halide Perovskite Nanocrystals Isolated in Vacuo
    Milosavljević, Aleksandar R.; Božanić, Dušan K.; Sadhu, Subha; Vukmirović, Nenad; Dojčilović, Radovan; Sapkota, Pitambar; Huang, Weixin; Bozek, John; Nicolas, Christophe; Nahon, Laurent; Ptasinska, Sylwia
    We report an investigation of lead halide perovskite CH3NH3PbBr3 nanocrystals and associated ligand molecules by combining several different state-of-the-art experimental techniques, including synchrotron radiation-based XPS and VUV PES of free-standing nanocrystals isolated in vacuum. By using this novel approach for perovskite materials, we could directly obtain complete band alignment to vacuum of both CH3NH3PbBr3 nanocrystals and the ligands widely used in their preparation. We discuss the possible influence of the ligand molecules to apparent perovskite properties, and we compare the electronic properties of nanocrystals to those of bulk material. The experimental results were supported by DFT calculations.