Effective p-type photocurrent sensitization of n-Bi2O3 with p-CuBi2O4 and p-CuO: Z-scheme photoelectrochemical system

Nanostructured n-Bi2O3/p-CuBi2O4/p-CuO photocathodes with incident photon-to-current conversion efficiency IPCEmax = 70% (λ = 400 nm) have been prepared using electrochemical and chemical methods. Platelet-like BiOI nanocrystals electrochemically deposited on FTO substrate were used as precursors. CuI nanoparticles were deposited on the BiOI surface by successive ionic layer adsorption and reaction technique. Oxidative heat treatment of BiOI/CuI heterostructure in air leads to the formation of the Bi2O3/CuBi2O4/CuO composite. Binary oxide was formed as a result of solid-state interaction between bismuth and copper oxides at their interface. Spectral sensitization of wide-gap n-Bi2O3 (band gap Eg = 2.80 eV) with narrow-gap p-CuBi2O4 (Eg = 1.80 eV) and p-CuO (Eg = 1.45 eV) extends spectral sensitivity range up to 800 nm by Z-scheme implementation: cathodic photocurrent is associated with the transition of photoelectrons from p-CuBi2O4 and p-CuO to the solution, while photoholes recombine with electrons of n-Bi2O3 conduction band. High quantum efficiency of photocurrent was achieved due to band-edge correlation in a three-component oxide heterostructure, combined with an internal electric field in p-CuBi2O4 and effective photon absorption by two narrow-band-gap p-CuBi2O4 and p-CuO semiconductors

Magnetic Anisotropy in Bicomponent Self-Assembled Ni and Ni-Pd Nanowires Studied by Magnetic Resonance Spectroscopy

Self-ordered arrays of Ni, Ni(50) Pd(50), and Ni(78) Pd(22) nanowires were synthesized by simultaneous electrochemical deposition of Ni and Pd components into porous templates of anodic aluminum oxide using alternating current. This paper is focused on the interplay of structure and chemical composition of Ni and Ni-Pd bicomponent nanowires arrays and the peculiarities of its magnetic anisotropy

Photoelectrochemical and Raman characterization of In2O3 mesoporous films sensitized by CdS nanoparticles

The method of successive ion layer adsorption and reaction was applied for the deposition of CdS nanoparticles onto a mesoporous In2O3 substrate. The filling of the nanopores in In2O3 films with CdS particles mainly occurs during the first 30 cycles of the SILAR deposition. The surface modification of In2O3 with CdS nanoparticles leads to the spectral sensitization of photoelectrochemical processes that manifests itself in a red shift of the long-wavelength edge in the photocurrent spectrum by 100–150 nm. Quantum-confinement effects lead to an increase of the bandgap from 2.49 to 2.68 eV when decreasing the number of SILAR cycles from 30 to 10. The spectral shift and the widening of the Raman line belonging to CdS evidences the lattice stress on the CdS/In2O3 interfaces and confirms the formation of a close contact between the nanoparticles

Pulse electrodeposited bismuth-tellurium superlattices with controllable bismuth content

Superlattice structures of (Bi2)m(Bi2Te3)n series with controllable Bi mole fraction from 0.41 to 0.71 are electrodeposited in pulse potentiostatic mode from acidic electrolytes containing Bi(NO3)3 and TeO2 as precursors. Two valence states of bismuth in superlattices are identified by X-ray photoelectron spectroscopy (XPS). One of those states is attributed to interlayered Bi0 which is present in (Bi2)m(Bi2Te3)n superlattice in the form of biatomic layers between bismuth telluride quintuples. X-ray difraction (XRD) analysis and density functional theory (DFT) calculations indicate an increase in subcell parameter asub and decrease in subcell parameter csub with the increase of Bi mole fraction. Biatomic layers of Bi0 are identified with cyclic voltammetry by characteristic anodic peak between potentials of metallic bismuth and Bi2Te3 oxidation. The selective oxidation of Bi-bilayers in (Bi2)m(Bi2Te3)n superlattice at the potential of the anodic peak results in the product corresponding to Bi2Te3 by stoichiometry, but having an expanded crystal structure. Superlattices with controllable Bi mole fraction and Bi2Te3 with “memory effect” may be of interest for design of new thermoelectric materials with controllable parameters