One-dimensional Bi₂O₃nanohooks: synthesis, characterization and optical properties

Abstract

We report the synthesis of one-dimensional (1D) Bi(2)O(3) nanohooks by the oxidative metal vapor phase deposition technique. Surface morphology observations confirm the formation of 1D nanohooks with nanoparticles at their tips. Structural analysis by x-ray diffraction (XRD) and transmission electron microscopy (TEM) reveals the crystalline nature of the 1D nanostructure. Elemental analysis confirms that the 1D nanohooks consist of only elements Bi and O. The XRD study suggests that the synthesized product is of two phases (α- and β-Bi(2)O(3)) with monoclinic and tetragonal crystal structures respectively. The phonon vibration modes corresponding to Bi(2)O(3) are determined by Raman scattering. A broadband visible photoluminescence (PL) is observed in the wavelength region 500-900 nm, also indicating the extension of luminescence into the near-infrared region. The existence of broadband visible emission can be attributed to the existence of defect/impurity states induced by oxygen vacancies.

Metastable γ-Bi2O3 tetrahedra: Phase-transition dominated by polyethylene glycol, photoluminescence and implications for internal structure by etch

“…2 P 1/2 transitions, giving rise to luminescence spectra peaked in the wavelength range 591-637 nm (2.10-1.95 eV) under UV excitation [43,44]. Low-energy emission is attributed to the crystal defects or defect levels associated with oxygen vacancies or bismuth interstitials that have formed during growth [45]. In the current work, the direct band gap value of metastable c-Bi 2 O 3 tetrahedra estimated from UV-visible diffuse reflectance spectrum is 2.83 eV (439 nm), the emission peak at 442 nm can be indexed as the band-to-band recombination in a direct transition manner.…”

A note on the characterization of bismuth black by Raman microspectroscopy

“…Nonetheless, Raman spectroscopy has been employed in recent studies of bismuth nanoparticles, [10 -12] clusters [13] and thin films [14] where the fundamental Raman modes, [15] E g and A 1g , were monitored to study changes in structural properties such as particle size and crystallinity. Raman spectroscopy also has been used to characterize bismuth oxide powders and single-crystals, [16 -18] and, more recently, bismuth oxide nanostructures [19,20] and thin films. [14] However, all these previous studies employed visible excitation wavelengths, ranging from 488 to 647 nm.…”

Enhanced photoelectrochemical activity of electro-synthesized CdS–Bi2S3 composite films grown with self-designed cross-linked structure

“…Shen et al [27] in an earlier work. There are several other small peaks located on the spectra of composite films, may be ascribed to the trace amount of different oxide phases Bi 2 O 3 [28,29] and CdO present as impurity in the matrices.…”