Radiative and non radiative recombinations study in the novel nanocomposites BiVO 4 /3DOM-TiO 2 , ZnO/3DOM-TiO 2 and BiVO 4 /3DOM-ZnO: Application to the photocatalysis

Mounira Mahdouani, Meriam Zalfani, Ramzi Bourguiga, Bao Lian Su

Research output: Contribution to journalArticle

Abstract

A theoretical investigation of optical proprieties of three nanostructures such as BiOV 4 /3DOM TiO 2 , ZnO/3DOM TiO 2 and BiOV 4 /3DOM ZnO has been presented and discussed. The study based on a one band effective mass approximation model was developed to calculate the charge carrier energies on various parameters of nanostructures including their size. We computed the optical properties for both spherical BiVO 4 and ZnO nanoparticles incorporated in the three dimensionally ordered macroporous inverse opal TiO 2 nanocomposites (3DOM-TiO 2 ). At first and by solving a three dimension Schrödinger equation we calculated the dependence of charge carriers energies on the size of nanoparticles. Then we investigated the variation of the excitonic energy of BiOV 4 /3DOM-TiO 2 , ZnO/3DOM-TiO 2 and BiOV 4 /3DOM-ZnO as function of the radius of these nanostructures into taken account the effects of dielectric and coulomb interaction between charge carriers. We showed that the radiative recombination lifetime is enhanced with decreasing BiVO 4 and ZnO quantum dots (QDs) size. It was found that as the size of the dot is reduced the confinement of charge carriers and the optical gap are increased. The optical gap of the ZnO/3DOM-TiO 2 is larger than both BiOV 4 /3DOM-TiO 2 and BiOV 4 /3DOM-ZnO especially for small radius. It was also found that radiative life time in the BiOV 4 /3DOM-TiO 2 , ZnO/3DOM-TiO 2 and BiOV 4 /3DOM-ZnO increased by increasing the radius of these nanostructures. In addition, we have also showed that, the radiative lifetime in the ZnO/3DOM-TiO 2 nanostructure is less than both BiOV 4 /3DOM-TiO 2 and BiOV 4 /3DOM-ZnO nanostructures. Finally, we have studied and discussed the Auger process in BiOV 4 /3DOM-TiO 2 , ZnO/3DOM-TiO 2 and BiOV 4 /3DOM-ZnO nanostructures. At first, we have showed that the auger process is important when the radiuses of nanostructures are less than 2 nm. Then we have also showed that this process is more important for ZnO/3DOM-TiO 2 compared to the other nanostructures.

Original languageEnglish
Pages (from-to)269-280
Number of pages12
JournalPhysica E: Low-Dimensional Systems and Nanostructures
Volume108
DOIs
Publication statusPublished - 1 Apr 2019

Keywords

  • Auger recombination lifetime
  • Nanocomposites
  • Photocatalysts
  • Radiative lifetime

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