Dielectric and optical properties of δ‐Bi2O3 quaternary semiconducting solid solutions

Quaternary compositions of polycrystalline Bi1.74Dy0.14W0.12‐xScxO3 (x = 0.02, 0.03, 0.04, 0.05, 0.06) solid solutions were synthesized by the solid‐state reaction method. The 4a site symmetry of the space group occupied by Sc3+ ion retains the cubic fluorite‐type over a wide temperature range (450‐700 oC) for low Sc3+ content without losing the δ‐phase. Dielectric and ionic conductivity by complex impedance in the frequency range from 0.1 to 100 kHz suggests a temperature and Sc3+‐dependent relaxation process. The ionic conductivity increases with the Sc3+ content over the whole tested temperature range. An oxygen ion conductivity of 0.102 Scm‐1 at 700 oC and an activation energy of 0.32 eV was achieved for x=0.06. Optical properties and Rietveld refinement indicate a band gap reduction due to a bond length reduction (Bi‐O). These materials have potential in photocatalysis and water‐splitting technology due to their UV and visible region absorption capabilities.This article is protected by copyright. All rights reserved.