Effect of Cl substitution on the microstructure, dielectric and optical properties of CaCu3Ti4O12 ceramics

Abstract

This study investigates the enhanced properties of CaCu3Ti4O12 (CCTO) ceramics by substituting oxygen anions with chlorine to form CaCu3Ti4O10Cl2 (CCTO-Cl2). The structural, morphological, optical, and dielectric characteristics of CCTO-Cl2 were systematically analyzed. Among the calcination temperatures studied, 900 °C emerged as the optimal condition, significantly enhancing all properties. X-ray diffraction (XRD) confirmed phase formation and a reduction in lattice parameters due to Cl− substitution and thermal treatment. Scanning electron microscopy (SEM) revealed substantial grain growth and densification, contributing to improved material density. Optical analysis showed a redshift in absorption peaks, and the band gap energy reduced to 1.68 eV, attributed to enhanced crystallinity and phase transformations. Dielectric measurements at 900 °C demonstrated a colossal dielectric constant of 3.259 × 104 and a reduced dielectric loss of 0.17, indicating exceptional energy storage potential. These findings underscore the effectiveness of Cl− substitution and calcination at 900 °C in optimizing CCTO-Cl2 ceramics for advanced dielectric and electronic applications.

Keywords

• Ceramics
• CaCu3Ti4O12
• Doping
• Optical
• Dielectric
• Impedance