Effect of Cl substitution on the microstructure, dielectric and optical properties of CaCu3Ti4O12 ceramics
Najwa Gouitaa, Sahil Kumar, Fatimazahra Ahjyaje, T. Lamcharfi, Amina. Benatia, Mustapha. Abarkan, Mamta Shandilya
Abstract
• Cl-doped CaCu 3 Ti 4 O 12 (CCTO-Cl 2 ) ceramics were synthesized using a solid-state reaction, enhancing dielectric properties. • SEM analysis showed significant grain growth and reduced porosity with increased calcination temperatures. • The band gap decreased from 2.41 eV to 1.68 eV, indicating potential for optoelectronic applications. • Peak dielectric permittivity of 3.259 × 10 4 and low dielectric loss of 0.17 were achieved at 900 °C. • Enhanced AC conductivity makes CCTO-Cl 2 suitable for advanced electronic devices like capacitors and microwave components. This study investigates the enhanced properties of CaCu 3 Ti 4 O 12 (CCTO) ceramics by substituting oxygen anions with chlorine to form CaCu 3 Ti 4 O 10 Cl 2 (CCTO-Cl 2 ). The structural, morphological, optical, and dielectric characteristics of CCTO-Cl 2 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 × 10 4 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-Cl 2 ceramics for advanced dielectric and electronic applications.