Abstract

Ge-doped CaCu3Ti4O12 ceramics with composition CaCu3Ti3.9Ge0.1O12 were synthesized using a wet chemical method and sintered at different temperatures to study their properties. X-ray diffraction confirmed single-phase cubic structure for all sintering temperatures, with improved crystallinity observed at higher sintering temperatures. Morphological analysis showed 1050°C as the optimal sintering temperature, balancing grain growth without excessive liquid phase. Optical studies revealed the lowest band gap of 2.16 eV for sample sintered at 1050°C, along with strong photoluminescence dominated by cyan emission at 513.5 nm. Ge doping allowed tunable emissions from 470 to 620 nm with an effective half lifetime of 1.30 ns, which can be very useful for optoelectronics. Dielectric measurements peaked for sample sintered at 1050°C, showing enhanced polarization and charge mobility, along with increased grain boundary resistance and non-Debye relaxation, indicating improved insulation and internal barrier layer capacitor behavior. Electrochemical tests demonstrated excellent pseudocapacitive performance with over 90 % capacitance retention after many cycles. Overall, CaCu3Ti3.9Ge0.1O12 is a promising multifunctional material for hybrid (Electrical and Electro-chemical) energy storage and optoelectronic applications.