Studies on structural, dielectric and optical properties of Cu/W double substituted calcium manganite for solar cells and thermistor applications

Abstract

In this communication, the synthesis of modified calcium manganate (CaCu1/3Mn1/3W1/3O3) ceramics by a conventional solid-state reaction technique is reported. The possibility of the incorporation of Cu/W ions in the B-site of the CaMnO3 ceramics is investigated. The structural analysis predicts a rhombohedral structure with space group R-3c (#167). The average crystallite size and lattice micro-strain are about 35.6 nm and 0.776%. The Raman study confirms the presence of all constituent while UV-Vis provides energy bandgap 4.69 eV; suitable for solar cell. The study of complex impedance suggests Cole–Cole type relaxation and bulk resistance decreases from 1.407 × 107 Ω at 25°C to 2.201 × 103 Ω at 500°C, which confirms the negative temperature coefficient of resistance (NTCR) character. The semi-circular arcs in the Cole–Cole and Nyquist plots confirm the semiconductor nature. Thermistor constant (β), sensitivity factor (α) and stability factor of the sample were calculated which confirm the characteristics of NTC thermistor.