Study of Temperature-Dependent High-Dielectric Constant and High-Conductivity Properties Using Impedance Spectroscopy on Multi-Walled Carbon Nanotube-Perovskite Embedded in Insulating Polymer

The objectives of this study were to achieve high-dielectric constant and high-conductivity by fabricating a device based on multi-wall carbon nanotubes (MWCNTs) and CH 3 NH 3 PbBr 3 nanoparticles embedded inside PVA polymer matrix. Four devices were fabricated using the sol–gel method and deposited by drop casting on FTO-coated glass substrates, namely Ag/PVA/FTO (D1), Ag/CH 3 NH 3 PbBr 3 –PVA/FTO (D2), Ag/MWCNT–PVA/FTO (D3), and Ag/MWCNT–CH 3 NH 3 PbBr 3 –PVA/FTO (D4). Dielectric measurements of these devices under ambient conditions showed that device D4 exhibited the highest dielectric constant of ∼1.1 × 10 4 and conductivity of ∼10 −6 Sm −1 due to the combined ionic polarization of CH 3 NH 3 PbBr 3 and the capacitive behaviour of MWCNTs in the PVA matrix. Additionally, temperature-dependent dielectric measurements of device D4 were performed from 30 to 100 °C. Initially, from temperature 30 to 70 °C, the dielectric parameters increased with temperature due to enhanced interfacial, dipolar, and ionic polarization, reaching their maximum at 70 °C. At 70 °C, the dielectric constant reached ∼3.6 × 10 5 with a conductivity of ∼10 ⁻3 Sm −1 . Beyond 70 °C, a decline was observed due to thermally induced disruption of polarization mechanisms. These findings demonstrate the potential of this study for applications in energy storage devices, high-k gate dielectrics, capacitive sensors, and non-volatile memory devices.