Investigation of Temperature‐Activated Charge‐Carrier Dynamics and Dielectric Relaxation in Fe, Cu–Doped CeO2

Cerium oxide (CeO2) is a material with unique dielectric properties that make it a promising candidate for various applications. High electrical resistance and a wide bandgap of pristine CeO2 limit its applicability in photovoltaics and photo‐electrocatalysis. CeO2 is co‐doped with transition metals (Fe+2/Fe+3 and Cu+2), which reduces its optical bandgap energy and electrical resistance. This study aims to investigate the dielectric relaxation behavior and charge‐carrier dynamics of Fe, Cu–CeO2. The enhanced charge‐carrier dynamics in the Fe, Cu–doped CeO2 compared to pristine CeO2 are reported. Using temperature‐dependent electrochemical impedance spectroscopy (TD‐EIS), the dielectric relaxation and carrier dynamics in pristine CeO2 and Fe, Cu–doped CeO2 in the temperature range 313–473 K along with the modulus spectroscopy are investigated. It is observed that Z′ values reduced with the temperature, thus showing the negative temperature coefficient of resistance in the frequency range 6.28–1.005  ×  105 radians s−1. Furthermore, a correlated study of –Z″ and M″ shows the charge‐carrier relaxation behavior changes from ideal Debye type to non‐Debye type with temperature rise in Fe, Cu–doped CeO2.