Thermally activated conduction and dielectric relaxation in the quasi-one-dimensional hybrid perovskite NH2(CH3)2CuCl3

Abstract

Organic–inorganic hybrid perovskite materials have attracted significant attention due to their unique structural versatility and promising optoelectronic properties. In this work, we present a detailed investigation of the structural, thermal, optical, and electrical characteristics of NH₂(CH₃)₂CuCl₃. Powder X-ray diffraction confirms the formation of a well-ordered monoclinic phase featuring one-dimensional \({\left[{Cu}_{2}{Cl}_{6}\right]}^{4-}\) dimer chains linked by organic cations, which give rise to pronounced anisotropy. Thermal analysis reveals a sharp triclinic-to-monoclinic phase transition near 287 K and thermal stability up to ~ 475 K (based on a 5% weight loss criterion). Optical absorption measurements identify a direct bandgap of 2.26 eV and a significant Urbach energy of 0.829 eV, reflecting lattice disorder and strong exciton–phonon coupling. Impedance spectroscopy and dielectric studies highlight thermally activated charge transport with non-Debye relaxation behavior, strongly influenced by the structural phase transition. AC conductivity analysis shows anomalous frequency exponents, pointing to complex conduction mechanisms that include dielectric relaxation, polaron hopping, and interfacial polarization. These results demonstrate the crucial interplay between structure and dynamics in NH₂(CH₃)₂CuCl₃, underlining its potential for advanced optoelectronic applications.