A new lead-free 1D hybrid copper perovskite and its structural, thermal, vibrational, optical and magnetic characterization

Abstract

A hybrid material based on a 1D copper chloride perovskite network with hexahydro-1,4-diazepine, (C₅H₁₄N₂)[CuCl₄], was grown at room temperature by slow evaporation. This compound crystallizes in the monoclinic space group P2₁/n. The framework is constructed from double edge-sharing copper chloride chains surrounded by organic cations to form a multiquantum well structure. The TG–DTA measurement shows that our compound is stable at ambient temperature and exhibits an endothermic phase transition at 83 °C. UV-Vis spectroscopy reveals that the Jahn–Teller effect arising at the Cu²⁺ cation within the CuCl₆ octahedra confers additional flexibility to the structure. The gap energy value was estimated to be 2.56 eV, which indicates that the new hybrid compound should be a semiconducting material. To the best of our knowledge, this is the first 1D copper(II) based perovskite, laying the foundation for further development of perovskites as alternative lead-free materials for solar cells. Magnetic measurements indicate the absence of magnetic interactions which are proposed to result from the cancelation of antiferromagnetic and ferromagnetic contributions.