Investigation of structural, optical and electrical conductivity of a new organic inorganic bromide: [CHN]ZnBr.

A new organic-inorganic hybrid, namely the [CHN]ZnBr compound, has been synthesized and studied by single-crystal X-ray diffraction and optical and complex impedance spectroscopy. It crystallized in the centrosymmetric 2/ space group at room temperature. The asymmetric unit is constituted by [ZnBr] anions, showing slightly distorted tetrahedral geometry, surrounded by four organic (CHN) cations. The crystal packing is stabilized by N-H⋯Br and C-H⋯Br hydrogen bonds arranged in a three-dimensional network. The optical absorption measurement confirms the semiconductor nature with a band gap of around 3.94 eV. Additionally, the analysis of Nyquist plots (-'' ') shows that the electrical properties of the material are heavily dependent on frequency and temperature, indicating a relaxation phenomenon and semiconductor-type behavior. Reduction in ' was observed as a function of temperature and frequency which indicates an increase in ac conductivity and the negative temperature coefficient of resistance. The frequency dependent plots of (-Z'') show that the electrical relaxation is non-Debye in nature. The ac conductivity spectrum obeys Jonscher's universal power law. The Correlated barrier hopping model CBH has been suggested to agree with the conduction mechanism of for the [CHN]ZnBr compound.