Nanostructured ZnO Thin Films for Optical, Electrical, and Photoelectrochemical Applications from a New Zn Complex

Abstract

New hexanuclear zinc complex, Zn₆(OAc)₈(μ-O)₂(dmae)₄ (<b>1</b>) (OAc = acetato, dmae = <i>N,N</i>-dimethyl aminoethanolato) has been synthesized and characterized by its melting point, elemental analysis, Fourier transform infrared spectroscopy, atmospheric-pressure chemical-ionization mass spectrometry, thermal gravimetric analysis, and single crystal X-ray analysis. The complex (<b>1</b>) crystallizes in the monoclinic space group <i>C</i>2/<i>c</i>. The high solubility of complex (<b>1</b>) in organic solvents such as alcohol, THF, and toluene and low decomposition temperature as compared to Zn­(OAc)₂ make it a promising single source candidate for the deposition of nanostructured ZnO thin films by aerosol-assisted chemical vapor deposition. Films with various nanostructures, morphology, and crystallographic orientation have been deposited by controlling the deposition temperature. The deposited films have been characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray analysis. The optical characterization of ZnO films deposited on the FTO substrate show a direct band gap of 3.31 eV, and the photoelectrochemical study revealed that the photocurrent onset is at about −0.32 V, whereas no photocurrent saturation was observed. The <i>I</i>–<i>V</i> measurements designated the deposited films as ohmic semiconductors