Sinthesys and Characterization of New Luminescent Complexes Based on Copper(I) Iodide

Complexes based on metals with d10 configuration (Cu, Ag, Au) are currently in the focus of numerous research studies because of the demand for materials active in optoelectronic devices. The interest arises from the increasing demand of more-affordable complexes in preference to luminescent metal complexes based on precious and rare-earth metals, Ir, Pt or Os, which are often quite expensive and environmentally problematic, which complicates their usage in high-volume productions. The copper iodide complexes present several advantages, because compared to the corresponding clusters with Br- and Cl- tend to be more stable in air and show a more intense luminescence in the solid state. Most of the complexes studied are characterized by a remarkable high quantum yield in solid state, they are characterized by a large variety of coordination geometries which arise from the many possible combinations of coordination numbers (two, three and four) available for copper(I) and geometries that can be adopted by the halide ions (from terminal to m2- and up to m8-bridging); they present different excited states which can be of a ligand centered, charge transfer or, in the case of polynuclear compounds, even metal-centered nature; and finally the reagents are cheap and the synthetic procedures are easy and occur in few steps. Copper iodide complexes can have a 3XLCT emission band if we are in the presence of aromatic ligand and a 3CC if the distances between the metal centers are shorter than the sum of the van der Waals radii, that in the case of Cu is 2.8 Å. Furthermore due to the great differences in the geometries of CuI compounds, lots of different synthetic techniques, such as the solution methods, mechanochemical (grinding and liquid assisted grinding), solvothermal, vapour or liquid diffusion, need to be used.