Influence of Donated Pair of Electrons by a Nitrito-Group Ligand on the Solid-State Properties of Lead Sulfide Thick Films

Abstract

In general, thick and thin films are developed to provide special properties that range from electrical properties, optical, mechanical and chemical properties that can satisfy the needs for specific applications in technology. Lead sulfide (PbS) is an example of such films. Lead sulfide thin films have been synthesized on glass substrates. Some of the advantages of PbS thin film in olar cell applications include low material consumption, shorter energy payback period, large area modules, monolithic integration, tuneable material properties, low-temperature processes, and transparent modules. PbS thin films help also help in preventing corrosion of metallic parts of many devices. They are also used to offer protection against wear in moving parts. Materials such as jewelry, wrist watches, and knives are often coated to avoid corrosion. For deposition of PbS thin films, lead acetate is used as lead precursor and for sulfur source thiourea, has been was used in many studies.in this study, three samples of lead sulphide thick films were deposited on microscope glass slides at varying nitrito-group ligand concentrations at room temperature using solution method. The nitrito group ligand has a capacity to coordinate a central metal {Pb) atom using two different sites. First, it can use the nitrogen (N) atom as donor atom (nitrito group) and the oxygen (O) as donor atom (nitrito group). Secondly, it can use a sulphur (S) atom as donor atom ( in a thiocyanate group) and nitrogen (N) atom as donor atom ( as in a isothiocyanate). The influence of nitrito-group ligand on the solid-State properties of PbS thin films deposited by chemical bath technique were investigated and characterized using UV-VIS spectrophotometer and Four-Point Probe (FPP) technique. They were analyzed graphically, and the results show that, the donated pair of electrons from the nitrito group ligand caused absorption edge to decreases towards longer wavelength region while band gap energy increase from 1.61eV to 3.71eV with increase concentration. On the sampled films, there was a consistent increase in the sheet resistance and electrical conductivity as the concentration of Nitrito-group ligand increases.