Chemical synthesis of Lead Iodide nanoparticles for photovoltaic and optoelectronic device applications

In the present study, highly recommended lead iodide (PbI2) nanoparticles and thin films based on PbI2 nanoparticles have been prepared for optoelectronics and solar cell applications. PbI2 is an anisotropic p-type semiconductor with a band gap of 2.57 eV at room temperature. PbI2 material has large potential applications in optical detector, digital X-ray imaging, gamma ray detector, etc. PbI2 layered semiconductor nanoparticles were stabilized using thioglycerol and investigated by Ultraviolet-Visible (UV-Vis) absorption spectroscopy, X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. The chemical bath deposition (CBD) method was used to deposit PbI2 thin films on fluorine-doped tin oxide (FTO) glass substrates. These films were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), mapping and atomic force microscopy (AFM). Thicknesses of PbI2 thin films were estimated using a laser profilometer. The blue shift was observed in UV-Vis absorption and PL spectra of PbI2 nanoparticles. TEM was used to obtain quantitative information on the PbI2 particle size distribution. Due to the low solubility of PbI2 in acetonitrile, approximately 20-30 nm sized circular particles are obtained. The variation of 18 Å was observed in the lateral dimensions of PbI2 nanoparticles. Pb4fXPS core level appeared at 138.5 eV corresponding to PbI2. There is no report published wherein the PbI2 nanoparticles and the PbI2 thin films were prepared by the aqueous chemical method and the CBD method respectively. In this study, the characterization results of PbI2 nanoparticles and PbI2 thin films were better than many other materials.