Low-cost and facile synthesis of chromium doped PbI₂ nanostructures for optoelectronic devices and radiation detectors: Comparative study

The synthesis of pure and different concentrations of Cr-doped (1, 2.5, 5, 7, 10 wt%) lead iodide (PbI₂) nanosheets was successfully achieved using a low-cost and simple microwave method. The prepared Cr-doped PbI₂ nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), FT-Raman, diffuse reflectance, dielectric, and gamma absorption analysis. The structural investigation confirmed the hexagonal phase of the proposed nanostructures without the impurity phase. Morphological studies proved that the undoped PbI₂ nanosheet has a size of less than 100 nm, and the size of the prepared Cr-doped PbI₂ samples was around 50-60 nm. FT-Raman and optical analysis investigated the doping effects on the pure PbI₂ matrix through the slight shifting of characteristics peaks and the energy bandgaps’ variations. The optical bandgap values of pure PbI₂ and Cr-doped PbI₂ samples were estimated to be ranged from 2.0 eV to 2.2 eV. The obtained values of the dielectric constant were increased from 20 to 27 due to introducing the Cr- ions into the host PbI₂ matrix. Together with Cr- dopants, the linear coefficient of Gamma absorption illustrates improvements. To conclude, due to the enhancement in structural morphology, optical, and radiation properties of the synthesized Cr-doped PbI₂ nanostructures, those proposed nanosheets potentially are remarkable candidates for various applications including optoelectronics and radiation detectors.