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.