Impact of Sb-insertion on structural, optical, and dielectric characteristics of the PbI2 thin film

Antimony (Sb) has been widely used as an additive in solar cells for enhanced performance. We described a simple, affordable, solution-processed approach for producing pure and antimony (Sb3+)-doped lead iodide (PbI2) thin films with varying doping ratios (0.5, 1.0, 2.0, and 3.0%). Structural, optical, and dielectric properties were investigated using XRD and UV-Vis spectroscopy. The XRD spectra illustrated that the synthesized PbI2 thin films have a preferred orientation along the c-axis (001) with a hexagonal structure. The crystalline sizes of PbI2 increased by increasing the Sb-doping concentration up to 1%, then decreased with 2% and 3% Sb-doping. In the visible and NIR regions, the optical transparency of the grown films were in between 70 and 80%. The optical band gap changes inversely with the crystalline sizes; it decreases with 0.5% and 1% Sb-doping and increases with further doping. As the energy gap is spanned between 2.39 and 2.27 eV, therefore, Sb: PbI2 films are ideal for use in solar cells. The resulting refractive index values were found to rise as the Sb doping concentration increased. Sb-doping decreases optical conductivity and dielectric constant.

Automated summary

A simple and affordable solution-processed method was used to produce pure and antimony-doped lead iodide thin films. The doping concentration affected the crystalline sizes, optical transparency, and energy gap of the films. The resulting films showed good optical transparency in the visible and near-infrared regions, making them suitable for use in solar cells. Antimony doping also influenced the refractive index and decreased the optical conductivity and dielectric constant of the films.