Gamma ray effects on the properties of PbI₂ thin films

This study reports the impact of γ-ray exposure on the nanostructural, morphological, and optical characteristics of lead iodide (PbI₂) thin films (TFs). These PbI₂ were deposited on glass substrates using a spin coating technique. The γ-ray irradiation was carried out using Co-60 gamma source with dose range from 0 to 100 kGy. The X-ray diffraction (XRD) results revealed a decrease in crystallinity and an increase in crystallite size of PbI₂ as a function of γ-ray dose. Field emission scanning electron microscopy (FESEM) exhibited the variations in surface morphology with increasing γ-ray dose. The elemental composition of as prepared TFs was confirmed by energy dispersive X-rays (EDX) analysis. The optical transmission of PbI₂ TFs was evaluated with varying the γ-ray doses. The estimated energy band gap (Eg) reduced from 2.54 to 2.45 eV with γ-ray dose. Photoluminescence (PL) spectra represent a broad peak centered at 507.64 nm with a hump present at 519.73 nm in the as prepared sample, which grow gradually with increasing the γ-ray dose. The maximum value of mobility was found to be 10.48 cm² V⁻¹ s⁻¹ at 50 kGy. The change in the mobility is associated with the density of structural defects influenced by γ-ray doses. These effects conclude that γ-irradiation played a key role in structural, electrical and optical properties of the PbI₂ TFs and proposes that the γ-irradiation response makes it a good candidate for radiation detecting material application.