Gamma ray-induced effects on the properties of CsPbBr3 perovskite thin film

Abstract

In the last two decades, the family of metal halide perovskites has received more attention in radiation detection applications. In this work, the radiation detection and dosimetric applicability of the CsPbBr3 thin film will be investigated. The impact of gamma irradiation on the structural, morphological, optical, and electrical properties of the CsPbBr3 thin film has been studied. The CsPbBr3 thin film was synthesized using a thermal evaporation deposition technique. The deposited thin films were exposed to different gamma-ray doses (0, 25, 50, 75, and 100 kGy) using a 60Co gamma source with an activity of 7.328 kGy/h. X-ray diffraction analysis of the thin films confirmed the orthorhombic crystal structure and also showed an increase in the crystalline and crystallite sizes, whereas the dislocation density and microstrain decreased as the gamma dose increased. Field-emission scanning electron microscopy results revealed that the surface morphology changed considerably due to gamma exposure. The optical properties exhibited a decreasing energy band gap value (from 2.35 to 2.14 eV) as the radiation dosage increased, which may have been due to the increasing crystallite size and induced defects. The photoluminescence (PL) peaks shifted toward longer wavelengths and intensity, while the full width half maxima of PL peaks increased along with the gamma dose, which was attributed to spectral broadening and enhancement in the recombination rate of electron–hole pairs. Impedance spectroscopy of all the irradiated samples showed the single semicircle feature, which is similar to that observed in the case of unirradiated samples. The grain boundary resistance reduced gradually as the gamma dosage increased. The achieved outcomes proved that the structural defects induced by gamma exposure had a superficial influence on the structural, morphological, optical, PL, and impedance properties of CsPbBr3 thin films. The impact of gamma dose on the properties makes CsPbBr3 thin films significantly useful as sensing materials.

Keywords

• Metal halide CsPbBr3 perovskite thin films
• Gamma irradiation
• XRD
• Optical properties
• Photoluminescence
• Impedance spectroscopy