Effect of methylammonium lead tribromide perovskite based-photoconductor under gamma photons radiation

Organic-inorganic perovskite materials are successfully employed for optoelectronics (UV–Visible photodetector and solar cell) and ionization radiation detector. The radiation hardness is a key issue for ionization applications based on perovskite materials. Here, the radiation effect on optical, structural and electrical properties of methylamine bromide (CH₃NH₃PbBr₃) single crystals under high dose gamma photons are systematically investigated. It is demonstrated from the X-ray diffraction pattern and surface morphologies that single crystals are evenly divided into several pieces after receiving an accumulative dose of 16.56 kGy. The transmittances significantly decrease with increasing the irradiation dose. It is shown from the photoluminescence spectroscopy that sub-bandgap emission is present after irradiation. The sensitivity of CH₃NH₃PbBr₃-based photoconductor improves about tenfold after irradiation at 5.52 kGy, and the highest sensitivity is 1.12 mC Gy⁻¹ cm⁻² when the applied voltage is 4 V. This phenomenon of improving the electrical properties of the crystal after gamma-ray irradiation is correlated with decomposition and self-healing behavior.