Radiation Tolerance of Hybrid Perovskite Solar Cells Studied with 8 MeV Proton Irradiation

Perovskite solar cells (PSCs) can be fabricated as lightweight, flexible, and highly efficient solar power devices at low cost. This advantage matches their applications to spacecrafts. We have evaluated the resistance of PSCs to high energy radiations, which is the biggest deterioration factor of the solar cells in the space. PSCs exhibit high radiation tolerance when the device is exposed to high fluences of 1 MeV electron and 50 keV proton beams, and perovskite crystals show a low minority-carrier diffusion length (DL) after irradiation of 1MeV electrons. It has been reported that the photocurrent-voltage (I-V) characteristics of InP solar cells, which have a low DL, recovers after radiation deterioration. To clarify whether or not that the perovskite crystals are introduced with substantial defects by radiation, I-V characteristics of PSC immediately after irradiation and its change over time have been evaluated. At room temperature, 8 MeV proton beam (an energy that can penetrates the PSC by causing deterioration to the all layers in PSC) was irradiated to high-efficiency PSCs with CsMAFAPb(IBr)₃ perovskite absorber. The energy incident on the PSC (<1 μm) after passing through the 0.3 mm thick quartz glass substrate was 4.4 MeV. We measured the remaining factor of the parameters of I-V characteristics of PSC (short-circuit current (Isc), open-circuit voltage (Voc) and fill factor (FF)) as a function of proton beam fluence. Up to a radiation dose of 1×10¹³ /cm², no significant degradation occurs in all parameters. With a radiation dose of 1×10¹⁴ /cm², degradation of less than 5% was observed in the Isc while FF decreased by 24% and Voc decreased by 9% immediately after irradiation. However, FF and Voc were almost recovered in 3 min after irradiation. The deterioration and recovery of I-V characteristics is considered to be due to some change of conductivity in the charge transport layers. The above investigation endorses that no defects are introduced into the perovskite crystals to deteriorate power generation performance with a radiation dose of 1×10¹⁴ /cm² and corroborate high radiation tolerance of the hybrid perovskite semiconductor.