Property degradation of mixed-cation perovskite films and solar cells irradiated with protons

Abstract

This study reports on the proton irradiation-induced property degradation in Cs0.01MA0.01FA0.98PbI3 [MA = CH3NH3+, FA = CH(NH2)2+] perovskite films and solar cells (PSCs). Both 100 keV and 2 MeV protons are employed for irradiation. It is found that the threshold fluence for degradation of photovoltaic properties in PSCs is between 1 × 1013 and 1 × 1014 p/cm2 for 100 keV proton irradiation, or between 1 × 1014 and 2.2 × 1015 p/cm2 for 2 MeV proton irradiation. The degradation leads to a significant decrease in the short-circuit current; the open-circuit voltage is reduced to a less extent probably because of an increase in the electrical resistance across the interface between the perovskite and carrier transport layers. Irradiation-induced decomposition of CsMAFAPbI3 to PbI2 is observed due to the electronic energy deposition (radiolysis). With increasing proton fluence, the top Au electrode layer is finally exfoliated from the underlying spiro-OMeTAD layer, which could be attributed to the volume deformation of the spiro-OMeTAD induced by the accumulation of the gaseous products of perovskite decomposition.