Yenal Yalcinkaya1,Pascal Rohrbeck1,Stefan Weber1
Max Planck Institute for Polymer Research1
Yenal Yalcinkaya1,Pascal Rohrbeck1,Stefan Weber1
Max Planck Institute for Polymer Research1
Defect tolerance behaviour of lead halide perovskites makes them significantly important for photovoltaic applications. However, defects at the interfaces such as grain or junction boundaries can result in deep trap states which lead to lower power conversion efficiencies. In this study, we studied effect of some passivation agents on methylammonium-free cesium formamidinium lead ioide (Cs-FAPI) which suffers from phase instability. To this end, we compared the phase stabilities, optical properties, and solar cell efficiencies of pristine and passivated Cs-FAPI films. Finally, we performed time-resolved Kelvin Probe Force Microscopy (tr-KPFM) measurements to map the defects and passivation effect by means of mapping the photovoltage behaviour. This study shows the improvements on Cs-FAPI films and devices by passivation agents on nanoscale.