Insights into Transient Photovoltage Lifetimes via Dark J-V Analysis in Perovskite Solar Cells

Transient photovoltage (TPV) decay measurements have commonly been used to estimate the charge carrier lifetimes in solar cell devices. However, it has recently been demonstrated that an intrinsic material property, such as the effective bulk carrier lifetime, can be severely masked by other device-related dynamics, such as the composite resistance-capacitance (RC) discharge times, particularly at lower illumination intensities. In this work, we systematically investigate these issues by examining the role that the device’s differential resistance plays on the TPV lifetimes as a function of the open circuit voltage. Using two different sets of perovskite solar cells, one of which was passivated through a special surface treatment chemistry, we clearly demonstrate that small differences in dark current density vs voltage (J-V) measurements are strongly correlated with TPV lifetime measurements in both devices. Using the two-diode recombination current model, we show that TPV lifetimes can be successfully predicted from a very fundamental yet often overlooked steady-state measurement technique.