  Pinpointing the origin of inefficiency can expedite the process of optimizing
the efficiency of perovskite photovoltaics. However, it is challenging to
discern and quantify the different loss pathways in a complete perovskite
photovoltaic device under operational conditions. To address this challenge, we
propose a modified diode model that can quantify bulk/interface defect-assisted
recombination and series/shunt resistive losses. By adopting drift-diffusion
simulation as the benchmark, we explore the physical meanings of the modified
diode model parameters and evaluate the performance of the model for simulation
parameters spanning many orders of magnitude. Our evaluation shows that, in
most practical cases, the proposed model can accurately quantify all the
aforementioned losses, and in some special cases, it is possible to identify
the predominant loss pathway. Moreover, we apply the modified diode model to
our lab-produced devices (based on Cs0.05FA0.95PbI3 perovskites), demonstrating
its effectiveness in quantifying entangled losses in practice. Finally, we
provide a set of guidelines for applying the modified diode model and
interpreting the results. Source code available at
https://github.com/WPT-Lab124/Modified-Diode-Model.
