What is a Charge Carrier Lifetime in a Perovskite Solar Cell?

Lifetimes of charge carriers are a key metric to quantify recombination in solar cells. However, due to different measurement modes, the word “lifetime” might mean many different things thereby making quantitative comparisons impossible. Here a consistent model for transient spectroscopy analysis is shown to solve this problem.

Recombination of charge carriers in solar cells is often analyzed using transient optical spectroscopy. Usually, the response of a sample to a laser pulse is studied and from the decay, conclusions about the severity of recombination are made. The downside of this approach is that it is unable to distinguish between a variety of different transient phenomena that occur in solar cells. To distinguish the mechanisms, a sensible model is required. Here, Krückemeier et al propose a relatively simple analytical model that allows to extract information from a variety of different methods such as transient photoluminescence (laser pulse in – luminescence transient out) and transient photovoltage (laser pulse in – voltage transient out). In particular, the model allows distinguishing different recombination mechanisms from each other as well as disentangling capacitive effects due to electrode charging and discharging from recombination.

Further information can be found here:
https://onlinelibrary.wiley.com/doi/full/10.1002/aenm.202102290