  While transient photoluminescence measurements are a very popular tool to
monitor the charge-carrier dynamics in the field of halide perovskite
photovoltaics, interpretation of data obtained on multilayer samples is highly
challenging due to the superposition of various effects that modulate the
charge-carrier concentration in the perovskite layer and thereby the measured
PL. These effects include bulk and interfacial recombination, charge transfer
to electron or hole transport layers and capacitive charging or discharging.
Here, numerical simulations with Sentauraus TCAD, analytical solutions and
experimental data with a dynamic range of ~7 orders of magnitude on a variety
of different sample geometries from perovskite films on glass to full devices
are combined to present an improved understanding of this method. A
presentation of the decay time of the TPL decay that follows from taking the
derivative of the photoluminescence at every time is proposed. Plotting this
decay time as a function of the time-dependent quasi-Fermi level splitting
enables distinguishing between the different contributions of radiative and
non-radiative recombination as well as charge extraction and capacitive effects
to the decay.
