Speaker
Description
Time-of-flight (ToF) measurements are widely used to probe charge transport properties in halide perovskites, including carrier mobility and trapping dynamics. While the technique is conceptually straightforward, its practical implementation is often affected by a range of experimental artifacts that can lead to significant misinterpretation of the results.
In this contribution, we present a practical guide to reliable ToF measurements on perovskite materials, based on common failure modes observed in real experiments. We demonstrate how excessive excitation density can distort signals via space-charge effects or plasma-like behavior, leading to incorrect transit time extraction. In thin samples and flexible detector structures, the measured current waveforms are often strongly shaped by device capacitance and the measurement circuit, requiring careful deconvolution or modeling of the instrument response.
We further discuss time-dependent changes in perovskite samples, emphasizing the need for control measurements and stability checks during data acquisition. Particular attention is given to solution-grown materials, where interfacial effects can produce apparent transit times unrelated to bulk transport, often resulting in overestimated mobilities.
Finally, we briefly address the role of ionic space charge and its impact on internal electric fields during measurement. The goal of this work is not to introduce a new method, but to provide a set of practical guidelines and diagnostic tools that help distinguish genuine transport phenomena from measurement artifacts.