Publication date: 17th July 2025
The efficiency of halide perovskite solar cells has been continuously rising over the past decade to values above 26%. Future technological development will have to deal with issues of device stability but also thrive to further minimize efficiency-limiting loss processes in the bulk and at interfaces within the cell stack. The identification and understanding of electrical losses will require the ability to characterize solar cells and multilayer stacks with a variety of steady-state, time-domain and frequency-domain techniques that are sensitive to the transport and recombination of charge carriers. Especially, time- and frequency-domain techniques offer a large amount of information on dynamic processes in the solar cell, while posing a substantial challenge in terms of the complexity of data analysis.1 Here, I discuss our recent work related to transient photoluminescence (TPL) applied to halide perovskites. I show that by using extremely low repetition rates and a gated CCD camera, we can obtain high dynamic range TPL data with continuously changing decay times that exceed 100µs.2-3 Furthermore, I show that by changing the repetition rate, basically any decay time can be extracted from one sample, whereby the extracted decay time is approximately the inverse repetition rate. I explain why this is the case both mathematically and physically. Further, I present recent results on the determination of diffusion lengths as a function of injection level4 using the reabsorption effect.