Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV22)
DOI: https://doi.org/10.29363/nanoge.hopv.2022.134
Publication date: 20th April 2022
Small perturbation techniques are widely used to extract device properties of solar cell devices. However, obtaining the electronic parameters for diffusion and recombination by impedance spectroscopy in perovskite solar cells has been so far elusive, since the measured spectra do not present the diffusion of electrons. Here we show that intensity modulated photocurrent and photovoltage spectroscopies (IMPS and IMVS) display a high frequency spiraling feature determined by the diffusion-recombination constants, under conditions of generation of carriers far from the collecting contact. We also demonstrate how the values of these constants prevent the diffusion trace from being distinguishable in impedance spectra. We present two different models and experiments for distinct configurations: the standard sandwich-contacts solar cell device and the quasi-interdigitated back-contact (QIBC) device for lateral long-range diffusion. The results of the measurements give hole diffusion coefficients and lifetimes that are in the order of what has been reported previously in the literature. The analysis in the frequency domain is effective to separate the carrier diffusion (at high frequency) from the ionic contact phenomena at a low frequency. This result opens the way for a systematic determination of transport and recombination features in a variety of operando conditions.