Modulated Techniques to Analyse Photoconversion Devices

Abstract

The urgent need for a sustainable energetic system to mitigate global warming has increased interest in solar energy as a promising solution. Currently, photoconversion technologies generate only a small fraction of the total energy consumption. There are promising emerging technologies, including perovskite solar cells and photoelectrochemical systems, for hydrogen generation. However, these technologies face stability and performance challenges. The investigation of these technologies using modulated techniques: impedance spectroscopy, intensity-modulated photocurrent and photovoltage spectroscopies, can contribute to identifying their limitations. In this thesis, we have correlated the “negative capacitance” in impedance spectroscopy and the “inverted hysteresis” in current-voltage curves, attributing them in solar cells to an ionic deleterious process. Furthermore, we have developed a methodology to analyse the three modulated techniques in combination, allowing for a deeper analysis. These results allow a better understanding of the performance of photoconversion devices, identifying their limitations, and thereby contributing to their improvement.