Recombination resistance identification through current-voltage curve reconstruction in perovskite solar cells

Abstract

Perovskite solar cells (PSCs) have demonstrated remarkable advancements in efficiency and stability, yet fully understanding the dynamic processes governing their performance remains a challenge. Impedance spectroscopy (IS) offers a powerful means to characterize PSCs over a wide range of time scales, revealing insights into the internal electronic and ionic processes. However, critical factors like recombination, charge extraction, and transport resistance are often coupled in the same spectra response, affecting their accurate identification. This study explores the use of the j-V curve reconstruction as a tool to identify when recombination governs the impedance response. Our findings show that recombination resistance can be accurately identified, regardless of the underlying recombination mechanism, in the solar cells with unhindered charge extraction. Conversely, in devices with hindered charge extraction, the IS fitting struggles to decouple the transport, extraction and recombination processes, resulting in inaccurate j-V reconstructions. These findings emphasize the importance of accurately identifying the physical processes influencing IS spectra to improve diagnostics and device performance in PSC technologies.