Quantitative loss analysis of opaque perovskite solar cells using transient and steady-state characterization

Perovskite solar cells have emerged as a promising technology in the field of photovoltaics, owing to their notable advancements in power-conversion efficiency. Recent investigations have revealed a crucial dependency of efficiency on the source of bromide within the perovskite absorption layer. To elucidate the underlying nature of traps within these solar cells, a comprehensive series of measurements was conducted under varying light intensities. Subsequently, employing an electrodynamic theoretical model, the intrinsic processes inherent to caesium and lead-based perovskite solar cells with different bromide sources were analyzed. The study reveals significant differences in transient photocurrent measurements and photocurrent-voltage characteristics among perovskites originating from different bromide sources, measured under different light intensities. Leveraging theoretical analyses on the picosecond scale, the recombination mechanism of crystal defects was meticulously described revealing the pronounced influence of capture rates on electron-hole recombination dynamics. Furthermore, the investigation substantiated the presence of a band-bending phenomenon at the interface between the hole transport layer (HTL) and perovskite, elucidating the observed transient photocurrent phenomena. The findings significantly advance the understanding of the mechanisms underlying perovskite solar cells, offering valuable insights into their performance and paving the way for enhanced efficiency and stability in future device design and optimization. Published by the American Physical Society 2024