Nanoscale Mapping in Organic and Perovskite Solar Cells: A Versatile Technique to Engineer the Photovoltaic Yields

Recently, organic solar cells (OSCs) and perovskite solar cells (PSCs) have emerged as solution-processable photovoltaic (PV) technologies with certified power conversion efficiencies (PCE) of about 18% and 25.7%, respectively, within a short time span. However, some challenges still exist in fully investigating and controlling the performance-limiting factors in the photoactive layers of OSCs and PSCs, such as surface conductivity, topography, and morphological distortions at the nanoscale. Although several efforts to investigate and address the above phenomena have been reported, the origin of the nanoscale defects and how they lead to performance losses have not yet been fully explained. This work aims to explain in-depth the nanoscale imaging and mapping within OSCs and PSCs and how remedies to the nanoscale defects can improve PV device performance. The similarities and differences in charge generation, charge separation, charge transport, charge collection, and charge recombination in these two technologies are discussed. These are linked back to the intrinsic material properties of organic and perovskite semiconductors, and how these factors impact photovoltaic device performance is elucidated. This nanoscale mapping technique can also be extended to test large-area active layer coatings fabricated through various deposition techniques, such as blade coating, slot-die coating, and doctor blading, to enhance the photovoltaic properties of scalable OSCs and PSCs.