A team of researchers led by Professor Sung-Yeon Jang from the School of Energy and Chemical Engineering at UNIST has introduced a groundbreaking ligand exchange technique, significantly advancing the efficiency of organic cation-based perovskite quantum dot (PQD) solar cells. This innovative approach, detailed in a recent study, not only achieves an impressive 18.1% efficiency but also addresses challenges related to stability and internal defects within the photoactive layer of solar cells.
Professor Jang highlighted the achievement, stating, “Our developed technology has achieved an impressive 18.1% efficiency in QD solar cells. This remarkable achievement represents the highest efficiency among quantum dot solar cells recognized by the prestigious National Renewable Energy Laboratory (NREL) in the United States.”
Perovskite quantum dots (PQDs) have been a focal point for researchers due to their exceptional photoelectric properties. The manufacturing process involves a straightforward spraying or application to a solvent, eliminating the need for growth processes on substrates, facilitating high-quality production in various manufacturing environments.
Despite their potential, the practical application of PQDs in solar cells required a technology capable of reducing the distance between quantum dots through ligand exchange. The team addressed challenges specific to organic PQDs by employing an alkyl ammonium iodide-based ligand exchange strategy. This approach effectively substituted ligands, enabling the creation of a photoactive layer with high substitution efficiency and controlled defects.
The breakthrough resulted in a significant enhancement of the efficiency of organic PQDs from 13% to an impressive 18.1%. Notably, these solar cells demonstrate exceptional stability, maintaining performance even after extended storage for over two years. This development marks a crucial stride in the utilization of organic PQDs, which have historically faced challenges, as inorganic PQDs with limited efficiency were predominantly used in solar cells.
Sang-Hak Lee, the first author of the study, emphasized the study’s impact, stating, “Through this study, we have demonstrated the potential by addressing the challenges associated with organic PQDs, which have proven difficult to utilize.”
Professor Jang concluded, “This study presents a new direction for the ligand exchange method in organic PQDs, serving as a catalyst to revolutionize the field of QD solar cell material research in the future.” The research opens doors to advancements in solar cell technology, with implications for both efficiency and stability in organic PQD-based solar cells.