Enhanced Stability and Energy Transfer in Perovskite Nanocrystals: Paving the Way for Moisture-Resistant Light-Harvesting Devices

Near-unity photoluminescence quantum yield (PLQY), low trap-state density, and high-power conversion efficiency (PCE) make perovskite nanocrystals (PNCs) promising for optoelectronics and photovoltaics. However, native long-chain capped PNCs suffer from environmental vulnerability and inefficient charge/energy transport, limiting commercialization. To address this issue, we designed multifunctional bolaamphiphilic surface ligands (NKE-n) with varying hydrophobic spacer lengths (n = 3, 5, 11) to create hydrophilic NKE-modified PNCs. Achieving moisture-insensitive PNCs with a low trap-state density remains a scientific challenge. Here, we have developed a postsynthetic ligand-exchange strategy to mitigate surface traps without compromising water stability, which is crucial for enhancing PCE in polar media. As a proof-of-concept, we utilized NKE-modified PNCs as donors and observed efficient spatial energy transfer (FRET) for light harvesting. Surprisingly, FRET efficiency (phi(FRET)) remained high despite the increased hydrophobic spacer length, demonstrating the flexible nature of long-chain NKE ligands in facilitating efficient energy transfer while maintaining water stability as compared to native monoamphiphiles (such as oleylamine and oleic acid). This study holds promise for various applications, including the development of moisture-resistant perovskite-based light-harvesting devices, photovoltaics, optoelectronics, photon upconversion, and photocatalysis.