Researchers at Ulsan National Institute of Science and Technology (UNIST) and Korea University have reported efficient, stable tin–lead halide perovskites (TLHP)-based PV and photoelectrochemical (PEC) devices containing a chemically protective cathode interlayer—amine-functionalized perylene diimide (PDINN). Their work may advance the commercialization of perovskite solar cells (PSCs) and have potential in green hydrogen production technology, ensuring long-term operation with high efficiency.
The presence of inherent ionic vacancies in tin-lead halide perovskites (TLHPs) has posed challenges, leading to accelerated device degradation through inward metal diffusion. To address this challenge, the research team developed the chemically protective cathode interlayer using amine-functionalized perylene diimide (PDINN). By leveraging its nucleophilic sites to form tridentate metal complexes, PDINN effectively extracts electrons and suppresses inward metal diffusion.
The novel solution-processed PDINN cathode interlayer has showcased remarkable performance in stabilizing TLHP-based photovoltaic (PV) and photoelectrochemical (PEC) devices.
The PV device achieved an impressive efficiency of 23.21%, with over 81% retention after 750 hours of operation at 60 °C, and more than 90% retention after 3100 hours at 23 ± 4 °C. Additionally, the TLHP-based PEC devices, coupled with biomass oxidation, exhibited a record-high bias-free solar hydrogen production rate of 33.0 mA cm−2, approximately 1.7-fold higher than the target set by the U.S. Department of Energy for one-sun hydrogen production.
The innovative design of the cathode interlayer has successfully demonstrated the potential of TLHPs for efficient and stable photoconversion.
"We have dramatically increased the long-term stability of tin-lead PSCs," explained Professor Jang. "Our goal is not only to convert light energy into electrical energy but also to develop eco-friendly methods for producing basic chemicals, such as hydrogen, which form the foundation of various industries."