A research team from Ulsan National Institute of Science and Technology (UNIST), University of New South Wales, University of Surrey and
Korea Research Institute of Chemical Technology have developed an interlayer that leverages the specificity of organic cations on the surface of perovskite solar cells (PSCs), simultaneously achieving high-efficiency and durability.
Credit: Joule (2025)
PSCs generate electrical energy by transferring charge carriers created when the light-absorbing material absorbs sunlight to the electrodes. Minimizing defects in this light-absorbing layer is essential for effectively delivering charges to the electrodes and enhancing cell efficiency. Previously, research focused on the use of single organic cations, which posed challenges such as structural collapse of the thin films due to the migration of individual cations and energy level misalignment. Energy levels serve as a "staircase" pathway for charge movement; if the interlayer energy levels are misaligned, charge losses can occur, leading to reduced efficiency.
To address this issue, the research team used a dual cation approach to design a thermally stable interlayer. By exploiting the differing intermolecular interactions of two types of organic cations, they stabilized the interface structure and naturally aligned the energy levels conducive to efficient hole transport. Additionally, the concentration of defects within the perovskite thin film was significantly decreased, leading to a marked improvement in charge retention.
The PSCs incorporating this interlayer technology achieved a power conversion efficiency (PCE) of 26.3%, rivaling the efficiencies of commercial silicon cells. Furthermore, when stored at room temperature for 9,000 hours, the cells maintained close to 100% of their original performance, demonstrating exceptional long-term stability.
Looking ahead, the team aims to develop PSCs that exceed 28% efficiency while maintaining high durability and plans to continue their efforts toward the commercialization of this technology.
