China's new coating boosts perovskite solar cells' efficiency to 26.6%

Chinese researchers from Xi’an Jiaotong University have developed a novel molecular press annealing (MPA) technique that significantly enhances the efficiency and durability of perovskite solar cells (PSCs). This method involves thermal and pressure bonding of a capping layer containing 2-pyridylethylamine, which forms a solid-state bidentate coordination complex with under-coordinated lead cations in the perovskite structure. This interaction preserves the lattice integrity, prevents iodide loss during the heating process, and suppresses defect formation that typically degrades the crystal structure and reduces efficiency. As a result, the n-i-p perovskite solar cells achieved a power conversion efficiency (PCE) of 26.6%, with devices retaining over 97% of their initial efficiency after prolonged operation under harsh conditions of 85°C and 60% relative humidity. The study, published in the journal Science, highlights that the MPA strategy not only boosts efficiency but also greatly