Cyclen molecule manipulation for efficient and stable perovskite solar cells

Abstract

Although perovskite solar cells (PSCs) have been developed rapidly, the poor quality of perovskite films and difficulty in the scalable fabrication under air conditions hinder the improvement of PSC performance. In this work, a novel ring molecule, 1,4,7,10-tetraazacyclododecane (cyclen), is introduced to manipulate high-quality film fabrication. We, for the first time, captured a key intermediate, cyclen-PbI₂-DMSO, which retarded the crystallization process, promoted the carrier lifetime, and decreased non-radiative recombination. According to DFT calculations and experimental characterization, the cyclen interacted well with Pb²⁺ ions to manipulate perovskite film crystallization and reduce defect density. Consequently, the small-area device with a power conversion efficiency up to 24.71% was fabricated and could still maintain 90% of its original PCE over 1600 h at 85 °C in an N₂ atmosphere without encapsulation. Additionally, the constructed 36 cm²-area cyclen modules yielded an efficiency of 20.08% via the auto-blade coating process under air conditions.