Tailored electron-deficient macrocycles guiding the perovskite crystallization process for solar cells

Abstract

Perovskite solar cells (PSCs) exhibit impressive power conversion efficiencies (PCEs), but their stability still falls short of industrial commercialization requirements, primarily due to inherent defects and halide ion migration within the perovskite materials. To address this shortcoming, we developed a novel electron-deficient biphen[n]arene macrocycle molecule, NBP[2], synthesized through the condensation of the monomer 2,2″,4,4″-tetramethoxy-4’,6’-dinitro-1,1’:3′,1″-terphenyl (NP) with paraformaldehyde. When the macrocyclic molecule is introduced into the perovskite film via the antisolvent injection method, it functions as a regulator of the crystallization process of perovskite and an inhibitor of halide anion migration. In addition, NBP[2] can effectively bind with uncoordinated halide ions and Pb²⁺, reducing intrinsic defects through Lewis acid–base and cation−π interactions. As a result, NBP[2]-modified PSCs achieve a PCE of up to 25.38% (compared to 23.89% for the control) and retain 95.8% of their initial efficiency after 1000 h of maximum power point tracking under 1-sun illumination at room temperature in an N₂ atmosphere.