Superior Stability and Efficiency Over 20% Perovskite Solar Cells Achieved by a Novel Molecularly Engineered Rutin–AgNPs/Thiophene Copolymer

Perovskite solar cells (PSCs) with efficiencies greater than 20% have been realized mostly with expensive spiro‐MeOTAD hole‐transporting material. PSCs are demonstrated that achieve stabilized efficiencies exceeding 20% with straightforward low‐cost molecularly engineered copolymer poly(1‐(4‐hexylphenyl)‐2,5‐di(thiophen‐2‐yl)‐1H‐pyrrole) (PHPT‐py) based on Rutin–silver nanoparticles (AgNPs) as the hole extraction layer. The Rutin–AgNPs additive enables the creation of compact, highly conformal PHPT‐py layers that facilitate rapid carrier extraction and collection. The spiro‐MeOTAD‐based PSCs show comparable efficiency, although their operational stability is poor. This instability originated from potential‐induced degradation of the spiro‐MeOTAD/Au contact. The addition of conductive Rutin–AgNPs into PHPT‐py layer allows PSCs to retain >97% of their initial efficiency up to 60 d without encapsulation under relative humidity. The PHPT‐py/ Rutin–AgNPs‐based devices surpass the stability of spiro‐MeOTAD‐based PSCs and potentially reduce the fabrication cost of PSCs.