Nano-thiophene-graphdiyne engineered buried interface toward homogeneous crystallization of perovskite films

The inherent inhomogeneous nucleation and growth of perovskite crystals are usually the causes that deteriorate the quality of perovskite films, limiting the construction of high-performance perovskite solar cells. Here, highly-dispersible and electron-rich nano-thiophene graphdiyne (SGDY) is prepared and strategically embedded onto the buried interface, which availably modulate the crystallization kinetics of perovskite. By providing uniformly distributed active intermolecular interaction sites, SGDY induces homogeneous generation of intermediate phases (FA 2 Pb 3 I 8 •2DMSO) via a δ-phase-free crystallization pathway. With the introduction of SGDY, the homogeneous nucleation and growth of perovskite facilitate the formation of smooth and dense films, displaying uniformly-distributed residual strain, reduced defect density, and suppressed non-radiative recombination. Moreover, the excellent electrical conductivity of SGDY ensures effective interfacial charge extraction and transport. Consequently, high-performance photovoltaic devices with a champion efficiency of 25.01 % (uncertified) were fabricated. Additionally, the unencapsulated devices retained 94.6 % of their initial efficiency after storage in a nitrogen atmosphere at room temperature. • Nano-thiophene-graphdiyne (SGDY) acts as a buried interfacial modifier, offering uniform active sites. • SGDY guides the formation of intermediate phase via a δ-phase-free pathway, yielding homogeneous perovskite crystallization. • Molecular-level SGDY interface engineering facilitates the construction of highly efficient and stable solar cells.