Chemical pre-regulation of 2D perovskite nucleation enables phase-homogeneous 2D/3D perovskite interfaces

Abstract

Two-dimensional/three-dimensional (2D/3D) perovskite heterojunctions are widely employed to enhance the efficiency and stability of perovskite solar cells; however, their performance is often limited by interfacial phase heterogeneity originating from uncontrolled 2D nucleation. Here, we introduce a chemical pre-regulation strategy for 2D perovskite nucleation based on bifunctional chelation, enabling the formation of phase-homogeneous 2D/3D perovskite heterostructures. Through pre-conditioning of the 3D perovskite surface with methylsulfonic anhydride prior to 2D growth, a chemically coupled interfacial environment is established that homogenizes 2D nucleation without disrupting the intrinsic layered perovskite structure. This pre-regulated nucleation pathway effectively suppresses lateral phase heterogeneity and light-induced phase segregation. Consequently, the resulting phase-homogenized 2D/3D interfaces exhibit reduced energetic disorder, suppressed non-radiative recombination, prolonged carrier lifetimes, and enhanced interfacial charge extraction. Perovskite solar cells incorporating this strategy achieve a champion efficiency of 24.37% together with markedly enhanced operational and thermal stability, retaining 94.03% of their initial efficiency after 720 h of continuous illumination and 92.91% after 1200 h at 65 °C. This work establishes chemical pre-regulation of nucleation as a decisive design principle for stabilizing low-dimensional perovskite interfaces, offering a versatile framework for engineering phase-homogeneous heterostructures in perovskite optoelectronics.