The controlled growth of two-dimensional (2D) perovskites on top of three-dimensional (3D) perovskite films can improve the performance and stability of perovskite solar cells (PSCs) by reducing interfacial recombination and impeding ion migration. However, the random orientation of the spontaneously formed 2D phase atop the pre-deposited 3D perovskite film can deteriorate charge extraction owing to energetic disorder, limiting the maximum attainable efficiency and long-term stability of the PSCs.
Schematic illustrating the reorientation of the 2D-MAP perovskite during and after the post-dripping process. Image credit: Nature Communications
Recently, an international team of scientists, including ones from Saudi Arabia’s KAUST, Korea University and the Chinese Academy of Science, developed a meta-amidinopyridine ligand and the solvent post-dripping step to generate a highly ordered 2D perovskite phase on the surface of a 3D perovskite film.
The reconstructed 2D/3D perovskite interface reportedly exhibited reduced energetic disorder and yielded cells with improved performance compared with control 2D/3D samples.
PSCs fabricated with the meta-amidinopyridine-induced phase-pure 2D perovskite passivation showed a maximum power conversion efficiency of 26.05% (a certified value of 25.44%).
Under damp heat and outdoor tests, the encapsulated PSCs maintained 82% and 75% of their initial PCE after 1000 h and 840 h, respectively, demonstrating improved practical durability.
The ligand post-dripping step was successfully applied using dip-coating and blade-coating deposition techniques, demonstrating the scalability of the proposed method.
This recent work highlights the importance of the reactivity of the ligand spacer with the perovskite to create high-quality monolithic 3D/2D perovskite interfaces for developing efficient perovskite photovoltaics.
