Dopamine Sulfonate Ligand-Assisted TiO₂ Deposition Enabling Highly Efficient and Stable Perovskite Solar Cells

The metal oxide electron transport layers (ETLs) with flat morphology and high electrical quality are essential to manufacture highly efficient perovskite solar cells (PSCs), in which the regulation of the metal oxide deposition process plays a crucial role. Herein, a judiciously designed dopamine sulfonate (DS) ligand-assisted deposition of titanium dioxide (TiO₂) films approach is implemented based on electrostatic repulsion and steric hindrance of assembled ligands to improve colloidal nanoparticles dispersity in precursor and effectively inhibit their aggregation, which could enable obtaining smooth topography of TiO₂ films and initiating growth of top high-quality perovskite films. Furthermore, sulfonate bridges bonded on the perovskite buried layer that is beneficial to form better buried interface contact and accelerate electron extraction. As a result, the PSCs employing DS/TiO₂ ETLs exhibit the best power conversion efficiency of 24.53% with impressive storage stability and operation stability, i.e., remaining more than 88% of their initial efficiency upon storage N₂ glovebox without encapsulation over 4000 h, and the efficiency does not attenuate significantly under maximum power point for 60 h.