ITO Nanoparticles to Stabilize the Self‐Assembly of Hole Transport Layer in Inverted Perovskite Solar Cells

Abstract Recently, inverted perovskite solar cells (PSCs) show rapidly improved efficiency with the use of self‐assembled molecules (SAM). However, device stability remains a challenge due to the easy desorption of the SAM molecule. Here, functionalized indium tin oxide nanoparticles (INPs) are introduced to promote and reinforce the self‐assembly of SAM on the substrate. INPs contain abundant ─OH groups to uniformly anchor SAM molecules. Importantly, different from traditional physically absorbed and easy‐desorbed ─OH in ITO substrate, the ─OH groups on INPs are stably bonded, resistant to solvent rinsing and long‐term aging, thus inhibiting SAM desorption during device aging. As a result, PSCs with INPs exhibit high efficiency of 26.44% with good operational stability under ISOS‐L‐2 protocol, retaining ∼≈91% of initial efficiency after maximum power point (MPP) tracking with continuous illumination at 85 °C.