Incorporation of 2D pyreneammonium iodide for enhancing the efficiency and stability of perovskite solar cells.

Despite the excellent performance of three-dimensional (3D) perovskite-based solar cells (PSCs), their poor stability under moisture and heating conditions limits their commercial application. To address this issue, a new pyreneammonium iodide (named TAPPyI), in which the pyrene-based compound 4,4',4'',4'''-(1,8-dihydropyrene-1,3,6,8-tetrayl)tetraaniline (named TAPPy) acts as the 2D cation, is introduced into 3D perovskite precursor solution for forming a 2D/3D heterostructured perovskite, which improves the quality of the perovskite film and enhances the stability of the perovskite film against moisture and heating. The planar pyrene endows TAPPyI with good charge transport properties, while the iodide on the arylamine side group effectively passivates the perovskite defects, thereby suppressing non-radiative recombination losses. Finally, the power conversion efficiency (PCE) of the TAPPyI-modified PSC is increased from 20.51% in the reference PSC to 22.73%. Furthermore, the stability of the TAPPyI-modified PSC is greatly improved, retaining 86% of the initial PCE after 360 hours in an environment of 85 °C and 85% humidity (ISOS-D-3), whereas the reference PSC only retains 2%. This work demonstrates that the conjugated planar molecule as a 2D cation to construct a 2D/3D heterostructured perovskite, which combines the good stability of 2D perovskite with the excellent carrier transport properties of 3D perovskite, can greatly enhance the efficiency and stability of PSCs.