Interfacial passivation with 2-aminopyridine for effective perovskite solar cells

Interface defect is one of the main factors that lead to non-radiative recombination of carriers at the interface and the decomposition of perovskites . This ultimately results in low efficiency and poor stability of perovskite solar cells (PSCs). Here, a passivated molecule called 2-Aminopyridine (2-APy) was proposed to reduce the defects of the interface between the perovskite and the hole transport layer. The results showed that the amino group in 2-aminopyridine can interact with the vacancy and free iodide ions on the surface of perovskite, thus passivating the defects at the interface and enhancing the hole transport capacity. As a result, 2-APy-modified PSCs exhibited inhibited non-radiative recombination, and the efficiency of PSCs increased to 21.46 %. The increase in the efficiency of PSCs is primarily seen in the rise of the open circuit voltage (V OC , from 1.12 to 1.15 V) and short circuit current (J SC , from 22.86 to 23.77 mA/cm 2 ). This work demonstrates that pyridine is an effective group for passivating the defects between the perovskite layer and the hole transport layer.