Enhanced stability and solar cell performance via π-conjugated Lewis base passivation of organic inorganic lead halide perovskites

Abstract

Abstract High power conversion efficiency (PCE) and good long-term stability of the perovskite solar cell (PSC) are two important factors on its commercial applications. Here, we propose a simple way to improve the PSC performance by adding 3,3′,5,5′-azobenzene-tetracarboxylic acid (H4abtc) into the lead iodide (PbI2) precursor solution with Lewis acid-base adduct via two-step solution method. 24% enhancement of the PCE is achieved for the PSC with 2.0% H4abtc comparing with the pure PSC without H4abtc. Further research suggests that the H4abtc can passivate grain boundaries of perovskite film by reacting with the lead cation, therefore leading to good thermal stability and anti-moisture of perovskite films. The paper provides a new method to prepare a stable and efficient PSC by employing a novel Lewis base to passivate grain boundaries and gain high-quality perovskite films.