Poly[Nitrilo(Diphenoxyphosphoranylidyne)] Passivated Mapbi3 Film Achieves 21.36% Efficiency and Superior Multivariate Stability for Air-Processed Perovskite Solar Cells

Abstract

The air-processed perovskite solar cells (PSCs) have garnered significant attention from researchers globally due to their straightforward and cost-effective fabrication process. However, perovskite thin films are susceptible to corrosion during their preparation, and the open-air environment often introduces numerous adverse factors. For instance, unsuitable humidity and oxygen atmosphere usually lead to imperfect perovskite crystallization and various surface defects, which severely reduce both the power conversion efficiency (PCE) and stability of ultimate device. Hence, in order to precisely alter the MAPbI3 perovskite layer, a polymer passivation technique is used via adding Poly[nitrilo(diphenoxyphosphoranylidyne)] (PDPP) additive into green anti-solvent. The polymer long chain of PDPP is made up of nitrogen and phosphorus ions that alternate, and ample oxygen and benzene rings are simultaneously inserted on both sides. Through Lewis acid-base interactions, phosphorus oxygen groups can form bonds with lead (Pb), while nitrogen can form hydrogen bonds with methylamine (MA). These two bonding processes can simultaneously fill the vacancies caused by I and Pb. The benzene ring exhibits both electrical activity and hydrophobic properties, which beneficial for improving the efficiency and stability of ultimate device. On the other hand, the flexible polymer chain could easily congregate at perovskite grain boundaries to enhance its bending resistance. As a result, the high-quality MAPbI3 film display enhanced crystallinity, larger grain size, suppressed non-radiative recombination and decreased defect density. The air-processed PDPP-passivated optimal device obtain 21.36% champion PCE, which almost caught up with the samples prepared in the glove box. Moreover, the unencapsulated PDPP-modified device also reveal excellent multivariate stability, including humidity, temperature, sunlight exposure, and bending. This simple, low cost and green strategy will advance its applicability.

Keywords: Perovskite solar cells, Air-processed, Poly[nitrilo(diphenoxyphosphoranylidyne)], Multivariate stability