Enhancing Efficiency and Durability of Perovskite Solar Cells with Chlorine-Functionalized Fully Conjugated Porous Aromatic Framework.

Abstract

Non-radiative recombination, caused by trap states, significantly hampers the efficiency and stability of perovskite solar cells (PSCs). The emerging porous organic polymers (POPs) show promise as a platform for designing novel defect passivation agents due to their rigid and porous structure. However, the POPs reported so far lack either sufficient stability or clear sites of interactions with the defects. Herein, two chlorine-functionalized, fully conjugated porous aromatic frameworks (PAFs) were constructed via a decarbonylation reaction. The chlorinated PAFs feature unique long-range conjugated networks bearing multiple chlorine atoms, significantly improving the photovoltaic performance and stability of doped solar cells. Combined experimental and theoretical analyses confirmed the strong passivation effects of conjugated structure to the defect through Cl sites. Specifically, PAF-159, bearing a triphenylamine moiety, demonstrated stronger Cl-Pb bonding and higher passivation efficiency due to the presence of π* anti-bonding orbitals, which elevate the HOMO energy level and facilitate Cl-Pb charge transfer. Consequently, we obtained high-performance PAF-159-doped devices with advanced PCE (24.3%), good storage stability (retaining 86% after 3000 hours), and good long-term operational stability (retaining 92% after 350 hours).