Low temperature processable perovskite solar cell based on SnO2 nanoparticle and polyelectrolytes

Abstract

Organic-inorganic mixed halide perovskite solar cell (PSCs) have been studied in recent years due to their superior optical, electrical properties, such as long charge diffusion lengths, panchromatic absorption, solution processability, a sharp optical bandgap, abundance of ingredients and very high absorption coefficient. To date, significant research efforts have been devoted in PSCs and a power conversion efficiency (PCE) have reached to 23% in less than five years. Recently, various studies have been carried out to achieve the remarkable progress of PSCs, for example, interface engineering, additives, solvent engineering, compositional engineering and diffusion engineering. Among various approaches, interfacial engineering has attracted considerable interest as effective and simple method for improving device performance. In this work, we employed the two well-known polyelectrolytes (PEs) including amine group on their side chain as cathode buffer layer in planar heterojunction solar cells: Poly[9,9-dioctyl-9',9'-bis[3-(trimethylammonio)propyl][2,2'-bi-9H-fluorene]-7,7'-diyl bromide (PFN-Br) and Polyethylenimine ethoxylated (PEIE). For planar perovskite solar cells, we fabricated the solar cells with the device architecture of glass / ITO / SnO2 / PEs / perovskite / Spiro-MeOTAD / MoO3 / Ag. Furthermore, we investigated the effect of two different PEs on the morphology, bandgap tuning and performance of perovskite solar cells. Finally, due to the interaction between SnO2 and the amine groups on the side chains of the both PEs, we could obtain the better device performance.