Poly(acrylic acid)‐Modified SnO₂ Electron Transport Layer for Perovskite Solar Cells

Abstract

SnO2 is one of the most used inorganic electron transport materials for organic‐inorganic halide perovskite solar cells. However, the surface defects of SnO2 will block the electron transport at the SnO2/perovskite buried interface and limit the device performance. Here, poly(acrylic acid) (PAA) is employed to modify the SnO2 electron transport layer. Carboxyl groups can react with KOH in the commercial SnO2 aqueous colloidal dispersion to produce potassium polyacrylate, the −COO− can combine not only with oxygen and Sn4+ on SnO2, but also can chelate with uncoordinated Pb2+ defects on perovskite. Moreover, carboxyl groups can form a chemical linker between SnO2 and perovskite via the esterification reaction, leading to the reduction of surface hydroxyl group defects of SnO2. The optimal solar cells with PAA modification achieve an enhanced power conversion efficiency of 18.88 % and improved stability.

Amino acid salt induced PbI2 crystal orientation optimization for high-efficiency perovskite solar cells with long-term stability

“…Following the modification of PL-Glu on SnO 2 , a blue shift in the –COO − stretching vibration peak was observed, indicating the interaction between SnO 2 and –COO − on PL-Glu. 36 This finding agrees with the XPS analysis results.…”