An In Situ Polymerization Strategy to Enhance Thermal Stability of Perovskite Solar Cells

The limited operational stability of perovskite solar cells (PSCs) remains the primary obstacle to their commercialization. Introducing organic molecules with coordination and hydrogen bonding has been demonstrated as an effective strategy for enhancing the stability of PSCs. Herein, we introduced acrylamides into the perovskite precursor solution, enabling in situ polymerization to form polyacrylamide at grain boundaries without sacrificing the crystal quality of perovskite films. The -C = O and -NH₂ functional groups in polyacrylamide form coordination bonds and hydrogen bonds with uncoordinated Pb²⁺ and I^- at grain boundaries, respectively. The nonradiative recombination has been obviously suppressed, with the efficiency improved from 24.55to 25.85%. Notably, the introduction of polyacrylamide transformed the lattice strain from a large tensile to compressive stress, significantly improving the thermal stability of perovskite films. The polyacrylamide modified device exhibited less than 3% efficiency degradation after continuous heating at 65 °C for 500 h, whereas the control device showed a loss of over 40% within 300 h. The results suggest that the in situ polymerization strategy holds great promise for enhancing the stability and efficiency of PSCs, thus advancing their path toward commercialization.