Perovskite Films Regulation via Hydrogen‐Bonded Polymer Network for Efficient and Stable Perovskite Solar Cells

Perovskite solar cells (PSCs) are considered as a promising photovoltaic technology due to their high efficiency and low cost. However, their long‐term stability, mechanical durability, and environmental risks are still unable to meet practical needs. To overcome these issues, we designed a multifunctional elastomer with abundant hydrogen bonds and carbonyl groups. The chemical bonding between polymer and perovskite could increase the growth activation energy of perovskite film and promote the preferential growth of high‐quality perovskite film. Owing to the low defect density and gradient energy‐level alignment, the corresponding device exhibited a champion efficiency of 23.10 %. Furthermore, due to the formation of the hydrogen‐bonded polymer network in the perovskite film, the target devices demonstrated excellent air stability and enhanced flexibility for the flexible PSCs. More importantly, the polymer network could coordinate with Pb 2+ ions, immobilizing lead atoms to reduce their release into the environment. This strategy paves the way for the industrialization of high‐performance flexible PSCs.