Enhancing the stability of perovskite solar cells through cross-linkable and hydrogen bonding multifunctional additives

Abstract

Ion migration, especially I⁻ migration, is a main issue limiting the stability of perovskite solar cells (PSCs). Here, we introduce a multifunctional additive of dipentaerythritol pentaacrylate (DPPA) into perovskite films to suppress the ion migration. The CH₂CH groups in DPPA will crosslink at grain boundaries and block the channels of ion migration. Importantly, the alkoxy (–O–CH₂) and hydroxyl (–OH) groups in DPPA can bond with the FA⁺ and I⁻ ions in the perovskite through hydrogen interaction, chemically immobilizing these migrated ions. As a result, ion migration in the perovskite is effectively inhibited owing to the synergistic function of DPPA. PSCs with DPPA exhibit a high efficiency of over 22% with good operational stability, retaining over 90% of maximum efficiency after maximum power point (MPP) tracking for 800 hours under continuous illumination. In addition, the air and thermal stabilities are also enhanced and over 90% of initial efficiency is retained after aging in air or at 85 °C for 1000 hours.