Upgraded antisolvent engineering enables 2D@3D quasi core-shell perovskite for achieving stable and 21.6%efficiency solar cells

Perovskite solar cells(PSCs)have become a promising alternative to sustainable energy due to their high power conversion efficiency(PCE)and low-cost processing.However,the practical applications of PSCs are still limited by the trade-off between high performance and poor stability under operation.Here,a2D@3D perovskite with quasi core-shell architecture linking the superiorities of both two-dimensional(2D)and three-dimensional(3D)perovskite is prepared through a novel upgraded antisolvent approach.The basic properties as well as the phase distribution and the charge transport behavior of the 2D@3D perovskite were systematically elucidated.A high PCE of 21.60%for 2D@3D PSCs is achieved due to the enhanced surface and grain boundaries passivation,improved energy level alignment and efficient holes transport.The 2D@3D perovskite device without encapsulation shows significantly improved stability at the room temperature(90%of initial PCE for 45 d with a relative humidity of 50%±5%)and relative thermal conditions(83%of initial PCE for 200 h under 85℃).Compared with traditional 3D PSCs,it proved that such 2D@3D perovskite configuration is an effective architecture for enhancing efficiency and improving stability and therefore will facilitate the further industrialization of PSCs.