Highly efficient and stable quasi two-dimensional perovskite solar cells via synergistic effect of dual additives

Recently, quasi two-dimensional (Q-2D) perovskites with alternating cations in the interlayer space (ACI) have attracted more attentions owing to their elevated stability compared with three-dimensional (3D) analogs. While the efficiency of the devices derived from Q-2D perovskites is much smaller than that based on 3D perovskites. Here, we utilized urea and methoxyamine hydrochloride (MOAH) dual additives to acquire high quality Q-2D ACI perovskite GA(MA)₅Pb₅I₁₆ (GA = guanidinium, MA = methylammonium) films. The efficiency of the perovskite solar cells (PSCs) derived from the Q-2D perovskite films induced by the synergistic effect of urea and MOAH dual additives increases to 20.32% from 17.21% for the devices without additive. This efficiency enhancement could be attributed to the enlarged grain size, improved crystallinity, optimized quantum well thickness distribution, and reduced trap states of the perovskite films. Moreover, the solar cells with dual additives present improved stability. The efficiency of devices with dual additives holds 95% of the original value after storage for 1600 h in ambient air. These results prove that the synergistic effect of urea and MOAH is an effective method to achieve highly efficient and stable Q-2D PSCs.