Perovskite solar cells with self-disintegrating seeds deliver an 83.64 % fill factor

Large-seed-induced regulation significantly impacts perovskite film grain growth; however, it inadequately addresses stress and defect issues at the perovskite interface. To counter this, we introduce an innovative self-disintegrating seed approach, employing 2D (4-FBZA)₂PbI₄ perovskite to enhance the crystallization process. During perovskite crystal growth, (4-FBZA)₂PbI₄ could disintegrate and release 4-FBZA⁺ ions. These ions effectively anchor the perovskite interface and interact with FA⁺ and [PbI₆]^4- within the lattice, passivating defects and releasing detrimental stress. This strategy results in reduced nonradiative recombination and residual stress, culminating in perovskite solar cells (PSCs) achieving a champion power conversion efficiency (PCE) of 23.73 % and a remarkable fill factor of 83.64 %. Crucially, unencapsulated PSCs retain over 90 % of their initial PCE following 2000 h of exposure in ambient conditions at 25±5 °C and 60 % relative humidity.