Superior stabilized α-FAPbI3 perovskite solar cells with efficiency exceeding 24 %

-Fabrication of a stabilized black phase of formamidinium triiodide perovskite film is a critical issue to warrant efficient perovskite solar cells with considerable intrinsic and external stability. To address this obstacle, the study focuses on assembling α-FAPbI 3 perovskite solar cells . To realize a stabilized α-FAPbI 3 , a δ-FAPbI 3 film was annealed at 150 °C at ambient air with a humidity level of 25 % to convert α-FAPbI 3 . Then, this δ → α FAPbI 3 was crushed, and some of it was added to a fresh FAPbI 3 perovskite precursor to fabricate desirable α-FAPbI 3 layers. The cost-effective method, along with the stabilization of α-FAPbI 3 , showed a high ability to promote charge transfer and suppress trap transitions in the perovskite layer. The engineered perovskite solar cells recorded a considerable filling factor of 82.89 % with a champion efficiency of 24.16 %, higher than the recorded efficiency of 21.25 %. In addition, the robust stability enables the FAPbI 3 solar cells to work steadily for more than 1200 h under simulated sunlight irradiance with just an 8 % loss in their performance. • Developed a method to stabilize α-FAPbI3 by annealing δ-FAPbI3 at 150 °C in ambient air with 25 % humidity. • Used a cost-effective approach by adding crushed δ.→α FAPbI3 to fresh precursors to create high-quality α-FAPbI3 layers. • Achieved a high filling factor of 82.89 % and an efficiency of 24.16 %, surpassing previous records of 21.25 %. • Solar cells maintained performance with only an 8 % loss after 1200 h of simulated sunlight exposure.