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 alpha-FAPbI(3) perovskite solar cells. To realize a stabilized alpha-FAPbI(3), a delta-FAPbI(3) film was annealed at 150 degrees C at ambient air with a humidity level of 25 % to convert alpha-FAPbI(3). Then, this delta ->alpha FAPbI(3) was crushed, and some of it was added to a fresh FAPbI(3) perovskite precursor to fabricate desirable alpha-FAPbI(3) layers. The cost-effective method, along with the stabilization of alpha-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.