Precursor-Level Molecular Coupling Enables High-Fill-Factor Wide-Bandgap Perovskite Solar Cells and 29.63% All-Perovskite Tandems.
Wide-bandgap (WBG) perovskites with a ∼1.78 eV bandgap are essential for monolithic all-perovskite tandem cells, yet their efficiency and stability are limited by complex precursor chemistry, uncontrolled crystallization, defect formation, and photoinduced halide segregation. Here, we report 4-(3-Carbamimidoylguanidino...