Room temperature slot-die coated perovskite layer modified with sulfonyl-γ-AApeptide for high performance perovskite solar devices

•Large area perovskite layer slot-die coated on CBD prepared c-TiO2 at room temperature.•The multi-functional F-GLU-S strongly coordinated with perovskite through Pb-C=O/N/O and N-H…Cl.•F-GLU-S modified the uncoordinated Pb2+ ions and I- vacancy concurrently.•F-GLU-S treatment improved PL, Voc and charge recombination resistance significantly.•F-GLU-S modified slot-die coated planar perovskite device produced 21.44% PCE.