A low-cost and green-solvent-processable hole-transport material enabled by a traditional bidentate ligand for highly efficient inverted perovskite solar cells

A bidentate ligand 1,10-phenanthroline enables a green-solvent-processable low-cost hole-transport materialM1, which efficiently passivates the Pb²⁺ion defects of perovskite toward high-performance inverted perovskite solar cells.