Organic Ligand Engineering for Tailoring Electron–Phonon Coupling in 2D Hybrid Perovskites

In the emerging two-dimensional organic–inorganic hybrid perovskites, the electronic structures and carrier behaviors are strongly impacted by intrinsic electron–phonon interactions, which have received inadequate attention. In this study, we report an intriguing phenomenon of negative carrier diffusion induced by electron–phonon coupling in (2T)2PbI4. Theoretical calculations reveal that the electron–phonon coupling drives the band alignment in (2T)2PbI4 to alternate between type I and type II heterostructures. As a consequence, photoexcited holes undergo transitions between the organic ligands and inorganic layers, resulting in abnormal carrier transport behavior compared to other two-dimensional hybrid perovskites. These findings provide valuable insights into the role of electron–phonon coupling in shaping the band alignments and carrier behaviors in two-dimensional hybrid perovskites. They also open up exciting avenues for designing and fabricating functional semiconductor heterostructures with tailored properties.