Modulating the Schottky barriers of metal-2D perovskite junctions through molecular engineering of spacer ligands

The crucial role of spacer ligands in affecting the contact properties of metal-2D perovskite junctions, which can severely affect device performance, is revealed in this work. We studied the contact properties of Ag, Au, and Pt with 2D perovskites that possess ligands with different sizes and functional groups. It is found that the interface binding energy, Schottky barrier height (SBH), and tunneling property depend strongly on the ligand size and functional group type. Small-size ligands can induce effective interface coupling and result in perturbed perovskite electronic properties and a high tunneling probability. In addition, high work-function metals and more electronegative functional groups can induce more severe band shifts at the interface. The features of diverse ligands ensure a widely tunable SBH ranging from 0-1.07 eV. This study provides guidance for developing more effective 2D perovskite-based electric nanodevices by tuning the contact properties through molecular engineering of spacer ligands. This work revealed another effective way to tune the contact properties of metal-2D perovskite junctions by spacer ligand engineering.