Two-dimensional hybrid halide perovskites composed of mixed corner- and edge-shared octahedron as broadband yellow-light emissions

Herein, we reported two new 2D perovskites of [DAPMA]2Pb3X12·2H2O (X = Cl (1), Br (2), DAPMA = N,N-Bis(3-aminopropyl)methylamine) containing special 2D [Pb3X12]6− layers formed by mixed corner- and edge-shared [PbX6] octahedrons. Both compounds 1 and 2 exhibit broadband yellow light emissions with promising photoluminescence quantum yields of 4.84% and 3.02%, respectively. According to detailed spectroscopy characterizations, the broadband light emissions should originate from self-trapped excitons (STEs). In addition, these 2D perovskites can be fabricated as white LEDs with highest color rendering index of 96.3%. This work provides a new type of structural model to probe into the relationship between luminescence behavior and structure.