Highly efficient and stable Eu3+-doped two-dimensional perovskites

Compared to the three-dimensional (3D) counterparts, single-layered two-dimensional (2D) perovskites show high stability, high exciton binding energy and structural flexibility that are beneficial for light-emitting diodes (LEDs) applications. Yet, the emission peaks of single-layered 2D perovskites are strongly limited to the blue-green region due to their very strong quantum confined effect, hampering their application. Doping ions has been recognized as a promising way to tune emission wavelengths. In this work, we have prepared Eu 3+ doped PEA 2 PbCl 4 perovskites by a hot-injection method. Its Eu 3+ emission is not stable, which disappears after exposed in the air due to the coordination of Eu 3+ with H 2 O or O 2 . By exploiting strong ligands of thenoyltrifluoroacetone (TTA), the H 2 O or O 2 can be replaced, resulting in a rigid coordination environment for Eu 3+ . Besides, energy level alignment can be modified by the passivation of TTA, leading to effective energy transfer from exciton to Eu 3+ . In the end, stable red-emitting perovskite is acquired with a photoluminescence quantum yield (PLQY) up to 83%. This work provides new synthetic strategies for the design of high-performance perovskite/lanthanide composites.