Molecular Bridging Strategy Enables High Performance and Stable Quasi-2D Perovskite Light-Emitting Devices

Quasi-two-dimensional (quasi-2D) Ruddlesden–Popper (RP) perovskites have attracted extraordinary attention due to their favorable energy funnel structures and outstanding optical performance. However, quasi-2D perovskites commonly contain the disordered mixture of phases, which results in low energy transfer between phases and subsequently limits the performance of the device. In this work, 4′-(Aminomethyl)-biphenyl-3-carboxylic acid (4-ABCA) was introduced into PEA 2 (FAPbBr 3 ) 2 PbBr 4 (PEA = phenethylammonium) film. The experimental and theoretical investigations demonstrate that 4-ABCA can coordinate Pb 2+ and Br – with its carboxyl and amion groups, respectively, which reconstructs the phase distribution of PEA 2 (FAPbBr 3 ) 2 PbBr 4 film, and simultaneously reduces the van der Waals gap, resulting in the efficient energy transfer of carriers. Finally, the external quantum efficiency (EQE) of 23.15% and the maximal brightness of 133560 cd/m 2 were achieved in the green perovskite light-emitting diodes (PeLEDs) based on quasi-2D film by adding 4-ABCA. Notably, it is the highest brightness for the pure green quasi-2D PeLEDs reported in the literature.