With rapid progress in perovskite light-emitting diodes (PeLEDs), the electroluminescence performance of large-area is of increasing interest. We investigated why large-area performance lags behind that achieved in laboratory-scale devices and found that defects in perovskite films—emerging from thermal convection during solvent evaporation, as well as electronic traps formed during perovskite crystallization—are chief causes. Here, we report a molecular modification strategy that simultaneously eliminates pinholes in perovskite layers by controlling the dynamics of film formation and that passivates defects in perovskites by incorporating Br species, thereby preventing shorts and non-radiative recombination. The molecular modifier 1,3,5-tris (bromomethyl) benzene (TBB) also modulates the electronic structure of injection or transport materials to achieve improved charge injection and balanced charge transport. As a result, we demonstrate 20 mm × 20 mm green perovskite nanocrystal LEDs that achieve an external quantum efficiency (EQE) of over 16%, a record for large-area PeLEDs.

随着钙钛矿发光二极管（PeLED）的快速发展，大面积的电致发光性能越来越受到关注。我们调查了为什么大面积性能落后于实验室规模的设备，发现钙钛矿薄膜中的缺陷（主要是由溶剂蒸发过程中的热对流产生的，以及钙钛矿结晶过程中形成的电子陷阱引起的）。在这里，我们报告了一种分子修饰策略，该策略通过控制成膜动力学同时消除钙钛矿层中的针孔，并通过掺入Br物种钝化钙钛矿中的缺陷，从而防止了短路和非辐射重组。分子改性剂1,3，5-三（溴甲基）苯（TBB）还可以调节注入或传输材料的电子结构，从而改善电荷注入和平衡电荷传输。结果，我们展示了20 mm×20 mm绿色钙钛矿纳米晶体LED，其外部量子效率（EQE）超过16％，这是大面积PeLED的记录。