High-Performance Blue Perovskite Light-Emitting Diodes Enabled by a Sacrificial Agent Maleic Anhydride

In addition to eliminating the defects to suppress electric-field-induced ionmigration, developing metal halide perovskites (MHPs) with good environmental stabilityagainst light, oxygen, moisture, and heat is highly desirable for the stability of perovskitelight-emitting diodes (PeLEDs). As for the environmental issues, moisture should beconsidered as the primary critical degradation pathway. Herein, we introduce a facileapproach to improving both the efficiency and the stability of blue PeLEDs via a sacrificialagent maleic anhydride (MAH). It is able to passivate the defects as well as absorb waterthat infiltrates into the perovskite to protect the perovskite against moisture. Furthermore,its resulting hydrolysis product maleic acid (MA) can also act as a passivation agent forthe perovskite via the interaction between the carboxyl groups and uncoordinated leadions. In addition, the incorporation of MAH into the perovskitefilm yields dense andsmooth morphology. As a result, the blue PeLED involving MAH shows increasedmaximum external quantum efficiency (EQEmax) from 4.0 to ca. 5.2%, and simultaneouslyimproved operational stability, in contrast with the pristine PeLED.