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 ion migration, developing metal halide perovskites (MHPs) with good environmental stability against light, oxygen, moisture, and heat is highly desirable for the stability of perovskite light-emitting diodes (PeLEDs). As for the environmental issues, moisture should be considered as the primary critical degradation pathway. Herein, we introduce a facile approach to improving both the efficiency and the stability of blue PeLEDs via a sacrificial agent maleic anhydride (MAH). It is able to passivate the defects as well as absorb water that 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 for the perovskite via the interaction between the carboxyl groups and uncoordinated lead ions. In addition, the incorporation of MAH into the perovskite film yields dense and smooth morphology. As a result, the blue PeLED involving MAH shows increased maximum external quantum efficiency (EQEmax) from 4.0 to ca. 5.2%, and simultaneously improved operational stability, in contrast with the pristine PeLED.