Zwitterions: An innovative class of additive materials for perovskite light-emitting diodes

Perovskite light-emitting diodes (PeLEDs) have made an extraordinary advancement recently and can realize external quantum efficiencies of over 30 %. However, poor operational stability is a major obstacle in the commercial application of PeLED devices. One of the prime factors responsible for the poor stability is the presence of imperfections and ion migration in metal-halide-perovskite (MHP) film. Recently, zwitterions have been evolved as an innovative class of additive materials for PeLEDs. With the rapid development of zwitterion materials, efficient PeLEDs have been made by incorporating them as passivation additives. Herein, recent advancements in PeLED devices by exploiting zwitterion additive materials (ZAMs) are highlighted. We have also explained the contribution of different ZAMs in high-performance PeLEDs so far. This study reveals the fact that zwitterions can be employed as additive/ligand molecule to eliminate the imperfections present in MHP film for future PeLED devices. Moreover, the potential advantages of ZAMs for practical applications are also described. Lastly, we have provided a perspective on the design strategies of ZAMs for next-generation PeLED devices. • Zwitterion Molecules. • Additives. • Passivation of Imperfections. • Ion Migration Inhibition. • Perovskite Light-Emitting Diodes.