Perovskite light-emitting diodes (PeLEDs) are considered promising candidates for future display and lighting technologies due to their excellent optoelectronic properties and simple fabrication methods. However, the performance of blue PeLEDs is not satisfactory. The introduction of the zwitterionic molecule 3-(benzyldimethylammonio)propanesulfonate (3-BAS) serves multiple purposes: it passivates defects on the perovskite surface, suppresses the migration of halide ions, and effectively regulates the crystallization process of perovskite thin films. This leads to the development of high-performance pure blue perovskite LEDs, which can further be applied in the field of visible light communications.