Pyridine-Derived Multifunctional Additive Enabling Highly Efficient Perovskite Light-Emitting Diodes

Benzene derivatives have been widely adopted as additives for passivating perovskite defects in perovskite light-emitting diodes (PeLEDs) due to their diverse functional group selection and the π-conjugated of benzene ring. However, the significant space steric hindrance of benzene rings renders benzene derivatives more susceptible to detachment from perovskites, resulting in limited passivation effects and durability. In this work, a pyridine additive, 3-pyridinylmethylammonium cation (3-pyA⁺), featuring dual-site binding functional groups of pyridine and ammonium, is introduced to fabricate efficient PeLEDs. The synergistic perovskite passivation effect of the pyridine and ammonium groups in 3-pyA⁺ facilitates the formation of uniform films with enhanced crystallinity and passivation durability. Compared to the benzene additive phenylmethanamine cation (PMA⁺)-incorporated perovskite films, the 3-pyA⁺-incorporated perovskite films exhibit an increased photoluminescence quantum yield, rising from 73 to 92%. As a result, the 3-pyA⁺-treated green PeLED exhibits a peak external quantum efficiency of 30.8% compared to 22.5% for the PMA⁺-treated PeLEDs, making it one of the best-performing green PeLEDs reported to date. Additionally, the corresponding device stability (T₅₀, tested at 100 cd m^-2 of the initial brightness) increases from 50 to 200 min, highlighting the superior passivation capabilities of pyridine additives for perovskites.