Researchers at Korea's Kyung Hee University have developed a dual-role approach utilizing octylammonium iodide (OAI) to simultaneously modulate perovskite crystallization and passivate defects in high-efficiency pure red PeLEDs. The incorporation of this additive governs the crystallization dynamics, suppressing uncontrolled grain growth and minimizing the formation of grain boundaries. The OAI additive also effectively passivates ionic and surface defects within the perovskite lattice, as validated by comprehensive optoelectronic and morphological analyses.
This synergistic approach combining regulated crystallization and defect passivation yields compact, uniform perovskite films with suppressed non-radiative recombination and enhanced charge transport. The team consequently fabricated PeLEDs that achieved pure red emission, delivering a maximum brightness (ELMax) of 1274.9 cd m−2, a peak external quantum efficiency (EQEMax) of 16.47 %, and a low turn-on voltage (Von) of 1.59 V, representing a 3.1-fold and 5.1-fold enhancement in ELMax and EQEMax, respectively, over the pristine device (409.6 cd m−2 and 3.26 %).
The EL emission of the optimized device with dual OAI achieve pure red emission peak (649 nm) than the control device (666 nm), falling in excellent gamut coverage ratio of 99.9 % in Rec.2020 standard. Furthermore, the OAI-optimized devices exhibited exceptional operational stability, maintaining spectral purity under prolonged operation and achieving a half-lifetime exceeding 9 h, a 4-fold improvement compared to control devices.
This work highlights the critical role of crystallization regulation and defect engineering in unlocking the full potential of perovskite emitters, offering a pathway toward efficient, stable, and color-pure PeLEDs for display applications.
