Jilin University researchers have developed a multifunctional molecular strategy to improve the phase purity and defect passivation of quasi‑two‑dimensional (quasi‑2D) perovskite films, addressing long‑standing challenges of uneven phase distribution and excessive non‑radiative recombination. Conventional quasi‑2D perovskites often suffer from random crystallization caused by long‑chain organic cations, which results in incomplete energy transfer and severely limits device efficiency.
To overcome this, the team introduced a methoxy‑methyl (diphenyl) phosphine oxide (MDPO) molecule as a bifunctional additive. Density functional theory (DFT) simulations revealed that the strong electron‑donating P = O group in MDPO coordinates with under‑coordinated Pb²⁺ ions, effectively passivating trap states, while simultaneously controlling crystallization. This coordination inhibits the formation of small‑n phases and promotes the growth of large‑n ones, resulting in a more uniform perovskite layer with fewer defects.
Using this approach, the optimized green perovskite light‑emitting diode (PeLED) achieved an external quantum efficiency (EQE) of 24.13% and a peak luminance of 156,138 cd m⁻², ranking among the top reported values for quasi‑2D perovskite emitters. The improved phase uniformity reduced non‑radiative recombination pathways and enhanced charge transfer across the active layer, significantly boosting both efficiency and stability under operational stress.
This molecular‑engineering strategy offers a practical pathway toward scalable fabrication of high‑performance perovskite optoelectronics. By enabling better control over crystallization and defect chemistry, it represents a promising step toward the reliable commercialization of perovskite‑based display and lighting technologies.
