Planar-type phosphine oxide molecules enhance the efficiency and stability of perovskite CsPbBr3 QLEDs.

Bulky tripodal phosphine oxide ligands exhibit weak binding affinity and severe steric hindrance, limiting defect passivation and charge transport, in perovskite QLEDs. A planar phosphine oxide (P-PO) was proposed to enhance coordination interactions and improve charge transport, delivering a maximum EQE of 27.5% and an extended T50 lifetime of 18.0 h at an initial luminance of 2000 cd m-2.