High-Performance\nInP Quantum-Dot Light-Emitting Diodes\nwith a NiO<sub><i>x</i></sub> Nanoparticle-Embedded Hybrid\nEmissive Layer

Quantum-dot (QD) light-emitting diodes\n(QLEDs) are garnering\nsignificant\nattention owing to their superb optoelectrical properties, but the\noverinjection of electrons compared to holes into the emissive layer\n(EML) is still a critical obstacle to be resolved. Current approaches,\nsuch as inserting a charge-balancing interlayer and mixing p-type\norganic additives into the EML, face issues of process complexity\nand poor miscibility. In this work, we demonstrate efficient InP QLEDs\nby simply embedding NiO<sub><i>x</i></sub> nanoparticles\n(NPs) into the EML which forms a homogeneous QD–metal oxide\nhybrid EML. Precisely changing the NiO<sub><i>x</i></sub> NPs concentration enables an effective modulation of the valence\nstate of the hybrid EML, while controlling the exciton quenching phenomena\nstemming from the metal oxide additives. Moreover, the inorganic hybrid\nEML exhibits superior electrical stability compared to that of typical\norganic additives. In detail, it possesses an upshifted valence state\nby approximately 0.2 eV, leading the QLEDs to a 3.7-fold increase\nin luminance, 1.7-fold improvement in external quantum efficiency,\nand 3-fold extension in operational half-lifetime, simultaneously.\nComprehensive analyses on the optoelectrical and morphological characteristics\nconfirm that the hybrid EML is suitable for realizing efficient and\nstable InP QLEDs via a simple fabrication method. Therefore, we expect\nthat this approach would provide valuable insights into the development\nof high-performance and low-cost QLEDs.