All-Inorganic Quantum-Dot Light-Emitting Diodes with Reduced Exciton Quenching by a MgO Decorated Inorganic Hole Transport Layer.

Here, wide-bandgap magnesium oxide (MgO) is employed as a decorator for the nickel oxide (NiO x) hole transport layer (HTL), by means of a bulk dopant as well as a surface modifier. QLEDs with Ni0.88Mg0.12O x serving as the HTL achieve an ∼19.5% efficiency improvement compared to devices using pristine NiO x. Further inserting an ultrathin MgO layer between the Ni0.88Mg0.12O x and QDs to separate the accumulated charges from excitons goes on boosting the peak efficiency by another ∼35%. Finally, a maximum brightness over 40 000 cd/m2 at 10 V is obtained, which is the highest among the reported values.