Enhanced Hole Injection at NiMgO – QD Interface for Efficient All-inorganic Quantum Dot Light-Emitting Diodes
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초록
내용
Nickel magnesium oxide (NiMgO) nanoparticles (NPs) is one of the promising choices for inorganic hole transport layers (HTLs) in quantum dot light-emitting diodes (QLEDs) due to their wide bandgap and high conductivity. Large energy offset between VBM of NiMgO and 1Sh states of QDs is likely to degrade the device performance due to spontaneous charge transfer and undesired negative charging. Herein, we introduce functional dipole ligands of NiMgO NPs to engineer the energy landscape of NiMgO – QD junction. Our findings reveal hole injection efficiency is influenced by the energetic offset at the interface, but also hole trapping defects on NiMgO NPs. We could clarify the role of dipole ligands on the electronic state of NiMgO NPs: carboxylate bond passivating surface states and electron-withdrawing moiety lowering the VBM. In this approach, we fabricated efficient all-inorganic QLEDs holding significant promise for next-generation display and lighting technologies demanding high brightness.