P‐113: Efficiency Enhancement of Quantum dot Light‐Emitting Diodes Via Ligand Exchange

The unique features of solution‐processed quantum dots (QDs) including emission tunability in the visible range, high‐quality saturated color and outstanding intrinsic stability in environment are highly desired in various application fields. Especially, quantum dot light‐emitting diodes (QLEDs) are promising light sources for applications in displays. However, the imbalance injection of holes and electrons have always been a challenging issue of QLED. In this study, the modified ligands which is synthesized by ourselves are incorporated into QDs through solution ligand exchange. The highest occupied molecular orbital (HOMO) of QDs is upshifted from ‐5.65eV to ‐5.35eV, leading to the decrement of the energy gap between the HOMO of QDs and the HOMO of hole transport layer. Through the successful ligands exchange, improvement by factors of 7.5 is achieved in maximum external quantum efficiency (EQE) compared with QLED with OA ligands.