Protective Hybrid Ligand Layer for Efficient and Stable ZnTeSe-Based Quantum Dots
발표자
()
초록
내용
ZnTeSe-based quantum dots (QDs) have become irreplaceable, Cd-free blue electroluminescent emitters in future display technology. Although their color purity and quantum yield (QY) have nearly reached to ultimate level, careful handling is demanded due to their vulnerable nature to photochemical stresses. Minimal electron confinement originating from quasi-type-II nature makes them susceptible to surface states generated by ligand desorption and/or oxidation in purification, storage and device fabrication, in turn, degrades photoluminescence QY by surface trapping. To resolve this issue, herein, we propose the hybrid ligand passivation for ZnTeSe-based QDs. Surface modification with zinc halide and alkylthiol significanly improved photochemical stability of QDs against repeating purification and storage under ambient condition. Surface analysis revealed a formation of partially-oxidized zinc thiolate layer, providing robust ligand binding and surface state passivation.