| 초록 |
Colloidal semiconductor nanocrystals, so called quantum dots (QDs) are employed as light-emitting materials in QLEDs. QDs have solubility in organic solvents by the action of stabilising ligands, which enables solution processing for device fabrications. However, when solutions of QDs in organic solvents are deposited on organic charge-transporting layers, they can damage them significantly. To resolve this issue, we adopted fluorous solvents which are immiscible with conventional organic materials. To demonstrate this concept, we carried out ligand exchange reactions of QDs with semi-perfluoroalkyl thiols, which provided them with good solubility in fluorous solvents for spin-casting on top of a hole-transporting layer composed of the organic material. The solution-processed QD layer did not show a sign of damage on the underlying layer, resulting in successful operation of QLEDs showing maximum external quantum efficiency and luminous efficiency of 4.2% and 4.4 cd‧A-1, respectively. |
