Ink for organic EL
According to one embodiment, an ink for organic EL includes an organic EL contributing material and an organic solvent. A relative energy difference RED based on Hansen solubility parameters which attribute to the organic EL contributing material and the organic solvent, respectively, is less than 0.5.
1. An ink for organic EL, comprising:
an organic EL contributing material; and
an organic solvent,
wherein a relative energy difference (RED) based on Hansen solubility parameters which attribute to the organic EL contributing material and the organic solvent, respectively, is less than 0.5, and
precipitation does not occur within 30 days after the organic EL contributing material is dissolved into the organic solvent.
2. The ink for organic EL, of claim 1 , wherein
the organic EL contributing material contains an organic compound having a molecular weight of 1,000 or less.
3. The ink for organic EL of claim 2 , wherein
the organic EL contributing material is one of a light-emitting material, a carrier transport material, a carrier injection material and a carrier blocking material.
4. The ink for organic EL, of claim 1 , wherein
the organic EL contributing material contains an organic compound of a molecular weight of exceeding 1,000.
5. The ink for organic EL of claim 4 , wherein
the organic EL contributing material is one of a light-emitting material, a carrier transport material, a carrier injection material and a carrier blocking material.
6. The ink for organic EL of claim 1 , wherein
the organic EL contributing material is one of a light-emitting material, a carrier transport material, a carrier injection material and a carrier blocking material.
7. The ink of organic EL of claim 1 , wherein
the organic EL contributing material comprises a fluorene-based copolymer having a molecular weight of 1,000 or less; and
the organic solvent is methyl benzoate, dimethyl salicylate, or 2-cyclopenten-1-one.