Organic light emitting device with increased light out coupling
View Patent ↗The invention relates to an organic light-emitting device (OLED) comprising at least: a first electrode; a second electrode; an organic light emissive layer arranged between said first electrode and said second electrode; and an organic charge transport layer arranged between said first electrode and said emissive layer, wherein i) the charge transport layer is patterned or provided with a periodic surface structure on a surface of the charge transport layer facing the emissive layer, and/or ii) an alignment layer which allows for charge transport to the emissive layer is provided between said charge transport layer and said emissive layer, which alignment layer promotes alignment of the optical dipoles of molecules of said light emissive layer towards a common preferred direction of the molecular axes. The use of the patterned or structured charge transport layer and/or the alignment layer provides improved light out coupling from the OLED layer stack, i.e. increased external quantum efficiency.
1. A method of producing an organic light emitting device comprising the steps of:
providing a first electrode layer on a substrate to form a layer stack;
forming a charge transport layer on the layer stack;
forming an optical alignment layer on the charge transport layer;
forming a light emissive layer on the alignment layer, the light emissive layer comprises modules, wherein each of the molecules of the light emissive layer have an axis, wherein the axes are aligned towards a common direction; and
disposing a second electrode layer over the light emissive layer.
2. The method according to claim 1 , wherein the forming of the charge transport layer is performed using a solution processing technique.
3. The method according to claim 1 , wherein forming the light emissive layer is performed using a vacuum processing technique.
4. The method according to claim 1 , wherein forming the second electrode layer is performed using a vacuum processing technique.
5. The method according to claim 1 , further comprising embossing the charge transport layer with a surface structure.
6. The method according to claim 5 , wherein the embossing is performed using a nanoimprint technique.
7. The method according to claim 1 , further comprising patterning the charge transport layer with a surface structure.
8. The method according to claim 7 , wherein the patterning of the charge transport layer is arranged to produce a discontinuous layer.
9. The method according to claim 1 , wherein the alignment layer promotes the alignment of the optical dipoles of the molecules of the light emissive layer.