TECHNICAL FIELD

The present invention relates to an organic photoelectronic element.

BACKGROUND ART

Heretofore, as a self-emission type element, an organic photoelectronic element (organic electroluminescent element, hereinafter, organic EL element) is known. The organic EL element has, as the basic structure, a structure in which plural types of layers such as a light emitting layer, an electron transport layer, a hole transport layer, etc. are laminated between a pair of electrodes.

The organic EL element emits light, as photons are generated by recombination of electrons supplied from a power source and holes in the internal light emitting layer. In the field of organic EL elements, by the research and development over the years, the “internal quantum efficiency” being the percentage of “photons generated inside of the element” to “the number of injected electrons” has reached close to 100%.

On the other hand, even with organic EL elements in recent years, the “external quantum efficiency” being the percentage of “photons extracted to outside of the element” to “the number of injected electrons” remains to be only about from 20 to 30%, and an improvement is desired.

One of causes as to why the external quantum efficiency is low, is considered to be internal reflection due to a difference in refractive indexes of the respective layers constituting the organic EL element. As described above, the organic EL element has a plurality of layers in addition to the light emitting layer. These layers have refractive indexes different from one another. Therefore, light generated in the light emitting layer is considered to be reflected at the interfaces between the layers having different refractive indexes and damped or absorbed inside of the element before it is emitted to outside of the element.

Whereas an organic EL element is known in which, by incorporating nano-sized porous silica particles in the charge transport layer, the refractive index of the charge transport layer has been reduced (see Patent Document 1). By the organic EL element described in Patent Document 1, it is expected that reflection occurring at the interface between the charge transport layer and the layer in contact with the charge transport layer, is suppressed, whereby the external quantum efficiency will be improved.

PRIOR ART DOCUMENT

Patent Document

Patent Document 1: WO 2013/108618

DISCLOSURE OF INVENTION

Technical Problems

However, in view of a market demand requiring low power consumption and long service life of the element, the external quantum efficiency of the organic EL element is preferably as high as possible. In this regard, the external quantum efficiency of the organic EL element described in Patent Document 1 has room for improvement.

The present invention has been made in view of such circumstances, and has an object to provide an organic photoelectronic element, of which the external quantum efficiency is improved, the power consumption is low and the service life is prolonged.

Solution to Problems

To solve the above problems, one embodiment of the present invention provides an organic photoelectronic element comprising a substrate, an anode provided on the substrate, a cathode facing the anode, a light emitting layer disposed between the anode and the cathode, a hole transport layer provided in contact with the light emitting layer between the light emitting layer and the anode, wherein the hole transport layer contains an organic semiconductor material and a fluorinated polymer, and at the surface of the hole transport layer in contact with the light emitting layer, the fluorinated polymer is present.

In one embodiment of the present invention, the construction may be such that in the hole transport layer, the refractive index is continuously increasing towards the anode from the light emitting layer.

In one embodiment of the present invention, the construction may be such that the element further has a hole injection layer which is disposed between the hole transport layer and the anode and which contains a semiconductor material and a fluorinated polymer.

In one embodiment of the present invention, the construction may be such that the element further has a functional layer disposed between the cathode and the light emitting layer, wherein the functional layer has at least one of an electron transport layer and an electron injection layer, and contains a semiconductor material and a fluorinated polymer.

Advantageous Effects of Invention

According to the present invention, it is possible to provide an organic photoelectronic element, of which the external quantum efficiency is improved, the power consumption is low, and the service life is prolonged.

