DISPLAY DEVICE AND METHOD OF MANUFACTURING THE SAME
According to one embodiment, a display device has such configuration that each of ΔE 1 _LUMO and ΔE 1 _HOMO is 0.35 eV or less (ΔE 1 ≤0.35 eV), each of ΔE 2 _LUMO and ΔE 2 _HOMO is 0.1 eV or more and 0.5 eV or less (0.1 eV≤ΔE 2 ≤0.5 eV), the light emitting layer includes a first material and a second material, a band gap of the first material is larger than a band gap of the second material, and a ratio of the first material to the second material is 5% or more and less than 40%.
1 . A display device comprising:
an anode;
an organic EL layer including a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer, an electron transport layer and an electron injection layer; and
a cathode, wherein
ΔE 1 _LUMO is defined as a potential barrier between the electron injection layer, and the electron transport layer and the hole blocking layer,
ΔE 1 _HOMO is defined as a potential barrier between the hole injection layer, and the hole transport layer and the electron blocking layer,
each of ΔE 1 _LUMO and ΔE 1 _HOMO is 0.35 eV or less (ΔE 1 ≤0.35 eV),
ΔE 2 _LUMO is defined as a potential barrier between the electron transport layer and the hole blocking layer, and the light emitting layer,
ΔE 2 _HOMO is defined as a potential barrier between the hole transport layer and the electron blocking layer, and the light emitting layer,
each of ΔE 2 _LUMO and ΔE 2 _HOMO is 0.1 eV or more and 0.5 eV or less (0.1 eV≤ΔE 2 ≤0.5 eV),
the light emitting layer includes a first material and a second material,
a band gap of the first material is larger than a band gap of the second material, and
a ratio of the first material to the second material is 5% or more and less than 40%.
2 . The display device according to claim 1 , wherein
the ratio of the first material to the second material is 5% or more and 30% or less.
3 . The display device according to claim 1 , wherein
the ratio of the first material to the second material is 5% or more and 20% or less.
4 . The display device according to claim 1 , wherein
the ΔE 1 _LUMO is 0.2 eV or less.
5 . The display device of claim 1 , wherein
the band gap of the first material is 3.05 eV and the band gap of the second material is 2.7 eV.
6 . A method for manufacturing a display device, wherein
the display device comprises
an anode;
an organic EL layer including a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer,
an electron transport layer and an electron injection layer; and
a cathode,
ΔE 1 _LUMO is defined as a potential barrier between the electron injection layer, and the electron transport layer and the hole blocking layer,
ΔE 1 _HOMO is defined as a potential barrier between the hole injection layer, and the hole transport layer and the electron blocking layer,
each of ΔE 1 _LUMO and ΔE 1 _HOMO is 0.35 eV or less (ΔE 1 ≤0.35 eV),
ΔE 2 _LUMO is defined as a potential barrier between the electron transport layer and the hole blocking layer, and the light emitting layer,
ΔE 2 _HOMO is defined as a potential barrier between the hole transport layer and the electron blocking layer, and the light emitting layer,
each of ΔE 2 _LUMO and ΔE 2 _HOMO is 0.1 eV or more and 0.5 eV or less (0.1 eV≤ΔE 2 ≤0.5 eV),
the light emitting layer includes a first material and a second material,
a band gap of the first material is larger than a band gap of the second material,
a ratio of the first material to the second material is 5% or more and less than 40%, and
the method comprising:
forming the light emitting layer by a linear scan evaporation method using a linearly arranged evaporation sources.
7 . The method according to claim 6 , wherein
the ratio of the first material to the second material is 5% or more and 30% or less.
8 . The method according to claim 6 , wherein
the ratio of the first material to the second material is 5% or more and 20% or less.
9 . The method according to claim 6 , wherein
the ΔE 1 _LUMO is 0.2 eV or less.
10 . The method according to claim 6 , wherein
the band gap of the first material is 3.05 eV and the band gap of the second material is 2.7 eV.