ORGANIC LIGHT-EMITTING DEVICE
An organic light-emitting device includes a first electrode; a second electrode; an emissive layer disposed between the first electrode and the second electrode; a first hole injection layer disposed between the first electrode and the emissive layer; a second hole injection layer disposed between the first electrode and the emissive layer; and an electron transport layer disposed between the emissive layer and the second electrode. The first hole injection layer includes a metal fluoride and a first hole injecting material. The second hole injection layer includes a molybdenum oxide and a second hole injecting material. The electron transport layer includes an electron transporting material and a metal oxide. The metal oxide may be one of lithium oxide (Li 2 O), molybdenum oxide (MoO 3 ), barium oxide (BaO), and boron oxide (B 2 O 3 ).
1 . An organic light-emitting device (OLED) comprising:
a first electrode;
a second electrode;
an emissive layer disposed between the first electrode and the second electrode;
a first hole injection layer disposed between the first electrode and the emissive layer;
a second hole injection layer disposed between the first hole injection layer and the emissive layer; and
an electron transport layer disposed between the emissive layer and the second electrode,
wherein
the first hole injection layer comprises a metal fluoride and a first hole injecting material,
the second hole injection layer comprises a molybdenum oxide and a second hole injecting material, and
the electron transport layer comprises an electron transporting material and a metal oxide, wherein the metal oxide is one of lithium oxide (Li 2 O), molybdenum oxide (MoO 3 ), barium oxide (BaO), and boron oxide (B 2 O 3 ).
2 . The organic light-emitting device of claim 1 , wherein the mixing ratio between the metal fluoride and the first hole injecting material in the first hole injection layer is 1:1 to 3:1.
3 . The organic light-emitting device of claim 1 , wherein the first hole injection layer is formed by co-depositing the metal fluoride and the first hole injecting layer.
4 . The organic light-emitting device of claim 1 , wherein the mixing ratio between the molybdenum oxide and the second hole injecting material in the second hole injecting layer is 1:1 to 3:1.
5 . The organic light-emitting device of claim 1 , wherein the second hole injection layer is formed by co-depositing the molybdenum oxide and the second hole injecting layer.
6 . The organic light-emitting device of claim 1 , wherein the metal in the metal fluoride is a Group 1 or a Group 2 element.
7 . The organic light-emitting device of claim 1 , wherein the metal fluoride is LiF, NaF, MgF 2 , BaF, or CsF.
8 . The organic light-emitting device of claim 1 , wherein the first hole injecting material and the second hole injecting material are each independently selected from the group consisting of copper phthalocyanine, 1,3,5-tricarbazolylbenzene, 4,4′-biscarbazolylbiphenyl, polyvinylcarbazole, m-biscarbazolylphenyl, 4,4′-biscarbazolyl-2,2′-dimethylbiphenyl, 4,4′,4″-tri(N-carbazolyl)triphenylamine (TCTA), 4,4′,4″-tris(3-methylphenylamino)triphenylamine (m-MTDATA), 1,3,5-tri(2-carbazolylphenyl)benzene, 1,3,5-tris(2-carbazolyl-5-methoxyphenyl)benzene, bis(4-carbazolylphenyl)silane, N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1′-biphenyl]-4,4′-diamine (TPD), N,N′-di(naphthalene-1-yl)-N,N′-diphenyl benzidine (α-NPD), N,N′-diphenyl-N,N′-bis(1-naphthyl)-(1,1′-biphenyl)-(1,1′-biphenyl)-4,4′-diamine (NPB), poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine (TFB) and poly(9,9-dioctylfluorene-co-bis-N,N-phenyl-1,4-phenylendiamine) (PFB).
9 . The organic light-emitting device of claim 1 , wherein the thickness ratio between the first hole injection layer and the second hole injection layer is 1:99 to 1:9.
10 . The organic light-emitting device of claim 1 , wherein the amount of the metal oxide is 30 to 60 parts by weight based on 100 parts by weight of the electron transporting material.
11 . The organic light-emitting device of claim 1 , wherein the electron mobility of the electron transporting material is 10 −8 cm/VS or greater in an electric field of 800-100 (V/cm) 1/2 .
12 . The organic light-emitting device of claim 1 , wherein the electron transporting material comprises at least one selected from the group consisting of tris(8-hydroxy-quinolinato) aluminum (Alq3), bis(10-hydroxybenzo[h]quinolinato beryllium) (Bebq2) represented by the structure below, and derivatives thereof:
13 . The organic light-emitting device of claim 1 , wherein the organic light emitting device does not have a separate electron injection layer.
14 . An organic light-emitting device (OLED) comprising:
a first electrode;
a second electrode;
an emissive layer disposed between the first electrode and the second electrode;
a first hole injection layer disposed between the first electrode and the emissive layer;
a second hole injection layer disposed between the first hole injection layer and the emissive layer;
an first electron transport layer disposed between the emissive layer and the second electrode, and
a second electron transport layer disposed between the first electron transport layer and the second electrode
wherein
the first hole injection layer comprises a metal fluoride and a first hole injecting material,
the second hole injection layer comprises a molybdenum oxide and a second hole injecting material,
the first electron transport layer comprises a first electron transporting material and does not include a metal oxide, and
the electron transport layer comprises a second electron transporting material and a metal oxide, wherein the metal oxide is one of lithium oxide (Li 2 O), molybdenum oxide (MoO 3 ), barium oxide (BaO), and boron oxide (B 2 O 3 ).
15 . The organic light-emitting device of claim 14 , wherein the first electron transport layer lowers an electron transport rate to the emitting layer, and the second electron transport layer lowers an electron injection barrier with respect to the second electrode.
16 . The organic light-emitting device of claim 14 , wherein the second electron transporting material has an electron mobility of 10 −3 cm/VS or greater in an electric field of 800-100 (V/cm) 1/2 .
17 . The organic light-emitting device of claim 14 , wherein the second electron transporting material has an electron mobility of 10 −3 to 10 −5 cm/VS in an electric field of 800-100 (V/cm) 1/2 .
18 . The organic light-emitting device of claim 14 , wherein the thickness ratio between the first electron transport layer and the second electron transport layer is 1:1 to 1:2.
19 . The organic light-emitting device of claim 1 , further comprising at least one layer selected from the group consisting of an additional hole injection layer, a hole transport layer, an electron blocking layer, an emissive layer, a hole blocking layer, an additional electron transport layer, and an electron injection layer.
20 . The organic light-emitting device of claim 1 , having one of the following structures:
first electrode/first hole injection layer/second hole injection layer/hole transport layer/emissive layer/electron transport layer/second electrode,
first electrode/first hole injection layer/second hole injection layer/hole transport layer/emissive layer/electron transport layer/electron injection layer/second electrode, and
first electrode/first hole injection layer/second hole injection layer/hole transport layer/emissive layer/hole blocking layer/electron transport layer/electron injection layer/second electrode.