White organic light emitting device

1. A white organic light emitting device, comprising:

a first light emitting unit, comprising a first light emitting element, wherein the first light emitting element comprises blue light emitting material;

a second light emitting unit, comprising a second light emitting element, wherein the second light emitting element comprises yellow light emitting material; and

a third light emitting unit, comprising a third light emitting element, wherein the third light emitting element comprises yellow light emitting material;

wherein the first light emitting unit, the second light emitting unit and the third light emitting unit are arranged in parallel,

wherein the first light emitting unit comprises a pair of a cathode and an anode and the first light emitting element is arranged therebetween; the second light emitting unit comprises a pair of a cathode and an anode and the second light emitting element is arranged therebetween; and the third light emitting unit comprises a pair of a cathode and an anode and the third light emitting element is arranged therebetween,

wherein a hole injection layer, a hole transport layer, an electron injection layer and an electron transport layer are between each pair of the anodes and the cathodes of the first light emitting unit, the second light emitting unit and the third light emitting unit,

wherein the anode of the first light emitting unit comprises a first ITO layer with a thickness of 15 nm, an Ag reflective layer with a thickness of 100 nm and a second ITO layer with a thickness of 15 nm, which are sequentially stacked;

the hole injection layer of the first light emitting unit comprises a first hole injection layer, which is made of CuPc and has a thickness of 30 nm, and a second hole injection layer, which is made of 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN) and has a thickness of 60 nm, and the first hole injection layer and the second hole injection layer are sequentially stacked;

the hole transport layer of the first light emitting unit is made of 4,4′-Cyclohexylidenebis[N,N-bis(4-methylphenyl)aniline] (TAPC) and has a thickness of 40 nm;

the electron transport layer of the first light emitting unit is made of 2,9-dimethyl-4.7-diphenyl-1,10-phenanthroline (BCP) and has a thickness of 30 nm;

the electron injection layer of the first light emitting unit is made of Liq(8-hydroxy-quinolinato lithium) and has a thickness of 10 nm;

the cathode of the first light emitting unit is formed through co-evaporation of magnesium and silver and has a thickness of 15 nm; and

the first light emitting element of the first light emitting unit is made of 5% doped FIrpic:mCP which is Bis[2-(4,6-difluorophenyl)pyridinato-C2, N](picolinato) iridium(III): 1,3-Di-9-carbazolylbenzene, and has a thickness of 25 nm,

wherein the anode of the second light emitting unit comprises a first ITO layer with a thickness of 15 nm, an Ag reflective layer with a thickness of 100 nm and a second ITO layer with a thickness of 15 nm, which are sequentially stacked;

the hole injection layer of the second light emitting unit comprises a first hole injection layer, which is made of CuPc and has a thickness of 30 nm, and a second hole injection layer, which is made of 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN) and has a thickness of 100 nm, and the first hole injection layer and the second hole injection layer are sequentially stacked;

the hole transport layer of the second light emitting unit is made of 4,4′-Cyclohexylidenebis[N,N-bis(4-methylphenyl) aniline] (TAPC) and has a thickness of 40 nm;

the electron transport layer of the second light emitting unit is made of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and has a thickness of 30 nm;

the electron injection layer of the second light emitting unit is made of Liq(8-hydroxy-quinolinato lithium) and has a thickness of 10 nm;

the cathode of the second light emitting unit is formed through co-evaporation of magnesium and silver and has a thickness of 15 nm; and

the second light emitting element of the second light emitting unit is made of 4% doped Ir(2-phq)2(acac):CBP which is Tris(2-phenylquinoline-C 2 , N′)iridium(III): 4,4′-Bis(N-carbazolyl)-1,1′-biphenyl, and has a thickness of 30 nm, and

wherein the anode of the third light emitting unit comprises a first ITO layer with a thickness of 15 nm, an Ag reflective layer with a thickness of 100 nm and a second ITO layer with a thickness of 15 nm, which are sequentially stacked;

the hole injection layer of the third light emitting unit comprises a first hole injection layer, which is made of CuPc and has a thickness of 30 nm, and a second hole injection layer, which is made of 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN) and has a thickness of 140 nm, and the first hole injection layer and the second hole injection layer are sequentially stacked;

the hole transport layer of the third light emitting unit is made of 4,4′-Cyclohexylidenebis[N,N-bis(4-methylphenyl) aniline] (TAPC) and has a thickness of 40 nm;

the electron transport layer of the third light emitting unit is made of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and has a thickness of 30 nm;

the electron injection layer of the third light emitting unit is made of Liq(8-hydroxy-quinolinato lithium) and has a thickness of 10 nm;

the cathode of the third light emitting unit is formed through co-evaporation of magnesium and silver and has a thickness of 15 nm; and

the third light emitting element of the third light emitting unit is made of 4% doped Ir(2-phq)2(acac):CBP which is Tris(2-phenylquinoline-C 2 , N′)iridium(III): 4,4′-Bis(N-carbazolyl)-1,1′-biphenyl, and has a thickness is 40 nm.

2. The white organic light emitting device according to claim 1 , wherein a peak position of an intrinsic emission spectrum of the blue light emitting material of the first light emitting element ranges from 430 nm to 480 nm, and a peak position of an intrinsic emission spectrum of the yellow light emitting material of the second light emitting element and a peak position of an intrinsic emission spectrum of the yellow light emitting material of the third light emitting element range from 560 nm to 600 nm.

3. The white organic light emitting device according to claim 2 , wherein the yellow light emitting material of the second light emitting element is the same as the yellow light emitting material of the third light emitting element.

4. The white organic light emitting device according to claim 1 , wherein each of the anodes of the first light emitting unit, the second light emitting unit and the third light emitting unit comprises a metal conductive layer, and each of the cathodes of the first light emitting unit, the second light emitting unit and the third light emitting unit comprises a transparent conductive layer.

5. The white organic light emitting device according to claim 1 , wherein the first light emitting unit emits blue light, and a peak wavelength of the blue light emitted by the first light emitting unit ranges from 430 nm to 480 nm.

6. The white organic light emitting device according to claim 5 , wherein an optical microcavity is formed between reflective surfaces of the anode and the cathode of the first light emitting unit, and the optical microcavity of the first light emitting unit satisfies the following formula:

∑

i

⁢

n

Bi

⁢

d

Bi

=

λ

B

2

⁢

m

B

wherein n Bi is a refractive index of an ith layer in the optical microcavity of the first light emitting unit, d Bi is a thickness of the ith layer in the optical microcavity of the first light emitting unit, λ B is a wavelength of the blue light predetermined to be emitted by the first light emitting unit, and m B is a modulus of the optical microcavity of the first light emitting unit, which is a positive integer.

7. The white organic light emitting device according to claim 1 , wherein a spectrum of yellow light emitted by the second light emitting element of the second light emitting unit has a blue shift, the second light emitting unit emits green light, and a peak wavelength of the green light emitted by the second light emitting unit ranges from 500 nm to 560 nm.

8. The white organic light emitting device according to claim 7 , wherein an optical microcavity is formed between reflective surfaces of the anode and the cathode of the second light emitting unit, and the optical microcavity satisfies following formula:

∑

i

⁢

n

Gi

⁢

d

Gi

=

λ

G

2

⁢

m

G

wherein n Gi is a refractive index of an ith layer in the optical microcavity of the second light emitting unit, d Gi is a thickness of the ith layer in the optical microcavity of the second light emitting unit, λ G is a wavelength of the green light predetermined to be emitted by the second light emitting unit, and m G is a modulus of the optical microcavity of the second light emitting unit, which is a positive integer.

9. The white organic light emitting device according to claim 1 , wherein a spectrum of yellow light emitted by the third light emitting element of the third light emitting unit has a red shift, the third light emitting unit emits red light, and a peak wavelength of the red light emitted by the third light emitting unit ranges from 600 nm to 650 nm.

10. The white organic light emitting device according to claim 9 , wherein an optical microcavity is formed between reflective surfaces of the anode and the cathode of the third light emitting unit, and the optical microcavity satisfies following formula:

∑

i

⁢

n

Ri

⁢

d

Ri

=

λ

R

2

⁢

m

R

wherein n Ri is a refractive index of an ith layer in the optical microcavity of the third light emitting unit, d Ri is a thickness of the ith layer in the optical microcavity of the third light emitting unit, λ R is a wavelength of the red light predetermined to be emitted by the third light emitting unit, and m R is a modulus of the optical microcavity of the third light emitting unit, which is a positive integer.