Organic electroluminescent device based on neutral free-radical electroluminescent material
Disclosed is an organic electroluminescent device, wherein the light-emitting layer is composed of a non-doped neutral free-radical electroluminescent material or a neutral free-radical electroluminescent material doped in a matrix material. The luminescence of the device is from the photons emitted from the transition of doublet electrons in the outer molecular orbit of the neutral free-radical electroluminescent material from an excited state to the ground state; since there is no limitation on spin-forbidden, the upper limit of the internal quantum efficiency of the device is 100%. The neutral free-radical electroluminescent material used in the device is 1,3-bis(diphenylene)-2-phenylallyl free radicals and derivatives thereof; tri(2,4,6-trichlorophenyl)methyl free radicals and derivatives thereof; (3,5-dichloro-4-pyridyl)bis(2,4,6-trichlorophenyl)methyl free radicals and derivatives thereof; (2,4,6-trichloro-5-pyrimidinyl)bis(2,4,6-trichlorophenyl)methyl free radicals and derivatives thereof.
1. An organic electroluminescent device, comprising a light-emitting layer that includes a neutral π-free-radical electroluminescent material,
wherein the neutral π-free-radical electroluminescent material is classified into four classes represented by the following Formulae (I)-(IV):
wherein n is 1, 2, or 3,
wherein R, R 1 , R 2 , and R 3 are the same or different,
R, R 1 , R 2 and R 3 are each independently selected from an aromatic amine, a heterocyclic aromatic hydrocarbon, a fused ring aromatic hydrocarbon compound, an atom, a group, or a combination thereof, wherein the aromatic amine, heterocyclic aromatic hydrocarbon, fused ring aromatic hydrocarbon compound, atom, or group are represented by the following formulae: H; F; Cl; CN;
2. An organic electroluminescent device, comprising a light-emitting layer that includes a neutral free-radical electroluminescent material doped in a matrix material,
wherein the neutral free-radical electroluminescent material is classified into four classes represented by the following Formulae (I)-(IV):
wherein n is 1, 2, or 3,
wherein R, R 1 , R 2 , and R 3 are the same or different,
R, R 1 , R 2 and R 3 are each independently selected from an aromatic amine, a heterocyclic aromatic hydro carbon, a fused ring aromatic hydrocarbon compound, an atom, a croup, or a combination thereof, wherein the aromatic amine, heterocyclic aromatic hydrocarbon, fused ring aromatic hydrocarbon compound, atom, or group are represented by the following formulae: H; F; Cl; CN;
3. The organic electroluminescent device according to claim 1 , wherein the organic electroluminescent device further comprises a substrate and a pair of electrodes including an anode and a cathode, and said light-emitting layer is located between the pair of electrodes.
4. The organic electroluminescent device according to claim 3 , wherein the organic electroluminescent device further comprises a hole transport layer disposed between the light-emitting layer and the anode, and said hole transport layer contains an aromatic amine derivative.
5. The organic electroluminescent device according to claim 4 , wherein the aromatic amine derivative is N,N′-diphenyl-N,N′-(1-naphthyl)-1, 1′-biphenyl-4,4′-diamine (NPB), 4,4′,4″-Tris(3-methylphenylphenylamino)triphenylamine (m-MTDATA).
6. The organic electroluminescent device according to claim 3 , wherein the organic electroluminescent device further comprises an electron transport layer disposed between the light-emitting layer and the cathode, and said electron transport layer includes electron-withdrawing groups.
7. The organic electroluminescent device according to claim 6 , wherein said electron transport layer includes 1,3,5-tri(1-phenyl-1-hydrogen-benzimidazole-2-yl)benzene (TPBi).
8. The organic electroluminescent device according to claim 4 wherein said organic electroluminescent device further comprises a hole injection layer located between the anode and the hole transport layer and said hole injection layer is a metal oxide.
9. The organic electroluminescent device according to claim 6 , wherein said organic electroluminescent device further comprises a electron injection layer located between the electron transport layer and the cathode, and said electron injection layer is formed of lithium fluoride (LiF), caesium fluoride (CsF) or caesium carbonate (Cs 2 CO 3 ).
10. The organic electroluminescent device according to claim 9 , wherein said organic electroluminescent device further comprises a hole blocking layer located between the electron transport layer and the light-emitting layer.
11. The organic electroluminescent device according to claim 4 , wherein said organic electroluminescent device further comprises an electron blocking layer located between the hole transport layer and the light-emitting layer.
12. The organic electroluminescent device according to claim 2 , wherein the organic electroluminescent device further comprises a substrate, and a pair of electrodes including an anode and a cathode, and said light-emitting layer is located between the anode and the cathode.
13. The organic electroluminescent device according to claim 5 , wherein said organic electroluminescent device further comprises a hole injection layer located between the anode and a hole transport layer, and said hole injection layer is a metal oxide.
14. The organic electroluminescent device according to claim 7 , wherein said organic electroluminescent device further comprises a electron injection layer located between an electron transport layer and the cathode, and said electron injection layer is lithium fluoride (LiF), caesium fluoride (CsF) or caesium carbonate (Cs 2 CO 3 ).
15. The organic electroluminescent device according to claim 7 , wherein said organic electroluminescent device further comprises a hole blocking layer located between an electron transport layer and the light-emitting layer.
16. The organic electroluminescent device according to claim 5 , wherein said organic electroluminescent device further comprises an electron blocking layer located between a hole transport layer and the light-emitting layer.