Organometallic compound, and organic light-emitting diode using same
The present invention relates to a novel organometallic compound, and more particularly, to a luminescent organometallic compound in which intermolecular interaction is inhibited by means of introducing a germanium substituent, thereby improving light-emitting characteristics. The present invention also relates to an organic electronic device, specifically, to an organic light-emitting diode using the compound. According to the present invention, a germanium substituent is introduced to the parent organometallic iridium compound, thus inhibiting an intermolecular interaction in the solid state and enabling the compound of the present invention to be effectively used in solution processing. When the compound of the present invention is used as part of a light-emitting layer of an organic light-emitting diode, the light-emitting efficiency of the light-emitting diode may be significantly improved. Therefore, the compound of the present invention may be effectively used as a material for an organic light-emitting diode.
1. An organometallic compound represented by Formula 1 below
(in Formula 1 above,
at least one among R 1 to R 4 is a substituent represented by Formula 2 below;
if there is no substituent of Formula 2 among R 1 to R 4 , R 1 to R 4 are independent ones from each other selected from the group consisting of hydrogen, deuterium, halogen, cyano, C 1 -C 18 straight or branched alkyl, C 1 -C 18 straight or branched alkoxy, C 6 -C 18 aryl, C 3 -C 18 cycloalkyl, C 4 -C 18 heteroaryl, and 5 to 6-membered heterocycloalkyl, where, the alkyl or alkoxy is non-substitutable or substituted with halogen; the aryl, cycloalkyl, heteroaryl, or heterocycloalkyl is non-substitutable or substituted with halogen or C 1 -C 18 straight or branched alkyl; and the heteroaryl or heterocycloalkyl comprises at least one atom selected from among N, O, and S in the ring; and,
R 5 to R 8 are independent ones from each other selected from the group consisting of hydrogen, deuterium, halogen, cyano, C 1 -C 18 straight or branched alkyl, C 1 -C 18 straight or branched alkoxy, C 6 -C 18 aryl, C 3 -C 18 cycloalkyl, C 4 -C 18 heteroaryl, and 5 to 6-membered heterocycloalkyl, where, the alkyl or alkoxy is non-substitutable or substituted with halogen; the aryl, cycloalkyl, heteroaryl, or heterocycloalkyl is non-substitutable or substituted with halogen or C 1 -C 18 straight or branched alkyl; and the heteroaryl or heterocycloalkyl comprises at least one atom selected from among N, O, and S in the ring; and,
is a bidentate ligand formed with coordinate bond with iridium;
m is 2 or 3),
(in Formula 2 above,
L 1 to L 3 are independent ones from each other selected from the group consisting of hydrogen, deuterium, halogen, cyano, C 1 -C 18 straight or branched alkyl, C 1 -C 18 straight or branched alkoxy, C 6 -C 18 aryl, C 3 -C 18 cycloalkyl, C 4 -C 18 heteroaryl, and 5 to 6-membered heterocycloalkyl, where, the alkyl or alkoxy is non-substitutable or substituted with halogen; the aryl, cycloalkyl, heteroaryl, or heterocycloalkyl is non-substitutable or substituted with halogen or C 1 -C 18 straight or branched alkyl; and the heteroaryl or heterocycloalkyl comprises at least one atom selected from among N, O, and S in the ring).
2. An organometallic compound represented by Formula 1A below:
(in the Formula 1A above, L 1 to L 3 , R 5 to R 8 ,
and m are as defined in Formula 1 and Formula 2 of claim 1 ).
3. The organometallic compound according to claim 2 , wherein the L 1 to L 3 are independent ones from each other selected from the group consisting of methyl, ethyl, propyl, isopropyl, cyclohexyl, and phenyl.
4. The organometallic compound according to claim 1 , wherein the R 5 to R 8 are independent ones from each other selected from the group consisting of hydrogen, methyl, phenyl, methylphenyl, and dimethylphenyl.
5. The organometallic compound according to claim 1 , wherein the A and B are independent ones from each other selected from among nitrogen (N), oxygen (O), sulfur (S), phosphorus (P), and carbon (C).
6. The organometallic compound according to claim 1 , wherein a partial structure, of the organometallic compound represented as
is selected from among compounds of the following formulas:
7. The organometallic compound according to claim 1 , wherein the organometallic compound is selected from among compounds of the following formulas:
8. An organic light-emitting diode comprising the organometallic compound of claim 1 .
9. The organic light-emitting diode according to claim 8 , wherein the organometallic compound is used as a dopant of a light-emitting layer.
10. The organic light-emitting diode comprising a first electrode; a second electrode; and one or more organic layers interposed between the first electrode and the second electrode, wherein the organic layer comprises one or more organometallic compounds according to claim 1 .
11. A method for forming a thin film for an organic light-emitting diode, the method comprising the following steps of:
preparing a solution by dissolving the organometallic compound of claim 1 in an organic solvent (step 1); and
forming a thin film on a substrate by dropping the solution of step 1 onto the substrate and rotating and drying the substrate (step 2).
12. The organometallic compound according to claim 2 , wherein the R 5 to R 8 are independent ones from each other selected from the group consisting of hydrogen, methyl, phenyl, methylphenyl, and dimethylphenyl.
13. The organometallic compound according to claim 2 , wherein the A and B are independent ones from each other selected from among nitrogen (N), oxygen (O), sulfur (S), phosphorus (P), and carbon (C).
14. The organometallic compound according to claim 2 , wherein a partial structure of the organometallic compound represented as
is selected from among compounds of the following formulas:
15. The organometallic compound according to claim 2 , wherein the organometallic compound is selected from among compounds of the following formulas:
16. An organic light-emitting diode comprising the organometallic compound of claim 2 .
17. The organic light-emitting diode comprising a first electrode; a second electrode; and one or more organic layers interposed between the more organometallic compounds according to claim 2 .
18. A method for forming a thin film for an organic light-emitting diode, the method comprising the following steps of:
preparing a solution by dissolving the organometallic compound of claim 2 in an organic solvent (step 1); and
forming a thin film on a substrate by dropping the solution of step 1 onto the substrate and rotating and drying the substrate (step 2).