Composition for electron transport layer, electron transport layer manufactured thereof, and organic electroluminescent device including the electron transport layer
View Patent ↗Provided are a composition for an electron transport layer which can be wet coated at a low temperature, an electron transport layer manufactured by coating and drying the composition, and an organic electroluminescent device including the electron transport layer. The organic electroluminescent device including the electron transport layer manufactured by wet coating the composition for an electron transport layer has an improved electron injection into a light emitting layer, thereby having an excellent light emitting efficiency, low operating voltage, and improved lifespan.
1. A composition for forming an electron transport layer, comprising:
Al 2 O 3 ;
a soluble titanium precursor comprising at least one selected from the group consisting of compounds represented by Formulae (1) through (4) and titanate chelate:
Ti(OR) 4 (1)
where R is each independently CH 3 CO—CH═C(CH 3 )—, C 2 H 5 OCO—CH═C(CH 3 )—, —(CH 3 )CH—COO − NH 4 + , —COR′, or —CO(C 6 H 4 )COOR″ where R′ is a substituted or unsubstituted C 1 -C 10 alkyl group, and R″ is a substituted or unsubstituted C 1 -C 10 alkyl group;
where R is a substituted or unsubstituted C 1 -C 10 alkyl group, and R′ is a substituted or unsubstituted C 1 -C 10 alkyl group;
where R is a substituted or unsubstituted C 1 -C 10 alkyl group;
where R 1 is a substituted or unsubstituted C 1 -C 10 alkyl group; and
a solvent.
2. The composition of claim 1 , wherein the Al 2 O 3 and the soluble titanium precursor are in a weight ratio of a range from 1:10 to 4:1.
3. The composition of claim 1 , wherein the soluble titanium precursor is represented by Formula 2:
where R is a substituted or unsubstituted C 1 -C 10 alkyl group, and R′ is a substituted or unsubstituted C 1 -C 10 alkyl group.
4. The composition of claim 1 , wherein the soluble titanium precursor comprises the titanate chelate.
5. The composition of claim 4 , wherein the titanate chelate includes at least one selected from the group consisting of compounds represented by Formulas 5 through 7:
where, R is a C1-C10 alkyl group.
6. The composition of claim 4 , wherein the titanate chelate is selected from the group consisting of acetylacetonate titanate chelate, ethyl acetoacetate titanate chelate, triethanolammine titanate, and ammonium salt of lactic acid titanate chelate.
7. The composition of claim 1 , wherein the amount of the solvent is in the range of 10 to 80 parts by weight based on 100 parts by weight of the total amount of Al 2 O 3 and the soluble titanium precursor.
8. An electron transport layer manufactured by coating and drying the composition of claim 1 .
9. An organic electroluminescent device comprising a pair of electrodes, and an organic layer interposed between the pair of electrodes, the organic layer comprising an organic light emitting layer and the electron transport layer of claim 8 .
10. The composition of claim 1 , wherein the soluble titanium precursor is represented by Formula 3:
where R is a substituted or unsubstituted C 1 -C 10 alkyl group.
11. The composition of claim 1 , wherein the soluble titanium precursor is represented by Formula 4:
where R 1 is a substituted or unsubstituted C 1 -C 10 alkyl group.
12. An organic electroluminescent device, comprising:
a first electrode;
a second electrode;
a light emitting layer interposed between the first electrode and the second electrode; and
an electron transport layer interposed between the second electrode and the light emitting layer, the electron transport layer formed from a composition comprising:
Al 2 O 3 ;
a soluble titanium precursor selected from the group consisting of compounds represented by Formulae 1 through 4 and titanate chelate:
Ti(OR) 4 (1)
where R is each independently CH 3 CO—CH═C(CH 3 )—, C 2 H 5 OCO—CH═C(CH 3 )—, —(CH 3 )CH—COO − NH 4 + , —COR′, or —CO(C 6 H 4 )COOR″ where R′ is a substituted or unsubstituted C 1 -C 10 alkyl group, and R″ is a substituted or unsubstituted C 1 -C 10 alkyl group;
where R is a substituted or unsubstituted C 1 -C 10 alkyl group, and R′ is a substituted or unsubstituted C 1 -C 10 alkyl group;
where R is a substituted or unsubstituted C 1 -C 10 alkyl group; and
where R 1 is a substituted or unsubstituted C 1 -C 10 alkyl group; and
a solvent.
13. The organic electroluminescent device of claim 12 , wherein the Al 2 O 3 and the soluble titanium precursor are in a weight ratio of a range from 1:9 to 4:1.
14. The organic electroluminescent device of claim 12 , wherein the soluble titanium precursor comprises the titanate chelate.
15. The composition of claim 14 , wherein the titanate chelate includes at least one selected from the group consisting of compounds represented by Formulas 5 through 7:
where, R is a C1-C10 alkyl group.
16. The organic electroluminescent device of claim 14 , wherein the titanate chelate is selected from the group consisting of acetylacetonate titanate chelate, ethyl acetoacetate titanate chelate, triethanolammine titanate, and ammonium salt of lactic acid titanate chelate.
17. The organic electroluminescent device of claim 12 , wherein the amount of the solvent is in the range of 10 to 80 parts by weight based on 100 parts by weight of the total amount of Al 2 O 3 and the soluble titanium precursor.
18. An organic electroluminescent device, comprising:
a substrate;
an anode formed on the substrate;
a hole transport layer formed on the anode;
a light emitting layer formed on the hole transport layer;
an electron transport layer formed on the light emitting layer, the electron transport layer formed by coating and drying a composition, the composition comprising:
Al 2 O 3 ;
a soluble titanium precursor selected from the group consisting of compounds represented by formulas 1 through 4 and titanate chelate:
Ti(OR) 4 (1)
where R is each independently CH 3 CO—CH═C(CH 3 )—, C 2 H 5 OCO—CH═C(CH 3 )—, —(CH 3 )CH—COO − NH 4 + , —COR′, or —CO(C 6 H 4 )COOR″, where R′ is a substituted or unsubstituted C 1 -C 10 alkyl group, and R″ is a substituted or unsubstituted C 1 -C 10 alkyl group;
where R is a substituted or unsubstituted C 1 -C 10 alkyl group, and R′ is a substituted or unsubstituted C 1 -C 10 alkyl group;
where R is a substituted or unsubstituted C 1 -C 10 alkyl group;
where R 1 is a substituted or unsubstituted C 1 -C 10 alkyl group; and
a solvent; and
a cathode formed on the electron transport layer.
19. The organic electroluminescent device of claim 18 , wherein the Al 2 O 3 has a specific surface area of 90 to 140 m 2 /g and a particle size of 20 nm to 150 nm.
20. The organic electroluminescent device of claim 18 , wherein the Al 2 O 3 and the soluble titanium precursor are in a weight ratio of a range from 1:9 to 4:1, and the amount of the solvent is in the range from 10 to 80 parts by weight based on 100 parts by weight of the total amount of Al 2 O 3 and the soluble titanium precursor.