Material for organic electroluminescence element and organic electroluminescence element using the same, and method for manufacturing organic electroluminescence element
A material for organic electroluminescence element, including: a phosphorescent compound; and a discotic liquid-crystalline host compound, wherein the phosphorescent compound has an aspect ratio of molecule core diameter to molecule core thickness (molecule core diameter/molecule core thickness) of at least 3, and wherein a size ratio of the molecular radius of the phosphorescent compound to the molecular radius of the discotic liquid-crystalline host compound (molecular radius of the phosphorescent compound/molecular radius of the discotic liquid-crystalline host compound) is 0.8 to 1.2.
1. A material for organic electroluminescence element, comprising:
a phosphorescent compound; and
a discotic liquid-crystalline host compound,
wherein the phosphorescent compound has an aspect ratio of molecule core diameter to molecule core thickness (molecule core diameter/molecule core thickness) of at least 3, and
wherein a size ratio of a molecular radius of the phosphorescent compound to a molecular radius of the discotic liquid-crystalline host compound (molecular radius of the phosphorescent compound/molecular radius of the discotic liquid-crystalline host compound) is 0.8 to 1.2,
wherein the discotic liquid-crystalline host compound is capable of developing a discotic-nematic liquid-crystalline phase; and
wherein the discotic liquid-crystalline host compound is represented by General Formula (1):
wherein H represents a mother nucleus portion of liquid crystal; L represents a divalent linking group; R 1 to R 9 represent a hydrogen atom or a substituent; n represents an integer of 1 to 12; and m represents an integer of 0 to 3;
and wherein the mother nucleus portion of liquid crystal is represented by one of General Formula (H-1) to (H-3)
wherein in General Formula (H-1), Z 100 to Z 102 each independently represents an aromatic ring containing substituted or unsubstituted five-membered or six-membered ring, and A 1 to A 3 each independently represents a carbon atom or a nitrogen atom;
wherein in General Formula (H-2), Z 103 to Z 105 each independently optionally represents an aromatic ring containing substituted or unsubstituted five-membered or six-membered ring;
wherein in General Formula (H-3), Z 106 to Z 107 each independently optionally represents an aromatic ring containing substituted or unsubstituted five-membered or six-membered ring.
2. The material for organic electroluminescence element according to claim 1 , wherein the phosphorescent compound is a platinum complex.
3. The material for organic electroluminescence element according to claim 1 , wherein the phosphorescent compound is at least any one compound represented by any one selected from Structural Formulae (1) to (5):
where, in Structural Formula (1), each of X, Y and Z represents a carbon atom or a nitrogen atom; at least one of Z and Y is a nitrogen atom, and X is a carbon atom when Y is a nitrogen atom; each of m, n, p and q represents an integer of 0 to 3; R 1 to R 4 represent any one of an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a fluorine atom, a cyano group, a silyl group and a heterocyclic group; when m, n, p or q is two or more, neighboring R 1 , R 2 , R 3 or R 4 may connect to each other to form a ring structure; and Ar represents a substituted or unsubstituted aryl group,
where, in Structural Formula (2), each of X, Y and Z represents any one of a carbon atom and a nitrogen atom; at least one of Z and Y is a nitrogen atom, and X is a carbon atom when Y is a nitrogen atom; each of r, s, t and u represents an integer of 0 to 3; R 5 to R 8 represent any one of an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a fluorine atom, a cyano group, a silyl group and a heterocyclic group; when r, s, t or u is two or more, neighboring R 5 , R 6 , R 7 or R 8 may connect to each other to form a ring structure; and W 1 and W 2 represent an alkyl group and may bind with each other to form a ring structure,
where, in Structural Formula (3), at least one of A and B represents a ring structure; when A forms a ring, B may or may not form a ring; when A does not form a ring, B forms a ring; when A forms a ring, A represents any one of an aromatic ring and a hetero ring, and when B forms a ring, B represents any one of a hetero ring and a heteroaryl; R 13 to R 16 represent any one of a hydrogen atom, an alkyl group, an aryl group, a silyl group and a heterocyclic ring; and R 14 and R 15 , or R 13 and R 16 , may bind with each other to form a ring structure;
where, in Structural Formula (4), R 1 to R 3 , X, Y, Z, Ar, m, n and p are synonymous to those in Structural Formula (1); M and Q independently represent any one of a carbon atom and a nitrogen atom; R 30 represents any one of an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a fluorine atom, a cyano group, a silyl group and a heterocyclic group; and g represents an integer of 0 to 3,
where, in Structural Formula (5), R 1 to R 2 , Z, Ar, m and n are synonymous to those in Structural Formula (1), and M, Q, R 30 and g are synonymous to those in Structural Formula (4).
4. The material for organic electroluminescence element according to claim 1 , wherein the phosphorescent compound is represented by Structural Formula (6):
where, in Structural Formula (6), B optionally forms any one of an aromatic ring and non-aromatic six-membered ring; R 17 to R 26 represent any one of an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a fluorine atom, a cyano group, a silyl group and a heterocyclic group; R 17 and R 18 , or R 18 and R 19 , or R 19 and R 20 , or R 21 and R 22 , or R 22 and R 23 , or R 23 and R 24 , or R 25 and R 26 , may bind with each other to form a ring structure.
5. An organic electroluminescence element, comprising:
an anode,
a cathode, and
a light-emitting layer between the anode and the cathode,
wherein the light-emitting layer comprises the material for organic electroluminescence element according to claim 1 ,
wherein the phosphorescent compound has a transition dipole moment oriented horizontally with respect to the anode.
6. The organic electroluminescence element according to claim 5 , wherein the light-emitting layer comprises a fluorine atom containing compound, wherein the amount of the fluorine atom containing compound in the light-emitting layer is 0.0001% by mass to 10% by mass.
7. The organic electroluminescence element according to claim 6 , wherein the fluorine atom containing compound comprises 3 or more alkyl groups or acyl groups each having 4 or more fluorine atoms.
8. The organic electroluminescence element according to claim 6 , wherein the fluorine atom containing compound is represented by any one of Structural Formulae (A) and (B):
where, in Structural Formula (A), R 27 and R 28 independently represent a substituted or unsubstituted alkyl group having 4 or more fluorine atoms,
where, in Structural Formula (B), R 29 represents any one of a substituted or unsubstituted alkyl group and an acyl group each having 4 or more fluorine atoms.
9. A method for manufacturing an organic electroluminescence element, comprising:
forming a light-emitting layer by a solution method using the material for organic electroluminescence element according to claim 1 .
10. A material for organic electroluminescence element, comprising:
a phosphorescent compound; and
a discotic liquid-crystalline host compound, wherein the discotic liquid-crystalline host compound is capable of developing a discotic-nematic liquid-crystalline phase,
wherein the phosphorescent compound has an aspect ratio of molecule core diameter to molecule core thickness (molecule core diameter/molecule core thickness) of at least 3, and
wherein a size ratio of a molecular radius of the phosphorescent compound to a molecular radius of the discotic liquid-crystalline host compound (molecular radius of the phosphorescent compound/molecular radius of the discotic liquid-crystalline host compound) is 0.8 to 1.2; and
wherein the phosphorescent compound is at least any one compound represented by any one selected from Structural Formulae (1) to (5):
where, in Structural Formula (1), each of X, Y and Z represents a carbon atom or a nitrogen atom; at least one of Z and Y is a nitrogen atom, and X is a carbon atom when Y is a nitrogen atom; each of m, n, p and q represents an integer of 0 to 3; R 1 to R 4 represent any one of an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a fluorine atom, a cyano group, a silyl group and a heterocyclic group; when m, n, p or q is two or more, neighboring R 1 , R 2 , R 3 or R 4 may connect to each other to form a ring structure; and Ar represents a substituted or unsubstituted aryl group,
where, in Structural Formula (2), each of X, Y and Z represents any one of a carbon atom and a nitrogen atom; at least one of Z and Y is a nitrogen atom, and X is a carbon atom when Y is a nitrogen atom; each of r, s, t and u represents an integer of 0 to 3; R 5 to R 8 represent any one of an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a fluorine atom, a cyano group, a silyl group and a heterocyclic group; when r, s, t or u is two or more, neighboring R 5 , R 6 , R 7 or R 8 may connect to each other to form a ring structure; and W 1 and W 2 represent an alkyl group and may bind with each other to form a ring structure,
where, in Structural Formula (3), at least one of A and B represents a ring structure; when A forms a ring, B may or may not form a ring; when A does not form a ring, B forms a ring; when A forms a ring, A represents any one of an aromatic ring and a hetero ring, and when B forms a ring, B represents any one of a hetero ring and a heteroaryl; R 13 to R 16 represent any one of a hydrogen atom, an alkyl group, an aryl group, a silyl group and a heterocyclic ring; and R 14 and R 15 , or R 13 and R 16 , may bind with each other to form a ring structure;
where, in Structural Formula (4), R 1 to R 3 , X, Y, Z, Ar, m, n and p are synonymous to those in Structural Formula (1); M and Q independently represent any one of a carbon atom and a nitrogen atom; R 30 represents any one of an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a fluorine atom, a cyano group, a silyl group and a heterocyclic group; and g represents an integer of 0 to 3,
where, in Structural Formula (5), R 1 to R 2 , Z, Ar, m and n are synonymous to those in Structural Formula (1), and M, Q, R 30 and g are synonymous to those in Structural Formula (4).
11. The material for organic electroluminescence element according to claim 10 , wherein the phosphorescent compound is represented by Structural Formula (6):
where, in Structural Formula (6), B optionally forms any one of an aromatic ring and non-aromatic six-membered ring; R 17 to R 26 represent any one of an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a fluorine atom, a cyano group, a silyl group and a heterocyclic group; R 17 and R 18 , or R 18 and R 19 , or R 19 and R 20 , or R 21 and R 22 , or R 22 and R 23 , or R 23 and R 24 , or R 25 and R 26 , may bind with each other to form a ring structure.