Organic electroluminescent element
An object of the present invention is to provide an organic EL element that has (1) high light emission efficiency and high power efficiency, (2) a low light-emission start voltage, (3) a low actual driving voltage, and (4) an especially long lifespan. According to the present invention, provided is an organic electroluminescent element, or organic EL element, having at least an anode, a hole injection layer, a first hole transport layer, a second hole transport layer, a light emitting layer, an electron transport layer, and a cathode, in this order, wherein the second hole transport layer contains an arylamine compound represented by the general formula (1) below, and the electron transport layer contains a pyrimidine derivative represented by the general formula (2) below. Note that A in the general formula (2) represents a monovalent group represented by the structural formula (3) below.
1. An organic electroluminescent element having at least an anode, a hole injection layer, a first hole transport layer, a second hole transport layer, a light emitting layer, an electron transport layer, and a cathode, in this order,
wherein the second hole transport layer contains an arylamine compound represented by the general formula (1) below, and
the electron transport layer contains a pyrimidine derivative represented by formula (2-125) below:
where Ar 1 to Ar 4 may be the same or different, and represent an aromatic hydrocarbon group, an aromatic heterocyclic group, or a condensed polycyclic aromatic group; and
2. The organic electroluminescent element according to claim 1 ,
wherein the first hole transport layer contains a triarylamine compound having three to six triarylamine structures in a molecule, the triarylamine structures being linked via a divalent group having no heteroatom or a single bond.
3. The organic electroluminescent element according to claim 2 ,
wherein the triarylamine compound represented by the following general formula (4), is a triarylamine compound that has four triarylamine structures in a molecule:
where R 5 to R 16 may be the same or different, and represent a heavy hydrogen atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkyloxy group having 1 to 6 carbon atoms, a cycloalkyloxy group having 5 to 10 carbon atoms, an aromatic hydrocarbon group, an aromatic heterocyclic group, a condensed polycyclic aromatic group, or an aryloxy group,
r 5 , r 6 , r 9 , r 12 , r 15 , and r 16 may be the same or different, and represent an integer of 0 to 5,
r 7 , r 8 , r 10 , r 11 , r 13 , and r 14 may be the same or different, and represent an integer of 0 to 4,
when r 5 , r 6 , r 9 , r 12 , r 15 , or r 16 is an integer of 2 to 5, or when r 7 , r 8 , r 10 , r 11 , r 13 , or r 14 is an integer of 2 to 4, the plurality of atoms or groups represented by the corresponding one of R 5 to R 16 which are bonded to the same benzene ring, may be the same or different, and may be bonded to each other to form a ring via a single bond, a methylene group, an oxygen atom, or a sulfur atom, and
L 1 to L 3 may be the same or different, and represent a divalent group represented by any of the following structural formulae (B) to (G) or a single bond:
where n1 represents an integer of 1 to 3.
4. The organic electroluminescent element according to claim 1 ,
wherein the first hole transport layer contains a triarylamine compound having two triarylamine structures in a molecule, the triarylamine structures being linked via a divalent group having no heteroatom or a single bond.
5. The organic electroluminescent element according to claim 4 ,
wherein the triarylamine compound is represented by the following general formula (5):
where R 17 to R 22 may be the same or different, and represent a heavy hydrogen atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkyloxy group having 1 to 6 carbon atoms, a cycloalkyloxy group having 5 to 10 carbon atoms, an aromatic hydrocarbon group, an aromatic heterocyclic group, a condensed polycyclic aromatic group, or an aryloxy group,
r 17 , r 18 , r 21 , and r 22 may be the same or different, and represent an integer of 0 to 5,
r 19 and r 20 may be the same or different, and represent an integer of 0 to 4,
when r 17 , r 18 , r 21 , or r 22 is an integer of 2 to 5, or when r 19 or r 20 is an integer of 2 to 4, the plurality of atoms or groups represented by the corresponding one of R 17 to R 22 which are bonded to the same benzene ring, may be the same or different, and may be bonded to each other to form a ring via a single bond, a methylene group, an oxygen atom, or a sulfur atom, and
L 4 represents a divalent group represented by any of the structural formulae (C) to (G) below or a single bond: