KR-20260066736-A - Benzoazole compound and organic electroluminescent device using the compound

KR20260066736AKR 20260066736 AKR20260066736 AKR 20260066736AKR-20260066736-A

Abstract

In order to improve the light extraction efficiency of an organic electroluminescence (EL) device, an organic EL device is provided that uses a compound having a high refractive index and a low decay coefficient at a wavelength of 450 nm to 750 nm in the capping layer. An organic EL device having an anode, a hole transport layer, a light-emitting layer, an electron transport layer, a cathode, and a capping layer in this order, wherein the capping layer contains a benzoazole compound represented by the following general formula (1): wherein A represents a benzoxazolyl ring, etc., B and C represent a phenyl group, a naphthyl group, a phenanthrolinyl group, or an oxazolopyridyl group, etc., D represents a hydrogen atom or an aryl group, etc., and L1 to L3 represent a single bond or a divalent aryl group, etc.

Inventors

가세 고우키
양 병선
차 현욱
김 희재
히라야마 유타
하야시 슈이치

Assignees

호도가야 가가쿠 고교 가부시키가이샤

Dates

Publication Date: 20260512
Application Date: 20240905
Priority Date: 20230908

Claims (11)

An organic electroluminescent device having an anode, a hole transport layer, a light-emitting layer, an electron transport layer, a cathode, and a capping layer in this order, wherein the capping layer contains a benzoazole compound represented by the following general formula (1): In the formula, A represents a benzoxazolyl ring or a benzothiazolyl ring, B and C independently represent a substituted or unsubstituted phenyl group, naphthyl group, quinolyl group, quinoxalinyl group, quinazolinyl group, phenanthrolinyl group, benzoxazolyl group, benzothiazolyl group, benzofuryl group, benzothienyl group, or oxazolopyridyl group, and D represents a hydrogen atom, or a substituted or unsubstituted aryl group or heteroaryl group, and L1 to L3 independently represent single bonds or unsubstituted divalent aryl groups or divalent heteroaryl groups.
In Article 1, An organic electroluminescent device in which, in the above general formula (1), L2 , L3 , and L1 are respectively bonded to the 2nd, 4th, and 6th positions of a benzoxazolyl ring or benzothiazolyl ring represented by A.
In Article 1, An organic electroluminescent element in which L1 to L3 in the above general formula (1) are independently single bonds or unsubstituted phenylene groups, biphenyllylene groups, or naphthylene groups.
In Article 1, An organic electroluminescent device in which the aryl group or heteroaryl group represented by D in the above general formula (1) is selected from the group consisting of a phenyl group, a biphenylal group, a naphthyl group, a furyl group, a quinolyl group, a benzoxazolyl group, a benzothiazolyl group, an oxazolopyridyl group, a quinoxalinyl group, a quinazolinyl group, and a phenanthrolinyl group.
In Article 4, An organic electroluminescent element in which D in the above general formula (1) is a hydrogen atom, a cyanophenyl group, or an unsubstituted phenyl group, a biphenyl group, a naphthyl group, a furyl group, a quinolyl group, a benzoxazolyl group, a benzothiazolyl group, an oxazolopyridyl group, a quinoxalinyl group, a quinazolinyl group, or a phenanthrolinyl group.
In Article 1, An organic electroluminescent element according to the above general formula (1), wherein at least one of B and C is an unsubstituted group selected from the group consisting of a phenyl group, a naphthyl group, a quinolyl group, a quinazolinyl group, a phenanthrolinyl group, a benzoxazolyl group, a benzothiazolyl group, and an oxazolopyridyl group.
In Article 1, An organic electroluminescence device having a refractive index of 1.70 or higher in the wavelength range of 450 nm to 750 nm when the capping layer is formed to a thickness of 30 nm to 120 nm.
In any one of paragraphs 1 to 7, An organic electroluminescent device in which the capping layer is a stacked or mixed layer containing two or more types of compounds including a benzoazole compound represented by the general formula (1).
Benzoazole compound represented by the following general formula (2): In the formula, A represents a benzoxazolyl ring or a benzothiazolyl ring, B and C independently represent a substituted or unsubstituted phenyl group, naphthyl group, quinolyl group, quinoxalinyl group, quinazolinyl group, phenanthrolinyl group, benzoxazolyl group, benzothiazolyl group, benzofuryl group, benzothienyl group, or oxazolopyridyl group, and D represents a hydrogen atom, or a substituted or unsubstituted phenyl group, biphenyll group, naphthyl group, furyl group, quinolyl group, quinoxalinyl group, quinazolinyl group, phenanthrolinyl group, benzoxazolyl group, benzothiazoyl group, benzofuryl group, benzothienyl group, or oxazolopyridyl group, and L1 to L3 independently represent single or unsubstituted phenylene, biphenylylene, or naphthylene groups, and L2 , L3 , and L1 are each bonded to the 2nd, 4th, and 6th positions of the benzoxazolyl ring or benzothiazolyl ring represented by A, and Satisfies either 1 or 2 of the following requirements: Requirement 1: At least one of B, C, and D comprises a structure selected from the group consisting of quinazolin, phenanthroline, and oxazolopyridine, provided, Where one or two of B, C, and D are substituted or unsubstituted phenanthrolinyl groups, and where all or two of B, C, and D that are not phenanthrolinyl groups are not groups selected from substituted or unsubstituted quinazolinyl groups and oxazolopyridyl groups, at least one selected from L1 , L2 , and L3 that binds to the phenanthrolinyl group is an unsubstituted phenylene group, a biphenyllylene group, or a naphthylene group. Where B, C, and D are all substituted or unsubstituted phenanthrolinyl groups, at least one selected from L1 , L2 , and L3 bonded to the phenanthrolinyl group is an unsubstituted phenylene group, biphenylylene group, or naphthylene group; Requirement 2: B, C, and D do not all contain structures selected from the group consisting of quinazoline, phenanthroline, and oxazolopyridine, L3 is a single bond, and D is a hydrogen atom.
In Article 9, A benzoazole compound according to the above general formula (2), wherein at least one of B and C is a substituted or unsubstituted group selected from the group consisting of a phenyl group, a naphthyl group, a quinolyl group, a quinazolinyl group, a phenanthrolinyl group, a benzoxazolyl group, a benzothiazolyl group, a benzofuryl group, and an oxazolopyridyl group.
An electronic device or electronic element having one pair of electrodes and at least one organic layer, wherein the organic layer contains a benzoazole compound described in claim 9 or 10.

Description

Benzoazole compound and organic electroluminescent device using the compound The present invention relates to a benzoazole compound suitable for a self-luminescent electronic element preferred for various display devices, particularly an organic electroluminescent element (hereinafter abbreviated as “organic EL element”), and to an organic EL element, an electronic device, and an electronic element using the compound. Active research has been conducted on organic EL devices because they are brighter, have superior visibility, and enable clearer display compared to liquid crystal devices. In 1987, C. W. Tang et al. of Eastman Kodak developed a stacked structure device in which various roles were distributed among the materials, thereby making organic EL devices using organic materials practical. To date, many improvements have been made to commercialize organic EL devices. By further subdividing the roles of each layer in the stacked structure and sequentially forming an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode on a substrate, and designing a light-emitting device with a bottom emission structure that emits light from the bottom, high efficiency and durability have been achieved (see Non-Patent Literature 1). Recently, light-emitting devices with a top emission structure, which emit light from the top using a metal with a high work function as the anode, have come into use. In contrast to light-emitting devices with a bottom emission structure, which extract light from the bottom portion containing a pixel circuit and thus limit the area of the light-emitting portion, light-emitting devices with a top emission structure have the advantage of being able to take on a wide light-emitting portion because the pixel circuit is not blocked since light is extracted from the top. On the other hand, in light-emitting devices with a top emission structure, there was a limitation that when light emitted from the light-emitting layer is incident on another film at an angle greater than a certain level, total internal reflection occurs at the interface between the light-emitting layer and the other film, so only a portion of the emitted light can be utilized. Therefore, to improve the light extraction efficiency, a light-emitting device has been proposed in which a capping layer with a high refractive index is formed on the outer side of a semi-transparent electrode (cathode) such as LiF/Al/Ag, Ca/Mg, or LiF/MgAg, which has a low refractive index (see Non-Patent Literature 2 and Non-Patent Literature 3). Figure 1 is a diagram showing a specific example of a benzoazole compound represented by general formula (1). Figure 2 is a diagram showing a specific example of a benzoazole compound represented by general formula (1). Figure 3 is a diagram showing a specific example of a benzoazole compound represented by general formula (1). Figure 4 is a diagram showing a specific example of a benzoazole compound represented by general formula (1). Figure 5 is a diagram showing a specific example of a benzoazole compound represented by general formula (1). Figure 6 is a diagram showing a specific example of a benzoazole compound represented by general formula (1). Figure 7 is a diagram showing a specific example of a benzoazole compound represented by general formula (1). FIG. 8 is a diagram showing a specific example of a benzoazole compound represented by general formula (1). FIG. 9 is a diagram showing a specific example of a benzoazole compound represented by general formula (1). FIG. 10 is a diagram showing an example of the configuration of an organic EL device of the present invention. <Organic EL Device> The organic EL device of the present invention has, at least, an anode, a hole transport layer, a light-emitting layer, an electron transport layer, a cathode, and a capping layer in this order. As for the structure of an organic EL device, for example, in the case of a light-emitting device with a top emission structure, as shown in FIG. 10, a structure in which an anode (2), a hole transport layer (4), a light-emitting layer (5), an electron transport layer (6), a cathode (8), and a capping layer (9) are sequentially stacked on a glass substrate (1). Additionally, a hole injection layer (3) between the anode (2) and the hole transport layer (4), an electron blocking layer (not shown) between the hole transport layer (4) and the light-emitting layer (5), a hole blocking layer (not shown) between the light-emitting layer (5) and the electron transport layer (6), and an electron injection layer (7) between the electron transport layer (6) and the cathode (8) may be provided. That is, as long as the organic EL device of the present invention has at least an anode, a hole transport layer, a light-emitting layer, an electron transport layer, a cathode, and a capping layer in this order, it does not exclude an embodiment ha