Organometallic compound, organic light-emitting device including the organometallic compound, and diagnostic composition including the organometallic compound

An organometallic compound represented by Formula 1:

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Korean Patent Application No. 10-2017-0027331, filed on Mar. 2, 2017, in the Korean Intellectual Property Office, and all the benefits accruing therefrom under 35 U.S.C. § 119, the content of which is incorporated herein in its entirety by reference.

BACKGROUND

One or more embodiments relate to an organometallic compound, an organic light-emitting device including the organometallic compound, and a diagnostic composition including the organometallic compound.

2. Description of the Related Art

Organic light-emitting devices (OLEDs) are self-emission devices, which have superior characteristics in terms of a viewing angle, a response time, a brightness, a driving voltage, and a response speed, and which produce full-color images.

Meanwhile, luminescent compounds may be used to monitor, sense, or detect a variety of biological materials including cells and proteins. An example of the luminescent compounds includes a phosphorescent luminescent compound.

Various types of organic light emitting devices are known. However, there still remains a need in OLEDs having low driving voltage, high efficiency, high brightness, and long lifespan.

SUMMARY

One or more embodiments include an organometallic compound, an organic light-emitting device including the organometallic compound, and a diagnostic composition including the organometallic compound.

According to one or more embodiments, an organometallic compound is represented by Formula 1:

In Formulae 1 and 2,

X1may be O or S, and a bond between X1and M may be a covalent bond,

X2to X4may each independently be N or C, one bond selected from a bond between X2and M, a bond between X3and M, and a bond between X4and M may be a covalent bond, and the others thereof may each be a coordinate bond,

Y1to Y9may each independently be C or N,

a bond between Y2and Y3, a bond between Y6and Y7, and a bond between Y8and Y9may each be a single bond,

CY1to CY5may each independently be a C5-C30carbocyclic group or a C1-C30heterocyclic group,

a cyclometallated ring formed by CY5, CY2, CY3, and M may be a 6-membered ring,

R7and R8may optionally be linked via a first linking group to form a substituted or unsubstituted C5-C30carbocyclic group or a substituted or unsubstituted C1-C30heterocyclic group,

L1to L4, L7, L8, L61, and L62may each independently be selected from a single bond, a substituted or unsubstituted C5-C30carbocyclic group, and a substituted or unsubstituted C1-C30heterocyclic group,

b1 to b4, b7, b8, b61, and b62 may each independently be an integer from 1 to 5,

c1 to c4, c7, c8, c61, and c62 may each independently be an integer from 1 to 5,

Z1to Z4may each independently be a group represented by Formula 2,

a1 to a4 and n1 to n4 may each independently be an integer from 0 to 20,

two in a plurality of neighboring groups R1may optionally be linked to form a substituted or unsubstituted C5-C30carbocyclic group or a substituted or unsubstituted C1-C30heterocyclic group,

two in a plurality of neighboring groups R2may optionally be linked to form a substituted or unsubstituted C5-C30carbocyclic group or a substituted or unsubstituted C1-C30heterocyclic group,

two in a plurality of groups R3may optionally be linked to form a substituted or unsubstituted C5-C30carbocyclic group or a substituted or unsubstituted C1-C30heterocyclic group,

two in a plurality of neighboring groups R4may optionally be linked to form a substituted or unsubstituted C5-C30carbocyclic group or a substituted or unsubstituted C1-C30heterocyclic group,

two or more in R1to R4may optionally be linked to form a substituted or unsubstituted C5-C30carbocyclic group or a substituted or unsubstituted C1-C30heterocyclic group,

i) when X51is O, S, C(═O), or N, the sum of n1, n2, n3, and n4 may be one or more, ii) when X51is N[(L7)b7-(R7)c7], C[(L7)b7-(R7)c7], or Si[(L7)b7-(R7)c7], R7may be a group represented by Formula 2 or the sum of n1, n2, n3, and n4 may be one or more, and iii) when X51is C[(L7)b7-(R7)c7][(L8)b8-(R8)c8] or Si[(L7)b7-(R7)c7][(L8)b8-(R8)c8], at least one of R7and R8may be a group represented by Formula 2 or the sum of n1, n2, n3, and n4 may be one or more,

* indicates a binding site to a neighboring atom,

According to one or more embodiments, an organic light-emitting device includes:

a first electrode;

a second electrode; and

an organic layer that is disposed between the first electrode and the second electrode,

wherein the organic layer includes an emission layer and at least one organometallic compound described above.

The organometallic compound may act as a dopant in the organic layer.

According to one or more embodiments, a diagnostic composition includes at least one organometallic compound represented by Formula 1.

DETAILED DESCRIPTION

Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of the present embodiments.

In an embodiment, an organometallic compound is provided. The organometallic compound according to an embodiment may be represented by Formula 1:

Z1to Z4in Formula 1 may each independently be a group represented by Formula 2:
*—N-[(L61)b61-(R61)c61][(L62)b62-(R62)c62].  Formula 2

Formula 2 is the same as described herein.

For example, M in Formula 1 may be platinum, but embodiments of the present disclosure are not limited thereto.

The organometallic compound represented by Formula 1 may be a neutral compound that does not consist of an ion pair of an anion and a cation.

In Formula 1, X1may be O or S, and a bond between X1and M may be a covalent bond.

For example, X1in Formula 1 may be O, but embodiments of the present disclosure are not limited thereto.

In Formula 1, X2to X4may each independently be N or C, one bond selected from a bond between X2and M, a bond between X3and M, and a bond between X4and M may be a covalent bond, and the others thereof may each be a coordinate bond.

For example, in Formula 1,

i) X2and X4may be N, X3may be C, a bond between X2and M and a bond between X4and M may each be a coordinate bond, and a bond between X3and M may be a covalent bond;

ii) X2and X3may be N, X4may be C, a bond between X2and M and a bond between X3and M may each be a coordinate bond, and a bond between X4and M may be a covalent bond; or

iii) X3and X4may be N, X2may be C, a bond between X3and M and a bond between X4and M may each be a coordinate bond, and a bond X2and M may be a covalent bond.

In Formula 1, Y1to Y9may each independently be C or N, and Y10and Y11may each independently be C, N, O, Si, or S.

For example, in Formula 1, Y1to Y9may each be C, and Y10and Y11may each independently be C or N, but embodiments of the present disclosure are not limited thereto.

CY1to CY5in Formula 1 may each independently be a C5-C30carbocyclic group or a C1-C30heterocyclic group.

In an embodiment, in Formula 1,

CY1, CY2, and CY4may each independently be a 6-membered ring group,

CY5may be a 5-membered ring group.

A cyclometallated ring formed by CY5, CY2, CY3, and M in Formula 1 may be a 6-membered ring.

In Formula 1, X51may be selected from O, S, N[(L7)b7-(R7)c7], C[(L7)b7-(R7)c7][(L8)b8-(R8)c8], Si[(L7)b7-(R7)c7][(L8)b8-(R8)c8], C(═O), N, C[(L7)b7-(R7)c7], and Si[(L7)b7-(R7)c7], and R7and R8may optionally be linked via a first linking group to form a substituted or unsubstituted C5-C30carbocyclic group or a substituted or unsubstituted C1-C30heterocyclic group (for example, a C5-C65-membered to 7-membered cyclic group; or a C5-C65-membered to 7-membered cyclic group substituted with at least one selected from deuterium, a cyano group, —F, C1-C10alkyl group, and a C6-C14aryl group). L7, L8, b7, b8, R7, R8, c7, and c8 are each independently the same as described below.

The first linking group may be selected from a single bond, *—O—*′, *—S—*′, —C(R5)(R6)—*′, *—C(R5)═*′, *═C(R6)—*′, *—C(R5)═C(R6)—*′, *—C(═O)—*′, *—C(═S)—′, *—C≡C—*′, *—N(R5)—*′, *—Si(R5)(R6)—*′, and *—P(R5)(R6)—*′, R5and R6are each independently the same as described in connection with R1, and * and *′ each indicate a binding site to a neighboring atom.

L1to L4, L7, L8, L61, and L62in Formulae 1 and 2 may each independently be selected from a single bond, a substituted or unsubstituted C5-C30carbocyclic group, and a substituted or unsubstituted C1-C30heterocyclic group.

Q31to Q39may each independently be selected from:

a single bond, a benzene group, a pyridine group, and a pyrimidine group; and

a benzene group, a pyridine group, and a pyrimidine group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C1-C20alkyl group, a C1-C20alkoxy group, a phenyl group, a pyridinyl group, a pyrimidinyl group, —N(Q31)(Q32), —Si(Q33)(Q34)(Q35), —B(Q36)(Q37), and —P(═O)(Q38)(Q39) (wherein Q31to Q39are each independently the same as described herein),

b1, b2, b3, b4, b7, b8, b61, and b62 in Formulae 1 and 2 respectively indicate the number of groups L1, the number of groups L2, the number of groups L3, the number of groups L4, the number of groups L7, the number of groups L8, the number of groups L61, and the number of groups L62, and may each independently be an integer from 1 to 5. b1 to b4, b7, b8, b61, and b62 may each independently be 1 or 2, but embodiments of the present disclosure are not limited thereto.

Q3to Q9and Q33to Q35are each independently the same as described herein.

Q3to Q9and Q33to Q35are each independently the same as described herein, but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, R1to R4, R7, R8, R61, and R62may each independently be selected from hydrogen, deuterium, —F, a cyano group, a nitro group, —SF5, —CH3, —CD3, —CD2H, —CDH2, —CF3, —CF2H, —CFH2, groups represented by Formulae 9-1 to 9-19, groups represented by Formulae 10-1 to 10-139, and —Si(Q3)(Q4)(Q5) (wherein Q3to Q9are each independently the same as described herein), but embodiments of the present disclosure are not limited thereto:

In Formulae 9-1 to 9-19 and 10-1 to 10-139, “Ph” indicates a phenyl group, “TMS” indicates a trimethylsilyl group, and “*” indicates a binding site to a neighboring atom.

c1, c2, c3, c4, c7, c8, c61, and c62 respectively indicate the number of groups R1, the number of groups R2, the number of groups R3, the number of groups R4, the number of groups R7, the number of groups R8, the number of groups R61, and the number of groups R62, and may each independently be an integer from 1 to 5. When c1 is two or more, two or more groups R1may be identical to or different from each other. c2 to c4, c7, c8, c61, and c62 are each independently the same as described in connection with c1.

In one or more embodiments, c1 to c4 Formula 1 may each independently be 1 or 2, but embodiments of the present disclosure are not limited thereto.

Z1to Z4in Formula 1 may each independently be a group represented by Formula 2.

a1, a2, a3, a4, n1, n2, n3, and n4 in Formula 1 respectively indicate the number of groups *-[(L1)b1-(R1)c1], the number of groups *-[(L2)b2-(R2)c2], the number of groups *-[(L3)b3-(R3)c3], the number of groups *-[(L4)b4-(R4)c4], the number of groups Z1, the number of groups Z2, the number of groups Z3, and the number of groups Z4, and may each independently be selected from 0 to 20 (for example, from 0 to 10). When a1 is two or more, two or more groups *-[(L1)b1-(R1)c1] may be identical to or different from each other, when a2 is two or more, two or more groups *-[(L2)b2-(R2)c2] may be identical to or different from each other, when a3 is two or more, two or more groups *-[(L3)b3-(R3)c3] may be identical to or different from each other, when a4 is two or more, two or more groups *-[(L4)b4-(R4)c4] may be identical to or different from each other, when n1 is two or more, two or more groups Z1may be identical to or different from each other, when n2 is two or more, two or more groups Z2may be identical to or different from each other, when n3 is two or more, two or more groups Z3may be identical to or different from each other, and when n4 is two or more, two or more groups Z4may be identical to or different from each other.

a1 to a4 and n1 to n4 in Formula 1 may each independently be 0, 1, 2, or 3.

The sum of n1, n2, n3, and n4 in Formula 1 may be 1 or 2.

For example, in Formula 1, i) n1=1 and n2=n3=n4=0; ii) n2=1 and n1=n3=n4=0; iii) n3=1 and n1=n2=n4=0; or iv) n4=1 and n1=n2=n4=0, but embodiments of the present disclosure are not limited thereto.

In Formula 1, two in a plurality of neighboring groups R1may optionally be linked to form a substituted or unsubstituted C5-C30carbocyclic group or a substituted or unsubstituted C1-C30heterocyclic group, two in a plurality of neighboring groups R2may optionally be linked to form a substituted or unsubstituted C5-C30carbocyclic group or a substituted or unsubstituted C1-C30heterocyclic group, two in a plurality of neighboring groups R3may optionally be linked to form a substituted or unsubstituted C5-C30carbocyclic group or a substituted or unsubstituted C1-C30heterocyclic group, two in a plurality of neighboring groups R4may optionally be linked to form a substituted or unsubstituted C5-C30carbocyclic group or a substituted or unsubstituted C1-C30heterocyclic group, and two or more in R1to R4may optionally be linked to form a substituted or unsubstituted C5-C30carbocyclic group or a substituted or unsubstituted C1-C30heterocyclic group.

For example, i) a substituted or unsubstituted C5-C30carbocyclic group or a substituted or unsubstituted C1-C30heterocyclic group, formed by linking two in the plurality of neighboring groups R1, ii) a substituted or unsubstituted C5-C30carbocyclic group or a substituted or unsubstituted C1-C30heterocyclic group, formed by linking two in the plurality of neighboring groups R2, iii) a substituted or unsubstituted C5-C30carbocyclic group or a substituted or unsubstituted C1-C30heterocyclic group, formed by linking two in the plurality of neighboring groups R3, iv) a substituted or unsubstituted C5-C30carbocyclic group or a substituted or unsubstituted C1-C30heterocyclic group, formed by linking two in the plurality of neighboring groups R4, and v) a substituted or unsubstituted C5-C30carbocyclic group or a substituted or unsubstituted C1-C30heterocyclic group, formed by linking two or more in R1to R4in Formula 1, may each independently be selected from:

R10is the same as described in connection with R1.

“Azabenzothiophene, azabenzofuran, azaindene, azaindole, azabenzosilole, azadibenzothiophene, azadibenzofuran, azafluorene, azacarbazole, and azadibenzosilole” as used herein may mean hetero-rings that respectively have the same backbones as “benzothiophene, benzofuran, indene, indole, azabenzosilole, dibenzothiophene, dibenzofuran, fluorene, carbazole, and dibenzosilole”, provided that at least one of carbons forming rings thereof is substituted with nitrogen.

In Formula 1,

i) when X51is O, S, C(═O), or N, the sum of n1, n2, n3, and n4 may be one or more,

ii) when X51is N[(L7)b7-(R7)c7], C[(L7)b7-(R7)c7], or Si[(L7)b7-(R7)c7], R7may be a group represented by Formula 2 or the sum of n1, n2, n3, and n4 may be one or more, or

That is, Formula 1 essentially includes at least one group represented by Formula 2.

In one or more embodiments, X51in Formula 1 may be N-[(L7)b7-(R7)c7], provided that R7is selected from a substituted or unsubstituted C3-C10cycloalkyl group, a substituted or unsubstituted C1-C10heterocycloalkyl group, a substituted or unsubstituted C3-C10cycloalkenyl group, a substituted or unsubstituted C1-C10heterocycloalkenyl group, a substituted or unsubstituted C6-C60aryl group, a substituted or unsubstituted C6-C60aryloxy group, a substituted or unsubstituted C6-C60arylthio group, a substituted or unsubstituted C1-C60heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group.

In one or more embodiments, X51in Formula 1 may be N-[(L7)b7-(R7)c7], provided that R7is selected from groups represented by Formulae 10-1 to 10-128 and 10-131 to 10-139, but embodiments of the present disclosure are not limited thereto.

In an embodiment, a moiety represented by

in Formula 1 may be selected from groups represented by Formulae CY1-1 to CY1-26:

In Formulae CY1-1 to CY1-26,

Y1, R1, Z1, and n1 are each independently the same as described herein, provided that n1 is 0, 1, or 2,

L19is the same as described in connection with L1,

b19 and c19 are each independently the same as described in connection with b1 and c1,

R11to R19, R19a, and R19bare each independently the same as described in connection with R1,

d2 may be an integer from 0 to 2,

d3 may be an integer from 0 to 3,

d4 may be an integer from 0 to 4,

d5 may be an integer from 0 to 5,

d6 may be an integer from 0 to 6, and

In one or more embodiments, a moiety represented by

in Formula 1 may be selected from groups represented by Formulae CY2-1 to CY2-12:

In Formulae CY2-1 to CY2-12,

X2, R2, Z2, and n2 are each independently the same as described herein, provided that n2 is 0, 1, or 2,

d2 may be an integer from 0 to 2,

d3 may be an integer from 0 to 3, and

*, *′, and *″ each indicate a binding site to a neighboring atom.

In one or more embodiments, a moiety represented by

in Formula 1 may be selected from groups represented by Formulae CY3-1 to CY3-12:

In Formulae CY3-1 to CY3-12,

X3, R3, Z3, and n3 are each independently the same as described herein, provided that n3 is 0, 1, or 2,

L39is the same as described in connection with L3,

b39 and c39 are each independently the same as described in connection with b3 and c3,

R39aand R39bare each independently the same as in connection with R3,

d2 may be an integer from 0 to 2,

d3 may be an integer from 0 to 3,

d4 may be an integer from 0 to 4,

d5 may be an integer from 0 to 5, and

*, *′, and *″ each indicate a binding site to a neighboring atom.

In one or more embodiments, a moiety represented by

in Formula 1 may be selected from groups represented by Formulae CY4-1 to CY4-26:

In Formulae CY4-1 to CY4-26,

X4, R4, Z4, and n4 are each independently the same as described herein, provided that n4 is 0, 1, or 2,

L49is the same as described in connection with L4,

b49 and c49 are each independently the same as described in connection with b4 and c4,

R41to, R49, R49a, and R49bare each independently the same as described herein connection with R4,

d2 may be an integer from 0 to 2,

d3 may be an integer from 0 to 3,

d4 may be an integer from 0 to 4,

d5 may be an integer from 0 to 5,

d6 may be an integer from 0 to 6, and

In one or more embodiments, in Formula 1,

a moiety represented by

may be selected from groups represented by Formulae CY1(1) to CY1(12), and/or

a moiety represented by

may be selected from groups represented by Formulae CY2(1) to CY2(3), and/or

a moiety represented by

may be selected from groups represented by Formulae CY3(1) to CY3(15), and/or

a moiety represented by

may be selected from groups represented by Formulae CY4(1) to CY4(12):

In Formulae CY1(1) to CY1(12), CY2(1) to CY2(3), CY3(1) to CY3(15), and CY4(1) to CY4(12),

R1aand R1bare each independently the same as described in connection with R1,

R3ato R3care each independently the same as described in connection with R3,

Z4aand Z4bare each independently the same as described in connection with Z4,

L39is the same as described in connection with L3,

b39 and c39 are each independently the same as described in connection with b3 and c3,

R39aand R39bare each independently the same as described in connection with R3,

*, *′, and *″ each indicate a binding site to a neighboring atom.

In one or more embodiments, the organometallic compound may satisfy at least one of Condition 1 to Condition 4:

a moiety represented by

in Formula 1 is selected from groups represented by Formulae CY1(9) to CY1(12),

a moiety represented by

in Formula 1 is selected from groups represented by Formulae CY2(2) and CY2(3),

a moiety represented by

in Formula 1 is selected from groups represented by Formulae CY3(13) to CY3(15), and

a moiety represented by

in Formula 1 is selected from groups represented by Formulae CY4(9) to CY4(12).

For example, the organometallic compound may be one of Compounds 1-101 to 1-112 and 1-201 to 1-228, but embodiments of the present disclosure are not limited thereto:

Formula 1 includes a 5-membered ring represented by CY5, and a cyclometallated ring formed by CY5, CY2, CY3, and M in Formula 1 is a 6-membered ring (see Formula 1′). Accordingly, a stable bond angle may be formed between a tetradentate ligand and a metal in Formula 1, thereby improving a molecular stability of the organometallic compound represented by Formula 1.

Also, Z1to Z4in Formula 1 may each independently be a group represented by Formula 2, provided that i) when X51is O, S, C(═O), or N, the sum of n1, n2, n3, and n4 is one or more, ii) when X51is N[(L7)b7-(R7)c7], C[(L7)b7-(R7)c7], or Si[(L7)b7-(R7)c7], R7is a group represented by Formula 2 or the sum of n1, n2, n3, and n4 is one or more, and iii) when X51is C[(L7)b7-(R7)c7][(L8)b8-(R8)c8] or Si[(L7)b7-(R7)c7][(L8)b8-(R8)c8], at least one of R7and R8is a group represented by Formula 2 or the sum of n1, n2, n3, and n4 is one or more. That is, Formula 1 essentially includes at least one group represented by Formula 2.

Therefore, a maximum emission wavelength of the organometallic compound represented by Formula 1 may be shifted to a red light area. Hence, the organometallic compound represented by Formula 1 may be used as a red phosphorescent dopant capable of providing high efficiency and a long lifespan.

For example, a highest occupied molecular orbital (HOMO) energy level, a lowest unoccupied molecular orbital (LUMO) energy level, a singlet (S1) energy level, and a triplet (T1) energy level of each of Compounds 1-103 and 1-218 were evaluated by using a density functional theory (DFT) method of a Gaussian program (a structure was optimized at a B3LYP, 6-31G(d,p) level). Evaluation results thereof are shown in Table 1.

Referring to Table 1, it is confirmed that Compounds 1-103 and 1-218 have a high HOMO energy level (that is, a small HOMO energy level absolute value) and a small S1-T1energy level, as compared with Compound A, and thus, the organometallic compound represented by Formula 1 has electrical characteristics suitable for use as a dopant of an electronic device, for example, an organic light-emitting device.

Synthesis methods of the organometallic compound represented by Formula 1 may be recognizable by one of ordinary skill in the art by referring to Synthesis Examples provided below.

The organometallic compound represented by Formula 1 is suitable for use in an organic layer of an organic light-emitting device, for example, for use as a dopant in an emission layer of the organic layer. Thus, another aspect of the present description provides an organic light-emitting device that includes:

a first electrode;

a second electrode; and

an organic layer that is disposed between the first electrode and the second electrode,

wherein the organic layer includes an emission layer and at least one organometallic compound represented by Formula 1.

The organic light-emitting device may have, due to the inclusion of an organic layer including the organometallic compound represented by Formula 1, a low driving voltage, high efficiency, high power, high quantum efficiency, a long lifespan, a low roll-off ratio, and excellent color purity.

The organometallic compound represented by Formula 1 may be used between a pair of electrodes of an organic light-emitting device. For example, the organometallic compound represented by Formula 1 may be included in the emission layer. In this regard, the organometallic compound may act as a dopant, and the emission layer may further include a host (that is, an amount of the organometallic compound represented by Formula 1 is smaller than an amount of the host).

The expression “(an organic layer) includes at least one of organometallic compounds” as used herein may include an embodiment in which “(an organic layer) includes identical organometallic compounds represented by Formula 1” and an embodiment in which “(an organic layer) includes two or more different organometallic compounds represented by Formula 1.”

For example, the organic layer may include, as the organometallic compound, only Compound 1. In this regard, Compound 1 may be included in an emission layer of the organic light-emitting device. In one or more embodiments, the organic layer may include, as the organometallic compound, Compound 1 and Compound 2. In this regard, Compound 1 and Compound 2 may be included in an identical layer (for example, Compound 1 and Compound 2 may both be included in an emission layer).

The first electrode may be an anode, which is a hole injection electrode, and the second electrode may be a cathode, which is an electron injection electrode; or the first electrode may be a cathode, which is an electron injection electrode, and the second electrode may be an anode, which is a hole injection electrode.

In an embodiment, in the organic light-emitting device, the first electrode is an anode, and the second electrode is a cathode, and the organic layer further includes a hole transport region disposed between the first electrode and the emission layer and an electron transport region disposed between the emission layer and the second electrode, wherein the hole transport region includes a hole injection layer, a hole transport layer, an electron blocking layer, or any combination thereof, and wherein the electron transport region includes a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.

The term “organic layer” as used herein refers to a single layer and/or a plurality of layers disposed between the first electrode and the second electrode of the organic light-emitting device. The “organic layer” may include, in addition to an organic compound, an organometallic complex including metal.

The FIGURE is a schematic view of an organic light-emitting device10according to an embodiment. Hereinafter, the structure of an organic light-emitting device according to an embodiment and a method of manufacturing an organic light-emitting device according to an embodiment will be described in connection with the FIGURE. The organic light-emitting device10includes a first electrode11, an organic layer15, and a second electrode19, which are sequentially stacked.

A substrate may be additionally disposed under the first electrode11or above the second electrode19. For use as the substrate, any substrate that is used in general organic light-emitting devices may be used, and the substrate may be a glass substrate or a transparent plastic substrate, each having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and water resistance.

The first electrode11may be formed by depositing or sputtering a material for forming the first electrode11on the substrate. The first electrode11may be an anode. The material for forming the first electrode11may be selected from materials with a high work function to facilitate hole injection. The first electrode11may be a reflective electrode, a semi-transmissive electrode, or a transmissive electrode. The material for forming the first electrode may be, for example, indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO2), and zinc oxide (ZnO). In one or more embodiments, magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), or magnesium-silver (Mg—Ag) may be used as the material for forming the first electrode.

The organic layer15is disposed on the first electrode11.

The hole transport region may be disposed between the first electrode11and the emission layer.

The hole transport region may include a hole injection layer, a hole transport layer, an electron blocking layer, a buffer layer, or any combination thereof.

The hole transport region may include only either a hole injection layer or a hole transport layer. In one or more embodiments, the hole transport region may have a hole injection layer/hole transport layer structure or a hole injection layer/hole transport layer/electron blocking layer structure, which are sequentially stacked in this stated order from the first electrode11.

A hole injection layer may be formed on the first electrode11by using one or more suitable methods selected from vacuum deposition, spin coating, casting, or Langmuir-Blodgett (LB) deposition.

When a hole injection layer is formed by vacuum deposition, the deposition conditions may vary according to a compound that is used to form the hole injection layer, and the structure and thermal characteristics of the hole injection layer. For example, the deposition conditions may include a deposition temperature of about 100° C. to about 500° C., a vacuum pressure of about 10−8torr to about 10−3torr, and a deposition rate of about 0.01 Angstroms per second (Å/sec) to about 0 Å/sec. However, the deposition conditions are not limited thereto.

When the hole injection layer is formed using spin coating, coating conditions may vary according to the material used to form the hole injection layer, and the structure and thermal properties of the hole injection layer. For example, a coating speed may be from about 2,000 revolutions per minute (rpm) to about 5,000 rpm, and a temperature at which a heat treatment is performed to remove a solvent after coating may be from about 80° C. to about 200° C. However, the coating conditions are not limited thereto.

Conditions for forming a hole transport layer and an electron blocking layer may be understood by referring to conditions for forming the hole injection layer.

Ar101and Ar102in Formula 201 may each independently be selected from:

xa and xb in Formula 201 may each independently be an integer from 0 to 5, or may each independently be 0, 1, or 2. For example, xa may be 1 and xb may be 0, but embodiments of the present disclosure are not limited thereto.

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C1-C10alkyl group (for example, a methyl group, an ethyl group, a propyl group, a butyl group, pentyl group, a hexyl group, and the like) and a C1-C10alkoxy group (for example, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group, and the like);

a phenyl group, a naphthyl group, an anthracenyl group, a fluorenyl group, and a pyrenyl group; and

R109in Formula 201 may be selected from:

a phenyl group, a naphthyl group, an anthracenyl group, and a pyridinyl group; and

According to an embodiment, the compound represented by Formula 201 may be represented by Formula 201A, but embodiments of the present disclosure are not limited thereto:

R101, R111, R112, and R109in Formula 201A may be understood by referring to the description provided herein.

For example, the compound represented by Formula 201, and the compound represented by Formula 202 may include compounds HT1 to HT20 illustrated below, but are not limited thereto.

The hole transport region may include a buffer layer.

Also, the buffer layer may compensate for an optical resonance distance according to a wavelength of light emitted from the emission layer, and thus, efficiency of a formed organic light-emitting device may be improved.

Then, an emission layer (EML) may be formed on the hole transport region by vacuum deposition, spin coating, casting, LB deposition, or the like. When the emission layer is formed by vacuum deposition or spin coating, the deposition or coating conditions may be similar to those applied in forming the hole injection layer although the deposition or coating conditions may vary according to a material that is used to form the emission layer.

Meanwhile, when the hole transport region includes an electron blocking layer, a material for the electron blocking layer may be selected from materials for the hole transport region described above and materials for a host to be explained later. However, the material for the electron blocking layer is not limited thereto. For example, when the hole transport region includes an electron blocking layer, a material for the electron blocking layer may be mCP, which will be explained later.

The emission layer may include a host and a dopant, and the dopant may include the organometallic compound represented by Formula 1.

The host may include at least one selected from TPBi, TBADN, ADN (also referred to as “DNA”), CBP, CDBP, TCP, mCP, Compound H50, and Compound H51:

In one or more embodiments, the host may further include a compound represented by Formula 301 below:

Ar111and Ar112in Formula 301 may each independently be selected from:

a phenylene group, a naphthylene group, a phenanthrenylene group, and a pyrenylene group; and

a phenylene group, a naphthylene group, a phenanthrenylene group, and a pyrenylene group, each substituted with at least one selected from a phenyl group, a naphthyl group, and an anthracenyl group.

Ar113to Ar116in Formula 301 may each independently be selected from:

a C1-C10alkyl group, a phenyl group, a naphthyl group, a phenanthrenyl group, and a pyrenyl group; and

a phenyl group, a naphthyl group, a phenanthrenyl group, and a pyrenyl group, each substituted with at least one selected from a phenyl group, a naphthyl group, and an anthracenyl group.

g, h, l, and j in Formula 301 may each independently be an integer from 0 to 4, for example, 0, 1, or 2.

Ar113to Ar116in Formula 301 may each independently be selected from:

a C1-C10alkyl group substituted with at least one selected from a phenyl group, a naphthyl group, and an anthracenyl group;

a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, and a fluorenyl group, each substituted with at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amino group, an amidino group, a hydrazine group, a hydrazone group, a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof, a C1-C60alkyl group, a C2-C60alkenyl group, a C2-C60alkynyl group, a C1-C60alkoxy group, a phenyl group, a naphthyl group, an anthracenyl group, a pyrenyl group, a phenanthrenyl group, and a fluorenyl group; and

In one or more embodiments, the host may include a compound represented by Formula 302:

Ar122to Ar125in Formula 302 are the same as described in detail in connection with Ar113in Formula 301.

Ar126and Ar127in Formula 302 may each independently be a C1-C10alkyl group (for example, a methyl group, an ethyl group, or a propyl group).

k and l in Formula 302 may each independently be an integer from 0 to 4. For example, k and l may be 0, 1, or 2.

The compound represented by Formula 301 and the compound represented by Formula 302 may include Compounds H1 to H42 illustrated below, but are not limited thereto.

When the organic light-emitting device is a full-color organic light-emitting device, the emission layer may be patterned into a red emission layer, a green emission layer, and a blue emission layer. In one or more embodiments, due to a stacked structure including a red emission layer, a green emission layer, and/or a blue emission layer, the emission layer may emit white light.

When the emission layer includes a host and a dopant, an amount of the dopant may be in a range of about 0.01 parts by weight to about 15 parts by weight based on 100 parts by weight of the host, but embodiments of the present disclosure are not limited thereto.

A thickness of the emission layer may be in a range of about 100 Å to about 1,000 Å, for example, about 200 Å to about 600 Å. While not wishing to be bound by theory, it is understood that when the thickness of the emission layer is within this range, excellent light-emission characteristics may be obtained without a substantial increase in driving voltage.

Then, an electron transport region may be disposed on the emission layer.

The electron transport region may include a hole blocking layer, an electron transport layer, an electron injection layer, or any combination thereof.

For example, the electron transport region may have a hole blocking layer/electron transport layer/electron injection layer structure or an electron transport layer/electron injection layer structure, but the structure of the electron transport region is not limited thereto. The electron transport layer may have a single-layered structure or a multi-layered structure including two or more different materials.

Conditions for forming the hole blocking layer, the electron transport layer, and the electron injection layer which constitute the electron transport region may be understood by referring to the conditions for forming the hole injection layer.

When the electron transport region includes a hole blocking layer, the hole blocking layer may include, for example, at least one of BCP, Bphen, and BAlq but embodiments of the present disclosure are not limited thereto.

A thickness of the hole blocking layer may be in a range of about 20 Å to about 1,000 Å, for example, about 30 Å to about 300 Å. While not wishing to be bound by theory, it is understood that when the thickness of the hole blocking layer is within these ranges, the hole blocking layer may have improved hole blocking ability without a substantial increase in driving voltage.

The electron transport layer may further include at least one selected from BCP, Bphen, Alq3, BAlq, TAZ, and NTAZ.

In one or more embodiments, the electron transport layer may include at least one of ET1 and ET25, but are not limited thereto:

The electron transport region may include an electron injection layer that promotes flow of electrons from the second electrode thereinto.

The electron injection layer may include at least one selected from LiF, NaCl, CsF, Li2O, and BaO.

A thickness of the electron injection layer may be in a range of about 1 Å to about 100 Å, for example, about 3 Å to about 90 Å. While not wishing to be bound by theory, it is understood that when the thickness of the electron injection layer is within the range described above, the electron injection layer may have satisfactory electron injection characteristics without a substantial increase in driving voltage.

The second electrode19is disposed on the organic layer15. The second electrode19may be a cathode. A material for forming the second electrode19may be selected from metal, an alloy, an electrically conductive compound, and a combination thereof, which have a relatively low work function. For example, lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al—Li), calcium (Ca), magnesium-indium (Mg—In), or magnesium-silver (Mg—Ag) may be used as a material for forming the second electrode19. In one or more embodiments, to manufacture a top-emission type light-emitting device, a transmissive electrode formed using ITO or IZO may be used as the second electrode19.

Hereinbefore, the organic light-emitting device has been described with reference to the FIGURE, but embodiments of the present disclosure are not limited thereto.

Another aspect of the present disclosure provides a diagnostic composition including at least one organometallic compound represented by Formula 1.

The organometallic compound represented by Formula 1 provides high luminescent efficiency. Accordingly, a diagnostic composition including the organometallic compound may have high diagnostic efficiency.

The diagnostic composition may be used in various applications including a diagnosis kit, a diagnosis reagent, a biosensor, and a biomarker.

The term “C6-C60aryloxy group” as used herein indicates —OA102(wherein A102is the C6-C60aryl group), and a C6-C60arylthio group as used herein indicates —SA103(wherein A103is the C6-C60aryl group).

The term “monovalent non-aromatic condensed heteropolycyclic group” as used herein refers to a monovalent group (for example, having 2 to 60 carbon atoms) having two or more rings condensed to each other, a heteroatom selected from N, O, P, Si, and S, other than carbon atoms, as a ring-forming atom, and no aromaticity in its entire molecular structure. Non-limiting examples of the monovalent non-aromatic condensed heteropolycyclic group include a carbazolyl group. The term “divalent non-aromatic condensed heteropolycyclic group” as used herein refers to a divalent group having the same structure as the monovalent non-aromatic condensed heteropolycyclic group.

The term “C5-C30carbocyclic group” as used herein refers to a saturated or unsaturated cyclic group having, as a ring-forming atom, 5 to 30 carbon atoms only. The C5-C30carbocyclic group may be a monocyclic group or a polycyclic group.

The term “C1-C30heterocyclic group” as used herein refers to a saturated or unsaturated cyclic group having, as a ring-forming atom, at least one heteroatom selected from N, O, Si, P, and S other than 1 to 30 carbon atoms. The C1-C30heterocyclic group may be a monocyclic group or a polycyclic group.

Hereinafter, a compound and an organic light-emitting device according to embodiments are described in detail with reference to Synthesis Examples and Examples. However, the organic light-emitting device is not limited thereto. The wording “B was used instead of A” used in describing Synthesis Examples means that an amount of A used was identical to an amount of B used, in terms of a molar equivalent.

EXAMPLES

Synthesis Example 1: Synthesis of Compound 1-103

Synthesis of Intermediate C (4-(diphenylamino)-2-(1-phenyl-4-(5-(4-phenylpyridin-2-yl)-[1,1′-biphenyl]-3-yl)-1H-benzo[d]imidazol-2-yl)phenol)

5.02 grams (g) (9.43 millimoles, mmol) of Intermediate A (2-(4-bromo-1-phenyl-1H-benzo[d]imidazol-2-yl)-4-(diphenylamino)phenol), 3.88 g (8.96 mmol) of Intermediate B (4-phenyl-2-(5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-[1,1′-biphenyl]-3-yl)pyridine), 0.76 g (0.66 mmol) of tetrakis(triphenylphosphine)palladium(0), and 3.26 g (23.57 mmol) of potassium carbonate were mixed with 70 milliliters (mL) of a mixture in which tetrahydrofuran (THF) and distilled water (H2O) were mixed at a ratio of 2:1, and then refluxed for 12 hours. The refluxed mixture was cooled to room temperature and the precipitate was filtered. A filtrate obtained therefrom was washed with ethyl acetate (EA)/H2O, and the crude product was purified by column chromatography (while increasing a rate of EA/Hex (hexane) to between 7% and 10%) to obtain 6.21 g (yield: 91%) of Intermediate C. The obtained product was confirmed by Mass and HPLC analysis.

Synthesis of Compound 1-103

6.21 g (8.18 mmol) of Intermediate C and 3.74 g (9.00 mmol) of K2PtCl4were mixed with 220 mL of a mixture containing 200 mL of AcOH and 20 mL of H2O, and the resulting mixture was refluxed for 16 hours. The refluxed mixture was cooled to room temperature and the precipitate was filtered. The obtained precipitate was dissolved again in methylene chloride (MC) and washed with H2O. The crude product was purified by column chromatography (MC 20%, EA 1%, Hex 79%) to obtain 4.57 g (purity: 99% or more, yield: 58%) of Compound 1-103. The obtained product was confirmed by Mass and HPLC analysis.

Synthesis Example 2: Synthesis of Compound 1-218

Synthesis of Intermediate E (N,N-diphenyl-3-(6-(tributylstannyl)-4-(trifluoromethyl)pyridin-2-yl)aniline)

2.00 g of 4.26 mmol of Intermediate D (3-(6-bromo-4-(trifluoromethyl)pyridin-2-yl)-N,N-diphenylaniline) was mixed with 14 mL of THF and stirred at a temperature of −78° C. Then, 2.93 mL (4.69 mmol) of n-butyllithium solution (1.6 M (molar) in hexane) was slowly added thereto. After 1 hour, 1.57 mL (5.54 mmol) of tributyltin chloride was added thereto, and the resulting mixture was slowly heated to room temperature. After the reaction was performed for 6 hours, the reaction solution was diluted with EA and washed with an excess amount of H2O. The solvent was removed therefrom under reduced pressure. 2.90 g (yield: 100%) of Intermediate E obtained therefrom was used in a subsequent reaction without additional purification.

Synthesis of Intermediate G (2,4-di-tert-butyl-6-(4-(6-(3-(diphenylamino)phenyl)-4-(trifluoromethyl)pyridin-2-yl)-1-phenyl-1H-benzo[d]imidazol-2-yl)phenol)

2.26 g (4.73 mmol) of Intermediate F (2-(4-bromo-1-phenyl-1H-benzo[d]imidazol-2-yl)-4,6-di-tert-butylphenol), 2.90 g (4.26 mmol) of Intermediate E, 0.38 g (0.33 mmol) of tetrakis(triphenylphosphine)palladium(0), and 0.55 g (9.47 mmol) of potassium fluoride were mixed with 25 mL of toluene, and the resulting mixture was refluxed for 12 hours. The refluxed mixture was cooled to room temperature and the precipitate was filtered. A filtrate obtained therefrom was washed with EA/H2O, and the crude product was purified by column chromatography (while increasing a rate of EA/Hex (hexane) to between 1% and 5%) to obtain 0.77 g (yield: 21%) of Intermediate G. The obtained product was confirmed by Mass and HPLC analysis.

Synthesis of Compound 1-218

0.77 g (0.98 mmol) of Intermediate G and 0.45 g (1.08 mmol) of K2PtCl4were mixed with 42 mL of a solvent containing a mixture of 40 mL of AcOH and 2 mL of H2O, and the resulting mixture was refluxed for 16 hours. The refluxed mixture was cooled to room temperature and the precipitate was filtered. The obtained precipitate was mixed again with MC and washed with H2O. The crude product was purified by column chromatography (MC 30%, Hex 70%) to obtain 0.68 g (purity: 99% or more, yield: 71%) of Compound 1-218. The obtained product was confirmed by Mass and HPLC analysis.

An ITO glass substrate was cut to a size of 50 mm×50 mm×0.5 mm (mm=millimeter), sonicated with acetone, iso-propyl alcohol, and pure water each for 15 minutes, and then cleaned by exposure to ultraviolet (UV) rays and ozone for 30 minutes.

Then, m-MTDATA was deposited on an ITO electrode (anode) of the ITO glass substrate at a deposition rate of 1 Angstroms per second (Å/sec) to form a hole injection layer having a thickness of 600 Å, and α-NPD was deposited on the hole injection layer at a deposition rate of 1 Å/sec to form a hole transport layer having a thickness of 250 Å.

Compound 1-103 (dopant) and CBP (host) were respectively co-deposited on the hole transport layer at deposition rates of 0.1 Å/sec and 1 Å/sec to form an emission layer having a thickness of 400 Å.

BAlq was deposited on the emission layer at a deposition rate of 1 Å/sec to form a hole blocking layer having a thickness of 50 Å, Alq3was deposited on the hole blocking layer to form an electron transport layer having a thickness of 300 Å, LiF was deposited on the electron transport layer to form an electron injection layer having a thickness of 10 Å, and Al was vacuum-deposited on the electron injection layer to form a second electrode (cathode) having a thickness of 1,200 Å, thereby completing the manufacture of an organic light-emitting device having a structure of ITO/m-MTDATA (600 Δ)/α-NPD (250 Δ)/CBP+Compound 1-103 (10%) (400 Δ)/BAlq (50 Δ)/Alq3(300 Δ)/LiF (10 Δ)/Al (1200 Δ).

An organic light-emitting device was manufactured in the same manner as in Example 1, except that Compound 1-218 was used instead of Compound 1-103 as a dopant in forming an emission layer.

Since the organometallic compound has excellent electrical characteristics and thermal stability, an organic light-emitting device including the organometallic compound may have excellent driving voltage, efficiency, power, color purity, and lifespan characteristics. Also, since the organometallic compound has excellent phosphorescent emission characteristics, a diagnostic composition having high diagnostic efficiency may be provided by using the organometallic compound.