LIGHT-EMITTING DEVICE, METHOD OF MANUFACTURING THE SAME, AND OPERATING METHOD OF THE SAME

Provided are a light-emitting device, a method of manufacturing the light-emitting device, and an operating method of the light-emitting device, wherein the light-emitting device includes a first conductive layer and a light-emitting group represented by Formula 1:  *-A3-(A1)m1-(A2)m2.  Formula 1 The detailed description of Formula 1 is the same as described in the present specification.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2021-0029052, filed on Mar. 4, 2021, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety.

BACKGROUND

The present disclosure relates to light-emitting devices, methods of manufacturing the light-emitting devices, and operating methods of the light-emitting devices.

2. Description of the Related Art

Recently, research on various light-emitting devices that can be used in devices such as various displays and light sources has been actively conducted. From among these devices, organic light-emitting devices are self-emissive devices, and have excellent characteristics in terms of viewing angles, response time, luminance, driving voltage, and response speed, and can produce full-color images.

Meanwhile, there are needs to develop, other than these organic light-emitting devices, next-generation light-emitting devices having a structure and a light-emitting mechanism which are different from those of organic light-emitting devices.

SUMMARY

Provided are light-emitting devices, methods of manufacturing the light-emitting devices, and operating methods of light-emitting devices.

According to one or more embodiments, a light-emitting device includes

a first conductive layer, and

a light-emitting group represented by Formula 1, wherein

the light-emitting group is chemically bonded to an atom on the surface of the first conductive layer.

In Formula 1,

* indicates a chemical binding site to an atom on the surface of the first conductive layer,

A3is an atom bonded to an atom on the surface of the first conductive layer,

m1 and m2 may each independently be an integer from 1 to 10, wherein, when m1 is 2 or more, two or more of A1(s) may be identical to or different from each other, and when m2 is 2 or more, two or more of A2(s) may be identical to each other or different from each other.

According to another aspect, provided is a method of manufacturing a light-emitting device, the method including

providing a first conductive layer, and

chemically bonding the light-emitting group represented by Formula 1 to an atom on the surface of the first conductive layer by bringing the first conductive layer into be in contact with a compound represented by Formula 1A.

in Formulae 1A and 1, A4is a moiety, and *, A3, A1, A2, m1, and m2 are the same as described above.

According to one or more embodiments, an operating method of a light-emitting device includes controlling a voltage applied to a first conductive layer of the light-emitting device.

DETAILED DESCRIPTION

“Or” means “and/or.” As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.

Description of FIG.1

The first conductive layer11may include a conductive material.

In an embodiment, the first conductive layer11may include metal, metalloid, carbon, nitrogen, oxygen, or a combination thereof.

In an embodiment, the first conductive layer11may include metal, metalloid, nitrogen, oxygen, or a combination thereof.

In an embodiment, the first conductive layer11may include metal, metalloid, oxygen, or a combination thereof.

In an embodiment, the first conductive layer11may include metal, metalloid, or a combination thereof as described above, and optionally, may further include oxygen.

In an embodiment, the first conductive layer11may include silver (Ag), gold (Au), zinc (Zn), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), tin (Sn), or any combination thereof. In an embodiment, the first conductive layer11may be an Au layer.

In an embodiment, the first conductive layer11may include silver (Ag), gold (Au), zinc (Zn), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), tin (Sn), or any combination thereof, and may further include oxygen. In an embodiment, the first conductive layer11may be an ITO layer.

The light-emitting group13may be chemically bonded to an atom (for example, metal, metalloid, carbon, nitrogen, oxygen, or a combination thereof) on the surface of the first conductive layer11. This structure is clearly distinguished from a structure in which luminescent compound molecules are randomly and physically stacked on an electrode through a deposition method (for example, a vacuum deposition method, etc.) and/or a coating method (for example, spin coating method, laser printing method, etc.).

In some embodiments, a monolayer including a plurality of light-emitting groups13is located on the surface of the first conductive layer11, and the monolayer including the plurality of light-emitting groups13may be in direct contact with the surface of the first conductive layer11. This structure could be identified from the feature wherein the light-emitting group13is represented by Formula 1 below and * in Formula 1 is a chemical binding site to an atom on the surface of the first conductive layer11.

The thickness (D1) of the monolayer including the plurality of light-emitting groups13may vary depending on the length of the light-emitting groups13. In an embodiment, the length of the light-emitting group13may be from about 0.1 nm to about 5.0 nm, or from about 0.5 nm to about 2.0 nm.

In addition to the light-emitting group13, the monolayer including the plurality of light-emitting groups13may further include any group that is different from the light-emitting group13. For example, the monolayer including the plurality of light-emitting groups13may further include a A2-free group. The A2-free group may be formed when the bond between A1and A2is broken, or A1and A2are not bonded to each other, in forming the monolayer including the plurality of light-emitting groups13. The A2-free group means a group not including A2.

The monolayer including the plurality of light-emitting groups13may be a self-assembled monolayer. Accordingly, a self-assembled monolayer including the plurality of light-emitting groups13may be located in direct contact with an upper portion of the first conductive layer11.

The light-emitting group13may be represented by Formula 1:

* in Formula 1 may indicate the chemical binding site of an atom on the surface of the first conductive layer11.

In an embodiment, * in Formula 1 may indicate a chemical binding site to metal, metalloid, carbon, nitrogen, or oxygen on the surface of the first conductive layer11.

In an embodiment, the atom on the surface of the first conductive layer11may include metalloid, and the metalloid may include boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), or a combination thereof.

In an embodiment, the first conductive layer11may include silver (Ag), gold (Au), zinc (Zn), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), tin (Sn), or any combination thereof, and * in Formula 1 may be a chemical binding site to silver (Ag), gold (Au), zinc (Zn), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), or tin (Sn) on the surface of the first conductive layer11.

A3in Formula 1 is an atom that fixes the light-emitting group13to the surface of the first conductive layer11, and may be an atom that is bonded to the atom on the surface of the first conductive layer11. A3may be, for example, O or S.

A1of Formula 1 is a linking group, and may connect A3and A2in Formula 1 to each other and may provide rigidity to the light-emitting group13. For example, since A1transfers charges to A2, which is a light-emitting moiety, when voltage is applied to the first conductive layer11, A1may be selected from among groups that can provide a conjugation system with A2.

For example, A1of Formula 1 may be a single bond, a substituted or unsubstituted C2-C60alkylene group, a substituted or unsubstituted C2-C60alkenylene group, a substituted or unsubstituted C2-C60alkynylene group, a substituted or unsubstituted C5-C30carbocyclic group or a substituted or unsubstituted C2-C30heterocyclic group.

In an embodiment, A1of Formula 1 may be a single bond, a C2-C60alkenylene group that is unsubstituted or substituted with at least one R10a, a C2-C60alkynylene group that is unsubstituted or substituted with at least one R10a, a C5-C30carbocyclic group that is unsubstituted or substituted with at least one R10a, or a C2-C30heterocyclic group that is unsubstituted or substituted with at least one R10a.

R10ais the same as described in connection with R10.

In an embodiment, A1of Formula 1 may be:

a single bond; or

A2in Formula 1 may be a luminescent moiety, a monovalent group derived from phosphorescent luminescent compounds, fluorescent luminescent compounds, or quantum dots.

A2in Formula 1 may be selected from luminescent moieties having a chemical structure in which a highest occupied molecular orbital (HOMO) of chromophore is relatively clearly separated from lowest unoccupied molecular orbital (LUMO) of chromophore in the molecule so that the maximum emission wavelength change amount of light emitted from light-emitting group13can be induced to a maximum value when voltage is applied to the first conductive layer11.

The phosphorescent luminescent compounds, fluorescent luminescent compounds, and quantum dots may be any phosphorescent luminescent compounds, fluorescent luminescent compounds, or quantum dots which are located between a pair of electrodes of a light-emitting device, for example, an organic light-emitting device.

The term “a monovalent group derived from material X” used herein refers to a group in which a site of material X from which an arbitrary atom (for example, hydrogen, etc.) is removed, becomes a binding site to a neighboring atom. For example, a monovalent group derived from methane (CH4) refers to a methyl group (*—CH3wherein * indicates a binding site to any other atom).

In an embodiment, A2in Formula 1 may not be a phenyl group substituted with a substituent.

In an embodiment, A2of Formula 1 may be a monovalent group derived from an organometallic compound capable of emitting phosphorescent light.

In an embodiment, the organometallic compound may include a transition metal. Thus, A2in Formula 1 may be a monovalent group derived from a transition metal-containing organometallic compound.

The organometallic compound may further include at least one ligand bound to the transition metal in addition to the transition metal as described above. The at least one ligand may be a ligand represented by one of Formulae 2-1 to 2-4:

A11to A14may each independently be a C5-C30carbocyclic group that is unsubstituted or substituted with at least one R10, a C1-C30heterocyclic group that is unsubstituted or substituted with at least one R10, or a non-cyclic group,

*1, *2, *3, and *4 each indicate a binding site to transition metal of the organometallic compound.

any combination thereof,

In an embodiment, A11to A14in Formulae 2-1 to 2-4 may each independently be:

In an embodiment, Y11to Y14in Formulae 2-1 to 2-4 may each independently be a chemical bond (for example, a covalent bond, a coordinate bond, etc.), O, or S.

In one or more embodiments, R10and R91to R94in Formula 2-1 to 2-4 may each independently be:

The organometallic compound may include, in addition to the ligands represented by Formulae 2-1 to 2-4, a ligand, for example, —F, —Cl, —I, —Br, or acetylacetonate.

In an embodiment, the organometallic compound may be represented by Formula 2(1):

M is a transition metal as described herein,

Y11is the same as described in the present specification,

R11to R14are each the same as described in connection with R10,

a11 and a14 may each independently be an integer from 0 to 4, and

a12 and a13 may each independently be an integer from 0 to 3.

For example, Y11in Formula 2(1) may be O or S.

In an embodiment, A2of Formula 1 may be a monovalent group derived from one of Compounds PD1 to PD87:

In addition, A2of Formula 1 may be a monovalent group derived from a fluorescent luminescent compound, which is a compound capable of emitting fluorescent light.

The fluorescence may be a prompt fluorescence, delayed fluorescence, etc. The delayed fluorescence may be thermally activated delayed fluorescence.

In an embodiment, the fluorescent luminescent compounds may be a thermally activated delayed fluorescence emitter. The thermally activated delayed fluorescence emitter may be selected from any compound that is capable of emitting delayed fluorescence according to the thermally activated delayed fluorescence emission mechanism.

The difference (absolute value) between the triplet energy level (eV) of the thermally activated delayed fluorescence emitter and the singlet energy level (eV) of the thermally activated delayed fluorescence emitter may be equal to or greater than 0 eV and less than or equal to 0.5 eV. When the difference between the triplet energy level (eV) of the thermally activated delayed fluorescence emitter and the singlet energy level (eV) of the thermally activated delayed fluorescence emitter satisfies the above range, the up-conversion from the triplet state to the singlet state may be effectively achieved, so that the thermally activated delayed fluorescence emitter may emit high-efficiency delayed fluorescence.

For example, the fluorescent luminescent compounds may be amino group-containing condensed cyclic compounds, compounds containing donors and acceptors, boron-containing compounds, and the like.

For example, the fluorescent luminescent compounds may be compounds represented by Formula 501:

Ar501may be a naphthalene group, a heptalene group, a fluorene group, a spiro-bifluorene group, a carbazole group, a benzofluorene group, a dibenzofluorene group, a phenalene group, a phenanthrene group, an anthracene group, a fluoranthene group, a triphenylene group, a pyrene group, a chrysene group, a naphthacene group, a picene group, a perylene group, a pentaphene group, or an indenoanthracene group, each substituted or unsubstituted with at least one R10a,

L501to L503may each independently be a C5-C30carbocyclic group that is unsubstituted or substituted with at least one R10aor a C2-C30heterocyclic group that is unsubstituted or substituted with at least one R10a,

xd1 to xd3 may each independently be an integer from 0 to 3, and

xd4 may be an integer from 0 to 4.

For example, xd4 of Formula 501 may be an integer from 2 to 4.

R10ais the same as described in connection with R10.

A compound represented by Formula 501 may emit prompt fluorescence.

For example, A2of Formula 1 may be a monovalent group derived from one of Compounds FD1 to FD14 or one of FD(1) to FD(17):

In an embodiment, the fluorescent luminescent compounds may include a compound represented by Formula 11:

For example, X1may be a single bond.

For example, ring CY1and ring CY2may each independently be a benzene group, a fluorene group, a carbazole group, a dibenzofuran group, a dibenzothiophene group, or a dibenzosilole group, and at least one of ring CY1and ring CY2may each independently be a benzene group.

L3and L4may each independently be a C5-C30carbocyclic group that is unsubstituted or substituted with at least one R10aor a C1-C30heterocyclic group that is unsubstituted or substituted with at least one R10a.

For example, L3and L4may each independently be a benzene group, a naphthalene group, a fluorene group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, a triazine group, a quinoline group, an isoquinoline group, a carbazole group, a dibenzofuran group, a dibenzothiophene group, or an indolocarbazole group, each unsubstituted or substituted with at least one R10a.

c3 and c4 indicate the number of L3and the number of L4, respectively, and may each independently be an integer of 0 to 4. When c3 is 2 or more, two or more of L3(s) may be identical to or different from each other, and when c4 is 2 or more, two or more of L4(s) may be identical to each other or different from each other. For example, c3 and c4 may each independently be 0, 1, or 2, but embodiments of the present disclosure are not limited thereto. When c3 is 0, *-(L3)c3-*′ may be a single bond, and when c4 is 0, *-(L4)c4-*′ may be a single bond.

R1to R6in Formula 11 are the same as described in connection with R10.

In an embodiment, R3in Formula 11 may include at least one π electron-deficient nitrogen-containing cyclic group.

In one or more embodiments, R3in Formula 11 may be

In an embodiment, the fluorescent luminescent compounds may include a compound represented by Formula 14A:

In an embodiment, A2in Formula 1 may be a monovalent group derived from one of Compounds D1-1 to D1-19:

Meanwhile, A2of Formula 1 may be a monovalent group derived from a quantum dot.

The quantum dot refers to a crystal of a semiconductor compound, and may include all materials that emit different lengths of emission wavelengths depending on the size of the crystal. A diameter of the quantum dot may be, for example, in a range of about 1 nm to about 10 nm.

In an embodiment, the quantum dot may be a Group III-VI semiconductor compound; a Group II-VI semiconductor compound; a Group III-V semiconductor compound; a Group IV-VI semiconductor compound; a Group IV element or compound; or any combination thereof.

For example, the Groups III-VI semiconductor compound may include a binary compound, such as In2S3; a ternary compound, such as AgInS, AgInS2, CuInS, or CuInS2; or any combination thereof.

For example, the Group IV-VI semiconductor compound may include a binary compound, such as SnS, SnSe, SnTe, PbS, PbSe, or PbTe; a ternary compound, such as SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, or SnPbTe; a quaternary compound, such as SnPbSSe, SnPbSeTe, or SnPbSTe; or any combination thereof.

For example, the Group IV element or compound may include a single element, such as Si or Ge; a binary compound, such as SiC or SiGe; or any combination thereof.

In this regard, respective elements included in the binary compound, the ternary compound, or the quaternary compound may exist in particles at uniform concentration or may exist in the same particle in a state in which a concentration distribution is partially different.

Meanwhile, the quantum dot may have a single structure or a dual core-shell structure. In the case of the quantum dot having a single structure, the concentration of each element included in the corresponding quantum dot may be uniform. In one or more embodiments, the material contained in the core and the material contained in the shell may be different from each other.

The shell of the quantum dot may act as a protective layer to prevent chemical degeneration of the core to maintain semiconductor characteristics and/or as a charging layer to impart electrophoretic characteristics to the quantum dot. The shell may be a single layer or a multi-layer. The interface between the core and the shell may have a concentration gradient in which the concentration of an element existing in the shell is decreased as the element is located closer to the center of the core.

Examples of the shell of the quantum dot may be an oxide of a metal, or a non-metal, a semiconductor compound, or any combination thereof. For example, the metal or non-metal oxide may include a binary compound, such as SiO2, Al2O3, TiO2, ZnO, MnO, Mn2O3, Mn3O4, CuO, FeO, Fe2O3, Fe3O4, CoO, Co3O4, or NiO, or a ternary compound, such as MgAl2O4, CoFe2O4, NiFe2O4, or CoMn2O4, but embodiments of the present disclosure are not limited thereto. In addition, the semiconductor compound may include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnSeS, ZnTeS, GaAs, GaP, GaSb, HgS, HgSe, HgTe, InAs, InP, InGaP, InSb, AlAs, AlP, AlSb, and the like, but embodiments of the present disclosure are not limited thereto.

The quantum dot may be a spherical particle, a pyramidal particle, a multi-arm particle, a cubic nanoparticle, a nanotube particle, a nanowire particle, a nanofiber particle, or a nanoplate particle, but embodiments of the present disclosure are not limited thereto.

m1 and m2 in Formula 1 indicate the number of A1(s) and the number of A2(s), respectively, and may each independently be an integer from 1 to 10. When m1 is 2 or more, two or more of A1(s) may be identical to or different from each other, and when m2 is 2 or more, two or more of A2(s) may be identical to or different from each other. For example, m1 may be an integer from 1 to 5, and m2 may be 1 or 2.

Description of FIG.2

FIG. 2shows a schematic cross-sectional view of a light-emitting device20according to an exemplary embodiment.

A first conductive layer11, a light-emitting group13, and the thickness (D1) of a monolayer including a plurality of light-emitting groups13of the light-emitting device20may be understood by referring to the first conductive layer11, the light-emitting group13, and the thickness (D1) of the monolayer including the plurality of light-emitting group13of the light-emitting device10inFIG. 1, respectively.

The light-emitting device20may further include a second conductive layer19facing the first conductive layer11, and the light-emitting group13of the light-emitting device20, that is, A2of Formula 1 may be located toward the second conductive layer19.

The first conductive layer11may be an anode, and the second conductive layer19may be a cathode. In an embodiment, a material for forming the second conductive layer19may be metal, an alloy, an electrically conductive compound, or a combination thereof, each of which has 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 the material for forming the second conductive layer19.

Besides the light-emitting group13, an interlayer15may be additionally located between the first conductive layer11and the second conductive layer19. At least a portion of the light-emitting group13may be located to be included within the interlayer15.

The interlayer15may include: a hole transport material, a light-emitting material, an electron transport material, or a combination thereof; or an insulating material, an electrolyte, air, or inert gas, and thus may maintain the structure of the light-emitting device20, and may assist charge transfer inside the light-emitting group13.

The hole transport material, the light-emitting material, and the electron transport material, which may be included in the interlayer15, may respectively be any hole transport material, any light-emitting material, and any electron transport material, which may be located between a pair of electrodes of an organic light-emitting device of the related art.

In addition, when the interlayer15includes a hole transport material, a light-emitting material, an electron transport material, or a combination thereof, a hole transport region including a hole injection layer, a hole transport layer, an electron-blocking layer, a buffer layer, or a combination thereof and/or an electron transport region including a hole-blocking layer, an electron transport layer, an electron injection layer or a combination thereof may be included.

xa and xb in Formula 201 may each independently be an integer from 0 to 5, or 0, 1, or 2. For example, xa may be 1 and xb may be 0.

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, or the like) or a C1-C10alkoxy group (for example, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group, or the like);

As the light-emitting material, any host that can be used in the emission layer of an organic light-emitting device may be used.

Examples of the host may include TPBi, TBADN, ADN (also referred to as “DNA”), CBP, CDBP, TCP, mCP, Compound H50, Compound H51, or any combination thereof:

Meanwhile, the interlayer15may include an insulating material that is used for a pixel defining layer, an electrolyte that is used for various batteries, air and an inert gas such as argon gas, depending on the purpose.

When a voltage is applied to the first conductive layer11of each of the light-emitting devices10and20ofFIGS. 1 and 2, light may be emitted from each of the light-emitting groups13chemically bonded to the surface of the first conductive layer11.

In an embodiment, according to a change in a voltage (for example, a change in a voltage intensity) applied to the first conductive layer11of each of the light-emitting devices10and20ofFIGS. 1 and 2, the electron density of the light-emitting group13may be changed.

In an embodiment, according to a change in the voltage applied to the first conductive layer11of each of the light-emitting devices10and20ofFIGS. 1 and 2, the wavelength of light emitted from the light-emitting group13may be changed.

In an embodiment, according to a continuous change in the voltage applied to the first conductive layer11of each of the light-emitting devices10and20ofFIGS. 1 and 2, the wavelength of light emitted from the light-emitting group13may be continuously changed.

Since in the light-emitting devices10and20ofFIGS. 1 and 2, the light-emitting group13is chemically directly bonded to the an atom on the surface of the first conductive layer11, by controlling the voltage applied to the first conductive layer11, the intensity and/or maximum emission wavelength of light emitted from the light-emitting group13may be easily controlled, without a change in the structure of the light-emitting devices10and20and/or the chemical structure of the light-emitting group13. That is, by controlling the voltage applied to the first conductive layer11, not by changing the chemical structure of the light-emitting group13and/or the structure of each of the light-emitting devices10and20, light emitted from the light-emitting devices10and20may be controlled. This is distinguishable from light-emitting devices in which luminescent compound molecules are randomly placed on a certain electrode through a deposition method (for example, vacuum deposition method, etc.) and/or a coating method (for example, a spin coating method, a laser printing method, etc.), and thus, even when the voltage applied to the electrode is changed, the intensity and/or maximum emission wavelength of light emitted from luminescent compound molecules are not able to be changed. Accordingly, the light-emitting devices10and20may be applicable in various ways to various displays, light sources, and monitors.

In addition, in manufacturing the light-emitting devices10and20that emit light having a certain level of color purity, half-width and/or maximum emission wavelength, there is no need to scarify the heat resistance and/or electrical stability of the light-emitting group13. In other words, the light-emitting group13having excellent heat resistance and electrical stability is chemically bonded to an atom on the surface of first conductive layer11, and then, the level of color purity, half-width and/or maximum emission wavelength of light emitted from the light-emitting group13may be adjusted by controlling the voltage applied to the first conductive layer11. Accordingly, without sacrificing the heat resistance and/or electrical stability of the light-emitting group13that may affect the lifespan of the light-emitting devices10and20ofFIGS. 1 and 2, the light emitted from the light-emitting devices10and20may be easily controlled.

A method of manufacturing the light-emitting device10ofFIG. 1includes:

providing a first conductive layer11, and

chemically bonding the light-emitting group13represented by Formula 1 to an atom on the surface of the first conductive layer11by bringing the first conductive layer11into contact with a compound represented by Formula 1A:

* indicates a chemical binding site to an atom on the surface of the first conductive layer11,

A3is an atom bonded to an atom on the surface of the first conductive layer11,

m1 and m2 are each independently an integer from 1 to 10, wherein, when m1 is 2 or more, two or more of A1(s) may be identical to or different from each other, and when m2 is 2 or more, two or more of A2(s) may be identical to each other or different from each other.

*, A3, A1, A2, m1, and m2 in Formulae 1A and 1 are each the same as described above.

In an embodiment, A4in Formula 1A may be hydrogen or a substituted or unsubstituted C1-C60alkyl group.

In an embodiment, the compound represented by Formula 1A may be a phosphorescent luminescent compound, a fluorescent luminescent compound, or a quantum dot, in which hydrogen is substituted with a hydroxyl group (—OH) or a thiol group (—SH).

In an embodiment, the compound represented by Formula 1A may be, for example, Compounds PD80A, PD86A, D1-19A or FD(17)A:

In an embodiment, the process of bringing the first conductive layer11to be in contact with the compound represented by Formula 1A so as to chemically bond the light-emitting group13represented by Formula 1 to an atom on the surface of the first conductive layer11, may be performed by a metal (for example, Au)-thiol reaction, in the case where in Formula 1A, A3is S and A4is hydrogen.

Meanwhile, the interlayer15ofFIG. 2may be formed on the first conductive layer11to which the light-emitting group13is chemically bonded, by using various methods for example, a vacuum deposition method, a spin coating method, a cast method, and an LB method.

In the case of forming the interlayer15by a vacuum deposition method, the deposition conditions differ depending on a compound for forming the interlayer15, the structure and thermal characteristics of the interlayer15, etc. 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 Å/sec to about 100 Å/sec.

When the interlayer15is formed using spin coating, coating conditions may vary according to a compound for forming the interlayer15, the structure and thermal properties of the interlayer15, etc. For example, a coating speed may be from about 2,000 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.

In an embodiment, in the interlayer15of the light-emitting device20, a spacer is arranged between the first conductive layer11and the second conductive layer19to secure a gap, and then the gap between the first conductive layer11and the second conductive layer19may be filled with the insulating material, electrolyte, air or inert gas by capillary phenomenon.

The operating method of the light-emitting devices10and20ofFIGS. 1 and 2may include controlling a voltage applied to the first conductive layer11of the light-emitting devices10and20. In this manner, the intensity and/or maximum emission wavelength of light emitted from light-emitting group13of light-emitting devices10and20may be controlled.

For example, the controlling of the voltage applied to the first conductive layer11of the light-emitting devices10and20may include continuously or discontinuously changing the voltage applied to the first conductive layer of the light-emitting device.

The term “C1-C60alkyl group” as used herein refers to a linear or branched saturated aliphatic hydrocarbon monovalent group having 1 to 60 carbon atoms, and the term “C1-C60alkylene group” as used herein refers to a divalent group having the same structure as the C1-C60alkyl group.

The term “C1-C60alkoxy group” as used herein refers to a monovalent group represented by —OA101(wherein A101is a C1-C60alkyl group). Examples thereof include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a pentoxy group.

The term “C1-C60alkylthio group” as used herein refers to a monovalent group represented by —SA102(wherein A102is the C1-C60alkyl group), and non-limiting examples thereof include a methylthio group, an ethylthio group, and an iso-propylthio group.

The term “C3-C10cycloalkyl group” as used herein refers to a monovalent saturated hydrocarbon cyclic group having 3 to 10 carbon atoms. The term “C3-C10cycloalkylene group” as used herein refers to a divalent group having the same structure as the C3-C10cycloalkyl group.

The term “C1-C10heterocycloalkyl group” as used herein refers to a saturated monovalent cyclic group having 1 to 10 carbon atoms and at least one heteroatom of N, O, P, Si, S, Se, Ge, and B as a ring-forming atom. The term “C1-C10heterocycloalkylene group” as used herein refers to a divalent group having the same structure as the C1-C10heterocycloalkyl group.

Examples of the C1-C10heterocycloalkyl group as used herein may include a silolanyl group, a silinanyl group, a tetrahydrofuranyl group, a tetrahydro-2H-pyranyl group, or a tetrahydrothiophenyl group.

The term “C6-C60aryloxy group” as used herein is represented by —OA102(wherein A102is the C6-C60aryl group). The term “C6-C60arylthio group” as used herein is represented by —SA103(wherein A103is the C6-C60aryl group). The term “C1-C60alkylthio group” as used herein is represented by —SA104(wherein A104is the C1-C6alkyl group).

The term “monovalent non-aromatic condensed polycyclic group” as used herein refers to a monovalent group that has two or more condensed rings and only carbon atoms (e.g., the number of carbon atoms may be in a range of 8 to 60) as ring-forming atoms, wherein the molecular structure as a whole is non-aromatic. Examples of the monovalent non-aromatic condensed polycyclic group include a fluorenyl group. The term “divalent non-aromatic condensed polycyclic group” as used herein refers to a divalent group having substantially the same structure as the monovalent non-aromatic condensed polycyclic group.

The term “monovalent non-aromatic condensed heteropolycyclic group” as used herein refers to a monovalent group that has two or more condensed rings and a heteroatom selected from N, O, P, Si, S, Se, Ge, and B and carbon atoms (e.g., the number of carbon atoms may be in a range of 1 to 60) as ring-forming atoms, wherein the molecular structure as a whole is non-aromatic. 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 substantially 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 including 5 to 30 carbon atoms only as ring-forming atoms. The C5-C30carbocyclic group may be a monocyclic group or a polycyclic group. Examples of the “C5-C30carbocyclic group (unsubstituted or substituted with at least one R10a)” may include an adamantane group, a norbornene group, a bicyclo[1.1.1]pentane group, a bicyclo[2.1.1]hexane group, a bicyclo[2.2.1]heptane group (a norbornane group), a bicyclo[2.2.2]octane group, a cyclopentane group, a cyclohexane group, a cyclohexene group, a benzene group, a naphthalene group, an anthracene group, a phenanthrene group, a triphenylene group, a pyrene group, a chrysene group, a 1,2,3,4-tetrahydronaphthalene group, a cyclopentadiene group, or a fluorene group, (each unsubstituted or substituted with at least one R10a).

Examples of the “C5-C30carbocyclic group” and the “C1-C30heterocyclic group” as used herein include i) a third ring, ii) a fourth ring, iii) a condensed ring in which at least two third rings are condensed, iv) a condensed ring in which at least two fourth rings are condensed, or v) a condensed ring in which at least one third ring and at least one fourth ring are condensed,

the fourth ring may be an adamantane group, a norbornane group, a norbornene group, a cyclohexane group, a cyclohexene group, a benzene group, a pyridine group, a pyrimidine group, a pyrazine group, a pyridazine group, or a triazine group.

The “deuterated C2-C20alkyl group” and the “deuterium-containing C1-C20alkyl group” as used herein may respectively be a C2-C20alkyl group or C1-C20alkyl group, each substituted with at least one deuterium. Examples of the “deuterated C1alkyl group (i.e., a deuterated methyl group)” may include —CD3, —CD2H, and —CDH2. The “deuterated C2-C20alkyl group” and the “deuterium-containing C1-C20alkyl group” may respectively be: i) a fully deuterated C2-C20alkyl group (or fully deuterated C1-C20alkyl group) in which all hydrogen atoms are substituted with deuterium atoms; or ii) a partially deuterated C2-C20alkyl group (or partially deuterated C1-C20alkyl group), in which some of hydrogen atoms are substituted with deuterium atoms.

The “(C1-C20alkyl)‘X’ group” refers to a ‘X’ group substituted with at least one C1-C20alkyl group. For example, The “(C1-C20alkyl)C3-C10cycloalkyl group” as used herein refers to a C3-C10cycloalkyl group substituted with at least one C1-C20alkyl group, and the “(C1-C20alkyl)phenyl group” as used herein refers to a phenyl group substituted with at least one C1-C20alkyl group. Examples of the (C1alkyl)phenyl group may include a toluyl group.

any combination thereof.

As used herein, the number of carbons in each group that is substituted (e.g., C1-C60) excludes the number of carbons in the substituent. For example, a C1-C6alkyl group can be substituted with a C1-C60alkyl group. The total number of carbons included in the C1-C60alkyl group substituted with the C1-C60alkyl group is not limited to 60 carbons. In addition, more than one C1-C60alkyl substituent may be present on the C1-C60alkyl group. This definition is not limited to the C1-C60alkyl group and applies to all substituted groups that recite a carbon range.

Hereinafter, a light-emitting device will be described in detail through Synthesis Examples and Examples.

EXAMPLES

Synthesis of Intermediate PD86A-1

6.70 g (24.5 mmol) of 2,6-dichloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridine, 7.90 g (29.4 mmol) of 1-bromo-3,5-di-tert-butylbenzene, 1.41 g (1.22 mmol) of Pd(PPh3)4, and 10.1 g (73.4 mmol) of potassium carbonate were added to a mixture including 80 mL of THF (tetrahydrofuran) and 40 mL of water, and then, stirred while refluxing for 24 hours. After the reaction was completed, the resultant solution was cooled to room temperature, an aqueous solution layer was removed therefrom through extraction, the organic layer was filtered through silica gel, and the filtrate obtained by filtration was concentrated under reduced pressure. The product obtained therefrom was separated by silica gel column chromatography to obtain 2.40 g (yield of 29%) of the target compound Intermediate PD86A-1.

Synthesis of Intermediate PD86A-2

2.30 g (6.84 mmol) of Intermediate PD86A-1, 1.00 g (7.18 mmol) of (2-hydroxyphenyl)boronic acid, 0.553 g (0.479 mmol) of Pd(PPh3)4, and 3.78 g (27.4 mmol) of potassium carbonate were added to a mixture including 25 mL of THF and 12 mL of water, and then, stirred while refluxing for 16 hours. After the reaction was completed, the resultant solution was cooled to room temperature, an aqueous solution layer was removed therefrom through extraction, the organic layer was filtered through silica gel, and the filtrate obtained was concentrated under reduced pressure. The product obtained therefrom was separated by silica gel column chromatography to obtain 2.10 g (yield of 78%) of Intermediate PD86A-2.

Synthesis of Intermediate PD86A-3

5.00 g (29.8 mmol) of 4-(methylthio)phenylboronic acid, 8.45 g (29.8 mmol) of 2-bromo-4-iodopyridine, 3.44 g (2.98 mmol) of Pd(PPh3)4, and 12.3 g (89.3 mmol) of potassium carbonate were added to a mixture including 100 mL of THF and 50 mL of water, and then stirred while refluxing for 24 hours. After the reaction was completed, the resultant solution was cooled to room temperature, an aqueous solution layer was removed therefrom through extraction, the organic layers was filtered through silica gel, and the filtrate obtained was concentrated under reduced pressure. The product obtained therefrom was separated by silica gel column chromatography to obtain 6.30 g (yield of 76%) of Intermediate PD86A-3.

Synthesis of Intermediate PD86A-4

6.00 g (21.4 mmol) of Intermediate PD86A-3, 4.73 g (23.6 mmol) of (3-bromophenyl)boronic acid, 1.24 g (1.07 mmol) of Pd(PPh3)4, and 8.88 g (64.2 mmol) of potassium carbonate were added to a mixture including 70 mL of THF and 35 mL of water, and then, stirred while refluxing for 4 hours. After the reaction was completed, the resultant solution was cooled to room temperature, an aqueous solution layer was removed therefrom through extraction, the organic layer was filtered through silica gel, and the filtrate obtained was concentrated under reduced pressure. The product obtained therefrom was separated by silica gel column chromatography to obtain 5.40 g (yield of 71%) of Intermediate PD86A-4.

Synthesis of Intermediate PD86A-5

1.50 g (4.21 mmol) of Intermediate PD86A-4 was dissolved in 20 mL of THF under nitrogen substitution condition, cooled to at a temperature of −78° C., and then 3.16 mL (1.6 M solution in hexane, 5.05 mmol) of n-BuLi (n-butyl lithium) was slowly added thereto, followed by 30 minutes of stirring. Then, 1.72 mL (8.42 mmol) of 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane was slowly added thereto, and 30 minutes after, the temperature thereof was raised to room temperature and stirred for 12 hours. After completion of the reaction, an organic layer was separated therefrom through extraction and concentrated under reduced pressure to obtain the target compound, Intermediate PD86A-5, which was then used in the next reaction without further purification.

Synthesis of Intermediate PD86A-6

Synthesis of Intermediate PD86A-7

0.150 g (0.242 mmol) of Intermediate PD86A-6 and 0.120 g (0.290 mmol) of K2PtCl4were added to a mixture including 3 mL of acetic acid (AcOH) and 0.5 mL of water, and then stirred while refluxing for 20 hours. After completion of the reaction, the temperature was decreased to room temperature, thereby obtaining a solid, which was then washed with water to obtain, as a target compound, 0.041 g (yield of 21%) of Intermediate PD86A-7.

Synthesis of Compound PD86A

40 mg (0.0484 mmol) of Intermediate PD86A-7 and 40 mg (80%, 0.386 mmol) of sodium ethanethiolate (NaSEt) were added to 1 mL of DMF (dimethylforamide) solvent, and then stirred while refluxing for 20 hours. After the reaction was completed, the temperature was decreased to room temperature and aq.NH4Cl solution was added thereto to separate the resulting solid by silica gel column chromatography, thereby obtaining Compound PD86A (6 mg, yield of 15%).

Synthesis of Intermediate D1-19A-1

5.00 g (11.6 mmol) of 9-(4-(4-chloro-6-phenyl-1,3,5-triazin-2-yl)phenyl)-9H-carbazole, 2.14 g (12.7 mmol) of 4-(methylthio)phenylboronic acid, 1.34 g (1.15 mmol) of Pd(PPh3)4, and 4.79 g (34.7 mmol) of potassium carbonate were added to a mixture including 40 mL of THF and 20 mL of water, and then stirred while refluxing for 12 hours. After the reaction was completed, the resultant solution was cooled to room temperature, an aqueous solution layer was removed therefrom through extraction, and the filtrate obtained by filtration under reduced pressure with silica gel was concentrated under reduced pressure. The product obtained therefrom was separated by silica gel column chromatography to obtain, as a target compound, 4.73 g (yield of 79%) of Intermediate D1-19A-1.

Synthesis of Compound D1-19A

1.00 g (1.92 mmol) of Intermediate D1-19A-1 and 1.62 g (80%, 15.4 mmol) of sodium ethanethiolate were added to 10 mL of DMF solvent, and then stirred while refluxing for 24 hours. After the reaction was completed, the mixture was cooled to room temperature and placed in an ice bath, and 120 mL of 3N HCl solution was added thereto and the solid generated therefrom was filtered. The solid was then purified through recrystallization to obtain Compound D1-19A (0.41 g, yield of 42%).

Synthesis of Intermediate FD(17)A-1

0.420 g (0.933 mmol) of [1-[(3,5-dimethyl-1H-pyrrol-2-yl)(3,5-dimethyl-2H-pyrrol-2-ylidene)methyl]-4-iodobenzene](difluoroborane), 0.249 g (1.31 mmol) of triisopropylsilanethiol, 0.065 g (0.0560 mmol) of Pd(PPh3)4, and 0.426 g (1.40 mmol) of cesium carbonate were added to 10 mL of toluene, and then, stirred while refluxing at a temperature of 100° C. for 20 hours. After the reaction was completed, the temperature was decreased to room temperature, and 10 mL of aq.NH4Cl solution was added thereto, and an aqueous solution layer was removed through extraction, followed by concentration of the organic layer under reduced pressure. The product obtained therefrom was separated by silica gel column chromatography to obtain, as a target compound, Intermediate FD(17)A-1 0.40 g (yield of 82%).

Synthesis of Compound FD(17)A

0.30 g (0.586 mmol) of Intermediate FD(17)A-1 was added to a mixture including 3 ml of THF and 3 mL of EtOH (ethanol), and then, 0.20 mL (2.34 mmol) of conc. HCl was added thereto, followed by 5 hours of stirring. After the reaction was completed, the mixture was concentrated under reduced pressure to remove the solvent therefrom, dissolved in DCM (dichloromethane), filtered, and then concentrated under reduced pressure. The product was separated by silica gel column chromatography, thereby obtaining Compound FD(17)A (0.125 g, yield of 60%).

An Au layer was immersed in a piranha solution for 1 hour, taken out, washed, and then treated with polishing paper to make the surface thereof to be smooth, and then immersed in 0.1 M sulfuric acid solution and subjected to cyclic voltammetry 10 cycles, thereby completely removing foreign substances from the surface of the Au layer. After that, the Au layer was immersed in 0.15 M KCl solution, and the surface of the Au layer was further cleaned using chronoamperometry and cyclic voltammetry. Subsequently, the Au layer was immersed in a mixture of compound FD(17)A and ethanol (concentration of 5 mM), and then stored for a day so that a chemical reaction between Au on the surface of the Au layer and Compound FD(17)A occurred, and then washed. Thus, a light-emitting device 1 was prepared in which Au on the surface of the Au layer was chemically bonded to a light-emitting group represented by Formula FD (17)B.

* in Formula FD(17)B indicates a chemical binding site with Au on the surface of the Au layer.

Evaluation Example 1

By using an ISC PC1 spectrofluorometer equipped with a Xenon lamp, the photoluminescence (PL) spectrum (at room temperature) of the light-emitting device 1 was measured while the applied voltage was changed as shown in Table 1. Accordingly, the maximum emission wavelength and color purity (CIE x and CIE y coordinates) of the light-emitting device depending on the applied voltage were evaluated. Results are shown in Table 1.

From Table 1, it can be seen that the light-emitting device 1 can emit light having various wavelengths and color purity according to applied voltage.

Since the light-emitting group of the light-emitting device is chemically bonded to an atom on the surface of the first conductive layer, the intensity and/or maximum emission wavelength of light emitted from the light-emitting group can be arbitrarily changed by controlling the voltage applied to the first conductive layer without a change in the structure of the light-emitting device and/or the chemical structure of the light-emitting group. Accordingly, the light-emitting device can be variously applied to various displays, light sources, monitors, and the like.