Patent Description:
One or more embodiments relate to a lighting apparatus including a perovskite compound.

A perovskite compound refers to a material having a three-dimensional crystal structure associated with a CaTiO<NUM> crystal structure, and may be used in various electronic apparatuses.

For example, a perovskite compound may be used as a light-emitting material, an electrode material, a light sensitive material, a light-absorbing material, or the like in a light-emitting device.

However, a conventional perovskite compound has a limitation in terms of implementing an electronic apparatus having high efficiency and a long lifespan. In particular, a perovskite compound including a Pb<NUM>+ cation may adversely affect the environment. <NPL> relates to perovskite materials for light-emitting diodes and lasers. <NPL> relates to doping lanthanides into perovskite nanocrystals. <NPL> relates to the preparation and properties of a luminescent organic-inorganic perovskite with a divalent rare-earth metal halide framework. <NPL> relates to chloro-perovskites with two-valent lanthanides. <NPL> relates to ternary bromides and iodies of divalent lanthanides and their AMX<NUM> and AM<NUM>X<NUM> type alkaline earth analogues.

Aspects of the present disclosure provide a lighting apparatus including a perovskite compound.

An aspect provides a lighting apparatus including: a light source; and a light conversion layer that absorbs at least part of light emitted from the light source and emits light having a wavelength band different from that of the absorbed light, wherein the light conversion layer includes a perovskite compound represented by one of Formulae <NUM> to <NUM>: <MAT> <MAT> <MAT> <MAT>.

The present disclosure will now be described with reference to embodiments. The disclosure may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and convey the concept of the disclosure to those skilled in the art. Advantages and features of the present inventive concept, and how to achieve them, will become apparent by reference to the embodiments that will be described later in detail, together with the accompanying drawings. This inventive concept may, however, be embodied in many different forms and should not be limited to the embodiments.

As used herein, the terms "first", "second", etc., are used only to distinguish one component from another, and such components should not be limited by these terms.

It will be further understood that the terms "comprises" and/or "comprising" used herein specify the presence of stated features or components, but do not preclude the presence or addition of one or more other features or components.

A perovskite compound included in an electronic apparatus according to an embodiment not forming part of the claimed invention or a lighting apparatus according to the claimed invention is represented by one of Formulae <NUM> to <NUM>: <MAT> <MAT> <MAT> <MAT>.

The perovskite compound refers to a compound having a perovskite crystal structure. The perovskite crystal structure refers to a three-dimensional crystal structure associated with a CaTiO<NUM> crystal structure.

A in Formulae <NUM> to <NUM> is at least one monovalent organic-cation, a monovalent inorganic cation, or any combination thereof.

For example, A may be i) one monovalent organic-cation, ii) one monovalent inorganic cation, iii) a combination of at least two different monovalent organic-cations, iv) a combination of at least two different monovalent inorganic cations, or v) a combination of a monovalent organic-cation and a monovalent inorganic cation.

In one embodiment, A may be (R<NUM>R<NUM>R<NUM>C)+, (R<NUM>R<NUM>R<NUM>R<NUM>N)+, (R<NUM>R<NUM>R<NUM>R<NUM>P)+, (R<NUM>R<NUM>R<NUM>R<NUM>As)+, (R<NUM>R<NUM>R<NUM>R<NUM>Sb)+, (R<NUM>R<NUM>N=C(R<NUM>)-NR<NUM>R<NUM>)*, a substituted or unsubstituted cycloheptatrienyl cation, a monovalent cation of a substituted or unsubstituted <NUM>-membered nitrogen-containing ring, a monovalent cation of a substituted or unsubstituted <NUM>-membered nitrogen-containing ring, Li+, Na+, K+, Rb+, Cs+, Fr+, or any combination thereof,.

The "<NUM>-membered nitrogen-containing ring" and the "<NUM>-membered nitrogen-containing ring" refer to an organic cyclic group including at least one N and at least one C as a ring-forming atom. For example, the "<NUM>-membered nitrogen-containing ring" may be an imidazole, a pyrazole, a thiazole, an oxazole, a pyrrolidine, a pyrroline, a pyrrole, or a triazolyl, and the "<NUM>-membered nitrogen-containing ring" may be a pyridine, a pyridazine, a pyrimidine, a pyrazine, or a piperidine, but embodiments of the present disclosure are not limited thereto.

For example, A in Formulae <NUM> to <NUM> may be (R<NUM>R<NUM>R<NUM>C)+, (R<NUM>R<NUM>R<NUM>R<NUM>N)+, (R<NUM>R<NUM>R<NUM>R<NUM>P)*, (R<NUM>R<NUM>R<NUM>R<NUM>As)+, (R<NUM>R<NUM>R<NUM>R<NUM>Sb)+, (R<NUM>R<NUM>N=C(R<NUM>)-NR<NUM>R<NUM>)*, a substituted or unsubstituted cycloheptatrienyl cation, a substituted or unsubstituted imidazolium, a substituted or unsubstituted pyridinium, a substituted or unsubstituted pyridazinium, a substituted or unsubstituted pyrimidinium, a substituted or unsubstituted pyrazinium, a substituted or unsubstituted pyrazolium, a substituted or unsubstituted thiazolium, a substituted or unsubstituted oxazolium, a substituted or unsubstituted piperidinium, a substituted or unsubstituted pyrrolidinium, a substituted or unsubstituted pyrrolium, a substituted or unsubstituted pyrrolium, a substituted or unsubstituted triazolium, Li+, Na+, K+, Rb+, Cs+, Fr+, or any combination thereof,.

R<NUM> to R<NUM> may each independently be selected from:.

In one or more embodiments, A in Formulae <NUM> to <NUM> may be (R<NUM>R<NUM>R<NUM>R<NUM>N)+, (R<NUM>R<NUM>R<NUM>R<NUM>P)+, (R<NUM>R<NUM>R<NUM>R<NUM>As)+, (R<NUM>R<NUM>R<NUM>R<NUM>Sb)+, Li+, Na+, K+, Rb+, Cs+, Fr+, or any combination thereof,.

In one or more embodiments, A in Formulae <NUM> to <NUM> may be (R<NUM>R<NUM>R<NUM>R<NUM>N)+, K+, Rb+, Cs+, or any combination thereof,.

In one or more embodiments, A in Formula <NUM> may be (NH<NUM>)+, (PH<NUM>)+, (AsH<NUM>)+, (SbH<NUM>)+, (NF<NUM>)+, (PF<NUM>)+, (NCl<NUM>)+, (PCl<NUM>)+, (CH<NUM>NH<NUM>)+, (CH<NUM>PH<NUM>)+, (CH<NUM>AsH<NUM>)+, (CH<NUM>SbH<NUM>)+, ((CH<NUM>)<NUM>NH<NUM>)+, ((CH<NUM>)<NUM>PH<NUM>)+, ((CH<NUM>)<NUM>AsH<NUM>)+, ((CH<NUM>)<NUM>SbH<NUM>)+, ((CH<NUM>)<NUM>NH)+, ((CH<NUM>)<NUM>PH)+, ((CH<NUM>)<NUM>AsH)+, ((CH<NUM>)<NUM>SbH)+, ((CH<NUM>CH<NUM>)NH<NUM>)+, ((CH<NUM>CH<NUM>)PH<NUM>)+, ((CH<NUM>CH<NUM>)AsH<NUM>)+, ((CH<NUM>CH<NUM>)SbH<NUM>)+, (CH<NUM>N<NUM>H<NUM>)+, (C<NUM>H<NUM>)+, (NH<NUM>OH)*, (NH<NUM>NH<NUM>)+, ((CH<NUM>)<NUM>NH<NUM>)+, (CH(NH<NUM>)<NUM>)+, (C<NUM>N<NUM>H<NUM>)+, (NC<NUM>H<NUM>)+, ((NH<NUM>)<NUM>C)+, K+, Rb+, Cs+, or any combination thereof, but embodiments of the present disclosure are not limited thereto.

In one or more embodiments, A in Formulae <NUM> to <NUM> may be (CH<NUM>NH<NUM>)+, K+, Rb+, or Cs+, but embodiments of the present disclosure are not limited thereto.

B<NUM> in Formulae <NUM> to <NUM> is a Sm<NUM>+ ion.

In Formulae <NUM> to <NUM>, B<NUM> is at least one divalent inorganic cation, and B<NUM> does not include a Sm<NUM>+ ion.

For example, B<NUM> in Formulae <NUM> to <NUM> may be i) one divalent inorganic cation, or ii) a combination of at least two different inorganic cations.

In one embodiment, B<NUM> in Formulae <NUM> to <NUM> may include a divalent cation of a rare earth metal, a divalent cation of an alkali earth metal, a divalent cation of a transition metal, a divalent cation of a late transition metal, or any combination thereof. For example, B<NUM> may be La<NUM>+, Ce<NUM>+, Pr<NUM>+, Nd<NUM>+, Pm<NUM>+, Eu<NUM>+, Bi<NUM>+, Ag<NUM>+, Mn<NUM>+, Sn<NUM>+, Gd<NUM>+, Tb<NUM>+, Ho<NUM>+, Er<NUM>+, Tm<NUM>+, Yb<NUM>+, Lu<NUM>+, Be<NUM>+, Mg<NUM>+, Ca<NUM>+, Sr<NUM>+, Ba<NUM>+, Ra<NUM>+, or any combination thereof.

In one embodiment, B<NUM> in Formulae <NUM> to <NUM> may be a divalent cation of a rare earth metal, a divalent cation of an alkali earth metal, or any combination thereof.

In one or more embodiments, B<NUM> in Formulae <NUM> to <NUM> may be La<NUM>+, Ce<NUM>+, Pr<NUM>+, Nd<NUM>+, Pm<NUM>+, Eu<NUM>+, Bi<NUM>+, Ag<NUM>+, Mn<NUM>+, Sn<NUM>+, Gd<NUM>+, Tb<NUM>+, Dy<NUM>+, Ho<NUM>+, Er<NUM>+, Yb<NUM>+, Lu<NUM>+, Be<NUM>+, Mg<NUM>+, Ca<NUM>+, Sr<NUM>+, Ba<NUM>+, Ra<NUM>+, or any combination thereof.

In one or more embodiments, B<NUM> in Formulae <NUM> to <NUM> may be La<NUM>+, Ce<NUM>+, Pr<NUM>+, Nd<NUM>+, Pm<NUM>+, Eu<NUM>+, Bi<NUM>+, Ag<NUM>+, Mn<NUM>+, Sn<NUM>+, Gd<NUM>+, Tb<NUM>+, Ho<NUM>+, Er<NUM>+, Yb<NUM>+, Mg<NUM>+, Ca<NUM>+, Sr<NUM>+, Ba<NUM>+, or Tm<NUM>+.

In one or more embodiments, B<NUM> in Formula <NUM> may also be Eu<NUM>+, Bi<NUM>+, Ag<NUM>+, Mn<NUM>+, Sn<NUM>+, or Yb<NUM>+, but embodiments of the present disclosure are not limited thereto.

n1 in Formula <NUM> is a real number satisfying <NUM> < n1 ≤ <NUM>.

n1 in Formula <NUM> may be a real number satisfying <NUM> < n1 < <NUM>. That is, since n1 in Formula <NUM> is not <NUM>, the perovskite compound represented by Formula <NUM> may essentially include Sm<NUM>+, and since n1 in Formula <NUM> is not <NUM>, the perovskite compound represented by Formula <NUM> may essentially include a divalent organic-cation other than Sm<NUM>+.

n2 in Formulae <NUM> to <NUM> is a real number satisfying <NUM> < n2 ≤ <NUM>.

n2 in Formulae <NUM> to <NUM> may be a real number satisfying <NUM> < n2 ≤ <NUM>. That is, since n2 in Formulae <NUM> to <NUM> is not <NUM>, the perovskite compound represented by Formulae <NUM> to <NUM> may essentially include Sm<NUM>+.

In one embodiment, n2 in Formulae <NUM> to <NUM> may be a real number satisfying <NUM> < n2 < <NUM>. For example, since n2 in Formulae <NUM> to <NUM> is not <NUM>, the perovskite compound represented by Formulae <NUM> to <NUM> may essentially include Sm<NUM>+, and since n2 in Formulae <NUM> to <NUM> is not <NUM>, the perovskite compound represented by Formulae <NUM> to <NUM> may essentially include a divalent organic-cation other than Sm<NUM>+.

In one embodiment, n1 in Formula <NUM> may be a real number satisfying <NUM> < n1 < <NUM>, and n2 in Formulae <NUM> to <NUM> may be a real number satisfying <NUM> < n2 < <NUM>.

In one embodiment, n1 in Formula <NUM> may be a real number satisfying <NUM> < n1 ≤ <NUM>, for example, a real number satisfying <NUM> ≤ n1 ≤ <NUM>, for example, a real number satisfying <NUM> ≤ n1 ≤ <NUM>. When n1 in Formula <NUM> is within this range, an optoelectronic device including the perovskite compound, for example, a light-emitting device including the perovskite compound, may effectively emit light in a visible light range.

In one embodiment, n2 in Formulae <NUM> to <NUM> may be a real number satisfying <NUM> < n2 ≤ <NUM>, for example, a real number satisfying <NUM> ≤ n2 ≤ <NUM>, for example, a real number satisfying <NUM> ≤ n2 ≤ <NUM>. When n2 in Formulae <NUM> to <NUM> is within this range, an optoelectronic device including the perovskite compound, for example, a light-emitting device including the perovskite compound may effectively emit light in a visible light range.

In one or more embodiments, an emission color from the perovskite compound may be adjusted by adjusting the range of n1 and n2 in Formulae <NUM> to <NUM>.

X in Formulae <NUM> to <NUM> is at least one monovalent anion.

For example, X in Formulae <NUM> to <NUM> may be i) one monovalent anion, or ii) a combination of at least two different monovalent anions.

In one embodiment, X in Formulae <NUM> to <NUM> may be at least one halide anion selected from Cl-, Br, and I-.

For example, X in Formulae <NUM> to <NUM> may be i) one halide anion selected from Cl-, Br, and I-, or ii) a combination of at least two different halide anions selected from Cl-, Br, and I-.

In one or more embodiments, X in Formulae <NUM> to <NUM> may be I-, but embodiments of the present disclosure are not limited thereto.

The perovskite compound represented by one of Formulae <NUM> to <NUM> may have an energy bandgap of about <NUM> eV or less.

In one embodiment, the energy bandgap of the perovskite compound may be adjusted by adjusting i) one halide anion or ii) a combination of at least two different halide anions, which is used as X in Formulae <NUM> to <NUM>. For example, in a case where X is Br, the energy bandgap may be expanded to implement a short wavelength, as compared with a case where X is I-. In a case where X is Cl-, the energy bandgap may be expanded to implement a short wavelength, as compared with a case where X is Br-.

An average grain size of the perovskite compound may be changed according to the type of the monovalent anion used as X. For example, in a case where the monovalent halide anion is used as X, when the halide anion is changed to I-, Br, Cl-, or the like, the energy bandgap may be adjusted and the light-emitting characteristics may be changed.

In one embodiment, the perovskite compound represented by Formula <NUM> may be selected from:.

In one embodiment, the perovskite compound may be in the form of a nano particle, a nanowire, a nanolayer, a multi-layer nanolayer, a micro particle, a microwire, a microlayer, or a multi-layer microlayer.

The energy bandgap and the maximum emission wavelength of the perovskite may be adjusted by adjusting the shape or size of the perovskite compound. For example, the perovskite compound represented by one of Formulae <NUM> to <NUM> may variously control the maximum emission wavelength emitted by the perovskite compound by controlling i) the average grain size or ii) a composition ratio.

For example, the maximum emission wavelength may be controlled by controlling the type (that is, the grain size) and the composition ratio of one of A, B<NUM>, B<NUM>, and X. In one embodiment, even when the types and the composition ratios of A and X among A, B<NUM>, B<NUM>, and X are identical to each other, the maximum emission wavelength emitted by the perovskite compound may be controlled by controlling the types or the composition ratios of B<NUM> and B<NUM>. In one embodiment, even when the types and the composition ratios of B<NUM>, B<NUM>, and X among A, B<NUM>, B<NUM>, and X are identical to each other, the maximum emission wavelength emitted by the perovskite compound may be controlled by controlling the type or the composition ratio of A. In one or more embodiments, even when the types and the composition ratios of A, B<NUM>, and B<NUM> among A, B<NUM>, B<NUM>, and X are identical to each other, the maximum emission wavelength emitted by the perovskite compound may be controlled by controlling the type or the composition ratio of X.

n1 and n2 in Formulae <NUM> to <NUM> are not <NUM>. That is, the perovskite compound represented by Formulae <NUM> to <NUM> includes Sm<NUM>+. Since Sm<NUM>+ has an ion radius similar to that of Pb<NUM>+ used in a conventional perovskite compound, the perovskite compound represented by Formulae <NUM> to <NUM> has a Goldschmidt's tolerance factor of about <NUM> and has a stable cubic structure. Therefore, although not limited by a particular theory, high quantum yields may be obtained by a quantum confinement effect.

Therefore, for example, a thin film including the perovskite compound represented by one of Formulae <NUM> to <NUM> may have high photoluminescence (PL) quantum yields (PLQY) and a small full width at half maximum (FWHM), and a light-emitting device including the perovskite compound represented by one of Formulae <NUM> to <NUM> may have excellent external quantum efficiency and light efficiency.

Another aspect provides a thin film (thin layer) including the perovskite compound represented by one of Formulae <NUM> to <NUM>.

The perovskite compound included in the thin film is the same as described above.

The thin film may be synthesized by a known synthesis method. Hereinafter, the synthesis method of the thin film including the perovskite compound will be described in detail.

The thin film may be manufactured by providing an A-containing precursor, a B<NUM>-containing precursor, and a B<NUM>-containing precursor on a predetermined substrate (for example, a region in which the thin film is to be formed) and performing thermal treatment thereon to form the thin film including the perovskite compound represented by one of Formulae <NUM> to <NUM>.

The description of A, B<NUM>, and B<NUM> in the A-containing precursor, the B<NUM>-containing precursor, and the B<NUM>-containing precursor is the same as the description of A, B<NUM>, and B<NUM> in Formulae <NUM> to <NUM>.

The A-containing precursor may be selected from halides of A (for example, (A)(X<NUM>)), the B<NUM>-containing precursor may be selected from halides of B<NUM> (for example, (B<NUM>)(X<NUM>)<NUM>), and the B<NUM>-containing precursor may be selected from halides of B<NUM> (for example, (B<NUM>)(X<NUM>)<NUM>). In (A)(X<NUM>), (B<NUM>)(X<NUM>)<NUM>, and (B<NUM>)(X<NUM>)<NUM>, A, B<NUM>, and B<NUM> are the same as described above, and X<NUM> to X<NUM> may each independently be selected from -F, -Cl, -Br, and -I.

In one embodiment, the A-containing precursor may be CH<NUM>NH<NUM>I, the B<NUM>-containing precursor may be SmI<NUM>, and the B<NUM>-containing precursor may be EuI<NUM>, but embodiments of the present disclosure are not limited thereto.

In one embodiment, the thin film including the perovskite compound represented by one of Formulae <NUM> to <NUM> may be manufactured by providing an A-containing precursor, a B<NUM>-containing precursor, and a B<NUM>-containing precursor on a predetermined substrate and simultaneously performing thermal treatment thereon to form the thin film including the perovskite compound represented by one of Formulae <NUM> to <NUM> (that is, one-step method).

In one or more embodiments, the thin film including the perovskite compound represented by one of Formulae <NUM> to <NUM> may be manufactured by providing an A-containing precursor, a B<NUM>-containing precursor, and a B<NUM>-containing precursor on a predetermined substrate to form a precursor-containing film, and performing thermal treatment on the precursor-containing film to form the thin film including the perovskite compound represented by one of Formulae <NUM> to <NUM> (that is, two-step method).

The thermal treatment condition in the thin film manufacturing method may be selected under different conditions according to whether A in the A-precursor includes a monovalent inorganic cation.

For example, i) when A does not include a monovalent inorganic cation, the thermal treatment condition in the thin film manufacturing method may be selected in a time range of about <NUM> minutes to about <NUM> hour and in a temperature range of about <NUM> to <NUM>, and ii) when A includes a monovalent inorganic cation, the thermal condition in the thin film manufacturing method may be selected in a time range of about <NUM> hours to <NUM> hours and a temperature range of about <NUM> to about <NUM>, but embodiments of the present disclosure are not limited thereto.

In addition, various modifications may be possible. For example, the thin film including the perovskite compound represented by one of Formulae <NUM> to <NUM> may be manufactured by providing a mixture including the perovskite compound represented by one of Formulae <NUM> to <NUM> on a predetermined substrate and performing thermal treatment thereon.

Another aspect not forming part of the claimed invention provides an electronic apparatus including the perovskite compound represented by one of Formulae <NUM> to <NUM>.

In one embodiment not forming part of the claimed invention, the electronic apparatus may include an optoelectronic device including the perovskite compound, and
the optoelectronic device may be a photovoltaic device, a photodiode, a phototransistor, a photomultiplier, a photo resistor, a photo detector, a light sensitive detector, a solid-state triode, a battery electrode, a light-emitting device, a light-emitting diode, an organic light-emitting device, a quantum dot light-emitting diode, a transistor, a solar cell, a laser, or a diode injection laser.

The perovskite compound may be used as a light-emitting material of an electronic apparatus (for example, a light-emitting material of a light-emitting device including an emission layer), a charge transport material (for example, a material for a hole transport layer of a light-emitting device including a hole transport region), an electrode material, a light sensitive material, a light-absorbing material (for example, a material for an active layer of a solar cell), a light conversion material (for example, material for a color filter when a light-emitting device includes a color filter), or the like.

In one embodiment not forming part of the claimed invention, the electronic apparatus includes a light-emitting device including: a first electrode; a second electrode facing the first electrode; and an intermediate layer between the first electrode and the second electrode and including an emission layer, wherein the emission layer includes a perovskite compound represented by one of Formulae <NUM> to <NUM>: <MAT> <MAT> <MAT> <MAT>.

The description of the perovskite is the same as described herein.

In one embodiment not forming part of the claimed invention, the electronic apparatus may be a display apparatus.

In one embodiment not forming part of the claimed invention, the light-emitting device included in the electronic apparatus may be, for example, an organic light-emitting device or a quantum dot light-emitting diode. For example, the electronic apparatus may be an organic light-emitting display apparatus including an organic light-emitting device. In one or more embodiments not forming part of the claimed invention, the electronic apparatus may be a quantum dot light-emitting display apparatus including a quantum dot light-emitting diode.

The intermediate layer in the light-emitting device may further include a hole transport region between the first electrode and the emission layer and an electron transport region between the emission layer and the second electrode.

At least one of the hole transport region and the electron transport region in the light-emitting device may include an inorganic material.

For example, at least one of the hole transport region and the electron transport region in the light-emitting device may include an inorganic material including a metal halide, a metal oxide, a metal chalcogenide, a metal selenide, or any combination thereof.

At least one of the hole transport region and the electron transport region in the light-emitting device may include:.

For example, at least one of the hole transport region and the electron transport region in the light-emitting device may include:.

x may be a real number greater than <NUM> and less than or equal to <NUM>.

At least one of the hole transport region and the electron transport region may include an organic material.

The hole transport region may include an amine-based compound, and the electron transport region may include a metal-free compound including at least one π electron-depleted nitrogen-containing ring.

An organic material and an additional material that may be included in the hole transport region and the electron transport region are the same as described below.

<FIG> is a schematic view of a light-emitting device <NUM> included in the electronic device according to an embodiment not forming part of the claimed invention. The light-emitting device <NUM> includes a first electrode <NUM>, a hole transport region <NUM>, an emission layer <NUM>, an electron transport region <NUM>, and a second electrode <NUM>.

Hereinafter, the structure of the light-emitting device <NUM> according to an embodiment not forming part of the claimed invention and a method of manufacturing the light-emitting device <NUM> will be described in connection with <FIG>.

In <FIG>, a substrate may be additionally disposed under the first electrode <NUM> or above the second electrode <NUM>. The substrate may be a glass substrate or a plastic substrate, each having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and water resistance.

The first electrode <NUM> may be formed by depositing or sputtering a material for forming the first electrode <NUM> on the substrate. When the first electrode <NUM> is an anode, the material for a first electrode may be selected from materials with a high work function to facilitate hole injection.

The first electrode <NUM> may be a reflective electrode, a semi-transmissive electrode, or a transmissive electrode. When the first electrode <NUM> is a transmissive electrode, a material for forming a first electrode may be selected from indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO<NUM>), zinc oxide (ZnO), and any combinations thereof. When the first electrode <NUM> is a semi-transmissive electrode or a reflectable electrode, a material for forming a first electrode may be selected from magnesium (Mg), silver (Ag), aluminium (Al), aluminium-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), and any combinations thereof.

The first electrode <NUM> may have a single-layered structure, or a multi-layered structure including two or more layers. For example, the first electrode <NUM> may have a three-layered structure of ITO/Ag/ITO, but the structure of the first electrode <NUM> is not limited thereto.

The hole transport region <NUM> may have i) a single-layered structure including a single layer including a single material, ii) a single-layered structure including a single layer including a plurality of different materials, or iii) a multi-layered structure having a plurality of layers including a plurality of different materials.

The hole transport region may include at least one layer selected from a hole injection layer, a hole transport layer, an emission auxiliary layer, and an electron blocking layer.

For example, the hole transport region may have a single-layered structure including a single layer including one type of a material (for example, a single-layered structure consisting of a hole transport layer including one type of a material), a single-layered structure including a single layer including a plurality of different materials, or a multi-layered structure having a hole injection layer/hole transport layer structure, a hole injection layer/hole transport layer/emission auxiliary layer structure, a hole injection layer/emission auxiliary layer structure, a hole transport layer/emission auxiliary layer structure, or a hole injection layer/hole transport layer/electron blocking layer structure, wherein for each structure, constituting layers are sequentially stacked from the first electrode <NUM> in this stated order, but the structure of the hole transport region is not limited thereto.

The hole transport region may include the inorganic material.

The hole transport region may include the perovskite compound represented by one of Formulae <NUM> to <NUM>.

The hole transport region may include an organic material.

Examples of the organic material include m-MTDATA, TDATA, <NUM>-TNATA, NPB(NPD), β-NPB, TPD, Spiro-TPD, Spiro-NPB, methylated-NPB, TAPC, HMTPD, <NUM>,<NUM>',<NUM>"-tris(N-carbazolyl)triphenylamine (TCTA), polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA), poly(<NUM>,<NUM>-ethylenedioxythiophene)/poly(<NUM>-styrenesulfonate) (PEDOT/PSS), polyaniline/camphor sulfonic acid (PANI/CSA), polyaniline/poly(<NUM>-styrenesulfonate) (PANI/PSS), a compound represented by Formula <NUM>, and a compound represented by Formula <NUM>:
<CHM>
<CHM>
<CHM>
<CHM>.

An example of the organic material includes an amine-based compound.

The hole transport layer may include at least one compound selected from a compound represented by Formula <NUM> and a compound represented by Formula <NUM> illustrated below:
<CHM>
<CHM>.

For example, in Formula <NUM>, R<NUM> and R<NUM> may optionally be linked via a single bond, a dimethyl-methylene group, or a diphenyl-methylene group, and R<NUM> and R<NUM> may optionally be linked via a single bond, a dimethyl-methylene group, or a diphenyl-methylene group.

In Formulae <NUM> and <NUM>, L<NUM> to L<NUM> may each independently be selected from:.

A thickness of the hole transport region may be in a range of about <NUM>Å to about <NUM>,<NUM>Å, for example, about <NUM>Å to about <NUM>Å, about <NUM>Å to about <NUM>Å, about <NUM>Å to about <NUM>Å, or about <NUM>Å to about <NUM>,<NUM>Å. When the hole transport region includes at least one of a hole injection layer and a hole transport layer, a thickness of the hole injection layer may be in a range of about <NUM>Å to about <NUM>,<NUM>Å, for example, about <NUM>Å to about <NUM>,<NUM>Å, about <NUM>Å to about <NUM>,<NUM>Å, about <NUM>Å to about <NUM>,<NUM>Å, about <NUM>Å to about <NUM>,<NUM>Å or about <NUM>Å to about <NUM>,<NUM>Å, and a thickness of the hole transport layer may be in a range of about <NUM>Å to about <NUM>,<NUM>Å, for example about <NUM>Å to about <NUM>,<NUM>Å, about <NUM>Å to about <NUM>,<NUM>Å, or about <NUM>Å to about <NUM>,<NUM>Å. When the thicknesses of the hole transport region, the hole injection layer, and the hole transport layer are within these ranges, satisfactory hole transporting characteristics may be obtained without a substantial increase in driving voltage.

The emission auxiliary layer may increase light-emission efficiency by compensating for an optical resonance distance according to the wavelength of light emitted by an emission layer, and the electron blocking layer may block the flow of electrons from an electron transport region. The emission auxiliary layer and the electron blocking layer may include the materials as described above.

The hole transport region may further include, in addition to these materials, a charge-generation material for the improvement of conductive properties. The charge-generation material may be homogeneously or non-homogeneously dispersed in the hole transport region.

The charge-generation material may be, for example, a p-dopant.

The p-dopant may have a lowest unoccupied molecular orbital (LUMO) level of - <NUM> eV or less.

The p-dopant may include at least one selected from a quinone derivative, a metal oxide, and a cyano group-containing compound.

For example, the p-dopant may include at least one selected from:.

In Formula <NUM>,
R<NUM> to R<NUM> may each independently be selected from a substituted or unsubstituted C<NUM>-C<NUM> cycloalkyl group, a substituted or unsubstituted C<NUM>-C<NUM> heterocycloalkyl group, a substituted or unsubstituted C<NUM>-C<NUM> cycloalkenyl group, a substituted or unsubstituted C<NUM>-C<NUM> heterocycloalkenyl group, a substituted or unsubstituted C<NUM>-C<NUM> (e.g. C<NUM>-C<NUM>) aryl group, a substituted or unsubstituted C<NUM>-C<NUM> (e.g. C<NUM>-C<NUM>) heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, wherein at least one selected from R<NUM> to R<NUM> may have at least one substituent selected from a cyano group, -F, -Cl, -Br, -I, a C<NUM>-C<NUM> alkyl group substituted with -F, a C<NUM>-C<NUM> alkyl group substituted with -Cl, a C<NUM>-C<NUM> alkyl group substituted with -Br, and a C<NUM>-C<NUM> alkyl group substituted with -I.

When the light-emitting diode is a quantum dot light-emitting diode, the emission layer <NUM> may include the perovskite compound represented by one of Formulae <NUM> to <NUM>. A method of forming the emission layer <NUM> may be referred by the description of a method of forming a thin film including the perovskite compound.

When the light-emitting diode is an organic light-emitting device, the emission layer <NUM> may include a host and a dopant. The dopant may include at least one selected from a phosphorescent dopant and a fluorescent dopant.

In the emission layer <NUM>, an amount of the dopant may be generally in a range of about <NUM> parts by weight to about <NUM> parts by weight based on <NUM> parts by weight of the host.

A thickness of the emission layer <NUM> may be in a range of about <NUM>Å to about <NUM>,<NUM>Å, for example, about <NUM>Å to about <NUM>Å, about <NUM>Å to about <NUM>Å, about <NUM>Å to about <NUM>Å, about <NUM>Å to about <NUM>Å, about <NUM>Å to about <NUM>Å or about <NUM>Å to about <NUM>Å. When the thickness of the emission layer <NUM> is within this range, excellent light-emission characteristics may be obtained without a substantial increase in driving voltage.

When the organic light-emitting device <NUM> is a full-color organic light-emitting device, the emission layer may be patterned into a red emission layer, a green emission layer, or a blue emission layer, according to a sub-pixel. The emission layer may have a stacked structure of two or more layers selected from a red emission layer, a green emission layer, and a blue emission layer, in which the two or more layers contact each other or are separated from each other. The emission layer may include two or more materials selected from a red light-emitting material, a green light-emitting material, and a blue light-emitting material, in which the two or more materials are mixed with each other in a single layer to emit white light.

The host may include a compound represented by Formula <NUM> below.

<Formula <NUM>>     [Ar<NUM>]xb11-[(L<NUM>)xb1-R<NUM>]xb21.

For example, Ar<NUM> may be a substituted or unsubstituted C<NUM>-C<NUM> carbocyclic group or a substituted or unsubstituted C<NUM>-C<NUM> heterocyclic group.

Ar<NUM> in Formula <NUM> may be selected from:.

When xb11 in Formula <NUM> is two or more, two or more Ar<NUM> (s) may be linked via a single bond.

The compound represented by Formula <NUM> may be represented by Formula <NUM>-<NUM> or <NUM>-<NUM> below:
<CHM>
<CHM>
<CHM>.

In Formulae <NUM>-<NUM> and <NUM>-<NUM>,.

For example, L<NUM> to L<NUM> in Formulae <NUM>, <NUM>-<NUM>, and <NUM>-<NUM> may each independently be selected from: a substituted or unsubstituted C<NUM>-C<NUM> cycloalkylene group, a substituted or unsubstituted C<NUM>-C<NUM> heterocycloalkylene group, a substituted or unsubstituted C<NUM>-C<NUM> cycloalkenylene group, a substituted or unsubstituted C<NUM>-C<NUM> heterocycloalkenylene group, a substituted or unsubstituted C<NUM>-C<NUM> arylene group, a substituted or unsubstituted C<NUM>-C<NUM> heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group.

For example, in Formulae <NUM>, <NUM>-<NUM>, and <NUM>-<NUM>, L<NUM> to L<NUM> may each independently be selected from:.

As another example, R<NUM> to R<NUM> in Formulae <NUM>, <NUM>-<NUM>, and <NUM>-<NUM> may each independently be selected from: deuterium, -F, -Cl, -Br, -I, a hydroxyl group, a cyano group, a nitro group, an amidino group, a hydrazino group, a hydrazono group, a substituted or unsubstituted C<NUM>-C<NUM> (e.g. C<NUM>-C<NUM>) alkyl group, a substituted or unsubstituted C<NUM>-C<NUM> (e.g. C<NUM>-C<NUM>) alkenyl group, a substituted or unsubstituted C<NUM>-C<NUM> (e.g. C<NUM>-C<NUM>) alkynyl group, a substituted or unsubstituted C<NUM>-C<NUM> (e.g. C<NUM>-C<NUM>) alkoxy group, a substituted or unsubstituted C<NUM>-C<NUM> cycloalkyl group, a substituted or unsubstituted C<NUM>-C<NUM> heterocycloalkyl group, a substituted or unsubstituted C<NUM>-C<NUM> cycloalkenyl group, a substituted or unsubstituted C<NUM>-C<NUM> heterocycloalkenyl group, a substituted or unsubstituted C<NUM>-C<NUM> aryl group, a substituted or unsubstituted C<NUM>-C<NUM> aryloxy group, a substituted or unsubstituted C<NUM>-C<NUM> arylthio group, a substituted or unsubstituted C<NUM>-C<NUM> heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, -Si(Q<NUM>)(Q<NUM>)(Q<NUM>), -N(Q<NUM>)(Q<NUM>), - B(Q<NUM>)(Q<NUM>), -C(=O)(Q<NUM>), -S(=O)<NUM>(Q<NUM>), and -P(=O)(Q<NUM>)(Q<NUM>).

In Formulae <NUM>, <NUM>-<NUM>, and <NUM>-<NUM>, R<NUM> to R<NUM> may each independently be selected from:.

The host may include an alkaline earth metal complex. For example, the host may include a complex selected from a Be complex (for example, Compound H55), a Mg complex, and a Zn complex. For example, the host may be selected from a Be complex (for example, Compound H55), a Mg complex, and a Zn complex.

The host may include at least one selected from <NUM>,<NUM>-di(<NUM>-naphthyl)anthracene (ADN), <NUM>-methyl-<NUM>,<NUM>-bis(naphthalen-<NUM>-yl)anthracene (MADN), <NUM>,<NUM>-di-(<NUM>-naphthyl)-<NUM>-t-butyl-anthracene (TBADN), <NUM>,<NUM>"-bis(N-carbazolyl)-<NUM>,<NUM>'-biphenyl(CBP), <NUM>,<NUM>-di-<NUM>-carbazolylbenzene (mCP), <NUM>,<NUM>,<NUM>-tri(carbazol-<NUM>-yl)benzene (TCP), and Compounds H1 to H55:
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>.

The phosphorescent dopant may include an organometallic complex represented by Formula <NUM> below:.

<Formula <NUM>>     M(L<NUM>)xc1(L<NUM>)xc2.

In Formula <NUM>, A<NUM> and A<NUM> may each independently be selected from a benzene group, a naphthalene group, a fluorene group, a spiro-bifluorene group, an indene group, a pyrrole group, a thiophene group, a furan group, an imidazole group, a pyrazole group, a thiazole group, an isothiazole group, an oxazole group, an isoxazole group, a pyridine group, a pyrazine group, a pyrimidine group, a pyridazine group, a quinoline group, an isoquinoline group, a benzoquinoline group, a quinoxaline group, a quinazoline group, a carbazole group, a benzimidazole group, a benzofuran group, a benzothiophene group, an isobenzothiophene group, a benzoxazole group, an isobenzoxazole group, a triazole group, a tetrazole group, an oxadiazole group, a triazine group, a dibenzofuran group, and a dibenzothiophene group.

In Formula <NUM>, i) X<NUM> may be nitrogen, and X<NUM> may be carbon, or ii) X<NUM> and X<NUM> may each be nitrogen at the same time.

In Formula <NUM>, R<NUM> and R<NUM> may each independently be selected from:.

In Formula <NUM>, when xc1 is two or more, two A<NUM>(s) among a plurality of L<NUM>(s) may optionally be linked via a linking group, X<NUM>, or two A<NUM>(s) may optionally be linked via a linking group, X<NUM> (see Compounds PD1 to PD4 and PD7). X<NUM> and X<NUM> may each independently be a single bond, *-O-*', *-S-*', *-C(=O)-*', *-N(Q<NUM>)-*', - C(Q<NUM>)(Q<NUM>)-*', or *-C(Q<NUM>)=C(Q<NUM>)-*' (wherein Q<NUM> and Q<NUM> may each independently be hydrogen, deuterium, a C<NUM>-C<NUM> alkyl group, a C<NUM>-C<NUM> alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, or a naphthyl group).

L<NUM> in Formula <NUM> may be a monovalent, divalent, or trivalent organic ligand. For example, L<NUM> may be selected from halogen, diketone (for example, acetylacetonate), carboxylic acid (for example, picolinate), -C(=O), isonitrile, -CN, and phosphorus (for example, phosphine, or phosphite).

The phosphorescent dopant may be selected from, for example, Compounds PD1 to PD25:
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>.

The fluorescent dopant may include an arylamine compound or a styrylamine compound.

The fluorescent dopant may include a compound represented by Formula <NUM> below. <CHM>
<CHM>.

L<NUM> to L<NUM> in Formula <NUM> may each independently be selected from:.

For example, the fluorescent dopant may be selected from Compounds FD1 to FD22:
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>
<CHM>.

The fluorescent dopant may be selected from the following compounds. <CHM>
<CHM>
<CHM>.

The electron transport region <NUM> may have i) a single-layered structure including a single layer including a single material, ii) a single-layered structure including a single layer including a plurality of different materials, or iii) a multi-layered structure having a plurality of layers including a plurality of different materials.

The electron transport region <NUM> may include at least one selected from a buffer layer, a hole blocking layer, an electron control layer, an electron transport layer, and an electron injection layer.

For example, the electron transport region <NUM> may have an electron transport layer/electron injection layer structure, a hole blocking layer/electron transport layer/electron injection layer structure, an electron control layer/electron transport layer/electron injection layer structure, or a buffer layer/electron transport layer/electron injection layer structure, wherein for each structure, constituting layers are sequentially stacked from an emission layer. However, the structure of the electron transport region is not limited thereto.

The electron transport region <NUM> may include an inorganic material, and the inorganic material is defined the same as described above.

The electron transport region <NUM> may include the perovskite compound represented by one of Formulae <NUM> to <NUM>.

The electron transport region <NUM> may include an organic material.

The organic material included in the electron transport region <NUM> may be a metal-free compound including at least one π electron-depleted nitrogen-containing ring.

The "π electron-depleted nitrogen-containing ring" indicates a C<NUM>-C<NUM> (e.g. a C<NUM>-C<NUM>) heterocyclic group having at least one *-N=*' moiety as a ring-forming moiety.

For example, the "π electron-depleted nitrogen-containing ring" may be i) a <NUM>-membered to <NUM>-membered heteromonocyclic group having at least one *-N=*' moiety, ii) a heteropolycyclic group in which two or more <NUM>-membered to <NUM>-membered heteromonocyclic groups each having at least one *-N=*' moiety are condensed with each other, or iii) a heteropolycyclic group in which at least one of <NUM>-membered to <NUM>-membered heteromonocyclic groups, each having at least one *-N=*' moiety, is condensed with at least one C<NUM>-C<NUM> (e.g. a C<NUM>-C<NUM>) carbocyclic group.

Examples of the π electron-depleted nitrogen-containing ring include an imidazole, a pyrazole, a thiazole, an isothiazole, an oxazole, an isoxazole, a pyridine, a pyrazine, a pyrimidine, a pyridazine, an indazole, a purine, a quinoline, an isoquinoline, a benzoquinoline, a phthalazine, a naphthyridine, a quinoxaline, a quinazoline, a cinnoline, a phenanthridine, an acridine, a phenanthroline, a phenazine, a benzimidazole, an isobenzothiazole, a benzoxazole, an isobenzoxazole, a triazole, a tetrazole, an oxadiazole, a triazine, thiadiazole, an imidazopyridine, an imidazopyrimidine, and an azacarbazole, but are not limited thereto.

For example, the electron transport region <NUM> may include a compound represented by Formula <NUM>.

<Formula <NUM>>     [Ar<NUM>]xe11-[(L<NUM>)xe1-R<NUM>]xe21.

At least one of Ar<NUM>(s) in the number of xe11 and R<NUM>(s) in the number of xe21 may include the π electron-depleted nitrogen-containing ring.

In Formula <NUM>, ring Ar<NUM> may be selected from:.

When xe11 in Formula <NUM> is two or more, two or more Ar601(s) may be linked via a single bond.

For example, L<NUM> and L<NUM> to L<NUM> in Formula <NUM> may each independently be selected from: a substituted or unsubstituted C<NUM>-C<NUM> cycloalkylene group, a substituted or unsubstituted C<NUM>-C<NUM> heterocycloalkylene group, a substituted or unsubstituted C<NUM>-C<NUM> cycloalkenylene group, a substituted or unsubstituted C<NUM>-C<NUM> heterocycloalkenylene group, a substituted or unsubstituted C<NUM>-C<NUM> arylene group, a substituted or unsubstituted C<NUM>-C<NUM> heteroarylene group, a substituted or unsubstituted divalent non-aromatic condensed polycyclic group, and a substituted or unsubstituted divalent non-aromatic condensed heteropolycyclic group.

L<NUM> and L<NUM> to L<NUM> in Formula <NUM> may each independently be selected from:.

In Formula <NUM>, xe1 and xe611 to xe613 may each independently be <NUM>, <NUM>, or <NUM>.

For example, R<NUM> and R<NUM> to R<NUM> in Formula <NUM> may each independently be selected from: a substituted or unsubstituted C<NUM>-C<NUM> cycloalkyl group, a substituted or unsubstituted C<NUM>-C<NUM> heterocycloalkyl group, a substituted or unsubstituted C<NUM>-C<NUM> cycloalkenyl group, a substituted or unsubstituted C<NUM>-C<NUM> heterocycloalkenyl group, a substituted or unsubstituted C<NUM>-C<NUM> aryl group, a substituted or unsubstituted C<NUM>-C<NUM> aryloxy group, a substituted or unsubstituted C<NUM>-C<NUM> arylthio group, a substituted or unsubstituted C<NUM>-C<NUM> heteroaryl group, a substituted or unsubstituted monovalent non-aromatic condensed polycyclic group, a substituted or unsubstituted monovalent non-aromatic condensed heteropolycyclic group, -Si(Q<NUM>)(Q<NUM>)(Q<NUM>), -C(=O)(Q<NUM>), - S(=O)<NUM>(Q<NUM>), and -P(=O)(Q<NUM>)(Q<NUM>).

In Formula <NUM>, R<NUM> and R<NUM> to R<NUM> may each independently be selected from:.

The electron transport region <NUM> may include at least one compound selected from <NUM>,<NUM>-dimethyl-<NUM>,<NUM>-diphenyl-<NUM>,<NUM>-phenanthroline (BCP), <NUM>,<NUM>-diphenyl-<NUM>,<NUM>-phenanthroline (Bphen), Alq<NUM>, BAlq, TAZ(<NUM>-(Biphenyl-<NUM>-yl)-<NUM>-(<NUM>-tert-butylphenyl)-<NUM>-phenyl-<NUM>-<NUM>,<NUM>,<NUM>-triazole), NTAZ, and TPBi:
<CHM>
<CHM>
<CHM>.

A thickness of the electron transport layer may be in a range of about <NUM>Å to about <NUM>,<NUM>Å, for example, about <NUM>Å to about <NUM>Å, about <NUM>Å to about <NUM>Å, about <NUM>Å to about <NUM>Å, or about <NUM>Å to about <NUM>Å. When the thickness of the electron transport layer is within the range described above, the electron transport layer may have satisfactory electron transport characteristics without a substantial increase in driving voltage.

The electron transport region <NUM> (for example, the electron transport layer in the electron transport region) may further include, in addition to the materials described above, a metal-containing material.

The metal-containing material may include at least one selected from alkali metal complex and alkaline earth-metal complex. The alkali metal complex may include a metal ion selected from a Li ion, a Na ion, a K ion, a Rb ion, and a Cs ion, and the alkaline earth-metal complex may include a metal ion selected from a Be ion, a Mg ion, a Ca ion, a Sr ion, and a Ba ion. A ligand coordinated with the metal ion of the alkali metal complex or the alkaline earth-metal complex may be selected from a hydroxy quinoline, a hydroxy isoquinoline, a hydroxy benzoquinoline, a hydroxy acridine, a hydroxy phenanthridine, a hydroxy phenyloxazole, a hydroxy phenylthiazole, a hydroxy diphenyloxadiazole, a hydroxy diphenylthiadiazole, a hydroxy phenylpyridine, a hydroxy phenylbenzimidazole, a hydroxy phenylbenzothiazole, a bipyridine, a phenanthroline, and a cyclopentadiene.

For example, the metal-containing material may include a Li complex. The Li complex may include, for example, Compound ET-D1 (lithium quinolate, LiQ) or ET-D2.

The electron transport region <NUM> may include an electron injection layer that facilitates injection of electrons from the second electrode <NUM>. The electron injection layer may directly contact the second electrode <NUM>.

The electron injection layer may have i) a single-layered structure including a single layer including a single material, ii) a single-layered structure including a single layer including a plurality of different materials, or iii) a multi-layered structure having a plurality of layers including a plurality of different materials.

The electron injection layer may include an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth-metal compound, a rare earth metal compound, an alkali metal complex, an alkaline earth-metal complex, a rare earth metal complex, or any combinations thereof.

The alkali metal may be selected from Li, Na, K, Rb, and Cs.

The alkaline earth metal may be selected from Mg, Ca, Sr, and Ba.

The rare earth metal may be selected from Sc, Y, Ce, Tb, Yb, and Gd.

The alkali metal compound, the alkaline earth-metal compound, and the rare earth metal compound may be selected from oxides and halides (for example, fluorides, chlorides, bromides, or iodides) of the alkali metal, the alkaline earth-metal, and the rare earth metal.

The alkali metal compound may be selected from alkali metal oxides, such as Li<NUM>O, Cs<NUM>O, or K<NUM>O, and alkali metal halides, such as LiF, NaF, CsF, KF, Lil, Nal, Csl, KI, or Rbl. The alkali metal compound may be selected from LiF, Li<NUM>O, NaF, Lil, Nal, Csl, KI, and Rbl.

The alkaline earth-metal compound may be selected from alkaline earth-metal oxides, such as BaO, SrO, CaO, BaxSr<NUM>-xO (<NUM><x<<NUM>), or BaxCa<NUM>-xO (<NUM><x<<NUM>). The alkaline earth-metal compound may be selected from BaO, SrO, and CaO.

The rare earth metal compound may be selected from YbF<NUM>, ScF<NUM>, Sc<NUM>O<NUM>, Y<NUM>O<NUM>, Ce<NUM>O<NUM>, GdF<NUM>, and TbF<NUM>. The rare earth metal compound may be selected from YbF<NUM>, ScF<NUM>, TbF<NUM>, YbI<NUM>, ScI<NUM>, and TbI<NUM>.

For example, the electron injection layer may include an alkali metal compound (for example, Rbl) and a rare earth metal compound (for example, Yb).

The alkali metal complex, the alkaline earth-metal complex, and the rare earth metal complex may include an ion of alkali metal, alkaline earth-metal, and rare earth metal as described above, and a ligand coordinated with a metal ion of the alkali metal complex, the alkaline earth-metal complex, or the rare earth metal complex may be selected from hydroxy quinoline, hydroxy isoquinoline, hydroxy benzoquinoline, hydroxy acridine, hydroxy phenanthridine, hydroxy phenyloxazole, hydroxy phenylthiazole, hydroxy diphenyloxadiazole, hydroxy diphenylthiadiazole, hydroxy phenylpyridine, hydroxy phenylbenzimidazole, hydroxy phenylbenzothiazole, bipyridine, phenanthroline, and cyclopentadiene.

The electron injection layer may consist of an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth-metal compound, a rare earth metal compound, an alkali metal complex, an alkaline earth-metal complex, a rare earth metal complex, or any combinations thereof, as described above. The electron injection layer may further include an organic material. When the electron injection layer further includes an organic material, an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth-metal compound, a rare earth metal compound, an alkali metal complex, an alkaline earth-metal complex, a rare earth metal complex, or any combinations thereof may be homogeneously or non-homogeneously dispersed in a matrix including the organic material.

A thickness of the electron injection layer may be in a range of about <NUM>Å to about <NUM>Å, for example, about <NUM>Å to about <NUM>Å or about <NUM>Å to about <NUM>Å. 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 electrode <NUM> may be disposed on the electron transport region <NUM> having such a structure. The second electrode <NUM> may be a cathode which is an electron injection electrode, and in this regard, a material for forming the second electrode <NUM> may be selected from metal, an alloy, an electrically conductive compound, and a combination thereof, which have a relatively low work function.

The second electrode <NUM> may include at least one selected from lithium (Li), silver (Ag), magnesium (Mg), aluminium (Al), aluminium-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), silver-magnesium (Ag-Mg), ITO, and IZO. The second electrode <NUM> may be a transmissive electrode, a semi-transmissive electrode, or a reflective electrode.

The second electrode <NUM> may have a single-layered structure, or a multi-layered structure including two or more layers.

Layers constituting the hole transport region <NUM> and layers constituting the electron transport region <NUM> may be formed in a certain region by using one or more suitable methods selected from vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) deposition, ink-jet printing, laser-printing, and laser-induced thermal imaging.

When layers constituting the hole transport region <NUM> and layers constituting the electron transport region <NUM> are formed by vacuum deposition, the deposition may be performed at a deposition temperature of about <NUM> to about <NUM>, a vacuum degree of about <NUM>-<NUM> torr to about <NUM>-<NUM> torr, and a deposition speed of about <NUM>Å/sec to about <NUM>Å/sec by taking into account a material to be included in a layer to be formed, and the structure of a layer to be formed.

When layers constituting the hole transport region <NUM> and layers constituting the electron transport region <NUM> are formed by spin coating, the spin coating may be performed at a coating speed of about <NUM>,<NUM> rpm to about <NUM>,<NUM> rpm and at a heat treatment temperature of about <NUM> to about <NUM> by taking into account a material to be included in a layer to be formed, and the structure of a layer to be formed.

In one embodiment not forming part of the claimed invention, an electronic apparatus includes: a first substrate; an organic light-emitting device; and a thin film disposed on (e.g. located in) at least one traveling direction (e.g. path) of light emitted from the organic light-emitting device, and.

the thin film may include a perovskite compound represented by one of Formulae <NUM> to <NUM>: <MAT> <MAT> <MAT> <MAT>.

The perovskite compound is the same as described above.

The description of the organic light-emitting device may be understood by referring to the others of the description of the light-emitting device, except for the description of the quantum dot light-emitting diode.

In one embodiment not forming part of the claimed invention, the electronic apparatus may be an organic light-emitting display apparatus.

<FIG> is a schematic cross-sectional view of an organic light-emitting display apparatus according to an embodiment not forming part of the claimed invention. <FIG> are schematic partial enlarged cross-sectional views of organic light-emitting display apparatuses according to embodiments.

Referring to <FIG>, the organic light-emitting display apparatus <NUM> not forming part of the claimed invention includes a first substrate <NUM>. The first substrate <NUM> may be a glass substrate or a plastic substrate, each having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and water resistance. In one embodiment not forming part of the claimed invention, since the organic light-emitting display apparatus <NUM> is a top-emission type display apparatus, the first substrate <NUM> may include iron, chromium, manganese, nickel, titanium, molybdenum, stainless steel, an Invar alloy, an Inconel alloy, a Kovar alloy, or any combination thereof.

An organic light-emitting device <NUM> is disposed on the first substrate <NUM>. The organic light-emitting device <NUM> may include: a first electrode; a second electrode facing the first electrode; and an organic layer between the first electrode and the second electrode and including an emission layer. The description of the first electrode, the second electrode, the emission layer, and the organic layer of the organic light-emitting device <NUM> may be understood by referring to the description of the light-emitting device <NUM>.

For example, the first electrode may be an anode, and the material for forming the first electrode may be selected from materials with a high work function to facilitate hole injection. In addition, the first electrode may be a reflective electrode, and the first electrode may include a material selected from magnesium (Mg), silver (Ag), aluminium (Al), aluminium-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), and any combination thereof.

The first electrode may include a transparent electrode material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

The first electrode may include a reflective electrode material, such as magnesium (Mg), silver (Ag), aluminium (Al), aluminium-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), and any combination thereof, and may further include a transparent electrode material such as ITO or IZO.

The first electrode may have a single-layered structure or a multi-layered structure including a transmissive layer and a reflective layer. For example, the first electrode may have a multi-layered structure of ITO/Ag/ITO.

In addition, the first electrode may further include an inclined surface having a predetermined angle with respect to the first substrate <NUM> around the first electrode, so that light emitted from the organic layer in the horizontal direction of the organic light-emitting display apparatus illustrated in <FIG> travels toward the thin film <NUM>. The inclined surface of the first electrode may be disposed on a pixel defining film. In this case, light emitted from the organic layer may be reflected from the inclined surface of the first electrode and travels toward the thin film <NUM>, thereby improving light efficiency of the organic light-emitting display apparatus.

For example, the organic layer may further include a hole transport region between the first electrode and the emission layer and an electron transport region between the emission layer and the second electrode.

For example, the second electrode may be a cathode, and a material for forming the second electrode may be selected from a metal, an alloy, an electrical conductive compound, and any combination thereof, which have a low work function. In addition, the second electrode may be a transmissive electrode or a semi-transmissive electrode, and a material for forming the second electrode may be selected from ITO, IZO, tin oxide (SnO<NUM>), zinc oxide (ZnO), magnesium (Mg), silver (Ag), aluminium (Al), aluminium-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), and any combination thereof.

A thin film <NUM> is disposed on the organic light-emitting device <NUM> on at least one traveling direction of light emitted from the organic light-emitting device <NUM>, and the thin film includes the perovskite compound.

The description of the thin film <NUM> comprising a perovskite compound is the same as described herein.

That the thin film <NUM> is disposed on at least one traveling direction of the light emitted from the organic light-emitting device <NUM> does not exclude a case where other elements are further included between the thin film <NUM> and the organic light-emitting device <NUM>.

A barrier film (not illustrated) may be further included on at least one surface of the thin film <NUM> so as to prevent contact with oxygen or moisture. Since the light conversion layer includes the barrier film, the perovskite compound that is vulnerable to oxygen and/or moisture may be maintained in a stable state.

For example, the barrier film may be formed on a light incidence surface of the thin film <NUM> (that is, a surface which absorbs light emitted from the organic light-emitting device <NUM>) and/or a light exit surface of the thin film <NUM> (that is, a surface from which light exits from the organic light-emitting device <NUM>). The barrier film may surround the entire thin film <NUM>.

The barrier film may include, for example, polyester, polycarbonate, polyolefin, cyclic olefin copolymer (COC), or polyimide.

The barrier film may further include a single-layered or multi-layered inorganic coating layer on the surface thereof. An inorganic material in the inorganic coating layer may include an inorganic oxide, for example, silica, alumina, titania, zirconia, or any combination thereof. Since the inorganic coating layer suppresses penetration of oxygen or moisture, the oxygen and/or moisture blocking function of the barrier film may be further reinforced by the inorganic coating layer.

Referring to <FIG>, an organic light-emitting device <NUM> may emit first light, and a thin film <NUM> may absorb the first light and emit second light. The first light and the second light may have different maximum emission wavelengths.

For example, the maximum emission wavelength of the first light may be less than the maximum emission wavelength of the second light.

In one embodiment, the first light and the second light may be combined to emit white light.

The first light may be blue light, and the second light may be at least one selected from green light, yellow light, and red light, but embodiments of the present disclosure are not limited thereto. For example, the first light may be blue light, and the second light may be yellow light or mixed light of green light and red light, but embodiments of the present disclosure are not limited thereto.

The first light may be ultraviolet (UV) light, the second light may be at least one selected from blue light, green light, and red light, but embodiments of the present disclosure are not limited thereto. For example, the first light may be UV light, and the second light may be mixed light of blue light (for example, light having a wavelength band between about <NUM> to about <NUM>), green light (for example, light having a wavelength band between about <NUM> to about <NUM>), and red light (for example, light having a wavelength band between about <NUM> to about <NUM>), but embodiments of the present disclosure are not limited thereto.

In one embodiment, the organic light-emitting device may emit blue light or UV light.

For example, the thin film <NUM> may include a first perovskite compound <NUM> represented by one of Formulae <NUM> to <NUM> and a second perovskite compound <NUM> represented by one of Formulae <NUM> to <NUM>. The maximum emission wavelengths of the first and second perovskite compounds may be different by differently adjusting the average grain sizes of the first and second perovskite compounds. The grain size of the perovskite compounds can be measured from the TEM images.

The thin film <NUM> may be a monolayer film in which the first and second perovskite compounds are uniformly dispersed. The thin film <NUM> may further include a binder resin <NUM> in which the first and second perovskite compounds are uniformly dispersed. A mixing ratio of the first and second perovskite compounds is not particularly limited and may be controlled in an appropriate range by taking into account desired optical characteristics. The binder resin <NUM> may include, for example, an epoxy resin, a silicone epoxy resin, a silicone resin, a polystyrene resin, a (meth)acrylate resin, or any combination thereof, but embodiments of the present disclosure are not limited thereto.

When the first light is blue light, the first perovskite compound <NUM> may emit red light, and the second perovskite compound <NUM> may emit green light. In this case, the average grain size of the first perovskite compound may be greater than the average grain size of the second perovskite compound and may be, for example, about <NUM> to about <NUM>. The average grain size of the second perovskite compound may be, for example, about <NUM> to about <NUM>.

As described above, the average grain size of the perovskite compound may be different according to the type of the monovalent anion used as X. For example, when the monovalent halide anion is used as X, the energy bandgap may be adjusted and the light-emitting characteristics may be changed by changing the halide anion to I-, Br-, Cl-, or the like.

The first light, the red light emitted from the first perovskite compound, and the green light emitted from the second perovskite compound may be combined to emit white light.

In one embodiment, the organic light-emitting device may emit blue light, and
the thin film may include:.

In one embodiment, referring to <FIG>, a thin film <NUM> may include a first perovskite compound <NUM> represented by one of Formulae <NUM> to <NUM>, a second perovskite compound <NUM> represented by one of Formulae <NUM> to <NUM>, and a third perovskite compound <NUM> represented by one of Formulae <NUM> to <NUM>. The maximum emission wavelengths emitted by the first, second, and third perovskite compounds may be different by differently adjusting the average grain sizes of the first, second, and third perovskite compounds. The thin film <NUM> may be a monolayer film in which the first, second, and third perovskite compounds are uniformly dispersed. The thin film <NUM> may further include a binder resin <NUM> in which the first, second, and third perovskite compounds are uniformly dispersed. A mixing ratio of the first, second, and third perovskite compounds is not particularly limited and may be controlled in an appropriate range by taking into account desired optical characteristics.

When the first light is UV light, the first perovskite compound <NUM> may emit red light, the second perovskite compound <NUM> may emit green light, and the third perovskite compound <NUM> may emit blue light. In this case, the average grain size of the first perovskite compound may be greater than the average grain size of the second perovskite compound and may be, for example, about <NUM> to about <NUM>. The average grain size of the second perovskite compound may be greater than the average grain size of the third perovskite compound and may be, for example, about <NUM> to about <NUM>. The average grain size of the third perovskite compound may be, for example, about <NUM> to about <NUM>. The first light, the red light emitted from the first perovskite compound, the green light emitted from the second perovskite compound, and the blue light emitted from the third perovskite compound may be combined to emit white light. The grain size of the perovskite compounds can be measured from the TEM images.

Referring to <FIG>, a thin film <NUM> may include a first thin film <NUM> and a second thin film <NUM>. An organic light-emitting device <NUM> may emit first light. The first thin film may absorb the first light and emit second light. The second thin film may absorb the first light and/or the second light and emit third light. The first light, the second light, and the third light may have different maximum emission wavelengths.

For example, the maximum emission wavelength of the first light may be less than the maximum emission wavelength of the second light and the maximum emission wavelength of the third light. In addition, the maximum emission wavelength of the second light may be less than the maximum emission wavelength of the third light.

In one embodiment, the first light, the second light, and the third light may be combined to emit white light.

The first light may be blue light, and the second light and the third light may each independently be at least one selected from green light and red light, but embodiments of the present disclosure are not limited thereto. For example, the first light may be blue light, the second light may be green light, and the third light may be red light.

The first light may be UV light, and the second light and the third light may each independently be at least one selected from blue light, cyan light, green light, yellow light, red light, and magenta light, but embodiments of the present disclosure are not limited thereto. For example, the first light may be UV light, the second light may be cyan light, and the third light may be red light. In one embodiment, the first light may be UV light, the second light may be green light, and the third light may be magenta light. In one embodiment, the first light may be UV light, the second light may be blue light, and the third light may be yellow light.

The first thin film <NUM> may include a first perovskite compound represented by one of Formulae <NUM> to <NUM>, and the second thin film <NUM> may include a second perovskite compound represented by one of Formulae <NUM> to <NUM>, but embodiments of the present disclosure are not limited thereto.

For example, the first light may be blue light, the first perovskite compound may emit green light, and the second perovskite compound may emit red light, but embodiments of the present disclosure are not limited thereto.

Referring to <FIG>, a thin film <NUM> may include a first thin film <NUM>, a second thin film <NUM>, and a third thin film <NUM>. An organic light-emitting device <NUM> may emit first light. The first thin film <NUM> may absorb the first light and emit second light. The second thin film <NUM> may absorb the first light and/or the second light and emit third light. The third thin film <NUM> may absorb the first light, the second light, and/or the third light and emit fourth light. The first light, the second light, the third light, and the fourth light may have different maximum emission wavelengths.

For example, the maximum emission wavelength of the first light may be less than the maximum emission wavelength of the second light, the maximum emission wavelength of the third light, and the maximum emission wavelength of the fourth light, but embodiments of the present disclosure are not limited thereto. In addition, the maximum emission wavelength of the second light may be less than the maximum emission wavelength of the third light and the maximum emission wavelength of the fourth light, but embodiments of the present disclosure are not limited thereto. In addition, the maximum emission wavelength of the third light may be less than the maximum emission wavelength of the fourth light, but embodiments of the present disclosure are not limited thereto.

In one embodiment, the first light, the second light, the third light, and the fourth light may be combined to emit white light.

The first light may be blue light, and the second light, the third light, and the fourth light may each independently be at least one selected from green light and red light, but embodiments of the present disclosure are not limited thereto.

The first light may be UV light, and the second light, the third light, and the fourth light may each independently be at least one selected from blue light, green light, and red light, but embodiments of the present disclosure are not limited thereto. For example, the first light may be UV light, the second light may be blue light, the third light may be green light, and the fourth light may be red light.

The first thin film <NUM> may include a first perovskite compound represented by one of Formulae <NUM> to <NUM>, the second thin film <NUM> may include a second perovskite compound represented by one of Formula <NUM>, and the third thin film <NUM> may include a third perovskite compound represented by one of Formulae <NUM> to <NUM>, but embodiments of the present disclosure are not limited thereto.

For example, the first light may be UV light, the first perovskite compound may emit blue light, the second perovskite compound may emit green light, and the third perovskite compound may emit red light, but embodiments of the present disclosure are not limited thereto.

The above description has been provided for the top-emission type light-emitting device and may be provided for a bottom-emission type light-emitting device. In this case, as opposed to the top-emission type light-emitting device, a first electrode may be a semi-transmissive electrode or a transparent electrode, and a second electrode may be a reflective electrode. In this case, a thin film including the perovskite compound represented by one of Formulae <NUM> to <NUM> may be disposed on a substrate.

<FIG> is a schematic cross-sectional view of an organic light-emitting display apparatus <NUM> according to an embodiment.

Referring to <FIG>, a color filter <NUM> may be disposed on at least one traveling direction of light emitted from a thin film <NUM>.

A first substrate <NUM> may include a plurality of sub-pixel regions, and the color filter <NUM> may include a plurality of color filter regions respectively corresponding to the plurality of sub-pixel regions.

A pixel defining film <NUM> may be formed between the sub-pixel regions to define the sub-pixel regions.

The color filter <NUM> may include light blocking patterns <NUM> between the color filter regions.

The color filter regions may include a first color filter region <NUM> emitting first color light, a second color filter region <NUM> emitting second color light, and a third color filter region <NUM> emitting third color light. The first color light, the second color light, and the third color light may be different from one another. For example, the first color light may be red light, the second color light may be green light, and the third color light may be blue light, but embodiments of the present disclosure are not limited thereto.

The organic light-emitting display apparatuses illustrated in <FIG> are an example of the electronic apparatus, and the electronic apparatus may have various known forms. To this end, various known configurations may be further included.

Hereinafter, a lighting apparatus according to an embodiment will be described.

The lighting apparatus includes: a light source; and a light conversion layer that absorbs at least part of light emitted from the light source and emits light having a wavelength band different from that of the absorbed light, wherein the light conversion layer includes the perovskite compound.

The perovskite compound may absorb at least part of light emitted from the light source. In this case, the type of the light source is not particularly limited. For example, the light source may receive an external voltage and emit light. In one embodiment, the light source may be a fluorescent lamp, a light emitting diode (LED), an organic light emitting diode (OLED), a quantum dot light emitting diode (QLED), or any combination thereof. The fluorescent lamp may include, for example, a cold cathode fluorescent lamp (CCFL) and/or an external electrode fluorescent lamp (EEFL), but embodiments of the present disclosure are not limited thereto.

The light source may emit blue light (for example, light having a wavelength band between about <NUM> to about <NUM>) or UV light (for example, light having a wavelength band between about <NUM> to about <NUM>). For example, the light source may be a blue LED that emits blue light or a UV LED that emits UV light, but embodiments of the present disclosure are not limited thereto.

In one embodiment, the light source may emit blue light, and the light conversion layer may include a perovskite compound that absorbs blue light emitted from the light source and emits light having a wavelength band different from that of the blue light.

For example, the light source may emit blue light, and the light conversion layer may include a perovskite compound that absorbs the blue light and emits yellow light (for example, light having a wavelength band between about <NUM> to about <NUM>). In this case, the blue light emitted from the light source and the yellow light emitted from the perovskite compound may be combined to emit white light.

The light conversion layer may be thin film including the perovskite compound. For example, the light conversion layer may be understood by referring to the description of the thin film provided herein.

In one embodiment, the light conversion layer may be a thin film in which the perovskite compound that emits the yellow light is stacked in a monocrystal form.

In one or more embodiments, the light conversion layer may be a thin film including the perovskite compound emitting the yellow light and having a nanostructure of less than about <NUM>. The nanostructure may be a particle form, for example, nanoparticles, nanorods, nanowires, nanotubes, branched nanostructures, nanotetrapods, nanotripods, or nanobipods. The nanostructure may be surrounded by, for example, at least one ligand or matrix resin. The ligand or matrix resin may improve the stability of the perovskite nanostructure and may protect the perovskite nanostructure from harmful external conditions including high temperature, high strength, external gas or moisture, or the like. The ligand may be, for example, a molecule having an amine group (oleylamine, triethylamine, hexylamine, naphthylamine, or the like) or polymer, a molecule having a carboxyl group (oleic acid or the like) or polymer, a molecule having a thiol group (butanethiol, hexanethiol, dodecanethiol, or the like) or polymer, a molecule having a pyridine group (pyridine or the like) or polymer, a molecule having a phosphine group (triphenylphosphine or the like), a molecule having a phosphine oxide group (trioctylphosphine oxide or the like), a molecule having a carbonyl group (alkyl ketone or the like), a molecule having a benzene ring (benzene, styrene, or the like) or polymer, or a molecule having a hydroxy group (butanol, hexanol, or the like) or polymer. The matrix resin may include, for example, an epoxy resin, a silicone epoxy resin, a silicone resin, a polystyrene resin, a (meth)acrylate resin, or any combination thereof, but embodiments of the present disclosure are not limited thereto.

In one embodiment, the light source may emit blue light, and the light conversion layer may include a first perovskite compound that absorbs the blue light and emits green light (for example, light having a wavelength band between about <NUM> to about <NUM>) and a second perovskite compound that absorbs the blue light and/or the green light and emits red light (for example, light having a wavelength band between about <NUM> to about <NUM>). In this case, the blue light emitted from the light source, the green light emitted from the first perovskite compound, and the red light emitted from the second perovskite compound may be combined to emit white light.

In one embodiment, the light source may emit blue light, and the light conversion layer may include a monofilm in which the first perovskite compound that emits the green light and the second perovskite compound that emits the red light are uniformly dispersed. In this case, both the first perovskite compound and the second perovskite compound may have a nanostructure form.

In one or more embodiments, the light source may emit blue light, and the light conversion layer may include: a first layer including a first perovskite compound that absorbs the blue light and emits green light; and a second layer including a second perovskite compound that absorbs the blue light and/or the green light and emits red light. In this case, the first layer may be disposed so that at least part of light emitted from the light source is incident on the first layer, and the second layer may be disposed so that light emitted from the light source and passing through the first layer and/or light emitted from the first layer is incident on the second layer. The first layer and the second layer may each independently be a thin film in which the perovskite compound is stacked in a monocrystal form, or a thin film including the perovskite compound in a nanostructure form.

In one or more embodiments, the light source may emit UV light, and the light conversion layer may include a perovskite compound that absorbs the UV light emitted from the light source and emits light having a wavelength band different from that of the UV light.

For example, the light source may emit UV light, and the light conversion layer may include: a first perovskite compound that absorbs the UV light and emits blue light; a second perovskite compound that absorbs the UV light and/or the blue light and emits green light; and a third perovskite compound that absorbs the UV light, the blue light, and/or the green light and emits red light. In this case, the blue light emitted from the first perovskite compound, the green light emitted from the second perovskite compound, and the red light emitted from the third perovskite compound may be combined to emit white light.

In one embodiment, the light source may emit UV light, and the light conversion layer may be a monofilm in which a first perovskite compound that absorbs the UV light and emits blue light, a second perovskite compound that absorbs the UV light and/or the blue light and emits green light, and a third perovskite compound that absorbs the UV light, the blue light, and/or the green light and emits red light are uniformly dispersed. In this case, the first perovskite compound, the second perovskite compound, and the third perovskite compound may have a nanostructure form.

In one or more embodiments, the light source may emit UV light, and the light conversion layer may include: a first layer including a first perovskite compound that absorbs the UV light and emits blue light and a second perovskite compound that absorbs the UV light and/or the blue light and emits green light; and a second layer including a third perovskite compound that absorbs the UV light, the blue light, and/or the green light and emits red light. In this case, the first layer may be disposed so that at least part of light emitted from the light source is incident on the first layer, and the second layer may be disposed so that light emitted from the light and passing through the first layer and/or light emitted from the first layer is incident on the second layer. The first layer may be a thin film including the first and second perovskite compounds in the nanostructure form, and the second layer may be a thin film in which the third perovskite compound is stacked in a monocrystal form, or a thin film including the third perovskite compound in a nanostructure form.

In one embodiment, the light source may emit UV light, and the light conversion layer may include: a first layer including a first perovskite compound that absorbs the UV light and emits blue light; and a second layer including a second perovskite compound that absorbs the UV light and/or the blue light and emits green light and a third perovskite compound that absorbs the UV light, the blue light, and/or the green light and emits red light. In this case, the first layer may be disposed so that at least part of light emitted from the light source is incident on the first layer, and the second layer may be disposed so that light emitted from the light source and passing through the first layer and/or light emitted from the first layer is incident on the second layer. The first layer may be a thin film in which the first perovskite compound is stacked in a monocrystal form, or a thin film including the first perovskite compound in a nanostructure form, and the second layer may be a thin film including the second and third perovskite compounds in a nanostructure form.

In one or more embodiments, the light source may emit UV light, and the light conversion layer may include: a first layer including a first perovskite compound that absorbs the UV light and emits blue light; a second layer including a second perovskite compound that absorbs the UV light and/or the blue light and emits green light; and a third layer including a third perovskite compound that absorbs the UV light, the blue light, and/or the green light and emits red light. In this case, the first layer may be disposed so that at least part of light emitted from the light source is incident on the first layer, the second layer may be disposed so that light emitted from the light source and passing through the first layer and/or light emitted from the first layer are incident on the second layer, and the third layer may be disposed so that light emitted from the light source and passing through the first layer and the second layer, light emitted from the first layer and passing through the second layer, and/or light emitted from the second layer are incident on the third layer. The first layer, the second layer, and the third layer may each independently be a thin film in which the perovskite compound is stacked in a monocrystal form, or a thin film including the perovskite compound in a nonastructure form.

The thicknesses of the layers included in the light conversion layers, the mixing ratios of the perovskite compounds when the light conversion layer includes at least two perovskite compounds, and the like are not particularly limited and may be set in appropriate ranges by taking into account desired optical characteristics.

The layer(s) including the perovskite compound included in the light conversion layer may be synthesized according to a known synthesis method. For example, the layer(s) including the perovskite compound may be synthesized by referring to the synthesis method of the thin film including the perovskite compound.

In one embodiment, the layer(s) including the perovskite compound included in the light conversion layer may be manufactured by providing a mixture including a perovskite compound, which is mixed on a matrix resin, on a predetermined substrate and performing drying or thermal treatment thereon. Various modifications may be made thereto.

In one embodiment, a barrier film may be further included on at least one surface of the light conversion layer so as to prevent contact with oxygen or moisture. Since the light conversion layer includes the barrier film, the perovskite compound may be maintained in a stable state.

For example, the barrier film may be formed on a light incidence surface of the light conversion layer (that is, a surface which absorbs light emitted from the light source) and/or a light exit surface of the light conversion layer (that is, a surface from which light exits from the light conversion layer). In one embodiment, the barrier film may surround the entire light conversion layer.

The light conversion layer is disposed so that at least part of light emitted from the light source is incident on the light conversion layer.

That the light conversion layer is disposed so that light emitted from the light source is incident on the light conversion layer does not exclude a case where other means is further included between the light source and the light conversion layer. Therefore, other means may be further included between the light source and the light conversion layer.

For example, the light source may directly contact the light conversion layer. Therefore, light emitted from the light source may be directly incident on the light conversion layer.

In one embodiment, the light source may be separated from the light conversion layer. For example, the light source may be separated from the light conversion layer, and other means may be included between the light source and the light conversion layer. That other means is included between the light source and the light conversion layer includes a case where the light source faces the light conversion layer and other means is disposed therebetween, and a case where other means is disposed on a traveling path of light emitted from the light source and incident on the light conversion layer.

The means may be, for example, a light guide plate that guides light, a diffusion plate that diffuses light, a predetermined optical sheet that improves optical characteristics such as luminance, a reflective film that reflects light from the light source so as to improve externally extracted optical efficiency, or any combination thereof.

The optical sheet may be, for example, a prism sheet, a micro lens sheet, a brightness enhancement sheet, or any combination thereof, but embodiments of the present disclosure are not limited thereto. Therefore, the optical sheet may include sheets having various functions.

In one embodiment, the light guide plate, the diffusion plate, the prism sheet, the micro lens sheet, the brightness enhancement sheet, the reflective film, or any combination thereof may be disposed between the light source and the light conversion layer. That the light guide plate, the diffusion plate, the prism sheet, the micro lens sheet, the brightness enhancement sheet, the reflective film, or any combination thereof is disposed between the light source and the light conversion layer means that the light guide plate, the diffusion plate, the prism sheet, the micro lens sheet, the brightness enhancement sheet, the reflective film, or any combination thereof is disposed on the traveling path of light emitted from the light source and incident on the light conversion layer.

In one or more embodiments, the light guide plate, the diffusion plate, the prism sheet, the micro lens sheet, the brightness enhancement sheet, the reflective film, or any combination thereof may be disposed on the light conversion layer.

For example, the lighting apparatus may further include the diffusion plate on the light source. In this case, the light conversion layer may be disposed between the light source and the diffusion plate, or may be disposed on the diffusion plate. The diffusion plate may be separated from the light conversion layer, or the diffusion plate may directly contact the light conversion layer.

In addition, the lighting apparatus may further include, in addition to the diffusion plate, a predetermined optical sheet. The lighting apparatus including the diffusion plate and the optical sheet may have, for example, a stacked structure of the light source/light conversion layer/diffusion layer/optical sheet, the light source/diffusion plate/light conversion layer/optical sheet, or the light source/diffusion plate/light conversion layer, but embodiments of the present disclosure are not limited thereto.

In one embodiment, the lighting apparatus may further include a light guide plate that guides light. The light guide plate may be disposed on the light source, or may be disposed on one side surface of the light source. In this case, the light conversion layer may be disposed between the light source and the light guide plate, or may be disposed on the light guide plate. The light guide plate may be separated from the light conversion layer, or the light guide plate may directly contact the light conversion layer.

In addition, the lighting apparatus may further include, in addition to the light guide plate on one surface of the light source, a diffusion plate and/or an optical sheet. For example, the diffusion plate and the optical sheet may be stacked on the light guide plate in this stated order. In this case, the light conversion layer may be disposed between the light source and the light guide plate, between the light guide plate and the diffusion plate, between the diffusion plate and the optical sheet, or on the optical sheet.

In one embodiment, the lighting apparatus may further include a reflective film that reflects light. The reflective film may be disposed between the light source and the light conversion layer, or may be disposed on the light conversion layer. The reflective film may be separated from the light conversion layer, or the reflective film may directly contact the light conversion layer.

In addition, the lighting apparatus may include a light conversion layer, a light guide plate, and a reflective film. In this case, the light guide plate may be disposed between the light conversion layer and the reflective film, but embodiments of the present disclosure are not limited thereto.

<FIG> are schematic views of lighting apparatuses <NUM> and <NUM> according to embodiments.

As illustrated in <FIG>, light sources <NUM>, <NUM>, <NUM>, and <NUM> and light conversion layers <NUM> and <NUM> in the lighting apparatuses are disposed so that light emitted from the light sources <NUM>, <NUM>, <NUM>, and <NUM> is incident on the light conversion layers <NUM> and <NUM>.

In <FIG>, the light sources <NUM>, <NUM>, and <NUM> may be disposed below the light conversion layer <NUM>, so that light emitted upward from the light sources <NUM>, <NUM>, and <NUM> is incident on the light conversion layer <NUM>.

In <FIG>, the light source <NUM> is disposed on the side of the light conversion layer <NUM>. In this case, like the light guide plate <NUM> that guides light, other means may be included so that light emitted from the light source <NUM> is more efficiently incident on the light conversion layer <NUM>.

The lighting apparatuses illustrated in <FIG> are merely an example, and the lighting apparatuses may have various known forms. To this end, various known configurations may be further included.

The above-described lighting apparatuses may be used for various purposes. For example, the lighting apparatuses may be used as backlight units of liquid crystal displays (LCDs). In addition, the lighting apparatuses may be used indoor or outdoor lighting, stage lighting, decorative lighting, and the like. The applications of the lighting apparatuses are not limited thereto.

Hereinafter, thin films and electronic apparatuses according embodiments will be described in more detail.

Films of Examples <NUM> to <NUM> and Comparative Examples <NUM> to <NUM> were manufactured by perovskite compounds shown in Table <NUM> on a glass substrate to a thickness of <NUM>.

The PLQY and FWHM of the films manufactured according to Examples <NUM> to <NUM> and Comparative Examples <NUM> to <NUM> were evaluated, and results thereof are shown in Table <NUM>. The PLQY of each film was evaluated by using a Hamamatsu Photonics absolute PL quantum yield measurement system including a xenon light source, a monochromator, a photonic multichannel analyzer, and an integrating sphere and employing PLQY measurement software (Hamamatsu Photonics, Ltd. , Shizuoka, Japan), and the FWHM each film was evaluated by analyzing a PL spectrum by using ISC PC1 Spectrofluorometer.

It is confirmed from Table <NUM> that the films of Examples <NUM> to <NUM> show PLQY and FWHM suitable for use in organic light-emitting devices. In particular, in the condition that the compositions of a metal and halogen X are the same, the film using the perovskite compound including Sm showed high PLQY and small FWHM, as compared with the film using the perovskite compound including Pb.

As a substrate and an anode, a glass substrate, in which a Corning <NUM>Ω/cm<NUM> (<NUM>) ITO was formed, was cut to a size of <NUM> x <NUM> x <NUM>, sonicated with acetone, isopropyl alcohol, and pure water each for <NUM> minutes, and then cleaned by exposure to ultraviolet rays and ozone for <NUM> minutes. Then, the glass substrate was provided to a vacuum deposition apparatus.

Cul was deposited on the ITO anode to form a hole transport layer having a thickness of <NUM>, thereby forming a hole transport region.

An emission layer including CsSmI<NUM> and having a thickness of <NUM> was formed on the hole transport region.

TPBi was deposited on the emission layer to form an electron transport layer having a thickness of <NUM>, and Rbl and Yb were co-deposited on the electron transport layer at a volume ratio of <NUM>:<NUM> to form an electron injection layer having a thickness of <NUM>, thereby forming an electron transport region.

Ag and Mg were co-deposited on the electron transport region at a volume ratio of <NUM>:<NUM> to form a cathode having a thickness of <NUM>, thereby completing the manufacture of a light-emitting device having a structure of ITO (<NUM>) / Cul (<NUM>) / CsSmI<NUM> (<NUM>) / TPBi (<NUM>) / Rbl:Yb (<NUM>) / AgMg (Mg <NUM> vol%, <NUM>).

Light-emitting devices were manufactured in the same manner as in Reference Example <NUM>, except that Compounds shown in Table <NUM> were each used instead of CsSmI<NUM> in forming an emission layer.

The driving voltage (at <NUM> mA/cm<NUM>), external quantum efficiency, and current efficiency of the organic light-emitting devices manufactured according to Reference Examples <NUM> to <NUM> and Comparative Examples <NUM> and <NUM> were measured by using Keithley MU <NUM> and a luminance meter PR650, and results thereof are shown in Table <NUM>.

It is confirmed from Table <NUM> that the organic light-emitting devices of Reference Examples <NUM> to <NUM> have significantly higher current efficiency, as compared with the organic light-emitting devices of Comparative Examples <NUM> and <NUM>.

A light conversion layer was formed by forming a first layer including CsSmBrI<NUM> and having a thickness of <NUM> on a glass substrate and forming a second layer including CsSmBr<NUM> and having a thickness of <NUM> on the first layer.

A solution including InP/ZnS (λem = <NUM>) quantum dots was spin-coated on a glass substrate at a speed of <NUM>,<NUM> rpm for <NUM> seconds to form a first layer having a thickness of <NUM>, and a solution including InP/ZnS (λem = <NUM>) quantum dots was spin-coated on the first layer at a speed of <NUM>,<NUM> rpm to <NUM>,<NUM> rpm for <NUM> seconds to form a second layer having a thickness of <NUM>, thereby forming a light conversion layer.

With respect to the light conversion layers manufactured according to Example <NUM> and Comparative Example <NUM>, and Comparative Example <NUM> in which the light conversion layer was not formed, the color reproducibility of each lighting apparatus was evaluated by using a blue LCD as a light source and using the NTSC <NUM> standard, and results thereof are shown in Table <NUM>.

In addition, with respect to the light conversion layers manufactured according to Example <NUM> and Comparative Example <NUM>, and Comparative Example <NUM> in which the light conversion layer was not formed, the color reproducibility of each lighting apparatus was evaluated by using a blue LED as a light source and using the NTSC <NUM> standard, and results thereof are shown in Table <NUM>.

It is confirmed from Tables <NUM> and <NUM> that the lighting apparatus including the light conversion layer of Example <NUM> has excellent color reproducibility, as compared with Comparative Examples <NUM> and <NUM>.

An electronic apparatus including a thin film including the perovskite compound may have high efficiency and/or a long lifespan. A lighting apparatus including a light conversion layer including the perovskite compound may have high color reproducibility.

Claim 1:
A lighting apparatus (<NUM>, <NUM>) comprising:
a light source (<NUM>, <NUM>, <NUM>, <NUM>); and
a light conversion layer (<NUM>, <NUM>) that absorbs at least part of light emitted from the light source (<NUM>, <NUM>, <NUM>, <NUM>) and emits light having a wavelength band different from that of the absorbed light,
characterised by the light conversion layer (<NUM>, <NUM>) comprising a perovskite compound (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) represented by one of Formulae <NUM> to <NUM>: <MAT> <MAT> <MAT> <MAT>
wherein, in Formulae <NUM> to <NUM>,
A is at least one monovalent organic-cation, a monovalent inorganic cation, or any combination thereof,
B<NUM> is a Sm<NUM>+ ion,
B<NUM> is at least one divalent inorganic cation and does not include a Sm<NUM>+ ion,
n1 is a real number satisfying <NUM> < n1 ≤ <NUM>,
n2 is a real number satisfying <NUM> < n2 ≤ <NUM>, and
X is at least one monovalent anion.