U.S. patent application number 14/303562 was filed with the patent office on 2015-06-18 for organic light emitting display device and fabricating method thereof.
The applicant listed for this patent is SAMSUNG DISPLAY CO., LTD.. Invention is credited to Eunji Choi, Woosik Jeon, Seil Kim, Sung Soo Lee, Yonghan Lee, Okkeun Song.
Application Number | 20150171371 14/303562 |
Document ID | / |
Family ID | 53369582 |
Filed Date | 2015-06-18 |
United States Patent
Application |
20150171371 |
Kind Code |
A1 |
Jeon; Woosik ; et
al. |
June 18, 2015 |
ORGANIC LIGHT EMITTING DISPLAY DEVICE AND FABRICATING METHOD
THEREOF
Abstract
An organic light emitting display (OLED) device includes: an
insulating substrate; a first electrode on the insulating
substrate; a second electrode on the first electrode; a
light-emitting layer between the first electrode and the second
electrode; a hole common layer between the first electrode and the
light-emitting layer; an electron common layer between the second
electrode and the light-emitting layer; and a scattering layer on
the insulating substrate and having a non-planar surface, wherein
the scattering layer includes at least one of benzene, naphthalene,
anthracene, tetracene, pentacene, amine, benzidine, biphenyl,
carbazole, pyridine, bipyridine, imidazole, phenanthroline,
phenylborane, pyrimidine, or triazine, and the base material of the
scattering layer includes a substituent including at least one of a
benzoyl group, a carboxyl group, an aminophenoxyl group, a
tricabonate group, or a styryl group.
Inventors: |
Jeon; Woosik; (Hwaseong-si,
KR) ; Kim; Seil; (Hwaseong-si, KR) ; Lee; Sung
Soo; (Suwon-si, KR) ; Lee; Yonghan;
(Seongnam-si, KR) ; Song; Okkeun; (Hwaseong-si,
KR) ; Choi; Eunji; (Bucheon-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SAMSUNG DISPLAY CO., LTD. |
Yongin-City |
|
KR |
|
|
Family ID: |
53369582 |
Appl. No.: |
14/303562 |
Filed: |
June 12, 2014 |
Current U.S.
Class: |
257/40 ;
438/29 |
Current CPC
Class: |
H01L 51/5268 20130101;
H01L 51/5253 20130101; H01L 51/5275 20130101 |
International
Class: |
H01L 51/52 20060101
H01L051/52; H01L 51/56 20060101 H01L051/56 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 16, 2013 |
KR |
10-2013-0156528 |
Claims
1. An organic light emitting display (OLED) device, comprising: an
insulating substrate; a first electrode on the insulating
substrate; a second electrode on the first electrode; a
light-emitting layer between the first electrode and the second
electrode; a hole common layer between the first electrode and the
light-emitting layer; an electron common layer between the second
electrode and the light-emitting layer; and a scattering layer on
the insulating substrate and having a non-planar surface, wherein
the scattering layer comprises at least one of benzene,
naphthalene, anthracene, tetracene, pentacene, amine, benzidine,
biphenyl, carbazole, pyridine, bipyridine, imidazole,
phenanthroline, phenylborane, pyrimidine, or triazine, and a base
material of the scattering layer comprises a substituent comprising
at least one of a benzoyl group, a carboxyl group, an aminophenoxyl
group, a tricabonate group, or a styryl group.
2. The device of claim 1, wherein the scattering layer is between
two adjacent ones among the first electrode, the hole common layer,
the light-emitting layer, the electron common layer, and the second
electrode, or is on the second electrode.
3. The device of claim 1, wherein the non-planar surface comprises
a plurality of concavo-convex portions.
4. The device of claim 1, wherein the base material comprises a
substitution position occupied by the substituent.
5. The device of claim 1, wherein the hole common layer comprises:
a hole injection layer on the first electrode; and a hole transport
layer on the hole injection layer, wherein the scattering layer is
between the hole injection layer and the hole transport layer.
6. The device of claim 1, wherein the electron common layer
comprises at least two of: a hole blocking layer on the
light-emitting layer; an electron transport layer on the hole
blocking layer; and an electron injection layer on the electron
transport layer, wherein the scattering layer is between adjacent
two of the hole blocking layer, the electron transport layer, or
the electron injection layer.
7. The device of claim 1, wherein the scattering layer insulates
the first electrode, the hole common layer, the light-emitting
layer, the electron common layer, and the second electrode from
external contaminants.
8. The device of claim 1, further comprising an encapsulation layer
on the second electrode to insulate the first electrode, the hole
common layer, the light-emitting layer, the electron common layer,
and the second electrode from external contaminants.
9. The device of claim 8, wherein at least one of the first
electrode, the hole common layer, the light-emitting layer, the
electron common layer, the second electrode, or the encapsulation
layer is on the scattering layer, thereby having an uneven surface
with concavo-convex portions.
10. The device of claim 1, further comprising a charge generation
layer configured to supply electric charges into the light-emitting
layer, wherein the light-emitting layer comprises a first
light-emitting layer and a second light-emitting layer spaced apart
from each other by the charge generation layer, and the scattering
layer is between the first light-emitting layer and the charge
generation layer or between the second light-emitting layer and the
charge generation layer.
11. The device of claim 10, wherein the hole common layer
comprises: a first hole common layer between the first electrode
and the first light-emitting layer; and a second hole common layer
between the charge generation layer and the second light-emitting
layer, wherein the electron common layer comprises: a first
electron common layer between the charge generation layer and the
first light-emitting layer; and a second electron common layer
between the second electrode and the second light-emitting
layer.
12. The device of claim 11, wherein each of the first hole common
layer and the second hole common layer comprises: a hole injection
layer; and a hole transport layer on the hole injection layer,
wherein the scattering layer is between the hole injection layer
and the hole transport layer.
13. The device of claim 11, wherein each of the first electron
common layer and the second electron common layer comprises at
least two of: a hole blocking layer; an electron transport layer on
the hole blocking layer; and an electron injection layer on the
electron transport layer, wherein the scattering layer is between
adjacent two of the hole blocking layer, the electron transport
layer, and the electron injection layer.
14. A method of fabricating an organic light emitting display
(OLED) device, comprising: forming a first electrode on an
insulating substrate; forming a hole common layer on the first
electrode; forming a light-emitting layer on the hole common layer;
forming an electron common layer on the light-emitting layer;
forming a second electrode on the electron common layer; and
forming a scattering layer with an uneven surface, on the
insulating substrate, wherein the scattering layer comprises at
least one of benzene, naphthalene, anthracene, tetracene,
pentacene, amine, benzidine, biphenyl, carbazole, pyridine,
bipyridine, imidazole, phenanthroline, phenylborane, pyrimidine, or
triazine, and a base material of the scattering layer comprises a
substituent comprising at least one of a benzoyl group, a carboxyl
group, an aminophenoxyl group, a tricabonate group, or a styryl
group.
15. The method of claim 14, further comprising forming the
scattering layer between adjacent two of the insulating substrate,
the first electrode, the hole common layer, the light-emitting
layer, the electron common layer, and the second electrode, or
after the forming of the second electrode.
16. The method of claim 14, wherein the forming of the scattering
layer is performed using a thermal deposition process or an
electron-beam deposition process.
17. The method of claim 14, wherein the base material comprises a
substitution position occupied by the substituent.
18. The method of claim 14, wherein the insulating substrate, the
first electrode, the hole common layer, the light-emitting layer,
the electron common layer, the second electrode, and the scattering
layer are formed using a same deposition technology.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This patent application claims priority to and the benefit
of Korean Patent Application No. 10-2013-0156528, filed on Dec. 16,
2013, in the Korean Intellectual Property Office, the entire
content of which is hereby incorporated by reference.
BACKGROUND
[0002] 1. Field
[0003] Aspects of example embodiments of the inventive concept
relate to an organic light emitting display device and a
fabricating method thereof.
[0004] 2. Description of the Related Art
[0005] Due to its self-luminous property, an organic light emitting
display (OLED) apparatus generally does not utilize an additional
light source and has the characteristic of enabling electronic
products to be relatively small and light compared to electronic
devices utilizing other display devices. Further, OLED devices may
have relatively lower power consumption, higher brightness, and
higher reaction rate compared to other display devices, and thus,
OLED devices have received attention as next-generation display
devices.
[0006] OLED devices include an anode, an organic light emitting
layer, and a cathode. Holes and electrons injected from the anode
and the cathode, respectively, are combined with each other in the
organic light emitting layer of the OLED device to produce
excitons. Light is emitted from the organic light emitting layer,
when the excitons are transited from an excited state to a ground
state.
[0007] Further, the light emitted from the organic light emitting
layer may be reflected by an interface between adjacent layers,
thereby causing a resonance phenomenon. However, as the result of
the resonance, the OLED device may suffer from a
viewing-angle-dependent color shift.
SUMMARY
[0008] Aspects of example embodiments of the inventive concept
include an organic light emitting display (OLED) device having
relatively high light extraction efficiency and a fabricating
method thereof.
[0009] Aspects of example embodiments of the inventive concept
include an OLED device, in which resonance and color shift can be
suppressed or reduced.
[0010] Aspects of example embodiments of the inventive concept
include a method of forming a scattering layer of an OLED
device.
[0011] According to aspects of example embodiments of the inventive
concept, an OLED device includes an insulating substrate; a first
electrode on the insulating substrate; a second electrode on the
first electrode; a light-emitting layer between the first electrode
and the second electrode; a hole common layer between the first
electrode and the light-emitting layer; an electron common layer
between the second electrode and the light-emitting layer; and a
scattering layer on the insulating substrate and having a
non-planar surface, wherein the scattering layer includes at least
one of benzene, naphthalene, anthracene, tetracene, pentacene,
amine, benzidine, biphenyl, carbazole, pyridine, bipyridine,
imidazole, phenanthroline, phenylborane, pyrimidine, or triazine,
and a base material of the scattering layer includes a substituent
including at least one of a benzoyl group, a carboxyl group, an
aminophenoxyl group, a tricabonate group, or a styryl group.
[0012] The scattering layer may be between two adjacent ones among
the first electrode, the hole common layer, the light-emitting
layer, the electron common layer, and the second electrode, or may
be on the second electrode.
[0013] The non-planar surface may include a plurality of
concavo-convex portions.
[0014] The base material may include a substitution position
occupied by the substituent.
[0015] The hole common layer may include: a hole injection layer on
the first electrode; and a hole transport layer on the hole
injection layer, and the scattering layer may be between the hole
injection layer and the hole transport layer.
[0016] The electron common layer may include at least two of: a
hole blocking layer on the light-emitting layer; an electron
transport layer on the hole blocking layer; and an electron
injection layer on the electron transport layer, and the scattering
layer may be between adjacent two of the hole blocking layer, the
electron transport layer, or the electron injection layer.
[0017] The scattering layer may insulates the first electrode, the
hole common layer, the light-emitting layer, the electron common
layer, and the second electrode from external contaminants.
[0018] The OLED device may further include an encapsulation layer
on the second electrode which may insulate the first electrode, the
hole common layer, the light-emitting layer, the electron common
layer, and the second electrode from external contaminants.
[0019] At least one of the first electrode, the hole common layer,
the light-emitting layer, the electron common layer, the second
electrode, or the encapsulation layer may be on the scattering
layer, and may have an uneven surface with concavo-convex
portions.
[0020] The OLED device may further include a charge generation
layer configured to supply electric charges into the light-emitting
layer, and the light-emitting layer may include a first
light-emitting layer and a second light-emitting layer spaced apart
from each other by the charge generation layer, and the scattering
layer may be between the first light-emitting layer and the charge
generation layer or between the second light-emitting layer and the
charge generation layer.
[0021] The hole common layer may include: a first hole common layer
between the first electrode and the first light-emitting layer; and
a second hole common layer between the charge generation layer and
the second light-emitting layer, and the electron common layer may
include: a first electron common layer between the charge
generation layer and the first light-emitting layer; and a second
electron common layer between the second electrode and the second
light-emitting layer.
[0022] Each of the first hole common layer and the second hole
common layer may include: a hole injection layer; and a hole
transport layer on the hole injection layer, and the scattering
layer is between the hole injection layer and the hole transport
layer.
[0023] Each of the first electron common layer and the second
electron common layer may include at least two of: a hole blocking
layer; an electron transport layer on the hole blocking layer; and
an electron injection layer on the electron transport layer, and
the scattering layer may be between adjacent two of the hole
blocking layer, the electron transport layer, and the electron
injection layer.
[0024] According to aspects of embodiments of the present
invention, a method of fabricating an OLED device includes: forming
a first electrode on an insulating substrate; forming a hole common
layer on the first electrode; forming a light-emitting layer on the
hole common layer; forming an electron common layer on the
light-emitting layer; forming a second electrode on the electron
common layer; and forming a scattering layer with an uneven
surface, on the insulating substrate, wherein the scattering layer
comprises at least one of benzene, naphthalene, anthracene,
tetracene, pentacene, amine, benzidine, biphenyl, carbazole,
pyridine, bipyridine, imidazole, phenanthroline, phenylborane,
pyrimidine, or triazine, and a base material of the scattering
layer comprises a substituent comprising at least one of a benzoyl
group, a carboxyl group, an aminophenoxyl group, a tricabonate
group, or a styryl group.
[0025] The method may further include forming the scattering layer
between adjacent two of the insulating substrate, the first
electrode, the hole common layer, the light-emitting layer, the
electron common layer, and the second electrode, or on the second
electrode.
[0026] The forming of the scattering layer may be performed using a
thermal deposition process or an electron-beam deposition
process.
[0027] The base material may include a substitution position
occupied by the substituent.
[0028] The insulating substrate, the first electrode, the hole
common layer, the light-emitting layer, the electron common layer,
the second electrode, and the scattering layer may be formed using
a same deposition technology.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Example embodiments will be more clearly understood from the
following brief description taken in conjunction with the
accompanying drawings. The accompanying drawings represent
non-limiting, example embodiments as described herein.
[0030] FIG. 1 is a sectional view schematically illustrating an
OLED device, according to example embodiments of the inventive
concept.
[0031] FIG. 2 is a sectional view illustrating one of pixels
constituting the OLED device of FIG. 1.
[0032] FIG. 3 is an image showing an uneven surface of the OLED
device.
[0033] FIG. 4 is a sectional view illustrating an OLED device,
according to other example embodiments of the inventive
concept.
[0034] FIG. 5 is a sectional view illustrating an OLED device,
according to still other example embodiments of the inventive
concept.
[0035] FIG. 6 is a flowchart illustrating a method of fabricating
the OLED device of FIG. 1.
[0036] It should be noted that these figures are intended to
illustrate the general characteristics of methods, structure and/or
materials utilized in certain example embodiments and to supplement
the written description provided below. These drawings are not,
however, to scale and may not precisely reflect the precise
structural or performance characteristics of any given embodiment,
and should not be interpreted as defining or limiting the range of
values or properties encompassed by example embodiments. For
example, the relative thicknesses and positioning of molecules,
layers, regions and/or structural elements may be reduced or
exaggerated for clarity. The use of similar or identical reference
numbers in the various drawings is intended to indicate the
presence of a similar or identical element or feature.
DETAILED DESCRIPTION
[0037] Example embodiments of the inventive concepts will now be
described more fully with reference to the accompanying drawings,
in which example embodiments are shown. Example embodiments of the
inventive concepts 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 more thorough and more
complete, and will more fully convey the concept of example
embodiments to those of ordinary skill in the art. In the drawings,
the thicknesses of layers and regions are exaggerated for clarity.
Like reference numerals in the drawings denote like elements, and
thus their description will be omitted.
[0038] It will be understood that when an element is referred to as
being "connected" or "coupled" to another element, it can be
directly connected or directly coupled to the other element or
intervening elements may be present. In contrast, when an element
is referred to as being "directly connected" or "directly coupled"
to another element, there are no intervening elements present. Like
numbers indicate like elements throughout. As used herein the term
"and/or" includes any and all combinations of one or more of the
associated listed items. Other words used to describe the
relationship between elements or layers should be interpreted in a
like fashion (e.g., "between" versus "directly between," "adjacent"
versus "directly adjacent," "on" versus "directly on").
[0039] It will be understood that, although the terms "first",
"second", etc., may be used herein to describe various elements,
components, regions, layers, and/or sections, these elements,
components, regions, layers, and/or sections should not be limited
by these terms. These terms are only used to distinguish one
element, component, region, layer, or section from another element,
component, region, layer, or section. Thus, a first element,
component, region, layer, or section discussed below could be
termed a second element, component, region, layer, or section
without departing from the teachings of example embodiments.
[0040] Spatially relative terms, such as "beneath," "below,"
"lower," "above," "upper" and the like, may be used herein for ease
of description to describe one element or feature's relationship to
another element(s) or feature(s) as illustrated in the figures. It
will be understood that the spatially relative terms are intended
to encompass different orientations of the device in use or
operation in addition to the orientation depicted in the figures.
For example, if the device in the figures is turned over, elements
described as "below" or "beneath" other elements or features would
then be oriented "above" the other elements or features. Thus, the
example term "below" can encompass both an orientation of above and
below. The device may be otherwise oriented (rotated 90 degrees or
at other orientations) and the spatially relative descriptors used
herein interpreted accordingly.
[0041] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
example embodiments. As used herein, the singular forms "a," "an"
and "the" are intended to include the plural forms as well, unless
the context clearly indicates otherwise. It will be further
understood that the terms "comprises", "comprising", "includes,"
and/or "including," if used herein, specify the presence of stated
features, integers, steps, operations, elements, and/or components,
but do not preclude the presence or addition of one or more other
features, integers, steps, operations, elements, components, and/or
groups thereof.
[0042] The phrase "at least two of" a group of elements (e.g.,
elements A, B, and C) does not refer to the individual elements of
the group, but instead refers to the group collectively. Therefore,
for example, for a component comprising at least two of: element
"A"; element "B"; and element "C," the component comprises at least
A and B, at least A and C, or at least B and C, and does not
necessarily comprise two of each of the elements A, B, and C.
[0043] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which example
embodiments of the inventive concepts belong. It will be further
understood that terms, such as those defined in commonly-used
dictionaries, should be interpreted as having a meaning that is
consistent with their meaning in the context of the relevant art
and will not be interpreted in an idealized or overly formal sense
unless expressly so defined herein.
[0044] FIG. 1 is a sectional view schematically illustrating an
OLED device 1000, according to example embodiments of the inventive
concept. FIG. 2 is a sectional view illustrating one of a plurality
of pixels constituting the OLED device 1000 of FIG. 1, and FIG. 3
is an image showing an uneven (e.g., non-planar) surface of the
OLED device 1000.
[0045] Referring to FIGS. 1 and 2, the OLED device 1000 may include
a driving device layer 50, a first electrode 100, a hole common
layer 300, a light-emitting layer 200, an electron common layer
400, a second electrode 500, an encapsulation layer 700, and a
scattering layer 600 provided on a substrate SB.
[0046] A thin-film transistor TR may be formed in the driving
device layer 50. The driving device layer 50 may include a
plurality of layers interposed between the first electrode 100 and
the substrate SB.
[0047] For example, a buffer layer 11 may be formed on the
substrate SB, and the thin-film transistor TR may be formed on the
buffer layer 11.
[0048] Although one thin-film transistor TR is illustrate in FIG.
2, the number of the thin-film transistors TR may not be limited to
the example of FIG. 2. For example, a plurality of thin-film
transistors may be provided in each pixel.
[0049] A semiconductor active layer 12 may be formed on the buffer
layer 11.
[0050] The buffer layer 11 may be configured to prevent or reduce
impurities from being injected into or otherwise contaminating the
thin-film transistors TR through the substrate SB and provide a
flat surface. The buffer layer 11 may be formed of at least one of
various materials capable of realizing such functions. For example,
the buffer layer 11 may contain at least one of inorganic materials
(e.g., silicon oxide, silicon nitride, silicon oxynitride, aluminum
oxide, aluminum nitride, titanium oxide or titanium nitride) or
organic materials (e.g., polyimide, polyester, or acrylic). In some
embodiments, the buffer layer 11 may be provided to include more
than one of the enumerated materials and thereby have a stack-like
structure. Nevertheless, in some embodiments, the buffer layer 11
may be omitted.
[0051] The semiconductor active layer 12 may be formed of poly
silicon, but example embodiments of the inventive concept may not
be limited thereto. For example, the semiconductor active layer 12
may be formed of oxide semiconductor (e.g., G-I-Z-O layer
[(In2O3)a(Ga2O3)b(ZnO)c layer, where a, b, and c are real numbers
satisfying conditions of a.gtoreq.0, b.gtoreq.0, and c>0,
respectively].
[0052] A gate insulating layer 13 may be formed to cover the
semiconductor active layer 12, and a gate electrode 14 may be
formed on the gate insulating layer 13.
[0053] An interlayered insulating layer 15 may be formed to cover
the gate electrode 14, and a source electrode 16 and a drain
electrode 17 may be formed on the interlayered insulating layer 15
and be electrically coupled to portions of the semiconductor active
layer 12.
[0054] Example embodiments of the inventive concept may not be
limited to the above-described structure of the thin-film
transistor TR. For example, the thin-film transistor TR may be
formed to have not only a top-gate structure, as shown in FIG. 2,
but also a bottom-gate structure, in which the gate electrode 14 is
positioned below the semiconductor active layer 12. Further, all
known types of the thin-film transistor may be used to realize the
OLED device according to example embodiments of the inventive
concept.
[0055] A passivation layer 18 may be formed on the source electrode
16 and the drain electrode 17. The passivation layer 18 may be
formed to have a flat top surface and include one or more
insulating layer(s). The passivation layer 18 may be formed of at
least one of inorganic and/or organic materials.
[0056] The first electrode 100 may be formed on the passivation
layer 18 and electrically coupled to the thin-film transistor TR.
The first electrode 100 may be provided in the form of island, and
each first electrode 100 may be provided in a corresponding one of
the pixels.
[0057] A pixel-defining layer 19 may be formed on the passivation
layer 218 to cover an edge portion of the first electrode 100. An
opening 19a may be formed in the pixel-defining layer 19 to expose
a central portion of the first electrode 100, while maintaining
coverage over the edge portion of the first electrode 100 by the
pixel-defining layer 19. In certain embodiments, the first
electrode 100 may serve as an anode. Here, the first electrode 100
may be a transparent electrode (e.g., of ITO or IZO).
Alternatively, the first electrode 100 may be formed of one
selected from the group consisting of Pt, Cr, Ag, Ni, Al, and any
alloys thereof, and in this case, it may serve as a reflection
electrode. Signals applied to the source electrode 16 may be
transferred to the drain electrode 17, in response to gate signal
applied to the gate electrode 14, and then, be transferred to the
first electrode 100.
[0058] The second electrode 500 may serve as a cathode. The second
electrode 500 may be a thin transparent electrode, which is made of
one selected from the group consisting of Mg, Ca, Al, Ag, Ba, and
any alloys thereof, or be a thick reflective electrode.
[0059] In some embodiments, the first and second electrodes 100 and
500 may be configured to serve as the cathode and the anode,
respectively.
[0060] The hole common layer 300 may be provided between the first
electrode 100 and the light-emitting layer 200. The hole common
layer 300 may include a hole injection layer 310 and a hole
transport layer 320.
[0061] The hole injection layer 310 may be provided on the first
electrode 100. The first hole injection layer 310 may be configured
in such a way that holes can be effectively injected from the first
electrode 100 to the light-emitting layer 200. For this, the hole
injection layer 310 may include, for example, copper phthalocyanine
(CuPc), poly(3,4)-ethylenedioxythiophene (PEDOT), polyaniline
(PANI), or N,N-dinaphthyl-N,N'-diphenylbenzidine (NPD), but example
embodiments of the inventive concept may not be limited
thereto.
[0062] The hole transport layer 320 may be provided on the hole
injection layer 310. The hole transport layer 320 may be configured
in such a way that the holes can be effectively transported from
the hole injection layer 310. Here, the hole transport layer 320
may be configured to have a highest occupied molecular energy
(HOMO) that is substantially lower than a work function of the
first electrode 100 and is substantially higher than a HOMO of the
light-emitting layer 200, and in this case, the hole transport
layer 320 may have an increased efficiency of hole transportation.
For this, the hole transport layer 320 may include, for example,
N,N-dinaphthyl-N,N'-diphenylbenzidine (NPD),
N,N'-bis-(3-methylphenyl)-N,N'-bis-(phenyl)-benzidine (TPD), s-TAD,
4,4',4''-Tris(N-3-methylphenyl-N-phenyl-amino)-triphenylamine
(MTDATA), but example embodiments of the inventive concept may not
be limited thereto.
[0063] The light-emitting layer 200 may be provided between the
first electrode 100 and the second electrode 500. The
light-emitting layer 200 may be provided on the hole transport
layer 320.
[0064] The light-emitting layer 200 may be formed of an organic
material or a mixture of organic and inorganic materials, which can
emit one of primary colors (e.g., three primary colors (red, green,
and blue)). For example, the light-emitting layer 200 may be formed
of a fluorescence or phosphorescence organic material. In example
embodiments, the light-emitting layer 200 may be formed of at least
one selected from the group consisting of
tris(4-methyl-8-quinolinolate)aluminum(III) (Alg3), 4-MAlq3, Gaq3
materials, Alq series, C-545T (C26H26N2O2S), DSA-amine, TBSA, BTP,
PAP-NPA, spiro-FPA, Ph3Si (PhTDAOXD), PPCP
(1,2,3,4,5-pentaphenyl-1,3-cyclopentadiene) as cyclopenadiene
derivatives, DPVBi (4,4'-bis(2,2'-diphenylyinyl)-1,1'-biphenyl),
distyrylbenzene or its derivatives, DCJTB
(4-(Dicyanomethylene)-2-tert-butyl-6-(1,1,7,7,-tetramethyljulolidyl-9-eny-
l)-4H-pyran), DDP, AARP, NPAMLI, Firpic, m-Firpic, N-Firpic,
bon2Ir(acac), (C6)2Ir(acac), bt2Ir(acac), dp2Ir(acac),
bzq2Ir(acac), bo2Ir(acac), F2Ir(bpy), F2Ir(acac), op2Ir(acac),
ppy2Ir(acac), tpy2Ir(acac), FIrppy
(fac-tris[2-(4,5'-difluorophenyl) pyridine-C'2,N]iridium(III)),
Btp2Ir (acac) (bis(2-(2'-benzo[4,5-a]thienyl) pyridinato-N,C3'-)
iridium(acetylactonate)), or phosphorescence materials, but example
embodiments of the inventive concept may not be limited thereto.
The light-emitting layer 200 may be configured to have a
Host-Dopant system, in which at least one of the enumerated
materials is used as host and at least one of perylene,
distyrylbiphenyl, DPT, quinacridone, rubrene, BTX, ABTX, or DCJTB
is used as dopants.
[0065] The electron common layer 400 may be provided between the
second electrode 500 and the light-emitting layer 200. The electron
common layer 400 may include at least two of a hole blocking layer
410, an electron transport layer 420, and an electron injection
layer 430. In example embodiments, the electron common layer 400
may be configured to include the hole blocking layer 410, the
electron transport layer 420, and the electron injection layer 430,
and the following description will be given on such
embodiments.
[0066] The hole blocking layer 410 may be provided on the
light-emitting layer 200. An electron mobility may be higher than
hole mobility in the light-emitting layer 200, and in this case,
the hole blocking layer 410 may be configured in such a way that
holes can be prevented or substantially prevented from being moved
away from the emitting region. The hole blocking layer 410 may be
formed of at least one selected from the group consisting of
2-biphenyl-4-yl-5-(4-t-butylphenyl)-1,3,4-oxydiazole (PBD),
spiro-PBD, and
3-(4'-tert-butylphenyl)-4-phenyl-5-(4'-biphenyl)-1,2,4-triazole
(TAZ).
[0067] The electron transport layer 420 may be provided on the hole
blocking layer 410. The electron transport layer 420 may be
configured in such a way that electrons can be effectively
transported from the electron injection layer 430. For example, the
electron transport layer 420 may include at least one selected from
the group consisting of Alq3 (tris(8-hydroxyquinolino)aluminum),
PBD, TAZ, spiro-PBD, BAlq, and SAlq, but example embodiments of the
inventive concept may not be limited thereto.
[0068] The electron injection layer 430 may be provided on the
electron transport layer 420. The electron injection layer 430 may
be configured in such a way that electrons can be effectively
injected from the second electrode 500 to the light-emitting layer
200. For example, the electron injection layer 430 may include at
least one selected from the group consisting of 1,3,4-Oxadiazole
derivatives, 1,2,4-triazole derivatives, and LiF, but example
embodiments of the inventive concept may not be limited
thereto.
[0069] The encapsulation layer 700 may be provided on the second
electrode 500. The encapsulation layer 700 may encapsulate the
first electrode 100, the hole common layer 300, the light-emitting
layer 200, the electron common layer 400, and the second electrode
500, which are positioned between the substrate SB and the
encapsulation layer 700. For example, the encapsulation layer 700
may be configured to block oxygen and moisture from the
outside.
[0070] The scattering layer 600 may be provided between adjacent
two of the first electrode 100, the hole injection layer 310, the
hole transport layer 320, the light-emitting layer 200, the hole
blocking layer 410, the electron transport layer 420, the electron
injection layer 430, the second electrode 500, and the
encapsulation layer 700. Further, the scattering layer 600 may be
provided on the encapsulation layer 700.
[0071] As shown in FIG. 1, the scattering layer 600 may be provided
between the electron injection layer 430 and the second electrode
500, but example embodiments of the inventive concept may not be
limited thereto, as described above.
[0072] The scattering layer 600 may be formed to have an uneven
(e.g., non-planar) surface. Referring to FIG. 3, the scattering
layer 600 may be formed to have concavo-convex portions, which may
be randomly distributed. As illustrated by the arrows of FIG. 1,
light emitted from the light-emitting layer 200 may be scattered by
the concavo-convex portions or the uneven surface, when it passes
through the scattering layer 600.
[0073] Due to the presence of the uneven surface of the scattering
layer 600, additional layers provided or formed on the scattering
layer 600 may also be formed to have an uneven surface or
concavo-convex portions. Accordingly, in the case where at least
one of the first electrode 100, the hole common layer 300, the
light-emitting layer 200, the electron common layer 400, the second
electrode 500, or the encapsulation layer 700 is provided on the
scattering layer 600, it may have an uneven surface. In the example
of FIG. 1, the second electrode 500 may be provided on the
scattering layer 600, and thus, the second electrode 500 may be
formed to have an uneven top surface. If the scattering layer 600
is provided between the first electrode 100 and the hole injection
layer 310, each of the hole injection layer 310, the hole transport
layer 320, the light-emitting layer 200, the hole blocking layer
410, the electron transport layer 420, the electron injection layer
430, and the second electrode 500 may have an uneven top
surface.
[0074] The scattering layer 600 may include at least one selected
from the base materials including benzene, naphthalene, anthracene,
tetracene, pentacene, amine, benzidine, biphenyl, carbazole,
pyridine, bipyridine, imidazole, phenanthroline, phenylborane,
pyrimidine, or triazine.
[0075] The base materials may be substituted by at least one
substituent, which may be selected from a benzoyl group, a carboxyl
group, an aminophenoxyl group, a tricabonate group, and a styryl
group.
[0076] The base material may have a plurality of substitution
positions, which can be substituted by the substituent.
Accordingly, for one molecule in the base material, a plurality of
substituents may be substituted at a plurality of substitution
positions.
[0077] Molecules constituting the base material may have a plane or
plane-like structure, and in this case, the base material may have
a laminated structure. Further, because the substituent may have a
flexible molecular structure, it may be prone to aggregation.
[0078] According to example embodiments of the inventive concept,
the OLED device 1000 may include the scattering layer 600
configured to scatter an incident light, thereby having increased
efficiency of light extraction.
[0079] For example, if the OLED device does not have the scattering
layer 600, light emitted from the light-emitting layer may be
reflected by an interface between adjacent layers, thereby causing
a resonance phenomenon and a viewing-angle-dependent color shift.
By contrast, according to example embodiments of the inventive
concept, because the scattering layer 600 in the OLED device 1000
may scatter the incident light, it may be possible to suppress or
reduce the resonance phenomena and the color shift from
occurring.
[0080] FIG. 4 is a sectional view illustrating an OLED device,
according to other example embodiments of the inventive
concept.
[0081] Referring to FIG. 4, an OLED device 1100 may include an
encapsulation layer 710 serving as the scattering layer. Except for
this difference, the OLED device 1100 may be configured to have
substantially the same features as those of FIG. 1. Thus, in the
following description of FIG. 4, a previously described element may
be identified by a similar or identical reference number without
repeating an overlapping description thereof, for the sake of
brevity.
[0082] The encapsulation layer 710 may be provided on the second
electrode. The encapsulation layer 710 may encapsulate the first
electrode 100, the hole common layer 300, the light-emitting layer
200, the electron common layer 400, and the second electrode 500,
which are positioned between the substrate SB and the encapsulation
layer 710. For example, the encapsulation layer 700 may be
configured to block or reduce oxygen and moisture from the outside
from contaminating the other layers.
[0083] The encapsulation layer 710 may be configured to provide the
same effect as that of the scattering layer 600 of FIG. 1. For
example, the encapsulation layer 710 may be formed to have an
uneven surface. In example embodiments, the encapsulation layer 710
may be formed to have concavo-convex portions, which may be
randomly distributed. Light emitted from the light-emitting layer
200 may be scattered by the concavo-convex portions or the uneven
surface of the encapsulation layer 710, when it passes through the
encapsulation layer 710.
[0084] The encapsulation layer 710 may include at least one
selected from base materials including benzene, naphthalene,
anthracene, tetracene, pentacene, amine, benzidine, biphenyl,
carbazole, pyridine, bipyridine, imidazole, phenanthroline,
phenylborane, pyrimidine, or triazine.
[0085] The base materials may be substituted by at least one
substituent, which may be selected from a benzoyl group, a carboxyl
group, an aminophenoxyl group, a tricabonate group, and a styryl
group.
[0086] FIG. 5 is a sectional view illustrating an OLED device,
according some example embodiments of the inventive concept.
[0087] For the sake of brevity, in the following description of
FIG. 5, previously described elements may be identified by similar
or identical reference numbers without repeating all of the
description thereof.
[0088] Referring to FIG. 5, an OLED device 1200 may include the
driving device layer 50, the first electrode 100, a first hole
common layer 300A, a first light-emitting layer 200A, a first
electron common layer 400A, a charge generation layer 800, a second
hole common layer 300B, a second light-emitting layer 200B, a
second electron common layer 400B, the second electrode 500, the
encapsulation layer 700, and a scattering layer 610 provided on the
substrate SB.
[0089] The driving device layer 50, the first electrode 100 and the
second electrode 500 may be configured to have substantially the
same features as those of FIG. 1, and thus, some repetitive
description thereto will be omitted below.
[0090] The first hole common layer 300A may be provided between the
first electrode 100 and the first light-emitting layer 200A. The
first hole common layer 300A may include a first hole injection
layer 310A and a first hole transport layer 320A.
[0091] The first hole injection layer 310A may be provided on the
first electrode 100. The first hole transport layer 320A may be
provided on the first hole injection layer 310A. The first hole
injection layer 310A and the first hole transport layer 320A may be
configured to provide the same effect as and contain the same
material as the hole injection layer 310 and the hole transport
layer 320, respectively, of FIG. 1.
[0092] The first light-emitting layer 200A may be provided between
the first electrode 100 and the charge generation layer 800. The
first light-emitting layer 200A may be configured to provide the
same effect as and contain the same material as the light-emitting
layer 200 of FIG. 1.
[0093] The first electron common layer 400A may be provided between
the charge generation layer 800 and the first light-emitting layer
200A. The first electron common layer 400A may include at least two
of a first hole blocking layer 410A, a first electron transport
layer 420A, and a first electron injection layer 430A. In example
embodiments, the first electron common layer 400A may be configured
to include each of the first hole blocking layer 410A, the first
electron common layer 420A, and the first electron injection layer
430A, and the following description will be given on such
embodiments.
[0094] The first hole blocking layer 410A may be provided on the
first light-emitting layer 200A. The first electron transport layer
420A may be provided on the first hole blocking layer 410A. The
first electron injection layer 430A may be provided on the first
electron transport layer 420A. The first hole blocking layer 410A,
the first electron transport layer 420A, and the first electron
injection layer 430A may be configured to provide the same effect
as and contain the same material as the hole blocking layer 410,
the electron transport layer 420, and the electron injection layer
430, respectively, of FIG. 1.
[0095] The charge generation layer 800 may be provided between the
first light-emitting layer 200A and the second light-emitting layer
200B. For example, the charge generation layer 800 may be provided
between the first electron common layer 400A and the second hole
common layer 300B. The charge generation layer 800 may serve as a
cathode substantially with respect to the first light-emitting
layer 200A and serve as an anode substantially with respect to the
second light-emitting layer 200B.
[0096] The charge generation layer 800 may have a single- or
double-layered structure. In example embodiments, the charge
generation layer 800 may be formed to have a single-layered
structure made of metal oxide (for example, including vanadium
oxide (VOx) or tungsten oxide (WOx)). In other example embodiments,
the charge generation layer 800 may be formed to have a
double-layered structure including a metal oxide layer and a metal
layer. In this case, the metal oxide layer may include vanadium
oxide or tungsten oxide, and the metal layer may include aluminum
or silver.
[0097] In the case where voltages are applied to the first
electrode 100 and the second electrode 500, electric charges (e.g.,
electrons or holes) may be generated in the charge generation layer
800 and be provided into the first light-emitting layer 200A and
the second light-emitting layer 200B positioned adjacent to the
charge generation layer 800.
[0098] The second hole common layer 300B may be provided between
the charge generation layer 800 and the second light-emitting layer
200B. The second hole common layer 300B may include a second hole
injection layer 310B and a second hole transport layer 320B.
[0099] The second hole injection layer 310B may be provided on the
charge generation layer 800. The second hole transport layer 320B
may be provided on the second hole injection layer 310B. The second
hole injection layer 310B and the second hole transport layer 320B
may be configured to provide the same effect as and contain the
same material as the hole injection layer 310 and the hole
transport layer 320, respectively, of FIG. 1.
[0100] The second light-emitting layer 200B may be provided between
the second electrode 500 and the charge generation layer 800. The
second light-emitting layer 200B may be configured to provide the
same effect as and contain the same material as the light-emitting
layer 200 of FIG. 1.
[0101] The second electron common layer 400B may be provided
between the second electrode 500 and the second light-emitting
layer 200B. The second electron common layer 400B may include at
least two of a second hole blocking layer 410B, a second electron
transport layer 420B, and a second electron injection layer 430B.
In example embodiments, the second electron common layer 400B may
be configured to include each of the second hole blocking layer
410B, the second electron common layer 420B, and the second
electron injection layer 430B, and the following description will
be given on such embodiments.
[0102] The second hole blocking layer 410B may be provided on the
second light-emitting layer 200B. The second electron transport
layer 420B may be provided on the second hole blocking layer 410B.
The second electron injection layer 430B may be provided on the
second electron transport layer 420B. The second hole blocking
layer 410B, the second electron transport layer 420B, and the
second electron injection layer 430B may be configured to provide
the same effect as and contain the same material as the hole
blocking layer 410, the electron transport layer 420, and the
electron injection layer 430, respectively, of FIG. 1.
[0103] The encapsulation layer 700 may be provided on the second
electrode 500. The encapsulation layer 700 may encapsulate the
first electrode 100, the first hole common layer 300A, the first
light-emitting layer 200A, the first electron common layer 400A,
the charge generation layer 800, the second hole common layer 300B,
the second light-emitting layer 200B, the second electron common
layer 400B, and the second electrode 500, which are positioned
between the substrate SB and the encapsulation layer 700. The
encapsulation layer 700 may be configured to block oxygen and
moisture from the outside.
[0104] The scattering layer 610 may be provided between adjacent
two of the first electrode 100, the first hole common layer 300A,
the first light-emitting layer 200A, the first electron common
layer 400A, the charge generation layer 800, the second hole common
layer 300B, the second light-emitting layer 200B, the second
electron common layer 400B, and the second electrode 500, and the
encapsulation layer 700. Further, the scattering layer 610 may be
provided on the encapsulation layer 700.
[0105] As shown in FIG. 5, the scattering layer 610 may be provided
between the charge generation layer 800 and the first electron
common layer 400A, but example embodiments of the inventive concept
may not be limited thereto, as described above.
[0106] The scattering layer 610 may be configured to have
substantially the same features as the scattering layer 600 of FIG.
1, in terms of shape, effect, function, and material.
[0107] FIG. 6 is a flowchart illustrating a method of fabricating
the OLED device 1000 of FIG. 1.
[0108] Referring to FIGS. 1 and 6, a method of fabricating the OLED
device 1000 may include a first step of providing an insulating
substrate; a second step of forming a first electrode; a third step
of forming a hole common layer on the first electrode; a fourth
step of forming a light-emitting layer on the hole common layer; a
fifth step of forming an electron common layer on the
light-emitting layer; a sixth step of forming a second electrode on
the electron common layer; and a step of forming a scattering layer
having an uneven surface on the insulating substrate.
[0109] The insulating substrate SB may be a transparent insulating
substrate.
[0110] The third step may include forming a hole injection layer
and forming a hole transport layer.
[0111] The fifth step may include forming an electron injection
layer and an electron transport layer.
[0112] At least one of the first to sixth steps may be performed
using a deposition process.
[0113] The step of forming the scattering layer may be performed
between adjacent two of the first to sixth steps. For example, the
step of forming the scattering layer may be performed after the
sixth step, but example embodiments of the inventive concept may
not be limited thereto. In other example embodiments, the step of
forming the scattering layer may be performed between steps of
forming the hole injection layer and the hole transport layer. In
still other example embodiments, the step of forming the scattering
layer may be performed between steps of forming the electron
injection layer and the electron transport layer.
[0114] In the description of FIGS. 1 and 6, an embodiment, in which
the scattering layer 600 is formed between the electron common
layer 400 and the second electrode 500, will be described as
example embodiments of the inventive concept.
[0115] The step of forming the scattering layer may be performed
using a thermal deposition process or an electron-beam deposition
process. In the case where the scattering layer 600 is formed using
the thermal deposition process, a deposition-target compound may be
provided in a deposition source container, and then, the deposition
source container may be heated. In this case, the deposition-target
compound may be evaporated and be deposited on the electron common
layer 400.
[0116] The deposition-target compound may include at least one
selected from base materials including benzene, naphthalene,
anthracene, tetracene, pentacene, amine, benzidine, biphenyl,
carbazole, pyridine, bipyridine, imidazole, phenanthroline,
phenylborane, pyrimidine, or triazine. The base materials may be
substituted by at least one substituent, which may be selected from
benzoyl group, carboxyl group, aminophenoxyl group, tricabonate
group, and styryl group.
[0117] The base material may have a plurality of substitution
positions, which can be substituted by the substituent.
Accordingly, for one molecule in the base material, a plurality of
substituents may be substituted at a plurality of substitution
positions.
[0118] Molecules constituting the base material may have a plane or
plane-like structure, and in this case, the base material may have
a laminated structure. Further, because the substituent may have a
flexible molecular structure, it may be prone to aggregation.
[0119] The thermal deposition process may be performed at a
temperature ranging from about 100.degree. C. to about 600.degree.
C.
[0120] During the thermal deposition process thereof, the
deposition-target compound may be aggregated to have an uneven
surface. In the case where the thermal deposition process is
performed at a relatively low temperature of, for example,
100.degree. C. or lower, it is relatively more difficult to
evaporate the deposition-target compound. By contrast, in the case
where the thermal deposition process is performed at a relatively
high temperature of, for example, 600.degree. C. or higher, the
insulating substrate SB, the first electrode 100, the hole common
layer 300, the light-emitting layer 200, or the electron common
layer 400 may be thermally damaged.
[0121] According to example embodiments of the inventive concept, a
method of fabricating the OLED device may include forming the
scattering layer using a thermal deposition process or an
electron-beam deposition process. It is possible to form the
scattering layer having the uneven surface or concavo-convex
portions without any additional photolithography process.
Accordingly, the scattering layer can be formed by a deposition
process (e.g., thermal deposition process), which may be performed
in the same manner as that for the first electrode 100, the hole
common layer 300, the light-emitting layer 200, and the electron
common layer 400, and the second electrode 500, and thus, it is
possible to reduce time and cost for the fabrication of the OLED
device.
[0122] According to example embodiments of the inventive concept,
the OLED device may include a scattering layer configured to
scatter an incident light, thereby having increased efficiency of
light extraction.
[0123] Further, due to the presence of the scattering layer
scattering the incident light, it may be possible to suppress or
reduce the resonance phenomena and the color shift from
occurring.
[0124] According to example embodiments of the inventive concept,
during a method of fabricating the OLED device, it may be possible
to form the scattering layer having the uneven surface or
concavo-convex portions without any additional photolithography
process. Accordingly, the scattering layer can be formed by a
deposition process (e.g., thermal deposition process), which may be
performed in the same manner as that for a first electrode, a hole
common layer, a light-emitting layer, an electron common layer, and
a second electrode, and thus, it is possible to reduce time and
cost for the fabrication of the OLED device.
[0125] While example embodiments of the inventive concepts have
been shown and described, it will be understood by one of ordinary
skill in the art that variations in form and detail may be made
therein without departing from the spirit and scope of the attached
claims, and their equivalents.
* * * * *