NEW COMPOUND AND ORGANIC LIGHT EMITTING DEVICE
USING THE SAME (8)
Technical Field
[1] The present invention relates to an organic light emitting device which comprises a
fluorene derivative capable of significantly improving a lifespan, efficiency, and electrochemical
and thermal stabilities thereof.
Background Art
[3] An organic light emission phenomenon is an example of a conversion of current
into visible rays through an internal process of a specific organic molecule. The
organic light emission phenomenon is based on the following mechanism. When
organic material layers are interposed between an anode and a cathode, if voltage is
applied between the two electrodes, electrons and holes are injected from the cathode
and the anode into the organic material layer. The electrons and the holes which are
injected into the organic material layer are recombined to form an exciton, and the
exciton is reduced to a bottom state to emit light. An organic light emitting device
which is based on the above mechanism typically comprises a cathode, an anode, and
organic material layer(s), for example, organic material layers including a hole
injection layer, a hole transport layer, a light emitting layer, and an electron transport
layer, interposed therebetween.
[4] The materials used in the organic light emitting device are mostly pure organic
materials or complexes of organic material and metal. The material used in the organic
light emitting device may be classified as a hole injection material, a hole transport
material, a light emitting material, an electron transport material, or an electron
injection material, according to its use. In connection with this, an organic material
having a p-type property, which is easily oxidized and is electrochemically stable when
it is oxidized, is mostly used as the hole injection material or the hole transport
material. Meanwhile, an organic material having an n-type property, which is easily
reduced and is electrochemically stable when it is reduced, is used as the electron
injection material or the electron transport material. As the light emitting layer
material, an organic material having both p-type and n-type properties is preferable,
which is stable when it is oxidized and when it is reduced. Also a material having high
light emission efficiency for conversion of the exciton into light when the exciton is
formed is preferable.
[5] In addition, it is preferable that the material used in the organic light emitting device
further have the following properties.
[6] First, it is preferable that the material used in the organic light emitting device have
excellent thermal stability. The reason is that joule heat is generated by movement of
electric charges in the organic light emitting device. NPB, which has recently been
used as the hole transport layer material, has a glass transition temperature of 100°C or
lower, thus it is difficult to apply to an organic light emitting device requiring a high
current.
[7] Second, in order to produce an organic light emitting device that is capable of being
actuated at low voltage and has high efficiency, holes and electrons which are injected
into the organic light emitting device must be smoothly transported to a light emitting
layer, and must not be released out of the light emitting layer. To achieve this, a
material used in the organic light emitting device must have a proper band gap and a
proper HOMO or LUMO energy levels. A LUMO energy level of PEDOT:PSS, which
is currently used as a hole transport material of an organic light emitting device
produced using a solution coating method, is lower than that of an organic material
used as a light emitting layer material, thus it is difficult to produce an organic light
emitting device having high efficiency and a long lifespan.
[8] Moreover, the material used in the organic light emitting device must have excellent
chemical stability, electric charge mobility, and interfacial characteristic with an
electrode or an adjacent layer. That is to say, the material used in the organic light
emitting device must be little deformed by moisture or oxygen. Furthermore, proper
hole or electron mobility must be assured so as to balance densities of the holes and of
the electrons in the light emitting layer of the organic light emitting device to
maximize the formation of excitons. Additionally, it has to be able to have a good
interface with an electrode including metal or metal oxides so as to assure stability of
the device.
[9] Accordingly, there is a need to develop an organic light emitting device including
an organic material having the above-mentioned requirements in the art.
Disclosure of Invention
Technical Problem
[11] Therefore, the object of the present inventions is to provide an organic light
emitting device which is capable of satisfying conditions required of a material usable
for an organic light emitting device, for example, a proper energy level, electrochemical
stability, and thermal stability, and which includes a fluorene derivative
having a chemical structure capable of playing various roles required in the organic
light emitting device, depending on a substituent group.
Technical Solution
The present invention provides an organic light emitting device which comprises a
first electrode, organic material layer(s) comprising a light emitting layer, and a second
electrode, wherein the first electrode, the organic material layer(s), and the second
electrode form a layered structure and at least one layer of the organic material layer(s)
includes a compound of the following Formula 1 or a compound of Formula 1 into
which a thermoserting or photo-crosslinkable functional group is introduced:
[Formula 1]
[19] a and b are zero or positive integer;
[20] Y is a bond; bivalent aromatic hydrocarbons; bivalent aromatic hydrocarbons which
are substituted with at least one substituent group selected from the group consisting of
nitro, nitrile, halogen, alkyl, alkoxy, and amino groups; a bivalent heterocyclic group;
or a bivalent heterocyclic group which is substituted with at least one substituent group
selected from the group consisting of nitro, nitrile, halogen, alkyl, alkoxy, and amino
groups.
[21] Yl to Y4 are each independently bivalent aromatic hydrocarbons; bivalent aromatic
hydrocarbons which are substituted with at least one substituent group selected from
the group consisting of nitro, nitrile, halogen, alkyl, alkoxy, and amino groups; a
bivalent heterocyclic group; or a bivalent heterocyclic group which is substituted with
at least one substituent group selected from the group consisting of nitro, nitrile,
halogen, alkyl, alkoxy, and amino groups.
[22] Zl to Z8 are each independently hydrogen; aliphatic hydrocarbons having a carbon
number of 1 - 20; aromatic hydrocarbons; aromatic hydrocarbons which are substituted
with at least one substituent group selected from the group consisting of the nitro,
nitrile, halogen, alkyl, alkoxy, amino, aromatic hydrocarbon, and heterocyclic groups;
a silicon group substituted with aromatic hydrocarbons; a heterocyclic group; a heterocyclic
group which is substituted with at least one substituent group selected from
the group consisting of the nitro, nitrile, halogen, alkyl, alkoxy, amino, aromatic hydrocarbon,
and heterocyclic groups; a thiophene group which is substituted with hydrocarbons
having a carbon number of 1 - 20 or aromatic hydrocarbons having a
carbon number of 6 - 20; or a boron group which is substituted with aromatic hydrocarbons.
[23] Rl to R4 and R6 to R9 are each independently selected from the group consisting of
hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted
alkoxy group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted
aryl group, a substituted or unsubstituted arylamine group, a substituted or
unsubstituted heterocyclic group, an amino group, a nitrile group, a nitro group, a
halogen group, an amide group, and an ester group. They may form aliphatic or hetero
condensation rings along with adjacent groups.
[24] R5 is selected from the group consisting of hydrogen, a substituted or unsubstituted
alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted
alkenyl group, a substituted or unsubstituted aryl group, and a substituted or
unsubstituted heterocyclic group.
[25] Carbon at an ortho-position of the aryl or heterocyclic group and R4 or R6 may
form a condensation ring along with a group selected from the group consisting of O,
S, NR, PR, C=O, CRR', and SiRR', with the proviso that R5 is the aryl group or the
heterocyclic group, wherein R and R' are each independently selected from the group
consisting of hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted
alkoxy group, a substituted or unsubstituted alkenyl group, a substituted or
unsubstituted aryl group, a substituted or unsubstituted arylamine group, a substituted
or unsubstituted heterocyclic group, a nitrile group, an amide group, and an ester
group, and R and R' may form a condensation ring to form a spiro compound.
[26] A detailed description will be given of the substituent groups of Formula 1.
[27] In Zl to Z8 as the substituent groups of Formula 1, the aromatic compounds are exemplified
by monocyclic aromatic rings, such as phenyl, biphenyl, and terphenyl, and
multicyclic aromatic rings, such as naphthyl, anthracenyl, pyrenyl, and perylenyl. The
hetero aromatic compounds are exemplified by thiophene, furan, pyrrole, imidazole,
thiazole, oxazole, oxadiazole, thiadiazole, triazole, pyridyl, pyridazyl, pyrazine,
quinoline, and isoquinoline.
[28] Examples of aliphatic hydrocarbons having a carbon number of 1 - 20 include
straight chain aliphatic hydrocarbons, branched chain aliphatic hydrocarbons, saturated
aliphatic hydrocarbons, and unsaturated aliphatic hydrocarbons. They are exemplified
by an alkyl group, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl
group, an n-butyl group, a sec-butyl group, an iso-butyl group, a ter-butyl
group, a pentyl group, and a hexyl group; an alkenyl group having a double bond, such
as styryl; and an alkynyl group having a triple bond, such as an acetylene group.
[29] The carbon number of the alkyl, alkoxy, and alkenyl groups of Rl to R9 of Formula
1 is not limited, but is preferably 1 - 20.
[30] The length of the alkyl group contained in the compound does not affect the
conjugate length of the compound, but may affect the method of applying the
compound to the organic light emitting device, for example, a vacuum deposition
method or a solution coating method.
[31] Illustrative, but non-limiting, examples of the aryl group of Rl to R9 of Formula 1
include monocyclic aromatic rings, such as a phenyl group, a biphenyl group, a
terphenyl group, and a stilbene group, and multicyclic aromatic rings, such as a
naphthyl group, an anthracenyl group, a phenanthrene group, a pyrenyl group, and a
perylenyl group.
[32] Illustrative, but non-limiting, examples of the arylamine group of Rl to R9 of
Formula 1 include a diphenylamine group, a dinaphthylamine group, a
dibiphenylamine group, a phenylnaphthylamine group, a phenyldiphetylamine group, a
ditolylamine group, a phenyltolylamine group, a carbazolyl group, and a triphenylamine
group.
[33] Illustrative, but non-limiting, examples of the heterocyclic group of Rl to R9 of
Formula 1 include a thiophene group, a furan group, a pyrrolyl group, an imidazolyl
group, a thiazolyl group, an oxazolyl group, an oxadiazolyl group, a triazolyl group, a
pyridyl group, a pyradazine group, a quinolinyl group, an isoquinoline group, and an
acridyl group.
[34] In addition, illustrative, but non-limiting, examples of the alkenyl, aryl, arylamine,
and heterocyclic groups of Rl to R9 of Formula 1 include compounds shown in the
following Formulae.
[35]
[36] In the above Formulae, Z is a group selected from the group consisting of hydrogen,
aliphatic hydrocarbons having a carbon number of 1 - 20, an alkoxy group, an
arylamine group, an aryl group, a heterocyclic group, a nitrile group, and an acetylene
group. Examples of the arylamine, aryl, and heterocyclic groups of Z are as shown in
the above-mentioned substituent groups of Rl to R9.
[37] According to a preferred embodiment of the present invention, R5 of Formula 1 is
an aryl or an heterocyclic group.
[38] According to another preferred embodiment of the present invention, R5 of
Formula 1 is an aryl or an heterocyclic group, and carbon at an ortho-position of the
aryl or heterocyclic group and R4 or R6 form a condensation ring along with a group
selected from the group consisting of O, S, NR, PR, C=O, CRR', and SiRR' (R and R'
are as defined in Formula 1).
[39] According to still another preferred embodiment of the present invention, R5 of
Formula 1 is an aryl or an heterocyclic group, and carbon at the ortho-position of the
aryl or heterocyclic group and R4, and carbon at the ortho-position of the aryl or heterocyclic
group and R6 form the condensation ring along with a group selected from
the group consisting of O, S, NR, PR, C=O, CRR', and SiRR' (R and R1 are as defined
in Formula 1).
According to the preferred embodiment of the present invention, illustrative, but
non-limiting, examples of the compound of Formula 1 include compounds of the
following Formulae 2 to 119.
Brief Description of the Drawings
FIG. 1 illustrates an organic light emitting device comprising a substrate 1, an
anode 2, a light emitting layer 3, and a cathode 4; and
FIG. 2 illustrates an organic light emitting device comprising a substrate 1, an
anode 2, a hole injection layer 5, a hole transport layer 6, a light emitting layer 7, an
electron transport layer 8, and a cathode 4.
Best Mode for Carrying Out the Invention
Hereinafter, a detailed description will be given of the present invention.
Various substituent groups are introduced into a core structure shown in Formula 1,
in detail, the core structure in which a fluorene group is bonded to a combination of an
acridine group and a carbazolyl group to form a spiro structure, thereby the compound
of Formula 1 has characteristics suitable for application to an organic material layer
used in an organic light emitting device. This will be described in detail, below.
The steric core structure of the compound of Formula 1 can be divided into two
portions, A and B, for explanation as shown in the following Formula.
The compound of Formula 1 has the steric core structure in which a plane A meets
with a plane B at right angles around X, and conjugation does not occur between the A
and B portions around X. Furthermore, since one nitrogen atom is positioned among
three aryl groups in the plane B, conjugation is limited in the plane B.
The conjugation length of the compound has a close relationship with an energy
band gap. In detail, the energy band gap is reduced as the conjugation length of the
compound increases. As described above, since a conjugation structure is limited in the
core structure of the compound of Formula 1, the core structure has a large energy
band gap.
As described above, in the present invention, various substituent groups are
introduced to Rl to R9 positions and Zl to Z8 positions of the core structure having
the large energy band gap so as to produce compounds having various energy band
gaps. Generally, it is easy to control the energy band gap by introducing substituent
groups into a core structure having a large energy band gap, but it is difficult to significantly
control the energy band gap by introducing substituent groups into a core
structure having a small energy band gap. Furthermore, in the present invention, it is
possible to control HOMO and LUMO energy levels of the compound by introducing
various substituent groups into Rl to R9 and Zl to Z8 of the core structure.
Additionally, various substituent groups are introduced into the core structure to
produce compounds having intrinsic characteristics of the substituent groups. For
example, substituent groups, which are frequently applied to hole injection layer, hole
transport layer, light emitting layer, and electron transport layer materials during the
production of the organic light emitting device, are introduced into the core structure
so as to produce substances capable of satisfying the requirements of each organic
material layer. Particularly, since the core structure of the compound of Formula
includes the arylamine structure, it has an energy level suitable for the hole injection
and/or hole transport materials in the organic light emitting device. In the present
invention, the compound having the proper energy level is selected depending on the
substituent group among the compounds represented by Formula 1 to be used in the
organic light emitting device, thereby it is possible to realize a device having a low
actuating voltage and a high light efficiency.
[90] Furthermore, various substituent groups are symmetrically introduced into the core
structure (the A and B portions are located at both sides of the core structure) so as to
precisely control the energy band gap, improve interfacial characteristics with organic
materials, and apply the compound to various fields.
[91] As well, if the numbers of nitrogen contained in the substituent groups A and B are
each set to 2 or more (if Yl to Y4 and Zl to Z8 are hetero aromatic amine compounds,
the number of nitrogen contained in them is not counted), it is possible to precisely
control the HOMO and LUMO energy levels and the energy band gap, and on the
other hand interfacial characteristics with the organic materials is improved and
thereby make it possible to apply the compound to various fields.
[92] Additionally, various substituent groups are introduced into the steric structure of
the compound of Formula 1 using spiro bonding to control the three-dimensional
structure of the organic material so as to minimize JT-JT interaction in the organic
material, thereby formation of excimers is prevented.
[93] Meanwhile, since the compound of Formula 1 has a high glass transition
temperature (Tg), it has excellent thermal stability. For example, the glass transition
temperature of the compound of Formula 3-1 is 159°C, which is still higher than that of
conventionally used NPB (Tg: 96°C). Such increase in thermal stability is an important
factor providing actuating stability to the device.
[94] Furthermore, the compound of Formula 1 may be used to form the organic material
layer using a vacuum deposition process or a solution coating process during the
production of the organic light emitting device. In connection with this, illustrative, but
non-limiting, examples of the solution coating process include a spin coating process, a
dip coating process, an inkjet printing process, a screen printing process, a spray
process, and a roll coating process.
[95] For example, the compound of Formula 1 has excellent solubility to a polar solvent,
such as xylene, dichloroethane, or NMP, which is used during the production of the
device, and forms a thin film very well through the process using a solution, thus the
solution coating process may be applied to produce the device.
[96] Tertiary alcohol, which is produced by a reaction of a lithiated aryl and keto group,
is heated in the presence of an acid catalyst to form a hexagonal cyclic structure while
water is removed, thereby producing the compound having a spiro structure according
to the present invention. The above-mentioned procedure for producing the compound
is well known in the art, and those skilled in the art can change the production
conditions during the production of the compound of Formula 1. The production will
be described in detail in the preparation examples later.
[97] In the organic light emitting device of the present invention, a compound, in which
a thermosetting or photo-crosslinkable functional group is introduced into the
compound of Formula 1, may be used instead of the compound of Formula 1. The
former compound has the basic physical properties of the compound of Formula 1, and
may be used to form a thin film using a solution coating process and then be cured so
as to form an organic material layer during the production of the device.
[98] The method of forming the organic material layer, which comprises introducing the
curable functional group into the organic material during the production of the organic
light emitting device, forming the organic thin film using the solution coating process,
and curing the resulting film, is disclosed in US Pat. No. 2003-0044518 and EP Pat.
No. 1146574 A2.
[99] The above documents state that, if the organic material layer is formed through the
above-mentioned method using a material having a thermosetting or photocrosslinkable
vinyl or acryl group so as to produce an organic light emitting device, it
is possible to produce an organic light emitting device having a low voltage and high
brightness as well as an organic light emitting device having a multilayered structure
using the solution coating process. This operation mechanism may be applied to the
compound of the present invention.
[100] In the present invention, the thermosetting or photo-crosslinkable functional group
may be a vinyl or acryl group.
[101] The organic light emitting device of the present invention can be produced using
known materials through a known process, modified only in that at least one layer of
organic material layer(s) include the compound of the present invention, that is, the
compound of Formula 1.
[102] The organic material layer(s) of the organic light emitting device according to the
present invention may have a single layer structure, or alternatively, a multilayered
structure in which two or more organic material layers are layered. For example, the
organic light emitting device of the present invention may comprise a hole injection
layer, a hole transport layer, a light emitting layer, an electron transport layer, or an
electron injection layer as the organic material layer(s). However, the structure of the
organic light emitting device is not limited to this, but may comprise a smaller number
of organic material layers.
Furthermore, the organic light emitting device of the present invention may be
produced, for example, by sequentially layering a first electrode, organic material
layer(s), and a second electrode on a substrate. In connection with this, a physical
vapor deposition (PVD) method, such as a sputtering method or an e-beam evaporation
method, may be used, but the method is not limited to these.
A method of producing the compound of Formula 1 and the production of the
organic light emitting device using the same will be described in detail in the following
preparation examples and examples. However, the following preparation examples and
examples are set forth to illustrate, but are not to be construed to limit the present
invention.
Mode for the Invention
A better understanding of a method of producing an organic compound represented
by Formula 1 and the production of an organic light emitting device using the same
may be obtained in light of the following preparation examples and examples which
are set forth to illustrate, but are not to be construed to limit the present invention.
In order to produce the compound represented by Formula 1, compounds of the
following Formulae, a or b, may be used as a starting material.
PREPARATION EXAMPLE 1: Production of a starting material represented by
Formula a
1) After 10 g of diphenylamine (59 mmol) and 8.04 ml of bromomethyl methyl
ether (88.6 mmol) were dissloved in 100 ml of tetrahydrofuran, 12.4 ml of triethylamine
(88.6 mmol) were added thereto. Stirring was conducted in a nitrogen
atmosphere for 5 hours, and an organic layer was then extracted using distilled water.
The extracted organic layer was subjected to a column separation process at a ratio of
n-hexane/tetrahydrofuran of 15:1, and vacuum dried to produce 12 g of tertiary amine
(yield 90 %).
[113] 2) The amine compound produced in 1) (12.0 g, 56.3 mmol) was dissolved in 100
ml of purified THF and cooled to -78°C, and n-BuLi (2.5 M hexane solution, 22.5 ml,
56.3 mmol) was slowly dropped thereon. Stirring was conducted at the same
temperature for 30 min, and a 2,7-dichloro-9-fluorenone compound (14.0 g, 56.3
mmol) was added thereto. After stirring at the same temperature for 40 min, the
temperature was raised to normal temperature and stirring was carried out for an
additional 3 hours. The reaction was completed in an ammonium chloride aqueous
solution, and extraction was conducted with ethyl ether. Water was removed from an
organic material layer using anhydrous magnesium sulfate, and an organic solvent was
then removed therefrom. The produced solid was dispersed in ethanol, stirred for one
day, filtered, and vacuum dried. After an intermediate material was dispersed in 100 ml
of acetic acid, ten drops of concentrated sulfuric acid were added thereto and reflux
was conducted for 4 hours. The resulting solid was filtered, washed with ethanol, and
vacuum dried to produce 21.8 g of amine (96.8 % yield). MS: [M+H]+ = 401.
[115] PREPARATION EXAMPLE 2: Preparation of a starting material represented by
[117] A compound of Formula a (9.00 g, 22.5 mmol), 1-iodonaphthalene (11.4 g, 45.0
mmol), potassium carbonate (6.22 g, 45.0 mmol), copper iodide (214 mg, 1.13 mmol),
and xylene (250 ml) were heated in a nitrogen atmosphere overnight. After cooling to
normal temperature, a product was extracted with ethyl acetate, water was removed
with anhydrous magnesium sulfate, and the solvent was removed at a reduced pressure.
The resulting product was passed through a silica gel column using a hexane solvent to
produce a compound, the solvent was removed at a reduced pressure, and vacuum
drying was conducted to produce the compound of Formula b (5.0 g, 42 % yield). MS:
[121] 1) Synthesis of arylamine (4-(N-phenyl-N-phenylamino)phenyl-l-phenylamine) to
produce the compound represented by Formula 3-1: 13.5 g of
4-bromophenyl-N-phenyl-N-phenylamine (41.6 mmol) and 3.98 ml of aniline (43.7
mmol) were dissolved in 120 ml of toluene, 10.00 g of sodium-tert-butoxide (104.1
mmol), 0.48 g of bis(dibenzylidene acetone)palladium(O) (0.83 mmol), and 0.58 ml of
50 wt% tri-tert-butylphosphine toluene solution (1.25 mmol) were added thereto, and
reflux was conducted in a nitrogen atmosphere for 2 hours. Distilled water was added
to the reaction solution to complete the reaction, and the organic layer was extracted. A
column separation process was conducted using a solvent of n-hexane and
tetrahydrofuran at a ratio of 10:1, stirring was conducted using petroleum ether, and
vacuum drying was conducted to produce an arylamine connection group (9.6 g, yield
69 %). MS: [M+H]+= 336.
[122] 2) 4.68 g of compound of Formula b (8.88 mmol) and 6.86 g of
4-(N-phenyl-N-phenylamino)phenyl-l-phenylamine (20.4 mmol) were dissolved in
120 ml of toluene, 5.89 g of sodium-tert-butoxide (61.3 mmol), 0.24 g of
tris(dibenzylidene acetone)dipalladium(O) (0.41 mmol), and 0.25 ml of 50 wt% tritert-
butylphosphine toluene solution (0.61 mmol) were added thereto, and reflux was
conducted in a nitrogen atmosphere for 2 hours. Distilled water was added to the
reaction solution to complete the reaction, and the organic layer was extracted. A
column separation process was conducted using a solvent of n-hexane and
tetrahydrofuran at a ratio of 4:1, stirring was conducted using petroleum ether, and
vacuum drying was conducted to produce the compound of Formula 3-1 (5.2 g, yield
52%).MS:[M+H]+=1127.
[124] EXAMPLE 2: Preparation of the compound represented by Formula 3-2
[ 126] 1) Synthesis of arylamine (4-(N-phenyl-N-phenylamino)phenyl-1 -naphthylamine)
to produce the compound represented by Formula 3-2: 15.0 g of
4-bromophenyl-N-phenyl-N-phenylamine (46.3 mmol) and 7.29 g of 1-naphthylamine
(50.9 mmol) were dissolved in 200 ml of toluene, 13.34 g of sodium-tert-butoxide
(138.8 mmol), 0.53 g of bis(dibenzylidene acetone)palladium(O) (0.93 mmol), and 0.56
ml of 50 wt% tri-tert-butylphosphine toluene solution (1.39 mmol) were added thereto,
and reflux was conducted in a nitrogen atmosphere for 2 hours. Distilled water was
added to the reaction solution to complete the reaction, and the organic layer was
extracted. A column separation process was conducted using a solvent of n-hexane and
tetrahydrofuran at a ratio of 10:1, stirring was conducted using petroleum ether, and
vacuum drying was conducted to produce an arylamine connection group (13 g, yield
73 %). MS: [M+H]+= 386.
[127] 2) 4.68 g of compound of Formula b (8.88 mmol) and 7.88 g of
4-(N-phenyl-N-phenylamino)phenyl-l-naphthylamine (20.4 mmol) were dissolved in
120 ml of toluene, 5.89 g of sodium-tert-butoxide (61.3 mmol), 0.24 g of
tris(dibenzylidene acetone)dipalladium(O) (0.41 mmol), and 0.25 ml of 50 wt% tritert-
butylphosphine toluene solution (0.61 mmol) were added thereto, and reflux was
52
conducted in a nitrogen atmosphere for 2 hours. Distilled water was added to the
reaction solution to complete the reaction, and the organic layer was extracted. A
column separation process was conducted using a solvent of n-hexane and
tetrahydrofuran at a ratio of 4:1, stirring was conducted using petroleum ether, and
vacuum drying was conducted to produce the compound of Formula 3-2 (5.4 g, yield
50 %). MS: [M+Hf= 1227.
[129] EXAMPLE 3: Preparation of the compound represented by Formula 3-4
[131] 1) Synthesis of arylamine (4- (N-phenyl-N-phenylamino)phenyl-1 -biphenylamine)
to produce the compound represented by Formula 3-4: 17.4 g of
4-bromophenyl-N-phenyl-N-phenylamine (53.7 mmol) and 9.99 g of 4-aminobiphenyl
(59.0 mmol) were dissolved in 250 ml of toluene, 17.02 g of sodium-tert-butoxide
(177.1 mmol), 0.68 g of bis(dibenzylidene acetone)palladium(O) (1.2 mmol), and 0.72
ml of 50 wt% tri-tert-butylphosphine toluene solution (1.8 mmol) were added thereto,
and reflux was conducted in a nitrogen atmosphere for 2 hours. Distilled water was
added to the reaction solution to complete the reaction, and the organic layer was
extracted. A column separation process was conducted using a solvent of n-hexane and
tetrahydrofuran at a ratio of 10:1, stirring was conducted using petroleum ether, and
vacuum drying was conducted to produce an arylamine connection group (16 g, yield
73%). MS: [M+H]+=412.
[132] 2) 4.68 g of compound of Formula b (8.88 mmol) and 8.42 g of
4-(N,N-diphenylamino)phenyl-4-biphenylamine (20.4 mmol) were dissolved in 120 ml
of toluene, 5.89 g of sodium-tert-butoxide (61.3 mmol), 0.24 g of tris(dibenzylidene
acetone)dipalladium(O) (0.41 mmol), and 0.25 ml of 50 wt% tri-tert-butylphosphine
toluene solution (0.61 mmol) were added thereto, and reflux was conducted in a
nitrogen atmosphere for 2 hours. Distilled water was added to the reaction solution to
complete the reaction, and the organic layer was extracted. A column separation
process was conducted using a solvent of n-hexane and tetrahydrofuran at a ratio of
4:1, stirring was conducted using petroleum ether, and vacuum drying was conducted
to produce the compound of Formula 3-4 (5.2 g, yield 45.8 %). MS: [M+H]+= 1279.
[134] EXAMPLE 4: Preparation of the compound represented by Formula 3-21
[136] 1) Synthesis of arylamine (4-(N-phenyl-N-naphthylarnino)phenyl-l-biphenylamine)
to produce the compound represented by Formula 3-21: 14.0 g of
4-bromophenyl-N-phenyl-N-naphthylamine (37.4 mmol) and 6.96 g of
4-aminobiphenyl (41.2 mmol) were dissolved in 200 ml of toluene, 0.47 g of
bis(dibenzylidene acetone)palladium(O) (0.82 mmol), 0.50 ml of 50 wt% tritert-
butylphosphine toluene solution (1.2 mmol), and 11.86 g of sodium-tert-butoxide
(123.4 mmol) were added thereto. After reflux was conducted in a nitrogen atmosphere
for 2 hours, distilled water was added to the reaction solution to complete the reaction.
The organic layer was extracted, and a column separation process was conducted using
a developing solvent of n-hexane and tetrahydrofuran at a ratio of 10:1, stirring was
conducted using petroleum ether, and vacuum drying was conducted to produce an
arylamine connection group (7.5 g, yield 43 %). MS: [M+H]""= 462.
[137] 2) 4.68 g of compound of Formula b (8.88 mmol) and 9.44 g of
4-(N-phenyl-l-naphthylamino)phenyl-4-biphenylamine (20.4 mmol) were dissolved in
120 ml of toluene, 5.89 g of sodium-tert-butoxide (61.3 mmol), 0.24 g of
tris(dibenzylidene acetone)dipalladium(O) (0.41 mmol), and 0.25 ml of 50 wt% tritert-
butylphosphine toluene solution (0.61 mmol) were added thereto, and reflux was
conducted in a nitrogen atmosphere for 2 hours. Distilled water was added to the
reaction solution to complete the reaction, and the organic layer was extracted. A
column separation process was conducted using a solvent of n-hexane and
tetrahydrofuran at a ratio of 4:1, stirring was conducted using petroleum ether, and
vacuum drying was conducted to produce the compound of Formula 3-21 (5.5 g, yield
45 %). MS: [M+H]+= 1379.
[139] EXAMPLE 5: Production of an organic light emitting device
[141] A glass substrate (corning 7059 glass), on which ITO (indium tin oxide) was
applied to a thickness of 1000 A to form a thin film, was put in distilled water, in
which a detergent was dissolved, and washed using ultrasonic waves. In connection
with this, a product manufactured by Fischer Inc. was used as the detergent, and
distilled water was produced by filtering twice using a filter manufactured by Millipore
Inc. After ITO was washed for 30 min, ultrasonic washing was conducted twice using
distilled water for 10 min. After the washing using distilled water was completed,
ultrasonic washing was conducted using isopropyl alcohol, acetone, and methanol
solvents, and drying was then conducted. Next, it was transported to a plasma washing
machine. The substrate was dry washed using oxygen plasma for 5 min, and then
transported to a vacuum evaporator.
[142] Hexanitrile hexaazatriphenylene (hereinafter, referred to as "HAT") of the
following Formula was vacuum deposited to a thickness of 80 A by heating on a
transparent ITO electrode, which was prepared through the above procedure, so as to
form an anode including an ITO conductive layer and an N-type organic material.
Interfacial characteristics between the substrate and a hole injection layer can be
improved using the thin film. Subsequently, the compound of Formula 3-1 was
deposited to a thickness of 800 A on the thin film to form the hole injection layer. NPB
was deposited thereon to a thickness of 300 A so as to form a hole transport layer, and
Alq3 was deposited thereon to a thickness of 300 A to form the light emitting layer. An
electron transport layer material of the following Formula was deposited to a thickness
of 200 A on the light emitting layer to form an electron transport layer.
Lithium fluoride (LiF) having a thickness of 12 A and aluminum having a thickness
of 2000 A were sequentially deposited on the electron transport layer to form a
cathode.
In the above procedure, the deposition speed of an organic material was maintained
at 0.3 - 0.8 A/sec. Furthermore, lithium fluoride and aluminum were deposited at
speeds of 0.3 A/sec and 1.5 - 2.5 A/sec, respectively, on the cathode. During the
deposition, a vacuum was maintained at 1 - 3 X 10-7.
The resulting device had an electric field of 4.76 V at a forward current density of
100 mA/cm2, and a spectrum having a light efficiency of 1.93 Im/W. The operation and
light emission of the device at the above-mentioned actuating voltage mean that the
compound of Formula 3-1, which formed the layer between the thin film on the
substrate and the hole transport layer, functions to inject holes.
[151] EXAMPLE 6: Production of an organic light emitting device
[153] The procedure of example 5 was repeated to produce a device except that the
compound of Formula 3-1 used as a hole injection layer was substituted with the
compound of Formula 3-2.
[154] The resulting device had an electric field of 4.72 V at a forward current density of
100 mA/cm2, and a spectrum having a light efficiency of 1.94 Im/W. The operation and
light emission of the device at the above-mentioned actuating voltage mean that the
compound of Formula 3-2, which formed a layer between a thin film on a substrate and
a hole transport layer, functions to inject holes.
[156] EXAMPLE 7: Production of an organic light emitting device
[158] The procedure of example 5 was repeated to produce a device except that the
compound of Formula 3-1 used as a hole injection layer was substituted with the
compound of Formula 3-4.
[159] The resulting device had an electric field of 4.65 V at a forward current density of
100 mA/cm2, and a spectrum having a light efficiency of 1.92 Im/W. The operation and
light emission of the device at the above-mentioned actuating voltage mean that the
compound of Formula 3-4, which formed a layer between a thin film on a substrate and
a hole transport layer, functions to inject holes.
[161] EXAMPLE 8: Production of an organic light emitting device
[163] The procedure of example 5 was repeated to produce a device except that the
compound of Formula 3-1 used as a hole injection layer was substituted with the
compound of Formula 3-21.
[164] The resulting device had an electric field of 4.60 V at a forward current density of
100 mA/cm2, and a spectrum having a light efficiency of 1.97 Im/W. The operation andlight emission of the device at the above-mentioned actuating voltage mean that und of Formula 3-21, which formed a layer between a thin film on a substrateand a hole transport layer, functions to inject holes.
[166] The compound of the present invention can be used as an organic material layer
material, particularly, hole injection and/or transport materials in an organic light
emitting device, and when applied to an organic light emitting device it is possible to
reduce the actuating voltage of the device, to improve the light efficiency thereof, and
to improve the lifespan of the device through the thermal stability of the compound.
Claims
[1] An organic light emitting device, comprising:
a first electrode;
organic material layer(s) comprising a light emitting layer, wherein at least one
layer of the organic material layer(s) includes the compound of Formula 1 or a
compound of Formula 1 into which a thermosetting or photo-crosslinkable
functional group is introduced; and
a second electrode;
wherein the first electrode, the organic material layer(s), and the second electrode
form layered structure.
[Formula 1]
wherein X is C or Si;
a and b are zero or positive integer;
Y is a bond; bivalent aromatic hydrocarbons; bivalent aromatic hydrocarbons
which are substituted with at least one substituent group selected from the group
consisting of nitro, nitrile, halogen, alkyl, alkoxy, and amino groups; a bivalent
heterocyclic group; or a bivalent heterocyclic group which is substituted with at
least one substituent group selected from the group consisting of nitro, nitrile,
halogen, alkyl, alkoxy, and amino groups;
Yl to Y4 are each independently bivalent aromatic hydrocarbons; bivalent
aromatic hydrocarbons which are substituted with at least one substituent group
selected from the group consisting of nitro, nitrile, halogen, alkyl, alkoxy, and
amino groups; a bivalent heterocyclic group; or a bivalent heterocyclic group
which is substituted with at least one substituent group selected from the group
consisting of nitro, nitrile, halogen, alkyl, alkoxy, and amino groups;
Zl to Z8 are each independently hydrogen; aliphatic hydrocarbons having a
carbon number of 1 - 20; aromatic hydrocarbons; aromatic hydrocarbons which
are substituted with at least one substituent group selected from the group
consisting of the nitro, nitrile, halogen, alkyl, alkoxy, amino, aromatic hydrocarbon,
and heterocyclic groups; a silicon group substituted with aromatic hydrocarbons;
a heterocyclic group; a heterocyclic group which is substituted with
at least one substituent group selected from the group consisting of the nitro,
nitrile, halogen, alkyl, alkoxy, amino, aromatic hydrocarbon, and heterocyclic
groups; a thiophene group which is substituted with hydrocarbons having a
carbon number of 1 - 20 or aromatic hydrocarbons having a carbon number of 6 -
20; or a boron group which is substituted with aromatic hydrocarbons;
Rl to R4, and R6 to R9 are each independently selected from the group
consisting of hydrogen, a substituted or unsubstituted alkyl group, a substituted
or unsubstituted alkoxy group, a substituted or unsubstituted alkenyl group, a
substituted or unsubstituted aryl group, a substituted or unsubstituted arylamine
group, a substituted or unsubstituted heterocyclic group, an amino group, a nitrile
group, a nitro group, a halogen group, an amide group, and an ester group, and
Rl to R4 and R6 to R9 may form aliphatic or hetero condensation rings along
with adjacent groups;
R5 is selected from the group consisting of hydrogen, a substituted or unsubstituted
alkyl group, a substituted or unsubstituted cycloalkyl group, a
substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl
group, and a substituted or unsubstituted heterocyclic group; and
with a proviso that R5 is the aryl group or the heterocyclic group, carbon at an
ortho-position of the aryl or heterocyclic group and R4 or R6 may form a condensation
ring along with a group selected from the group consisting of O, S,
NR, PR, C=O, CRR', and SiRR', wherein R and R' each independently are
selected from the group consisting of hydrogen, a substituted or unsubstituted
alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted
alkenyl group, a substituted or unsubstituted aryl group, a substituted
or unsubstituted arylamine group, a substituted or unsubstituted heterocyclic
group, a nitrile group, an amide group, and an ester group, and may form a condensation
ring to form a spiro compound.
[2] The organic light emitting device as set forth in claim 1, wherein R5 of Formula
1 is an aryl or a heterocyclic group.
The organic light emitting device as set forth in claim 2, wherein R5 of Formula
1 is an aryl or a heterocyclic group, and carbon at the ortho-position of the aryl or
heterocyclic group and R4 or R6 form the condensation ring along with a group
selected from the group consisting of O, S, NR, PR, C=O, CRR', and SiRR' (R
and R' being as defined in Formula 1).
The organic light emitting device as set forth in claim 1, wherein the compound
of Formula 1 is any one of compounds of Formulae 2 to 119:
in the Formulae 2 to 119, A and B are as defined in claim 1.
The organic light emitting device as set forth in claim 4, wherein A and B are
each independently any one of following groups:
The organic light emitting device as set forth in claim 1, wherein the organic
material layer(s) comprise a hole transport layer, and the hole transport layer
includes the compound of Formula 1 or the compound of Formula 1 into which a
thermosetting or photo-crosslinkable functional group is introduced.
The organic light emitting device as set forth in claim 1, wherein the organic
material layer(s) comprise a hole injection layer, and the hole injection layer
includes the compound of Formula 1 or the compound of Formula 1 into which a
thermosetting or photo-crosslinkable functional group is introduced.
The organic light emitting device as set forth in claim 1, wherein the organic
material layer(s) comprise a layer which both injects and transports holes and
which includes the compound of Formula 1 or the compound of Formula 1 into
which a thermosetting or photo-crosslinkable functional group is introduced.