{13} INTERNATIONAL APPLECATION PUBLISHED UNDER THE PATENT COOPERATIONTREATY (PCT}
`
`{£9} World Iatellecteal Property Organization
`international Bureag
`
`{43} International Pablication Date
`24 July 2003 (24.07,2003)
`
`
`
`pPpcT
`
`AEEn
`
`(16) International Publication Namber
`WoO 03/0609056 AZ
`
`{SP Laternational Fateut Ctassifieation’:
`
`HL
`
`é21) International Application Nambers
`:
`A005
`ate: 17 Tanuary 200%
`ii
`“aati
`oF
`(22) International Filing Date:
`17 January 2003 (17.01.2005)
`
`PCIRROSONN IS
`
`(25) Filing Language:
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`(25) Publication Language:
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`Enotish
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`10-02-25 TS dangary 2002 CPS.GL2|
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`AZ, BA, BB BO BE BY BA
`CALCHL EN, ©2, ©KR, CHU,>
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`
`(34) Tide: NEWMATERIAL POR TRANSPORTING ELECTRONS AND ORGANIC BLISCTROLUMIENESCENT DISPLAY
`
`TSING THE SAME
`
`HT
`
`
`
`ATC 937060956
`
`A2 {57} Abstract: Novel materials for electron Injectionfransportation and omiiing layers can greatly improve the siabllity of an or
`
`
`
`at kv vortage levels,
`gunic glecimluminescent display. Mlectrahumingscent displays Incorporating rhea materials prodace bine Haht
`
`
`"Shese novel organic iiateriais inchide compninds inowhich { to 2 imidaxde functional groups are iintroduead in the 2 or 2 S-site
`of 9.10 substivied anthracene. An organic electooluminescemt display with an organic compoundlayer of these materials bas eh
`efficiency, themual stability, operationally statality and naaictaias driving voltage before acd alter operation.
`
`WO
`
`

`

`wo 03/0e0056 A2 TINTED
`
`M4. NOON, OM. POL PEL. PT, RO, REL SCL SB, SE, SG,
`SK, SLOG CPM. UN, TR.CPR CORA, UA, OG, te VE,~¥N,
`YU ZA, AM. AW.
`
`Published:
`oo
` ouGhout international search reper! and ar be republished
`wpor reoeigot of that report
`
`84) Designated States Geofonad}: ARTPO patent (3H, GM,
`
`KE LS, MW, MZ. SB, SE,See at UG, 2M, “~ Far deo-iotter codes and oiker abbreviations, refer io fhe “CGrusd-
`
`Taropean patent iN
`
`8CM, GA,GN,
`BS, PEPRGR, GR, HL
`
`SK, TH). OAFL patent GF
`OK, CAY, MIL. MR. NE, SN, PD, Th.
`
`anoecaciag af the begin~
`ance Notes on Cades and ARbbrestatines”
`Fest of each reeudar iS8me orehe PCP Gasetie.
`
`

`

`WO 8S/AG0086
`
`POCYT/RROS112
`
`- 4-
`
`NEW MATERIAL FOR TRANSPORTING ELECTRONS AND ORGANIC
`ELECTROLUMINESCENT DISPLAY USING THE SAME
`
`This application claims priority of Korean Patent Application No.
`
`2002-0003025, filed January 18, 2002, the entire content of which is hereby
`
`incorporated by reference.
`
`BACKS
`
`ND OF THE INVENTION
`
`Field of the Invention
`
`The present
`
`invention relates ta a novel material
`
`for electron
`
`transportation and emitting layers, and an organic slectroluminescent display
`
`16
`
`using the same.
`
`Description of the Related Art
`
`An electroluminescent display is a luminescent device using
`
`electrolurminescence of a solid fluorescent material.
`
`Current practical
`
`technology uses an inorganic electroluminescent display with an inorganic
`
`material
`
`as
`
`an : illuminant.
`
`However,
`
`the
`
`conventional
`
`inorganic
`
`electroluminescent display requires a high voltage of 100 V or more for
`
`luminescence, and ft
`
`is difficull for Rh to emit blue light) As a result, full
`
`colorization by the thres colors of RGB {red, green, blue) is difficult.
`
`Although studies
`
`of electrolurninescent devices using organic
`
`materials have attracted attention for a long time, only a small number of
`
`devices have been commercialized due to their lack of stability and low
`
`efficiency compared to conventional display devices such as fiquid crystal
`
`displays and cathode ray tubes. Organic electroluminescent displays are
`
`

`

`WOO3AK0086
`
`PCTARROSANHLL2
`
`- Bo
`
`based on the theory that electrons and holes injected into an organic thin film
`
`of small molecules (sublimable malecules) or a palymer by way of an anode
`
`and a cathode form an exciton, and light with a specific wavelength is
`
`generated when the high-energy exciton returns to Ns ground states. This
`
`th
`
`effect was first discovered with a single crystal of anthracene by Pape, et al.
`
`in 1965 (M. Pope et al., J. Chem. Phys., 42, 2540, 1965).
`
`In 1987, an
`
`organic electroluminescent display with a laminated structure of a function-
`
`separation type dividing organic material into a hole transporting layer and a
`
`emitting layer was suggested by Tang, from Kadak Company, and it has been
`
`16
`
`confirmed that low voltage of 10 V or less and high luminance can be
`
`obtained (Tang, GC. W.; VanSlyke, S. A. Appl Phys. Leff. 1987, 57, 913.}.
`
`Since then, organic electroluminescent displays began to attract attention.
`
`At present, studies of organic slectroluminescent displays with this sarne
`
`function-separation type laminated structure are progressing.
`
`The structure of a conventional organic eiectraluminescent display
`
`contains, as shown in Fig. 1, a substrate (1), an anode (2), a hole injection
`
`layer (3) for receiving holes fram the anode, a hole transportation layer (4) far
`
`transporting holes, an emitting layer 6) in which holes and electrons are
`
`bound to emil light, an electron transportation layer (6) for receiving electrons
`
`28
`
`from a cathode to transfer them to the emitting layer, and a cathade (7). The
`
`emitting layer (5) can be composed of two or more different molecules to
`further increase the device efficiency by separating the roles of light emission
`
`and transporting both electrons and holes.
`
`Generally,
`
`the molecule
`
`transporting both holes and electrons is called a host molecule and the other
`
`boon
`
`molecule emilting light
`
`is called a dopant moiecule. Usually, the emitting
`
`

`

`Wd? 03/060936
`
`POCT/RROSA2
`
`~ §-
`
`layer (5) is composed of a majority of host molecules and small amounts ( to
`
`20 %} of dopant molecules. The requirements of a dopant molecule include
`
`high fluorescent or phosphorescent efficiency with proper band structure
`
`relative to the hast molecule. According to the circumstances, a small
`
`Or
`
`amount of fluorescent or phosphorescent dye is doped on the electron
`
`transportation layer (6) or on the hole transportation layer (4) to comprise an
`
`emitting layer therein without a separate emitting layer (5). Also i is possible
`
`to dope more than one layer such as electron transporting, emitting and hole
`
`transporting layers to improve the operational stability or to have multiple
`
`1
`
`G
`
`emissions. Organic thin films between two electrodes are farmed by vacuum
`
`deposition, spin coating,
`
`ink jet printing,
`
`roll coating, etc.
`
`For efficient
`
`injection of electrons from the cathode, a separate electron injection layer is
`
`often inserted.
`
`The reason for manufacturing an organic electroluminescent display
`
`with a multHlayered thin film structure includes stabilization of the interfaces
`
`between the electrodes and the organic layers.
`
`in addition,
`
`in organic
`
`materials, the mobility of electrons and holes significantly differ, and thus, if
`
`appropriate hole transporiation and electron transportation layers are used,
`
`holes and electrons can be efficiently transferred to the luminescent layer.
`
`g
`
`0
`
`Also,
`
`if the density of the holes and electrons are balanced in the emitting
`
`layer, luminescence efficiency can increase.
`
`The proper combination of organic layers described above can
`
`enhance the device efficiency and lfetime. However,
`
`it has been very
`
`difficult to find an organic material that satisfies all the requirements for use in
`
`bo om
`
`practical devices.
`
`For example,
`
`tis-{8-hydroxyquinoline} aluminum (Alg3)
`
`

`

`Wd? 03/060936
`
`POCT/RROSA2
`
`- G-
`
`has been used as an electron transport material for more than 15 years, and
`
`there have been many publications and patents claiming they have superior
`
`properties. Therefore,
`
`it
`
`is crucial to find a molecule that has superior
`
`properties compared to the conventional material in all practical aspects, such
`
`on
`
`as high efficiency, thermal stability, operational stability and maintaining the
`
`driving voltage before and after operation.
`
`SUMMARY OF THE INVENTION
`
`The invention is madein consideration and is directed at overcoming
`
`the problems of the conventional art electroluminescent displays. An object
`of the invention, In part, is to provide a novel material for electron transport
`
`and emitting layers that can largely improve luminescence efficiency, stability,
`
`and display lifetime of an organic electroluminescent display using the same.
`
`The invention, in pari, provides a compound represented by Chemical
`
`Formula 1, a compound represented by Chemical Formula 2, a compound
`
`represented by Chemical Formula 3, a compound represented by Chemical
`
`Formula 4, and a compound represented by Chemical Formula 5:
`
`

`

`WO §3.4)100056
`
`PCTAK RO300112
`
`- §-
`
`{Chemical Formula 1)
`
`|
`Ri
`— ee, OOa Ar
`oo Ja
`[
`~
`ote ~ 2
`~~
`“y ~
`R2
`
`Rg
`
`for,
`i
`if
`NOS
`Baal
`\
`Rp4
`
`.
`
`(1)
`
`(Chemical Formula 2)
`
`a \
`
`NTS _f
`oofofl
`.
`oo” ™
`No ~ ““So —
`ry “RA
`l
`SY
`Ye
`
`-_
`2)
`
`fi
`S
`RI NO
`3
`Bl
`/
`ONA , et OTN
`Ra
`aN
`5
`
`

`

`WOO3AK0086
`
`PCTARROSANHLL2
`
`(Chemical Formula 4}
`
`~ §-
`
`Rt
`
`we,
`
`[
`No we SI
`
`
`
`|p
`
`NN
`
`s,
`
`R4
`
`am
`
`i
`te
`tS
`OH
`uy~Ss
`
`
`
`—_f
`No QL!
`[of
`N
`4
`
`(4)
`
`poe
`
`A
`
`iNON
`ul cn’
`AK
`R4
`
`AY
`
`(5)
`
`(Chemical Formula 5)
`
`.
`
`.
`
`RY
`e1 :OS
`
`Noe we aoe Se sean
`|
`an.
`®J R4
`
`R2
`
`ist
`
`wherein
`
`R' and PR’ are independently cr simultaneously a hydrogen atom, a
`
`Gis, aliphatic hydrocarbon, benzene, naphthalene, biphenyl, anthracene, or a
`
`group derived from an aromatic heterocycle or an aromatic ring, and R' and
`R* cannot simultaneously be hydrogen atoms;
`
`10
`
`Ar is benzene, naphthalene, biphenyl, anthracene, or a group derived
`
`from an aromatic heterocycle or an aromatic ring:
`
`FR?
`
`is a hydrogen atom, a C,,, alkyl or aliphatic hydrocarbon, a
`
`substituted or unsubstituted benzene, naphthalene, biphenyl, anthracene, or
`
`an aromatic heterocycle or aromatic ring;
`
`

`

`WO 03/860956
`
`PCTKROSNOHI2
`
`- F-
`
`R* is a hydrogen atom, a ©,,. alkyl or aliphatic hydrocarbon, benzene,
`
`naphthalene, biphenyl, anthracene, or a group derived from an aromatic
`
`heterocycle or aromatic ring.
`
`The invention,
`
`in part, also provides an organic electroluminescent
`
`9
`
`device having an organic layer containing an organic compound selected
`
`fram compounds represented by the above Chemical Formula 1, Chemical
`
`Formula 2, Ghemical Formula 3, Chemical Formula 4, or Chemical Farmulia 5,
`
`or a mixture thereof,
`
`in the electroluminescent display of the invention, at least one of the
`
`10
`
`organic jayers can be located between an anode that injects holes and a
`
`cathode that injects electrons. Also, at least one of the organic layers can
`
`be an electron injectionfransporting layer performing functions of electron
`
`injection and transportation. Further, at least one of the organic layers can
`
`be an electron injection/transporting and emitting layer performing functions of
`
`feton
`
`electron injection and luminescence. Yet further, at feast ane of the organic
`
`layers oan be an electron transportation and emitting layer performing
`
`functions of electron transportation and light emission. Also, one of the
`
`organic jayers can be an emitting layer performing the function of light
`
`emission.
`
`2a}
`
`The invention,
`
`in part, pertains to an organic electroluminescent
`
`display having a substrate, an anode over the substrate, a hole injection layer
`
`over the anode, a hole transportation layer over the hole injection layer, an
`
`emitting layer over the transportation layer, an electron transporting layer over
`
`the emitting layer and a cathode over the electron transporting layer; and the
`
`iS CA
`
`organic compound is contained in at least the emitting layer. Alternatively,
`
`

`

`Wd? 03/060936
`
`POCT/RROSA2
`
`- §-
`
`the organic electroluminescent display has a substrate, an anode over the
`
`substrate, a hole injection layer over the anode, a hole iransporiation layer
`
`over the hole injection layer, an emfting layer over the hole transportation
`
`layer, an electron injecting/ransporting Jayer over the emitting layer, and a
`
`uo
`
`cathode over the electron transportation layer; and the organic compound is
`
`contained in at least one of the electron infectingAransporting layer.
`
`it is to be understood that bath the foregoing general description and
`
`the following detailed description are exemplary and explanatory and are
`
`intended to provide further explanation of the invention as claimed.
`
`10
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The accompanying drawings are included to provide a further
`
`understanding of the invention. The drawings iustrate embodiments of the
`
`invention and together with the description serve to explain the principles of
`
`on
`
`the embodiments of the invention.
`
`Fig.
`
`1
`
`iS a cross sectional view showing an example of an organic
`
`electroluminescent display.
`
`Fig. 2 shows the brightness of the device of Example 6 as a function
`
`of driving time.
`
`bo
`
`Fig. 3 shows the brightness of the device of Comparative Exampie 1
`
`as a function of driving time.
`
`Fig. 4 shows the brightness of the device of Comparative Example 4
`
`as a function of driving time.
`
`Fig. & shows the voliages of Example 6, Comparative Example 1 and
`
`boce
`
`Comparative Example 2 as a function of driving time.
`
`

`

`WOO3AK0086
`
`PCTARROSANHLL2
`
`- g-
`
`Fig. 6 shows the brightness of the device of Example 7 as a function
`
`of driving time.
`
`Fig. 7 shows the voltages of Example 7 and Comparative Exampis 3
`
`as a function of driving firme.
`
`in
`
`DETAILED DESCRIPTION
`
`Advantages of the invention will become more apparent from the
`
`detailed description given herein after. However,
`
`it should be understood
`
`that the detailed description and specific examples, while indicating preferred
`
`1
`
`embodiments of the invention, are given by way of dlusiration only, since
`
`various changes and modifications within the spirit and scope of the invention
`
`will become apparent fo those skilled in the art from this detailed description.
`
`The invention provides a novel material in which 1 to 2 imidazole
`
`containing groups are introduced at 2 or 2,6-sites of 9,10 substituted
`
`eeCyt
`
`anthracene. This material
`
`is contained in an organic compound layer of
`
`organic electroluminescent (EL) devices to improve luminescence efficiency
`
`and lifetime, and an organic electrcluminescent devices comprising the same
`
`in an organic compound layer.
`
`The structure of organic electroluminescent devices to which the
`
`a0
`
`novel material of the invention can be applied will be explained.
`
`Fig. 1 is a cross-sectional view showing an example of the applicable
`
`structure of an organic electroluminescent dispiay. Reference numeral
`
`1
`
`indicates a substrate, 2 an anode, 3 a hole injection layer, 4 a hole
`
`transportation layer, 5 an emitting layer, G an electron transportation layer,
`
`and 7 a cathode.
`
`

`

`WOO3AK0086
`
`PCTARROSANHLL2
`
`-
`
`4O-
`
`The substrate (1) supports of an organic electroluminescent device,
`
`and a silicon wafer, a quartz or glass plate, a metal plate, a plastic film or
`sheet, etc. can be used. Also, the substrate layer can be a thin protective
`
`layer on top of the anode when the device fabrication process starts from the
`
`cathode side.
`
`On the substrate (1}, an anode (2) is located. The anode (2) injects
`
`holes into a hole injection layer @) located thereon.
`
`For this, a metal such
`
`as aluminum, gold, silver, nickel, palladium, platinurn, etc., or a material with a
`
`large work function such as indium-tin oxide GTO}, indium-zince oxide (ZO),
`
`1G
`
`gic. can be used, and a conductive polymer such as carbon black,
`
`polythiophene, polypyrrole, or polyaniline, etc. can also be used,
`
`Over the anode (2), a holeinfection layer (3) is located. Material for
`
`the hole injection Jayer (3) should have high hole iniection efficiency fram the
`
`anode and should efficiently transport infected holes.
`
`For this, the material
`
`should have a low fonization potential, high transparency to visible fight rays
`
`and have superior stability for holes.
`
`Over the hole injection layer @), a hole transportation layer (4)
`
`is
`
`located. The hole transporiation fayer (4) receives holes from the hole
`injection layer (8) to transport them fo an emitting layer (5) located thereon,
`
`a
`
`and it also has a high hole transportation degree, stability for holes and
`
`blocks electrons well.
`
`in addition to these general requirements,
`
`If applied
`
`for a display for vehicles, heat resistance of the display is required, and a
`
`material having a glass transition temperature (Tg) over 70°C is preferable.
`
`Materials satisfying these requirements include NPD {or NPB) QN’,N-di{t-
`
`Bi
`
`naphthy)-N,N'-diphenyl-1 1 -diphenyl-4-4"
`
`diamine),
`
`spiro-arylamine
`
`

`

`WO 03/060056
`
`PCTASROSM6112
`
`~
`
`t1-
`
`compounds,
`
`perylene-arylamine
`
`compounds,
`
`azacycioheptatriene
`
`compounds, bis(diphenylvinylphenylanthracene,
`
`silicon-germanium oxide
`
`compounds, silicon arylamine compounds, etc.
`
`Overthe holetransportation layer (4), an emitting layer (5) is located.
`
`cn
`
`in the emitting layer (5), holes and electrons respectively injected from the
`
`anode (2) anda cathode (7) recombine to emit light, and the emitting layer (5)
`
`is farmed from a material with high quantum efficiency. To make a stable
`
`device, it is crucial to have an emitting material which is stable to both holes
`
`and electrons.
`
`HH the emilting material lacks stability to one of the carriers
`
`1
`
`feither a hole or an electron), if is necessary to provide special circumstances
`
`for the omitting material not
`
`to be exposed to the carrier, which can
`
`deteriorate the emitting material. One method to evade such a condition is
`
`to dope a fluorescent or phosphorescent material
`
`that can accept and
`
`transport the problernatic carriers instead of the host material. Another
`
`method is to Introduce an excessive amount of the opposite carrier to
`
`minimize the chance of having the problematic carrier to attack the neutral
`
`host material. Therefore, it is very difficult to produce such conditions while
`
`maintaining optimum balancing of both carriers and introducing the proper
`
`amount of dopant material to maximize the quantum efficiency. Also, the
`
`choice of dopants capable of producing such a condition would be limited.
`For this reason, it is very important to have emitting material having stabilities
`
`io both carriers.
`
`Materials used for emitting layers include, for grean, Alg3; and for
`
`blue, Balg
`(8-hydroxyquinoline
`diphenyleihyeny)-1,7 -bipheny},
`
`beryllium sal}, DPVBi
`(4,4’-bis(2.2-
`spiro-DPVBi
`(spiro-4,4’-bis(2,2-
`
`

`

`Wd? 03/060936
`
`POCT/RROSA2
`
`- 12-
`
`diphenylethyenyl1,1-biphenyl), LIPBO (@-2{-benzoxazoy)-phenollithium salt},
`
`aluminum-quinoline metal complexes, derivatives of imidazole, thiazole, and
`
`oxazole and also their metal complexes, etc.
`
`in order to increase blue
`
`luminescenceefficiency, a small amount of perylene and BezVBi (3,910 .1’-
`
`3
`
`biphenyi}-4,4"-diyidi-2, 1-sthenediyl}bis(Q-sthy)-QH-carbazole,
`
`or
`
`DSA
`
`(distrylamine}, can be doped therein. For red, a small amount of material
`
`such
`
`as DOJTB
`
`(2-(1,1-dimethylethy!)-6-[2-(2,3,6,7-tetrahydro-1 ,1,7,7-
`
`tetramethyl-1H,5H-benzotl pquinalizin-9-y) ethenylj4H -pyran-4-yiidens}-
`
`propanedinitrile) is doped on green emitting material.
`
`HW the emitting layer is
`
`formed by a process such as ink jet printing, roll coating, spin coating, etc., a
`
`polypheyilenevinylene (PPV) polymer or polyfuorens, etc. can be used for the
`
`emitting layer (5).
`
`An electron transportation layer (6) is located over the emitting layer
`
`(6). The electron transportation layer (6) requires a material that has a high
`
`electron injection efficiency from a cathode (7) located thereon and that can
`
`efficiently transport the injected electrons. For this, it should be made of a
`
`material having a high electron affinity and mobility and superior stabilty for
`
`electrons. Also, the electron transportation layer (6) requires stable interface
`
`formation with the cathade material, otherwise delamination of the cathode
`
`layer and inefficient electron injection during operation occurs, resulting in a
`
`significant voltage increase. A voltage increase due to inefficient electron
`
`injection makes the display device less efficient and requires more power
`
`consumption.
`
`Ajso,
`
`it has been known that doping of the electron
`
`transporiation fayer with conductive metals having low work-functions
`
`enhances the electron injection from the cathode and forms a stable interface
`
`

`

`WOO3AK0086
`
`PCTARROSANHLL2
`
`- 43-
`
`with metallic cathode layers. Materials used for the electron transportation
`
`layer
`
`include aromatic compounds such as tetraphenyl butadiene, etc.
`
`(Japanese Laid Open Patent Publication No. Sho 57-51781}; metal
`
`complexes such as 8-hydroxyquinoline, efc. Japanese Laid Open Patent
`
`Publication No. Sho 59-194393); metal complexes of 10-hydroxy benzofh]
`
`quinoline (Japanese Laid Open Patent Publication No. Hel 6-322362);
`
`cyclopentadiene derivatives (Japanese Laid Open Patent Publication No. Hei
`
`2-289675); bis styryl benzene derivatives (Japanese Laid Open Patent
`
`Publication No. Hei 1-245087 and Japanese Laid Open Patent Publication No.
`
`1D
`
`Heil 2-222484); perylene derivatives (Japanese Laid Open Patent Publication
`
`No. Hel 2-189890 and Japanese Laid Open Patent Publication No. Hei 3-
`
`791); p-phenylene derivatives (Japanese Laid Open Patent Publication No.
`
`Hei 8-33183);
`
`imidazole derivatives (U.S Pat, Patent No. 5,766,779}; and
`
`oxazole derivatives (Japanese Laid Open Patent Publication No. Hei 11-
`
`15
`
`345686), etc.
`
`A cathode (7) is located over the electron transporiation layer (6).
`
`The cathode (7} injects electrons into the electron transportation layer (6).
`
`As materials for the cathode, a metal having a low work function is preferable.
`
`Particularly, an appropriate metal such as fin, magnesium, indium, calcium,
`
`au
`
`sodium, ithium, aluminum, silver, etc., or an appropriate alloy thereof can be
`
`used. Additionally, an electrode with a double-layered structure such as
`
`fthium fluoride and aluminum,
`
`lithium oxide and aluminum, strontium oxide
`
`and aluminum, etc. can be used. Although aluminum is known to have a
`
`work function of 4.2 eV, which Is not low enough for efficient electron injection,
`
`>on
`
`@ thin layer of Insulating material enhances the electron injection by tunneling
`
`

`

`WO G34O8kG
`
`FACTAR REGSANOTER
`
`- 74-
`
`effect. Also, it is possible to co-depasit the cathodic metals with the electran
`
`transporting layer to enhanceinterfacial strength and electron injection.
`
`The four layer organic structure located between opposite electrodes,
`
`exemplified above, can be altered. Adding more organic layers such as a
`
`5
`
` hole-blocking or an electron blocking layer can improve the performance of
`
`the organic electroluminescence devices. Also, using less than four layers
`
`can simplify device structure.
`
`Accordingly, at least one organic compound layer comprising the
`
`organic compound represented by the above Chemical Formutas 1 to 5 of the
`
`10s
`
`invention is located between an anode and a cathode. As explained, the
`
`novel material of the invention is contained in an organic compound layer
`
`between an anode and a cathade, preferably an electron, transportation, and
`
`emitting layers, thereby largely improving efficiency and device lifetime of an
`organic electroluminescent device.
`Also, an organic electroluminescent
`
`16
`
`device that
`
`lowers operation vollage and has superior stability can be
`
`provided. A sullable dopant can be added fo the material used in the
`invention to simultaneously perform functions of the electran transportation
`
`layer and the emitting layer without a separate emitting layer.
`
`Thus far, organic small molecules having imidazole groups, oxazole
`
`20
`
`groups, and ihlazole groups have been frequently reported as materials for
`
`electron injection and transportation layers. However, before such materials
`
`were reported as materials for electron transportation,
`
`ft had already been
`
`reported In EP 0700917 A2 (Motorola Company) that metal complexes of
`
`such materiais were applied for blue luminescent or blue-green luminescent
`
`fn
`
`ort
`
`layers of an organic electroluminescent display. Additionally, U.S. Patent
`
`

`

`Wd? 03/060936
`
`POCT/RROSA2
`
`~
`
`t5-
`
`Nos. 5,766,779 and 5,645,948 discuss organic electroluminescent displays in
`
`which organic materials having imidazole, thiazole, or oxazole groups are
`
`used for electron transportation layers and luminescent layers. According to
`
`U.S. Patent No. 5,766,779, 2 to 8 of such hetero functional groups are
`
`contained in one molecule that was applied for an electron transportation
`
`layer of an organic electroluminescent device.
`
`In addition, U.S. Patent No.
`
`5,645,948 used an organic material comprising 3 ta 8 of
`
`the same
`
`heterofunctional groups in one molecule applied for an emifting layer.
`
`in
`
`contrast, the invention has 1 to 2 heterofunctional groups are introduced at 2-
`
`1
`
`or 2,6- positions of a 9,1 0-substituted anthracene moiety for use as a material
`
`for electron injection, transportation and light emitting layers.
`
`TPBI (Chemical Formula 6} was introduced by Kodak Company in
`
`7996 and discussed in U.S. Patent Nos. 5,645,948 and 5,766,779 has been
`
`known as a representative material for electron transportation and blue
`
`emission. TPBI has an imidazole group, and as shown in the following
`
`Chemical Formula 6, 8 contains three N-phenyl benzimidazole groups in
`
`1,3,5-substitution sites of benzene and performs functions for transporting
`
`electrons or as an emitting layer. However,
`
`in practical applications for
`
`displays, TPB! has flower operational stability as an electron transporting
`
`&
`
`material as well as an emitting material than the material claimed in the
`
`invention, as is shown in the experimental parts the disclosure.
`
`

`

`Wd? 03/060936
`
`POCT/RROSA2
`
`(Chemical Formula 8)
`
`6)
`
`~aN SL fen
`% ¢
`. \ #
`No io "N
`eo .,
`Peo
`& a aL -
`NOON SY
`
`i
`
`}
`
`os
`
`\ac
`
`s
`
`2
`
`V4
`
`In addition, Japanese Laid Open Patent Publication Hel 11-345686
`
`discusses a material for electron transportation disclosed in containing an
`
`us
`
`oxazole group and a ihiazole group as shown in the following Chemical
`
`Formulas 7 ta 10, and it has been reported to be applicable for a
`
`luminescence layer. However, ff put to practical use, it is not satisfactory in
`
`terms of operation voltage, brightness, and Hfe cycle of a display.
`
`(Chemical Formula 7)
`
`10
`
`ae ae
`-BuT
`
`(Chemical Formuta 8}
`
`Bu oy
`
`aYr°,—“s, oo ’oO“YTAy
`weee IBl aN -a X “
`. wok
`awFa,A
`ee
`‘
`N oe ‘Me 8}
`
`(Chemical Formula 9}
`
`ceeCOrktS
`
`‘Bu {9)
`
`

`

`WOO3AK0086
`
`PCTARROSAW LIZ
`
`-
`
`4IF-
`
`(Chemical Formula 10)
`
`CH
`Fst
`Aon<)p yTkYH Co,wi|3
`\ SHO)
`
`CHL
`
`(10)
`
`As seen from the conventional art, it had been understood that any
`
`organic material except an organometal complex such as Alq3 is difficult to
`
`nractically use for a display. Thus, the present inventors synthesized a novel
`
`organic material represented by the above Chemical Formulas 1
`
`to 5,
`
`selected apprapriate hole injection and hole transportation, and emitting
`
`layers, and then applied it for electron injection and transportation layers.
`
`Therefore,
`
`they could obtain much superior resulis in terms of operation
`
`voltage, efficiency and lifetime of the display.
`
`Alisa, when the organic
`
`material represented by the above Chemical Formulas 1 to 5 is used as an
`emitting layer with a proper selection of hole Injection, hole transportation and
`
`electron transporting Jayers, one could obtain an organic eleciroluminescent
`
`devices with superior operation voliage, and ifetime of the display
`
`The anthracene moiety used for novel emitting layers by the present
`
`inventors had been studied by Kodak Company, TDK, é6tc.
`
`in the U.S. and
`
`disclosed in various patents, but the historical origin of this anthracene
`
`technology had already begun in the early 1960's. Helfrich and Pope first
`
`announced the organic eleciroluminescence phenomenon using anthracene
`
`single crystals, buf there was a lot of problems in practical use because the
`
`luminescence efficiency was low and a high vollage was required (WW. Helfrich,
`
`W. G. Schneider, Phys, Rev. Lett. 14, 229, 1965. M. Pope, H. Kallmann, J.
`
`

`

`Wd? 03/060936
`
`POCT/RROSA2
`
`~ 8-
`
`Giachino, J. Chem. Phys., 42,2540, 1965).
`
`Therefore, in order to develop an organic electroluminescent display
`
`having Superior performance,
`
`it is very important which functional group is
`
`introduced at which site of the 10 reaction/substitution sites of anthracene.
`
`CFI
`
`Most of the anthracene derivatives announced by Kodak Company and TDK,
`
`eic. are characterized by only being used for a juminescent layer of an
`
`organic
`
`eslectroluminescent device.
`
`Although
`
`anthracene derivatives
`
`disclosed in Japanese Laid Open Patent Publication No. Hei 11-345686 were
`
`asserted to be applicable for a juminescent
`
`layer and an electron
`
`transportation material, it was only included In the broad claims of the patent,
`
`and there was no mention in the Synthesis example or Examples, and so far
`
`there have been no examples for practically using it for electron injection and
`
`transportation materials.
`
`in order to overcome these problems, the present inventors used the
`
`LS
`
`2, 6, 9, 10 substitution sites of anthracene, while Japanese Laid Open Patent
`
`Publication No. Hel 11-345686 is characterized in that two substitution sites of
`
`{ and 5, 7 and 8, or 2 and 6 were used, and the 9, 10 sites were substituted
`
`by hydrogen ators.
`
`The structural characteristics of the compounds represented by the
`
`above Chemical Formulas 1 to 5 synthesized by the present inventors are as
`
`follows. Anthracene has 10 substitution sites, and the present inventors
`
`focused on discovering an optimal compound while varying the four
`
`substitution sites of 2, 6, 9, 10 of anthracene, which is most characteristic in
`
`the present invention. Specifically, for 9, 10 sites of anthracene, aromatic
`
`fooh
`
`hydrocarbons such as phenyl, naphthyl, biphenyl, etc. were independently or
`
`

`

`WOO3AK0086
`
`PCTARROSANHLL2
`
`~ 49-
`
`simultaneously substituted.
`
`For the
`
`2 or 2,6 sites, imidazole groups were
`
`independently or simultaneously substituted, or aromatic hydrocarbons such
`as phenyl,
`ete. were substituted,
`and then imidazole groups were
`
`independently or simultaneously substituted to synthesize the material.
`
`os
`
`When the material is used for a layer having an electron transpartation
`
`capacity in an organic electroluminescent display, operation voltage and Iife
`
`cycle of the display can be simultaneously improved.
`
`Representative
`
`materials will be explained in the following Examples in more detail.
`
`Representative materials of the present invention having electron transporting
`
`13
`
`and emitting capacity are compounds of the following Chemical Formulas 1-1
`
`to 1-10, Chemical Formulas 2-1 fo 2-5, Chemical Formulas 3-1 to 9-5,
`
`Chemical Formulas 4-1 to 4-5, and Chemical Formulas 5-1 to 5-5.
`
`(Chemical Formula 1-1)
`
`(Chemical Formula 1-2)
`
`
`
`Jeo oat
`
`(1-1)
`
`(1-2)
`
`

`

`Wd? 03/060936
`
`POCT/RROSA2
`
`20 -
`
`{Chamical Formula 1-3)
`
`(Chemical Formula 1-4}
`
`(CT OAM
`
`Jf
`cy OY
`eggSgtiSe oF
`(es Ay
`Sy
`
`os - bd
`
`wie
`
`a wg
`
`~ oe~ee
`
`weA
`SS)
`
`(1-3)
`
`{1-4
`
`(1-5)
`
`

`

`WO G34O8kG
`
`FACTAR REGSANOTER
`
`~ 2 -
`
`(Chemical Formula 1-6)
`
`
`
`{Chemical Formula 1-7}
`
`(1-7)
`
`Se
`
`we
`pe
`
`ILt,
`
`in3
`I
`ey
`wa
`
`_y
`
`f
`
`oe
`ng
`a ee
`¥
`
`ah
`ee,
`7 :$
`;
`
`“
`
`(1-8)
`
`

`

`WO §3.4)100056
`
`PACPAR RGSAO TED
`
`- 22.
`
`(Ghemical Formula 1-9)
`
`OO
`
`
`
`(1-9)
`
`5s
`
`{Chemical Formula 1-10)
`
`y
`<a
`\, Pett
`
`{
`L
`oN a Nz
`LLe
`i
`
`(1-10)
`
`

`

`WO G34O8kG
`
`FACTAR REGSANOTER
`
`(Chemical Formula 2-1)
`
`aN ite,
`
`x
`
`‘
`
`a
`com
`
`e
`
`.NoeJl ae
`‘Sone
`
`Net
`all
`POON
`
`§
`
`(Chemical Formula 2-2)
`
`oe,
`
`age,ce a
`
`a4
`rte fo
`& Qe i .
`® ew \
`
`oth
`
`(2-1)
`
`a
`
`(2-2)
`
`

`

`WO §3.4)100056
`
`PACPAR RGSAO TED
`
`a4 ~
`
`(Chemical Formula 2-3)
`
`{Chemical Formula 2-4)
`
`(2-3)
`
`(2-4)
`
`
`
`

`

`WOO3AK0086
`
`PCTARROSANHLL2
`
`(Chemical Formula 2-5)
`
`(2-5)
`
`(Chemical Formula 3-1}
`
`(Chemical Fo