The application requires the rights and interests of korean patent application No.10-2005-0126101 that submits on December 20th, 2005 in Korea S Department of Intellectual Property and the No.10-2005-0129922 that submitted on December 26th, 2005, and the disclosure that this paper introduces them in full as a reference.
Summary of the invention
One aspect of the present invention provides a kind of oganic light-emitting display device, comprising: first electrode; Second electrode; Be inserted in the emission layer between first and second electrodes; Be inserted in first hole injection layer between first electrode and the emission layer; Be inserted in second hole injection layer between first hole injection layer and the emission layer; Be inserted in the charge generation layer between first hole injection layer and second hole injection layer, charge generation layer is doped with p-type dopant.
Charge generation layer can comprise the compound of representing with formula 1:
Formula 1
Wherein R is itrile group (CN), sulfuryl (SO
2R '), sulfoxide group (SOR '), sulfonamide base (SO
2NR '
2), sulfonic group (SO
3R '), nitro (NO
2) or trifluoromethyl (CF
3); And wherein R ' has 1-60 carbon atom and alkyl, aryl or heterocyclic radical for not replacing or being replaced by amine, acid amides, ether or ester.
P-type dopant can comprise and is selected from six itrile group six azepines, three penylenes (hexanitrilehexaazatriphenylene), tetrafluoro-four cyano quino bismethane (tetrafluoro-tetraacyanoquinodimethane, F
4-TCNQ), FeCl
3, F
16At least a in CuPc and the metal oxide.Metal oxide can comprise and is selected from vanadium oxide (V
2O
5), rheium oxide (Re
2O
7) and tin indium oxide (ITO) at least a.P-type dopant can have lowest unoccupied molecular orbital (LUMO) energy level.In first and second hole injection layers at least one can comprise the material with highest occupied molecular orbital (HOMO) energy level.Difference in lowest unoccupied molecular orbital (LUMO) energy level of p-type dopant and first and second hole injection layers between highest occupied molecular orbital (HOMO) energy level of the material of at least one can be between pact-2eV peace treaty+2eV.
Equipment can comprise a large amount of pixels, and charge generation layer can form the shared layer of at least two pixels.Charge generation layer can have the thickness of about 10 -Yue 200 .Charge generation layer can have the thickness of about 20 -Yue 80 .
Oganic light-emitting display device also can comprise the hole transport layer that is inserted between first electrode and the emission layer, and is inserted in hole blocking layer, electron transfer layer and the electron injecting layer between the emission layer and second electrode at least one.Oganic light-emitting display device also can comprise the electron transfer layer that is inserted between second electrode and the emission layer.Oganic light-emitting display device also can comprise substrate, and wherein first electrode is formed on the substrate.Oganic light-emitting display device also can comprise the electron injecting layer that is inserted between the electron transfer layer and second electrode.Oganic light-emitting display device also can comprise the hole blocking layer that is inserted between electron transfer layer and the emission layer.
Another aspect of the present invention provides a kind of electronic equipment that comprises above-mentioned oganic light-emitting display device.
Another aspect of the present invention provides a kind of method of making oganic light-emitting display device, and this method comprises: form first hole injection layer on first electrode; Form charge generation layer on first hole injection layer, charge generation layer is doped with p-type dopant; With formation second hole injection layer on charge generation layer.
This method also can comprise: form emission layer on second hole injection layer; With formation second electrode on emission layer.This method also can comprise: form hole transport layer after forming second hole injection layer and before forming emission layer; With after forming emission layer and form at least one that forms before second electrode in hole blocking layer, electron transfer layer and the electron injecting layer.
Charge generation layer can comprise the compound of representing with formula 1:
Formula 1
Wherein R is itrile group (CN), sulfuryl (SO
2R '), sulfoxide group (SOR '), sulfonamide base (SO
2NR '
2), sulfonic group (SO
3R '), nitro (NO
2) or trifluoromethyl (CF
3); And wherein R ' has 1-60 carbon atom and alkyl, aryl or heterocyclic radical for not replacing or being replaced by amine, acid amides, ether or ester.
P-type dopant can comprise and is selected from six itrile groups, six azepines, three penylenes, tetrafluoro-four cyano quino bismethane (F
4-TCNQ), FeCl
3, F
16At least a in CuPc and the metal oxide.Metal oxide can be and is selected from vanadium oxide (V
2O
5), rheium oxide (Re
2O
7) and tin indium oxide (ITO) at least a.P-type dopant can have lowest unoccupied molecular orbital (LUMO) energy level.In first and second hole injection layers at least one can comprise the material with highest occupied molecular orbital (HOMO) energy level.Difference in lowest unoccupied molecular orbital (LUMO) energy level of p-type dopant and first and second hole injection layers between highest occupied molecular orbital (HOMO) energy level of the material of at least one can be between pact-2eV peace treaty+2eV.
Forming charge generation layer can comprise making and be heated by resistive vapour deposition, electron-beam vapor deposition, laser beam vapour deposition or sputtering sedimentation.Charge generation layer can have the thickness of about 10 -Yue 200 .
Another aspect of the present invention provides a kind of oganic light-emitting display device and its manufacture method with driving voltage of reduction.
Another aspect of the present invention provides a kind of oganic light-emitting display device that has emission layer between first electrode and second electrode, and this equipment comprises: first hole injection layer between first electrode and emission layer and second hole injection layer; And the charge generation layer that is doped with p-type dopant between first hole injection layer and second hole injection layer.
Of the present invention also providing on the one hand is manufactured on the method that has the oganic light-emitting display device of emission layer between first electrode and second electrode, and this method comprises: form first hole injection layer on first electrode; On first hole injection layer, form the charge generation layer that is doped with p-type dopant; With formation second hole injection layer on charge generation layer.
Embodiment
Hereinafter, will describe the disclosure in detail by some invention embodiment is described with reference to the accompanying drawings.
Be included in first hole injection layer and second hole injection layer between first electrode and the emission layer according to a kind of organic electroluminescent (EL) display device that between first electrode and second electrode, has emission layer of embodiment.Organic el device can comprise charge generation layer between first hole injection layer and second hole injection layer.Charge generation layer can be doped with p-type dopant.
Charge generation layer according to this embodiment can comprise the compound of representing with formula 1:
Formula 1
In formula 1, R is itrile group (CN), sulfuryl (SO
2R '), sulfoxide group (SOR '), sulfonamide base (SO
2NR '
2), sulfonic group (SO
3R '), nitro (NO
2) or trifluoromethyl (CF
3) (wherein R ' has 1-60 carbon atom and alkyl, aryl or heterocyclic radical for not replacing or being replaced by amine, acid amides, ether or ester).The example of the compound of formula 1 includes but not limited to the compound represented with following formula:
In the superincumbent formula, R ' has 1-60 carbon atom and alkyl, aryl or heterocycle for not replacing or being replaced by amine, acid amides, ether or ester.The organic material of the formation charge generation layer of representing with top formula only is used for illustration purpose, rather than is limited to this.
P-type dopant in the charge generation layer can be and is selected from six itrile groups, six azepines, three penylenes, tetrafluoro-four cyano quino bismethane (F
4-TCNQ), FeCl
3, F
16A kind of in CuPc and the metal oxide.Metal oxide can be vanadium oxide (V
2O
5), rheium oxide (Re
2O
7) or tin indium oxide (ITO).
P-type dopant material can be the material that energy level is different from the energy level of the first and/or second hole injection layer material.Difference between highest occupied molecular orbital (HOMO) energy level of lowest unoccupied molecular orbital (LUMO) energy level of p-type dopant material and first hole injection layer and/or the second hole injection layer material can be pact-2eV to pact+2eV.
For example, six azepines, three penylenes have about 9.6eV to the HOMO energy level of about 9.7eV and the lumo energy of about 5.5eV.In addition, tetrafluoro-four cyano quino bismethane (F
4-TCNQ) have the HOMO energy level of about 8.53eV and the lumo energy of about 6.23eV.The first and second hole injection layer materials that use in the oganic light-emitting display device according to the present embodiment have the HOMO energy level of about 4.5eV to about 5.5eV.Therefore, when using six azepines, three penylenes as p-type dopant material, the difference between the HOMO energy level of the lumo energy of charge generation layer and the first hole injection layer material or the second hole injection layer material is that pact-1.0eV is to 0eV.In addition, when using tetrafluoro-four cyano quino bismethane (F
4-during TCNQ) as the p-type dopant material in the charge generation layer, the difference between the HOMO energy level of the lumo energy of charge generation layer and first hole injection layer or second hole injection layer is approximately-0.73 to about 1.73eV.
By using charge generating material between first hole injection layer and second hole injection layer, to form charge generation layer, can reduce the driving voltage of oganic light-emitting display device.
According to a kind of embodiment, can make formation charge generation layers such as being heated by resistive vapour deposition, electron-beam vapor deposition, laser beam vapour deposition, sputtering sedimentation.Charge generation layer can be formed by the compound of representing with formula 1, and the R ' in its Chinese style 1 is C unsubstituted or that replaced by amine, acid amides, ether or ester
5-C
60Alkyl.Can form charge generation layer by ink jet printing, spin coating, blade coating, roller coat etc.In these methods, use solution to replace using CVD (Chemical Vapor Deposition) method to form charge generation layer.
In one embodiment, charge generation layer can form each shared layer of a plurality of pixels.Charge generation layer can have the thickness of about 10 -Yue 200 , randomly about 20 -Yue 80 .When the thickness of charge generation layer during less than 10 , the charge generation effect is lower.When the thickness that produces layer during, cause the driving voltage increase or crosstalk owing to leakage current can occur greater than 200 .
Oganic light-emitting display device according to current embodiment also can comprise hole transport layer between first electrode and emission layer.This equipment also can comprise at least one in hole blocking layer, electron transfer layer and the electron injecting layer between the emission layer and second electrode.
According to another embodiment, provide to be manufactured on the method that has the oganic light-emitting display device of emission layer between first electrode and second electrode, this method comprises: form first hole injection layer on first electrode; On first hole injection layer, form the charge generation layer that is doped with p-type dopant; With formation second hole injection layer on charge generation layer.To describe method now in detail according to the manufacturing oganic light-emitting display device of present embodiment.
Fig. 2 A to 2C illustrates the method according to the manufacturing oganic light-emitting display device of an embodiment.At first, deposition anode (first electrode) material forms anode on substrate.Here, can use any substrate of oganic light-emitting display device that is applicable to as substrate.The example of substrate can include but not limited to have good transparency, surface flatness, the easily glass or the transparent plastic substrate of the property handled and water proofing property.Anode material can comprise tin indium oxide (ITO), indium zinc oxide (IZO), the tin oxide (SnO of high work function metal (〉=about 4.5eV) or transparent and highly conductive
2), zinc oxide (ZnO) etc.
First hole is injected (HIL) layer and can be formed on the anode.Can form first hole injection layer by thermal evaporation hole injection layer material in high vacuum.In other embodiments, can use the material of solution form.In these embodiments, can be by spin coating, dip-coating, blade coating, ink jet printing or heat transfer, organic vapor phase deposition cambium layer such as (OVPD).
As mentioned above, can use vacuum heat deposition, spin coating etc. to form first hole injection layer (HIL).The thickness of first hole injection layer can be about 100 -Yue 1500 .When the thickness of first hole injection layer during less than 100 , the hole injection properties descends.When the thickness of first hole injection layer during greater than 1500 , driving voltage increases.In a kind of embodiment of top emission structure oganic light-emitting display device, the thickness of first hole injection layer can be in the scope of about 1500 of about 1000-.
The first hole injection layer examples of material includes but not limited to that copper phthalocyanine (CuPc) or T_Starburst amine series are as TCTA, m-MTDATA, IDE406 (can obtain from Tokyo IdemitsuKosan company) etc.Be the chemical formula of CuPc, TCTA and m-MTDATA below.
Can on first hole injection layer, form charge generation layer.The material of formation charge generation layer can be but is not limited to use the compound of representing as shown in the formula 1:
Formula 1
In formula 1,, R is itrile group (CN), sulfuryl (SO
2R '), sulfoxide group (SOR '), sulfonamide base (SO
2NR '
2), sulfonic group (SO
3R '), nitro (NO
2) or trifluoromethyl (CF
3).R ' has 1-60 carbon atom and alkyl, aryl or heterocyclic radical for not replacing or being replaced by amine, acid amides, ether or ester.
Charge generation layer can be doped with p-type dopant.P-type dopant can be and is selected from six itrile groups, six azepines, three penylenes, tetrafluoro-four cyano quino bismethane (F
4-TCNQ), FeCl
3, F
16At least a in CuPc and the metal oxide.Metal oxide can be vanadium oxide (V
2O
5), rheium oxide (Re
2O
7) or tin indium oxide (ITO).
Can be heated by resistive deposited charge on first hole injection layer such as vapour deposition, electron-beam vapor deposition, laser beam vapour deposition, sputter and produce layer material and form charge generation layer by making.Charge generation layer can form the shared layer of a plurality of pixels.Charge generation layer can have the thickness of about 10 -Yue 200 , randomly about 20 -Yue 80 .When the thickness of charge generation layer during less than 10 , the charge generation effect reduces.When the thickness of charge generation layer during greater than 200 , driving voltage increases.
Can form second hole injection layer (HIL) by the deposition second hole injection layer material on charge generation layer.Can make ins all sorts of ways forms the 2nd HIL as vacuum heat deposition, spin coating etc.Material to second hole injection layer does not have particular restriction, but can be identical with the used material of first hole injection layer.The thickness of second hole injection layer can be about 50 -Yue 1000 .
When the thickness of second hole injection layer during less than 50 , the hole-transfer characteristic descends.When the thickness of second hole injection layer during greater than 1000 , driving voltage increases.
Can randomly form hole transport layer (HTL) by deposition hole-transfer layer material on second hole injection layer.Can make ins all sorts of ways forms HTL as vacuum heat deposition, spin coating etc.The hole transport layer examples of material includes but not limited to N, N '-two (3-aminomethyl phenyl)-N, N '-diphenyl-[1, the 1-xenyl]-4,4 '-diamines (TPD), N, N '-two (naphthalene-1-yl)-N, N '-diphenylbenzidine (α-NPD), IDE 320 (can obtain) etc. from Idemitsu Kosan company.The thickness of hole transport layer can be about 50 -Yue 500 .
When the thickness of hole transport layer during less than 50 , the hole-transfer characteristic descends.When the thickness of hole transport layer during greater than 500 , driving voltage increases.
Can on hole transport layer, form emission layer (EML).The method that forms emission layer is not had particular restriction, and can make ins all sorts of ways forms emission layer as vacuum moulding machine, ink jet printing, laser induced thermal imaging, photoetching, organic vapor phase deposition (OVPD) etc.The thickness of emission layer can be about 800 of about 100-.
When the thickness of emission layer during less than 100 , its efficient and life-span reduce.When the thickness of emission layer during greater than 800 , driving voltage increases.Can randomly form HBL by using aforesaid vacuum moulding machine or being spin-coated on the material that deposits formation hole blocking layer (HBL) on the emission layer.The material that forms HBL is not had particular restriction, have electron transport ability and the ionization potential material higher than emitting compound but can be.The examples of material that forms HBL comprises Balq, BCP, TPBI etc.The thickness of hole blocking layer can be about 30 -Yue 500 .
When the thickness of hole blocking layer during less than 30 , the hole barrier characteristic is poor, causes efficient to reduce.When the thickness of hole blocking layer during greater than 500 , driving voltage increases.
Can use vacuum moulding machine or be spin-coated on and form electron transfer layer (ETL) on the hole blocking layer.Material to electron transfer layer does not have particular restriction, and can be Alq3.The thickness of electron transfer layer can be about 50 -Yue 600 .
When the thickness of electron transfer layer during less than 50 , reduce equipment life.When the thickness of electron transfer layer during greater than 600 , driving voltage increases.
In addition, can on electron transfer layer, form electron injecting layer (EIL) optionally.The material that forms electron injecting layer can be LiF, NaCl, CsF, Li
2O, BaO, Liq etc.The thickness of electron injecting layer can be about 1 -Yue 100 .
When the thickness of electron injecting layer during, can not be used as electron injecting layer effectively less than 1 .When the thickness of electron injecting layer during greater than 100 , it is as insulating barrier, thereby has high driving voltage.
Subsequently, can form negative electrode (or second electrode) by on electron injecting layer, depositing the metal that is used to form negative electrode.Can use vacuum heat deposition, sputter, metal-organic chemical vapor deposition etc. to form negative electrode.The example that is used to form the metal of negative electrode includes but not limited to lithium (Li), magnesium (Mg), aluminium (Al), aluminium-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In) and magnesium-Yin (Mg-Ag).
As mentioned above, the oganic light-emitting display device according to the present embodiment comprises anode, first hole injection layer, charge generation layer, second hole injection layer, hole transport layer, emission layer, electron transfer layer, electron injecting layer and negative electrode.This equipment also can comprise the intermediate layer between above-mentioned layer two.This equipment also can comprise electronic barrier layer between emission layer and hole transport layer.
Hereinafter, will the disclosure be described in more detail in conjunction with the following examples.These embodiment only are used for the illustrative purpose, and are not intended to limit the scope of the invention.
Embodiment 1
Will be as the 15 Ω/cm of anode
2(1200 ) Corning ito glass substrate (can be from Corning, Inc., Corning, NY obtains) is cut to 50mm * 50mm * 0.7mm, and each personal ultrasonic washing 5 minutes in isopropyl alcohol and pure water respectively, uses UV and ozone clean 30 minutes then.
Vacuum moulding machine m-MTDATA forms the first thick hole injection layer of 1300 on substrate.The vapour deposition of use resistance heat deposits the thickness as six azepines, three penylene to 20 of the material that forms charge generation layer on first hole injection layer.Vacuum deposited copper m-MTDATA forms the second thick hole injection layer of 200 on charge generation layer.Vacuum moulding machine N on second hole injection layer, N '-two (1-naphthyl)-N, (α-NPD) forms the thick hole transport layer of 200 to N '-diphenylbenzidine.
Use organic vapor phase deposition (OVPD) to form the emission layer of about 400 of thickness.Deposition electron transport materials A lq3 forms the thick electron transfer layer of 300 on emission layer.The Mg-Ag alloy (negative electrode) of the LiF (electron injecting layer) of vacuum moulding machine 10 and 200 forms the LiF/Al electrode successively on electron transfer layer, has so just finished oganic light-emitting display device.
Embodiment 2
Make oganic light-emitting display device by the mode identical, except the thickness of charge generation layer is 50 with embodiment 1.
Embodiment 3
Make oganic light-emitting display device by the mode identical, except the thickness of charge generation layer is 80 with embodiment 1.
The comparative example 1
Will be as the 15 Ω/cm of anode
2(1200 ) Corning ito glass substrate is cut to 50mm * 50mm * 0.7mm, and each personal ultrasonic washing 5 minutes in isopropyl alcohol and pure water respectively, uses UV and ozone clean 30 minutes then.
Vacuum moulding machine m-MTDATA forms the thick hole injection layer of 1500 on substrate.Vacuum moulding machine N on hole injection layer, N '-two (1-naphthyl)-N, (α-NPD) forms the thick hole transport layer of 200 to N '-diphenylbenzidine.
Use organic vapor phase deposition (OVPD) to form the emission layer of about 400 of thickness.Deposition electron transport materials A lq3 forms the thick electron transfer layer of 300 on emission layer.The Mg-Ag alloy (negative electrode) of the LiF (electron injecting layer) of vacuum moulding machine 10 and 200 forms the LiF/Al electrode successively on electron transfer layer, has so just made oganic light-emitting display device as shown in Figure 1.
Measurement is according to driving voltage, efficient and the life-span of the oganic light-emitting display device of embodiment 1 to 3 and comparative example's 1 manufacturing, and the result is presented in the following table 1.
Table 1
|
Driving voltage (V) |
Efficient (cd/A) |
Life-span (hour) |
Embodiment 1 |
5.73 |
27.18 |
1,500 |
Embodiment 2 |
5.71 |
26.90 |
1,500 |
Embodiment 3 |
5.60 |
26.85 |
1,500 |
The comparative example 1 |
7.59 |
26.79 |
1,000 |
In embodiment 1 to 3, driving voltage is 5.73-5.60V, and in comparative example 1, driving voltage is 7.59V.In addition, in embodiment 1 to 3, at 1900cd/m
2Brightness under efficient be 27.18-26.90cd/A, in comparative example 1, at 1900cd/m
2Brightness under efficient be 26.85cd/A.
In addition, the life-span is defined as brightness and is reduced to the 50% needed time of original intensity.In embodiment 1 to 3, at 9500cd/m
2Under life-span be about 1500 hours, in comparative example 1, at 9500cd/m
2Under life-span be about 1000 hours.Therefore, the life-span that can find out embodiment 1-3 is comparative example 1 about 1.5 times of life-span.
Comprise charge generation layer according to oganic light-emitting display device of the present disclosure, thereby reduced the driving voltage of oganic light-emitting display device, and improved its efficient and life-span.
Although the embodiment of reference example specifically describes and has described the disclosure, but those ordinarily skilled in the art can be recognized, only otherwise break away from as the following the spirit and scope of the present invention that claim limited, can make the various variations on form and the details.