CN117835719A - Blue light fluorescence organic light-emitting diode and preparation method thereof - Google Patents
Blue light fluorescence organic light-emitting diode and preparation method thereof Download PDFInfo
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Abstract
The invention discloses a blue light fluorescence organic light-emitting diode, which sequentially comprises a substrate, an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an efficiency enhancement layer, an electron transport layer, an electron injection layer and a cathode; the efficiency enhancing layer material is 4- (2, 7-di (naphthalene-2-yl) -9H-carbazole-9-yl) benzonitrile; the light-emitting layer is composed of a host material and a fluorescent guest dopant; the host material is 9- (4- (10-phenyl-9-anthryl) phenyl ] 9H-carbazole, the fluorescent guest dopant is 1-4-di- [4- (N, N-diphenyl) amino ] styryl benzene, and the efficiency enhancement layer can obtain 100% of exciton utilization rate at maximum through the opposite system cross-over process of the high-energy triplet state, so that the electroluminescent efficiency of the device is greatly improved, and good stability is kept.
Description
Technical Field
The invention relates to the technical field of organic light-emitting diodes, in particular to a blue light fluorescence organic light-emitting diode and a preparation method thereof.
Background
Organic Light-Emitting Diodes (OLEDs) have the advantages of wide color gamut, self-luminescence, thinness, etc., and can be manufactured to have a large-area flexible device. Over thirty years of vigorous development, OLEDs have been primarily implemented for industrial production and applications as a new generation of display and lighting technologies. Currently, red and green OLEDs have met commercial application demands, while blue OLEDs have still been difficult to break through in electroluminescent efficiency and stability, and thus further development is needed.
According to the spin statistics theory, in the electroluminescence process, the conventional fluorescent material can only realize the radiation transition emission of 25% of singlet excitons, so that the electroluminescence efficiency of OLEDs prepared based on the conventional fluorescent material is lower than 5%. Therefore, development of new light-emitting mechanisms to further enhance the utilization ratio of triplet excitons is an important and difficult point of research on blue fluorescence OLEDs.
In recent years, researchers have found that triplet-triplet annihilation (TTF) mechanisms, such as thermally activated delayed fluorescence (thermally active delayed fluorescence, TADF), and triplet-triplet fusion (TTF), and "thermo-exciton" (hot exciton process) mechanisms, can increase triplet exciton utilization to as high as 100% as possible, however, blue fluorescence OLEDs based on TADF and thermo-exciton materials as emitters still have problems in terms of stability, whereas devices with TTF materials as emitters have good stability, but are difficult to break through in terms of electroluminescent efficiency. To further increase the efficiency of TTF-based blue-fluorescence OLEDs, researchers have developed new high performance TTF materials and reported Efficiency Enhancement Layer (EEL) device structures with improved efficiency. In the prior art, the EEL layer is made of TTF materials, and the TTF light-emitting mechanism can only emit light by using 62.5% singlet excitons at most, so that the efficiency of the TTF-based blue light fluorescent OLED is still difficult to break through.
Disclosure of Invention
In order to overcome the above-mentioned drawbacks and disadvantages of the prior art, the present invention is directed to a blue light fluorescent organic light emitting diode, in which 4- (2, 7-di (n-2-yl) -9H-carbazol-9-yl) benzonitrile (2 Na-CzCN) is used as an efficiency enhancement layer, and the efficiency enhancement layer can obtain the highest exciton utilization rate of 100% through the high-lying triplet states reverse intersystem crossing, hnsc process, thereby greatly improving the electroluminescent efficiency of the device and maintaining good stability.
Another object of the present invention is to provide a method for manufacturing the blue light fluorescent organic light emitting diode.
The aim of the invention is achieved by the following technical scheme:
a blue light fluorescence organic light emitting diode sequentially comprises a substrate, an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, an efficiency enhancement layer, an electron transport layer, an electron injection layer and a cathode;
the material of the efficiency enhancing layer is 4- (2, 7-di (naphthalene-2-yl) -9H-carbazole-9-yl) benzonitrile;
the light-emitting layer is composed of a host material and a fluorescent guest dopant;
the main material is a TTF up-conversion material CzPA (9- (4- (10-phenyl-9-anthryl) phenyl) 9H-carbazole);
the fluorescent guest dopant is DSA-ph (1-4-di- [4- (N, N-diphenyl) amino ] styryl benzene).
Preferably, the thickness of the efficiency enhancing layer is 5-15 nm.
Preferably, the doping concentration of the fluorescent guest dopant is 1 to 10wt.% (mass of DSA-ph/(mass of DSA-ph+mass of CzPA)).
Preferably, the doping concentration of the fluorescent guest dopant is 1.5 to 2.5wt.%.
Preferably, the thickness of the light emitting layer is 5 to 30nm.
Preferably, it is an organic material HAT-CN (2, 3,6,7,10, 11-hexacyano-1,4,5,8,9,2-azabenzophenanthrene) or an inorganic material MoO 3 (molybdenum oxide) or V 2 O 5 One of the (vanadium pentoxide) and the hole injection layer has a thickness of 5-15 nm.
Preferably, the hole transport layer material is TAPC (4, 4' -cyclohexylbis [ N, N-bis (4-methylphenyl) aniline ]), and the thickness of the hole transport layer is 50-100 nm.
Preferably, the electron blocking layer material is TCTA (4, 4' -tris (carbazol-9-yl) triphenylamine), or the thickness of the electron blocking layer adopting mCBP (3, 3' -bis (9H-carbazol-9-yl) -1,1' -biphenyl) is 5-20 nm.
Preferably, the electron transport layer material is one of TPBi (1, 3, 5-tri (1-phenyl-1H-benzimidazol-2-yl) benzene), bmPyPB (1, 3 di [3,5 bis (pyridyl 3 yl) phenyl ] benzene) or TmPyPB (3, 3'- [5' - [3- (3-pyridyl) phenyl ] [1,1':3',1 '-terphenyl ] -3, 3' -diyl ] bipyridine), and the thickness of the electron transport layer is 30-60 nm.
Preferably, the electron injection layer material is LiF (lithium fluoride), li 2 CO 3 (lithium carbonate) or Cs 2 CO 3 (cesium carbonate) one of the following; the thickness of the electron injection layer is 1-3 nm.
Preferably, the substrate is one of glass, quartz, a polymer material or a metal material.
Preferably, the anode is one of ITO (indium tin oxide), metal or graphene, and the thickness of the anode is 100-150 nm.
Preferably, the cathode material is one of metal Al (aluminum), ag (silver) or Mg: al (magnesium aluminum alloy), and the thickness of the cathode is 100-150 nm.
The preparation method of the blue light fluorescence organic light emitting diode comprises the following steps:
firstly, pretreating a substrate with an anode, wherein the pretreatment comprises alkali liquor ultrasonic treatment, deionized water flushing, high-pressure nitrogen blow-drying, oven baking and ultraviolet ozone treatment;
then placing the substrate with anode into a film plating machine, and vacuumizing the film plating machine to a pressure of 1×10 by using a mechanical pump and a molecular pump -4 And (3) evaporating a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, an efficiency enhancement layer, an electron transport layer, an electron injection layer and a cathode on the surface of the substrate with the anode in sequence below Pa to obtain the blue light fluorescence organic light emitting diode.
Preferably, the evaporation rate of the efficiency enhancing layer is
The principle of the invention is as follows:
the present invention provides that by employing 4- (2, 7-di (naphthalen-2-yl) -9H-carbazol-9-yl) benzonitrile as the efficiency enhancing layer, 4- (2, 7-di (naphthalen-2-yl) -9H-carbazol-9-yl) benzonitrile has an efficient "thermal exciton" channel, excitons can be utilized by the hRISC process first, after which due to S of 2Na-CzCN 1 S with energy level of CzPA 1 Above the energy level, the singlet exciton energy of 2Na-CzCN therefore passesThe energy transfer reaches CzPA. At the same time, due to T of 2Na-CzCN 1 T at energy level of CzPA 1 Above the energy level such that T is reached due to switching 1 Can be transferred to CzPA by the decter energy, and then re-use of triplet excitons is achieved by TTF process of CzPA, finally, due to S of DSA-ph 1 S with energy level lower than CzPA 1 Thus, the energy of CzPA can pass +.>Energy is transferred to the DSA-ph dopant to radiate light.
Compared with the prior art, the invention has the following advantages and beneficial effects:
according to the invention, 4- (2, 7-di (naphthalene-2-yl) -9H-carbazole-9-yl) benzonitrile is adopted as the efficiency enhancement layer, so that excitons can be utilized firstly through a 'thermal exciton' channel, and because the thermal exciton channel is rapid and efficient, no extra exciton loss is caused, and thus the exciton utilization rate can be effectively improved. Thereafter, the converted exciton energy which is not utilized by the exciton channel is further utilized again by up-conversion of the TTF material, and finally byEnergy transfer to the DSA-ph dopant achieves efficient radiative emission. In addition, because the excitons are dispersed to the light emitting layer and the efficiency enhancing layer, the quenching phenomenon of the excitons is improved, and finally, blue light fluorescence OLEDs with high electroluminescent efficiency and stability can be obtained.
Drawings
FIG. 1 is a schematic diagram of a device structure of blue light fluorescent OLEDs using 2Na-CzCN as an efficiency enhancing layer according to an embodiment of the present invention.
FIG. 2 is a schematic diagram of a blue light fluorescence OLEDs using 2Na-CzCN as an efficiency enhancing layer according to an embodiment of the present invention.
FIG. 3 is a graph showing the current efficiency, power efficiency and external quantum efficiency versus luminance characteristics of blue light fluorescent OLEDs with 2Na-CzCN as the efficiency enhancing layer according to an embodiment of the present invention.
FIG. 4 is a graph showing the current efficiency, power efficiency and external quantum efficiency versus luminance characteristics of blue light fluorescent OLEDs with 2Na-CzCN as the efficiency enhancing layer according to an embodiment of the present invention.
FIG. 5 shows a blue fluorescence OLEDs (with EEL) with 2Na-CzCN as an efficiency enhancing layer and a blue fluorescence OLEDs (without EEL) without 2Na-CzCN as an efficiency enhancing layer at 1000cd/m according to an embodiment of the invention 2 An electroluminescence spectrum under.
FIG. 6 is a graph of current density versus luminance versus voltage for a blue fluorescence OLEDs (with EEL) with 2Na-CzCN as an efficiency enhancing layer and a blue fluorescence OLEDs (without EEL) without a 2Na-CzCN efficiency enhancing layer according to an embodiment of the invention.
FIG. 7 shows a blue fluorescence OLEDs (with EEL) with 2Na-CzCN as an efficiency enhancing layer and a blue fluorescence OLEDs (without EEL) without 2Na-CzCN as an efficiency enhancing layer at 1000cd/m according to an embodiment of the invention 2 Device luminance versus time profile at initial luminance.
Detailed Description
The present invention will be described in further detail with reference to examples, but embodiments of the present invention are not limited thereto.
Examples
The schematic structural diagram of the blue light fluorescence OLEDs using 2Na-CzCN as the efficiency enhancing layer in this embodiment is shown in fig. 1, and the blue light fluorescence OLEDs include a substrate, an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, an efficiency enhancing layer, an electron transport layer, an electron injection layer, and a cathode, which are sequentially stacked.
In this embodiment, the light emitting layer is composed of a host material and a dopant material.
In this example, the host material was TTF up-conversion material CzPA (9- (4- (10-phenyl-9-anthryl) phenyl ] 9H-carbazole). The dopant was conventional blue-light fluorescent luminescent material DSA-ph (1-4-bis- [4- (N, N-diphenyl) amino ] styrylbenzene). The dopant concentration of DSA-ph was 2wt.%.
The preparation method of the blue light fluorescence OLEDs with 2Na-CzCN as an efficiency enhancing layer comprises the following steps:
firstly, conducting ultrasonic treatment on a conductive ITO glass substrate by using an alkaline cleaning agent, rubbing and washing the surface of the conductive ITO glass substrate by using tap water, flushing the surface of the conductive ITO glass substrate by using deionized water, drying by using high-purity nitrogen, putting the conductive ITO glass substrate into a baking oven for baking at 120 ℃ for 30 minutes, then, treating the conductive ITO glass substrate by using ultraviolet ozone for 6 minutes, putting the conductive ITO glass substrate into a vacuum coating machine, and waiting until the pressure of the vacuum coating machine is reduced to 1 multiplied by 10 -4 And in Pa, sequentially evaporating films on the surface of the conductive ITO glass substrate. Firstly, evaporating a hole injection layer material HAT-CN with the evaporation rate ofThe vapor deposition thickness is 10nm, then the cavity transport layer material TAPC is sequentially vapor deposited, and the vapor deposition rate is +.>The evaporation thickness is 60nm; the electron blocking layer material TCTA has vapor deposition rate of +.>The evaporation thickness is 5nm; the light-emitting layer is CzPA: DSA-ph (2 wt.%) and CzPA and DSA-ph were vapor deposited at the respective rates +.>And->The evaporation thickness of the luminescent layer is 16nm; the material of the efficiency enhancement layer is 2Na-CzCN, and the evaporation rate is +.>The evaporation thickness is 7nm; electron transport layer material BmPyPB, evaporation rate of +.>The vapor deposition thickness is 30nm; electron injection layer material LiF, evaporation rate is +.>The thickness is 1nm, and finally the cathode material Al is evaporated at a deposition rate of +>The thickness was 100nm. The evaporation rate and thickness of each functional layer are controlled by a quartz crystal vibrating diaphragm thickness detector, and the finally obtained device structure of the blue light fluorescence OLEDs with the thermoexciton material as an efficiency enhancement layer is as follows: ITO/HAT-CN (10 nm)/TAPC (60 nm)/TCTA (5 nm)/CzPA: DSA-ph (98:2 wt.%,16 nm)/2 Na-CzCN (7 nm)/BmPyPB (30 nm)/LiF (1 nm)/Al (100 nm).
The blue fluorescence OLEDs with 2Na-CzCN as the efficiency enhancing layer prepared in this example has a light emitting mechanism shown in fig. 2:
by employing 4- (2, 7-di (naphthalen-2-yl) -9H-carbazol-9-yl) benzonitrile as a benefitThe rate enhancing layer, 4- (2, 7-di (naphthalen-2-yl) -9H-carbazol-9-yl) benzonitrile has a highly efficient "thermal exciton" channel, excitons can be utilized first by the hRISC process, after which due to S of 2Na-CzCN 1 S with energy level of CzPA 1 Above the energy level, the singlet exciton energy of 2Na-CzCN therefore passesThe energy transfer reaches CzPA. At the same time, due to T of 2Na-CzCN 1 T at energy level of CzPA 1 Above the energy level such that T is reached due to switching 1 Can be transferred to CzPA by the decter energy, and then re-use of triplet excitons is achieved by TTF process of CzPA, finally, due to S of DSA-ph 1 S with energy level lower than CzPA 1 Thus, the energy of CzPA can pass +.>Energy is transferred to the DSA-ph dopant to radiate light.
To compare the effect of the efficiency enhancing layer with or without a thermo-exciton on the EL performance of the device, blue fluorescent OLEDs without an efficiency enhancing layer were also prepared. The preparation method of the blue light fluorescence OLEDs without the efficiency enhancing layer of the embodiment comprises the following steps:
firstly, conducting ultrasonic treatment on a conductive ITO glass substrate by using an alkaline cleaning agent, rubbing and washing the surface of the conductive ITO glass substrate by using tap water, flushing the surface of the conductive ITO glass substrate by using deionized water, drying by using high-purity nitrogen, putting the conductive ITO glass substrate into a baking oven for baking at 120 ℃ for 30 minutes, then, treating the conductive ITO glass substrate by using ultraviolet ozone for 6 minutes, putting the conductive ITO glass substrate into a vacuum coating machine, and waiting until the pressure of the vacuum coating machine is reduced to 1 multiplied by 10 -4 And in Pa, sequentially evaporating films on the surface of the conductive ITO glass substrate. Firstly, evaporating a hole injection layer material HAT-CN with the evaporation rate ofThe vapor deposition thickness is 10nm, then the cavity transport layer material TAPC is sequentially vapor deposited, and the vapor deposition rate is +.>The evaporation thickness is 60nm; the electron blocking layer material TCTA has vapor deposition rate of +.>The evaporation thickness is 5nm; the light-emitting layer is CzPA: DSA-ph (2 wt.%) and CzPA and DSA-ph were vapor deposited at the respective rates +.>And->The evaporation thickness of the luminescent layer is 16nm; electron transport layer material BmPyPB, evaporation rate of +.>The vapor deposition thickness is 30nm; electron injection layer material LiF, evaporation rate is +.>The thickness is 1nm, and finally the cathode material Al is evaporated at a deposition rate of +>The thickness was 100nm. The evaporation rate and the thickness of each functional layer are controlled by a quartz crystal vibrating diaphragm thickness detector, and finally the device structure of the blue light fluorescence OLEDs without the efficiency enhancement layer is obtained: ITO/HAT-CN (10 nm)/TAPC (60 nm)/TCTA (5 nm)/CzPA: DSA-ph (98:2 wt.%,16 nm)/BmPyPB (30 nm)/LiF (1 nm)/Al (100 nm).
The current efficiency, power efficiency and external quantum efficiency-brightness characteristic curves of the blue light fluorescence OLEDs of the embodiment of the invention using 2Na-CzCN as the efficiency enhancing layer are shown in fig. 3.
The current efficiency, power efficiency and external quantum efficiency-luminance characteristic curves of the blue light fluorescence OLEDs of the embodiment of the present invention using 2Na-CzCN as the efficiency enhancing layer are shown in fig. 4.
Blue light fluorescence OLEDs (with EEL) with 2Na-CzCN as efficiency enhancement layer and without 2Na-CzCN efficiency enhancement layerBlue fluorescence OLEDs (without EEL) at 1000cd/m 2 The lower electroluminescent spectrum is shown in FIG. 5.
The current density-luminance-voltage characteristic curves of the blue fluorescence OLEDs (with EEL) with 2Na-CzCN as the efficiency enhancing layer and the blue fluorescence OLEDs (without EEL) without 2Na-CzCN efficiency enhancing layer of the embodiment of the present invention are shown in fig. 6.
The blue light fluorescence OLEDs (with EEL) with 2Na-CzCN as the efficiency enhancement layer and the blue light fluorescence OLEDs (without EEL) without the 2Na-CzCN efficiency enhancement layer of the embodiment of the invention are 1000cd/m 2 At initial brightness, a device brightness versus time plot is shown in fig. 7.
As can be seen from fig. 2,3, 4,5, 6 and 7, by introducing 2Na-CzCN as an efficiency enhancing layer and TTF material CzPA as a host and conventional blue fluorescent dopant DSA-ph as an object, excitons are efficiently utilized through a thermal exciton process and a TTF process, and electroluminescent efficiency and stability of the device are effectively improved. As can be seen from the electroluminescent spectrum of the device, the luminescence peak of the device is the fluorescence emission of the dopant DSA-ph, demonstrating efficient energy transfer between the efficiency enhancing layer, host and fluorescent guest. The maximum current efficiency, power efficiency and external quantum efficiency obtained by the device of the blue light fluorescence OLEDs with 2Na-CzCN as the efficiency enhancing layer are 25.0cd/a,21.5lm/W and 15.2% respectively, while the maximum current efficiency, power efficiency and external quantum efficiency obtained by the device of the blue light fluorescence OLEDs without the efficiency enhancing layer are only 17.2cd/a,15.5lm/W and 10.6% respectively, which indicates that the prepared thermal exciton material has excellent electroluminescent performance as the blue light fluorescence OLEDs with the efficiency enhancing layer and the efficiency roll-off of the device under high brightness is very low. In addition, blue fluorescence OLEDs with 2Na-CzCN as efficiency enhancement layer at 1000cd/m 2 Is reduced to 50% for a time (LT 50 ) Up to 40 hours, without an efficiency enhancing layer, of blue fluorescent OLEDs 50 Only 7 hours, which shows that by introducing 2Na-CzCN as an efficiency enhancement layer, excitons can be utilized efficiently and dispersed from EEL to EML, quenching phenomenon of triplet state excitons with long service life is reduced, and stability of the device is improvedSex.
In the above embodiment, the anode may be one of metal or graphene, and the thickness of the anode is 100-150 nm.
In the above embodiment, the hole injection layer may also be made of inorganic material MoO 3 (molybdenum oxide) or V 2 O 5 One of the (vanadium pentoxide) and the hole injection layer has a thickness of 5-15 nm.
In the above embodiment, mCBP (3, 3 '-bis (9H-carbazol-9-yl) -1,1' -biphenyl) may be further used as the electron blocking layer material, and the thickness of the electron blocking layer may be 2 to 20nm.
In the above embodiment, the electron transport layer material may also be one of BmPyPB (1, 3 bis [3,5 bis (pyridyl 3 yl) phenyl ] benzene) or TmPyPB (3, 3'- [5' - [3- (3-pyridyl) phenyl ] [1,1':3',1 "-terphenyl ] -3,3" -diyl ] bipyridine), and the electron transport layer has a thickness of 30 to 60nm.
In the above embodiment, the electron injection layer material may also be Li 2 CO 3 (lithium carbonate) or Cs 2 CO 3 (cesium carbonate) and the electron injection layer has a thickness of 0.5 to 3nm.
In the above embodiment, the cathode material may be one of Ag (silver) and Mg: al (magnesium aluminum alloy material), and the thickness of the cathode is 100-150 nm.
The embodiments described above are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the embodiments described above, and any other changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit and principles of the present invention should be made in the equivalent manner, and are included in the scope of the present invention.
Claims (10)
1. The blue light fluorescence organic light-emitting diode is characterized by sequentially comprising a substrate, an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, an efficiency enhancement layer, an electron transport layer, an electron injection layer and a cathode;
the material of the efficiency enhancing layer is 4- (2, 7-di (naphthalene-2-yl) -9H-carbazole-9-yl) benzonitrile;
the light-emitting layer is composed of a host material and a fluorescent guest dopant;
the main material is 9- (4- (10-phenyl-9-anthryl) phenyl ] 9H-carbazole;
the fluorescent guest dopant is 1-4-di- [4- (N, N-diphenyl) amino ] styryl benzene.
2. The blue-emitting fluorescent organic light-emitting diode according to claim 1, wherein the thickness of the efficiency-enhancing layer is 5 to 15nm.
3. The blue-emitting fluorescent organic light-emitting diode according to claim 1, wherein the doping concentration of the fluorescent guest dopant is 1 to 10wt.%.
4. The blue-emitting fluorescent organic light-emitting diode according to claim 1, wherein the doping concentration of the fluorescent guest dopant is 1.5 to 2.5wt.%.
5. The blue-emitting fluorescent organic light-emitting diode according to claim 1, wherein the thickness of the light-emitting layer is 5 to 30nm.
6. The blue-emitting diode according to claim 1, wherein the hole injection layer is made of organic material 2,3,6,7,10, 11-hexacyano-1,4,5,8,9,2-azabenzophenanthrene, moO3, V 2 O 5 The thickness of the hole injection layer is 5-15 nm.
7. The blue light-emitting diode according to claim 1, wherein the hole transport layer is 4,4' -cyclohexylbis [ N, N-bis (4-methylphenyl) aniline ], and the thickness of the hole transport layer is 50 to 100nm.
8. The blue-light fluorescent organic light emitting diode according to claim 1, wherein the electron blocking layer material is 4,4',4 "-tris (carbazol-9-yl) triphenylamine, and the thickness of the electron blocking layer is 5 to 20nm.
9. The blue-light fluorescent organic light emitting diode according to claim 1, wherein the electron transport layer is one of 1, 3-bis [3, 5-bis (pyridin-3-yl) phenyl ] benzene), 1,3, 5-tris (1-phenyl-1H-benzimidazol-2-yl) benzene or 3,3'- [5' - [3- (3-pyridyl) phenyl ] [1,1':3',1 "-terphenyl ] -3,3" -diyl ] bipyridine, and the electron transport layer has a thickness of 30 to 60nm;
the electron injection layer material is LiF, li 2 CO 3 Or Cs 2 CO 3 The thickness of the electron injection layer is 1-3 nm.
10. The method for preparing the blue light fluorescent organic light emitting diode according to any one of claims 1 to 9, comprising the steps of:
firstly, pretreating a substrate with an anode, wherein the pretreatment comprises alkali liquor ultrasonic treatment, deionized water flushing, high-pressure nitrogen blow-drying, oven baking and ultraviolet ozone treatment;
then placing the substrate with anode into a film plating machine, and vacuumizing the film plating machine to a pressure of 1×10 by using a mechanical pump and a molecular pump -4 And (3) evaporating a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, an efficiency enhancement layer, an electron transport layer, an electron injection layer and a cathode on the surface of the substrate with the anode in sequence below Pa to obtain the blue light fluorescence organic light emitting diode.
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