CN1514678A - Single layer organic electro luminuous device - Google Patents
Single layer organic electro luminuous device Download PDFInfo
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Abstract
Micromolecule material with ambipolar dopant being adulterated is utilized in organic luminous layer of the device. Doping density is 0.01 wt% - 90 wt% of micromolecule. Ambipolar dopant improves transmission procedure of carriers, making transmission of electrons and cavities in composite zone of luminosity reach balance so as to raise luminous efficiency and stability of the device.
Description
Technical Field
The present invention relates to a single-layer organic electroluminescent device, and more particularly, to a single-layer organic electroluminescent device having high luminous efficiency and good stability.
Background
Nowadays, with the development of multimedia technology and the coming of information society, the requirements for the performance of flat panel displays are higher and higher. Three new display technologies have emerged in recent years: plasma displays, field emission displays and organic electroluminescent displays, all make up for the deficiencies of cathode ray tubes and liquid crystal displays to a certain extent. Compared with a liquid crystal display, the organic electroluminescent display does not need a backlight source, has a large viewing angle and low power, has the response speed which can reach 1000 times that of the liquid crystal display, and has the manufacturing cost which is lower than that of the liquid crystal display with the same resolution, so the organic electroluminescent display has wide application prospect.
In 1987, C.W.TANG et al (C.W.Tang, S.A.Slyke, appl.Phys.Lett.51, 913(1987)) of Kodak corporation in America firstly adopted a double-layer structure, and used aromatic diamine derivatives as hole transport materials, and used an organic small molecule material-Alq which has high fluorescence efficiency and can be made into a uniform and compact high-quality film by a vacuum coating method3As a luminescent layer material, the material has the advantages of high quantum efficiency (1%), high luminescent efficiency (more than 1.51m/W) and high brightness (more than 1000 cd/m)2) And Organic electroluminescent devices (OLEDs) with low driving voltage (< 10V), have made extensive research efforts in this field. In 1990, Burroughes and colleagues in the Kavindesi laboratory of Cambridge university, UK found that the polymer material also has good electroluminescent property, and this important finding popularized the research of organic electroluminescent materials into the polymer field. For more than ten years, people continuously improve the preparation process of the organic electroluminescent device, and the related technology is rapidly developed。
At present, in the field of organic electroluminescence technology, one of effective methods for improving the luminous efficiency of a device is to adjust and control the balance of carrier electron and hole concentration by adjusting the structure of the device. In the current device with a double-layer or multi-layer structure, the hole transport material has poor stability due to lower glass transition temperature compared with the electron transport material, so that the stability of the device is influenced, and the upper limit of the working temperature of the device is greatly limited.
Therefore, the single-layer organic electroluminescent device without the traditional hole transport layer structure is designed and prepared, the preparation process of the device can be simplified, the production efficiency is improved, and the stability of the device is expected to be further improved. US patent US5,853,905 (publication date: 12/29/1998) discloses a structure of a single-layer organic electroluminescent device,the device employs one or two buffer layers of insulating material that are sufficiently thin that carriers can tunnel into the organic light-emitting layer. The above patent has a major problem that the carrier injection efficiency of the buffer layer made of an insulating material is not high enough, and electrons and holes are seriously unbalanced in the device, so that the light emitting efficiency of the manufactured single-layer device is low, and the stability is poor. Y.D. Gao et al (Y.D. Gao, appl. Phys. Lett. 82, 155(2003)) propose a single-layer device structure with an anode (indium tin oxide (ITO) buffer layer) which has the functions of blocking indium ion diffusion and improving hole injection, thereby improving the luminous performance of the single-layer device and achieving the maximum luminous brightness of 16000cd/m2. However, in the currently known single-layer device, although the light emission luminance is improved to a large extent, the light emission efficiency is low, and the light emission lifetime is yet to be further improved.
Disclosure of Invention
The invention aims to provide a single-layer organic electroluminescent device with high luminous efficiency and good stability.
In order to achieve the above object, the present invention provides a single-layer organic electroluminescent device, which includes a transparent substrate, a first electrode layer, a second electrode layer, and a single-layer organic light-emitting layer sandwiched between the first electrode layer and the second electrode layer, wherein the single-layer organic light-emitting layer is made of a small molecule material, and the single-layer organic electroluminescent device is characterized in that: the small molecule material is doped with a bipolar dopant.
The bipolar dopant in the technical scheme of the invention is one of triphenylamine-oxadiazole, biphenyl-carbazole or benzene-carbazole compounds.
In the technical scheme of the invention, the doping concentration of the bipolar dopant is 0.01-90 wt% of that of the micromolecular material.
The bipolar dopant in the technical scheme is a material with both hole transport capacity and electron transport capacity. Typical electron transport materials have an electron mobility of 10-3～10-6cm2A hole mobility of the hole transport material in the range of/V.s of 10-2～10-5cm2In the range of/V.s. If one material has an electron mobility of 10-3～10-6cm2In the/V · s range, and the difference between the electron mobility and the hole mobility of the material is less than 100 times, the material can be considered as a bipolar material. When the light emitting layer of the single-layer OLEDs adopts the metal organic complex, electrons are majority carriers, so that the number of the electrons in the light emitting layer is far larger than that of holes, and a large number of carriers are subjected to ineffective recombination, so that the light emitting efficiency of a single-layer device is low. On the other hand, the wide recombination region in the single-layer device makes the light-emitting layer have to play a role in transporting holes in addition to transporting electrons, and the metal complex cation generally has poor stability, which also restricts the service life of the single-layer device. The introduction of bipolar dopants into the light emitting layer of single layer OLEDs alters the transport process of the carriers. The metal organic complex Alq is adopted by a single-layer light-emitting layer3To illustrate the improvement of the carrier transport process by doping the bipolar dopant D. In the light emitting layer Alq of a single layer device3When the doping is not carried out, the transmission and recombination processes of the carriers are as follows ① - ④:
from Alq3The transmission process of the current carrier whether to dope D can be seen, the transmission and recombination process of the current carrier in the luminescent layer after doping D is improved, and unstable Alq in the luminescent layer is reduced3 +The content of (3) in the composite light-emitting region can balance the electron and hole transmission of the composite light-emitting region, so that the light-emitting efficiency and stability of the device can be greatly improved.
In the technical scheme, the bipolar dopant triphenylamine-oxadiazole, biphenyl-carbazole or benzene-carbazole compounds have groups suitable for transmitting holes in the molecular structures thereof, such as triphenylamine, biphenyl, benzene and other structural groups. Oxadiazole and carbazole groups suitable for electron transport are also present. Therefore, the bipolar dopant can have better capability of transmitting electrons and holes simultaneously in terms of performance.
In the technical scheme of the invention, the micromolecular material is also doped with a dye, and the dye is one of polyphenyl, coumarin or dual-pyran compounds.
The small molecule material in the technical scheme is doped with the dye, and the concentration of the doped dye is generally very low relative to the concentration of the host material (small molecule material), so that the concentration of dye excitons is very low, and the concentration quenching of excitons cannot be generated. Besides a bipolar dopant, a dye is doped in a single-layer organic light-emitting layer of the device, so that the light-emitting efficiency and stability of single-layer OLEDs can be further improved.
In the technical scheme of the invention, a buffer layer can be clamped between the first electrode layer and the single-layer organic light-emitting layer, and the buffer layer thin film is made of a polymer material with uniformly distributed nano structures on the surface of the film.
The single-layer organic electroluminescent device provided by the invention has the following advantages: a bipolar dopant is doped in the single-layer organic light-emitting layer, so that the electron and hole transmission of the composite light-emitting region is balanced, and the light-emitting efficiency and the stability of the device are improved.
Drawings
The present invention will become more apparent from the following detailed description and examples, which are to be read in conjunction with the accompanying drawings.
Fig. 1 is a schematic view of the structure of a single-layer organic electroluminescent device (the schematic view shows that the device structure includes a buffer layer), where 1 is a transparent substrate, 2 is a first electrode layer (anode layer), 3 is a buffer layer, 4 is a single-layer organic light-emitting layer, 5 is a second electrode layer (cathode layer), and 6 is a power supply.
Fig. 2 is a luminance-voltage curve of single-layer OLEDs with different CBP doping concentrations proposed by the present invention (the device structures are shown in structural formulas (1), (3)).
Fig. 3 is a graph of luminous efficiency versus current for single-layer OLEDs with different CBP doping concentrations proposed by the present invention (device structures are shown in structural formulas (1), (3)).
Fig. 4 is a graph of luminance versus operating time for single layer OLEDs with different CBP doping concentrations proposed by the present invention (the device structure is shown in formula (1)).
FIG. 5 is an atomic force microscope (hereinafter referred to as AFM) view of a buffer polytetrafluoroethylene (hereinafter referred to as Teflon) thin film having a uniform distribution of nanostructures on the surface of the film prepared by a vacuum thermal evaporation method in example 3 of the present invention.
Fig. 6 is a graph of luminance versus voltage (right-hand curve) and current density versus voltage (left-hand curve) for comparative example 2 device of the invention, OLED versus 2.
Fig. 7 is a plot of luminous efficiency versus current density for comparative example 2 device of the present invention-OLED pair 2.
Fig. 8 shows the luminance-voltage curve (right-hand curve) and the current density-voltage curve (left-hand curve) of the device OLED6 doped with CBP and DMQA simultaneously according to the present invention.
Fig. 9 is a graph of luminance versus operating time for the device OLED6 of the present invention, doped with CBP and DMQA simultaneously, and the device of comparative example 2, OLED pair 2.
The present invention will be described in detail with reference to the accompanying drawings and specific embodiments, it being understood that the invention is not limited to the preferred embodiments described below, which are intended as illustrative embodiments of the invention only.
Detailed Description
For reference, some abbreviations and full-scale comparisons of organic materials referred to in this specification are listed below:
TABLE 1
One structure of the single-layer organic electroluminescent device provided by the present invention is shown in fig. 1, in which: 1 is a transparent substrate which can be glass or a flexible substrate, wherein the flexible substrate is made of one of polyester and polyimide compounds; 2, a first electrode layer (anode layer) can be made of inorganic materials or organic conducting polymers, the inorganic materials are generally metal oxides such as ITO, zinc oxide, tin zinc oxide and the like or metals with higher work functions such as gold, copper, silver and the like, the optimized selection is ITO, and the organic conducting polymers are preferably one of PEDOT, PSS and PANI; 3 is a buffer layer, the buffer layer film is made of polymer material with uniformly distributed nano-structure on the film surface, such as Teflon, polyimide (PI for short), PMMA, polyethylene terephthalate (PET for short), the invention is preferably Teflon; 4 is a single-layer organic light-emitting layer, a micromolecular material is adopted, the micromolecular material is doped with a bipolar dopant, the doping concentration is 0.01-90 wt% of the micromolecular material, the preferred doping concentration is 5-20 wt%, the micromolecular material is an electron transport material, and is generally a metal organic complex (such as Alq)3、Gaq3Al (Saph-q) or Ga (Saph-q)), aromatic condensed rings (e.g. pentacene, perylene) or phenanthroline (e.g. Bphen) compounds, bisThe polar dopant is one of triphenylamine-oxadiazole (such as A, B, EM1, EM2, EM3, EM4 or EM5), biphenyl-carbazole (such as CBP) or benzene-carbazole (such as DCB and CPF) compounds, the invention is preferably CBP, the small molecule material is also doped with a dye, and the doping concentration is higher than that of the small molecule materialIs 0.01 wt% -20 wt% of small molecule material, the dye is one of aromatic condensed ring (such as rubrene), coumarin (such as DMQA, C545T) or dual-pyran (such as DCJTB, DCM) compound; 5 is a second electrode layer (cathode layer, metal layer), generally adopting metals with lower work function such as lithium, magnesium, calcium, strontium, aluminum, indium, etc. or their alloys with copper, gold, silver, the invention preferably selects a Mg: Ag alloy layer, an Ag layer and a LiF layer, an Al layer in turn; 6 is a power supply.
A preferred monolayer OLEDs of the above structure have the following structural formula (1):
Glass/ITO/Teflon/Alq3∶CBP/Mg∶Ag/Ag (1)
according to the above formula (1), detailed embodiments of the fabrication steps of the bonding device are set forth below:
①, cleaning the transparent conductive substrate ITO glass by using boiled detergent ultrasound and deionized water ultrasound methods, and drying the transparent conductive substrate ITO glass under an infrared lamp, wherein an ITO film on the conductive substrate is used as an anode layer of a device, the square resistance of the ITO film is 5-100 omega, and the film thickness is 80-280 nm;
② placing the cleaned and dried ITO glass in a vacuum chamber, and vacuumizing to 1 × 10-5～9×10-3Pa, evaporating and plating a Teflon layer on the ITO film to serve as a buffer layer of the device, wherein the evaporation rate of the film is 0.01-0.2 nm/s, and the film thickness is 0.5-20 nm;
③ evaporating a layer of CBP-doped Alq on the Teflon buffer layer3Doping by using a double-source evaporation method as a single-layer organic light-emitting layer of the device, wherein Alq is3The evaporation rate ratio of CBP is 1000: 1-1: 1000, and CBP is in Alq3The doping concentration in the film is 0.01 wt% -90 wt%, the total evaporation rate is 0.02-0.6 nm/s, and the total evaporation film thickness is 40-100 nm;
④ finally, evaporating a Mg/Ag alloy layer and an Ag layer as the cathode layer of the device in sequence on the doped single-layer organic luminescent layer, wherein the alloy layer is doped by adopting a double-source evaporation method, the evaporation rate ratio of Mg and Ag in the alloy layer is 10: 1, the total evaporation rate is 0.6-2.0 nm/s, the total evaporation thickness is 50-200 nm, the evaporation rate of the Ag layer is 0.3-0.8 nm/s, and the thickness is 40-200 nm.
Another monolayer OLEDs preferred for the above structure have the following structural formula (2):
Glass/ITO/Teflon/Alq3∶CBP∶DMQA/LiF/Al (2)
according to the above formula (2), detailed embodiments of the fabrication steps of the bonding device are set forth below:
① - ② is the same as ① - ② in the preparation step of the structural formula (1);
③ evaporating a layer of Alq doped with CBP and DMQA on the Teflon buffer layer3Doping by using a three-source evaporation method as a single-layer organic light-emitting layer of the device, and Alq3Ratio of Evaporation Rate of CBP and DMQAThe ratio of CBP to Alq is 1000: 1: 0.1-1: 1000: 103The doping concentration in the material is 0.01 wt% -90 wt%, and DMQA is in Alq3The doping concentration in the film is 0.01 wt% -20 wt%, the total evaporation rate is 0.02-0.6 nm/s, and the total evaporation film thickness is 40-100 nm;
④ finally, sequentially evaporating a LiF layer and an Al layer on the doped single-layer organic light-emitting layer to serve as a cathode layer of the device, wherein the evaporation rate of the LiF layer is 0.01-0.04 nm/s, the thickness of the LiF layer is 0.2-2 nm, the evaporation rate of the Al layer is 0.02-1.0 nm/s, and the thickness of the Al layer is 150-200 nm.
Examples 1-5 (device No. OLED1-5)
5 single-layer OLEDs were prepared in the same manner as described above for the device of formula (1). In addition, in order to facilitate the comparison of the device performance, the thickness of the ITO layer of 5 OLEDs is 200nm, the thickness of the Teflon buffer layer is 6nm, and the Alq doped with CBP3The film thickness of the single-layer organic electroluminescent layer is 60nm, the thicknesses of the Mg: Ag alloy layer and the Ag layer are 100nm respectively, and the doping concentrations of CBP in 5 OLEDs are 5 wt%, 10 wt%, 20 wt%, 35 wt% and 50 wt% respectively. The structures of 5 OLEDs are shown in tables 2 and 3 below, the luminance-voltage curve, the luminous efficiency-current curve and the luminance-working time curve of the device are respectively shown in fig. 2, 3 and 4, and fig. 5 shows that the OLED3 is prepared by a vacuum thermal evaporation method to form a film with a surface having a certain colorAFM images of buffer Teflon thin films with uniformly distributed nanostructures.
Comparative example 1 (device No. OLED pair 1)
A single layer OLED was prepared in the same manner as in examples 1-5, but the organic light-emitting layer of the single layer device was not doped with CBP (single source evaporation). The device has the following structural formula (3):
Glass/ITO/Teflon/Alq3/Mg∶Ag/Ag (3)
TABLE 2
| Device numbering | CBP doping concentration/wt% | OLED structure | |
| Comparative example 1 Example 1 Example 2 Example 3 Example 4 Example 5 | | 5 10 20 35 50 | ITO/Teflon(6nm)/Alq3(60nm)/Mg∶Ag/Ag ITO/Teflon(6nm)/Alq3(60nm)∶CBP 5wt％(60nm)/Mg∶Ag/Ag ITO/Teflon(6nm)/Alq3(60nm)∶CBP 10wt％(60nm)/Mg∶Ag/Ag ITO/Teflon(6nm)/Alq3(60nm)∶CBP 20wt％(60nm)/Mg∶Ag/Ag ITO/Teflon(6nm)/Alq3(60nm)∶CBP 35wt％(60nm)/Mg∶Ag/Ag ITO/Teflon(6nm)/Alq3(60nm)∶CBP 50wt％(60nm)/Mg∶Ag/Ag |
TABLE 3
| Comparative example 1 | Example 1 | Example 2 | Example 3 | Example 4 | Example 5 | |||
| Device | OLED pair | 1 | OLED1 | OLED2 | OLED3 | OLED4 | OLED5 | |
| Layer(s) | Material | Film thickness/nm | ||||||
| Anode layer | ITO | 200 | ||||||
| | Teflon | 6 | ||||||
| Single-layer organic hair Optical layer |
Alq3∶ | 60 | ||||||
|
CBP doping concentration/ | 5 | 10 | 20 | 35 | 50 | |||
| Cathode layer |
| 100 | ||||||
|
| 100 | |||||||
| Device for cleaning the skin Piece Ginseng radix (Panax ginseng C.A. Meyer) Number of |
Current density/A/ | 3000 | ||||||
| Luminance/cd/m2 | 6700 | 11000 | 12000 | 9800 | 8200 | 4300 | ||
| Luminous efficiency/cd/A | 2.4 | 3.7 | 4 | 3.2 | 2.7 | 1.4 | ||
| Initial luminance/cd/m2 | 100 | |||||||
| T1/2/h | 0.01 | 7 | 20 | 15 | 15 | 10 | ||
| Life/h | 0.01 | 7 | 20 | 15 | 15 | 10 | ||
Under the experimental conditions of the present invention, it can be seen from table 3 that the light emitting efficiency of the single-layer OLEDs with the light emitting layer doped with the bipolar dopant CBP is increased under the same current density, and when the CBP doping concentration is 10 wt%, the performance of the device (OLED2) is most outstanding, and the light emitting brightness is 12000cd/m2. When the light-emitting layer is subjected to low-concentration CBP doping, the efficiency of the corresponding device is improved, and when the CBP doping concentration is 10 wt%, the light-emitting efficiency of the device (OLED2) is 4cd/A, which is 66.7% higher than that of the device (OLED pair 1) without CBP doping. And after the light-emitting layer is doped with CBP, the service life of the single-layer OLEDs is obviously improved, and the service life of the device is prolonged by more than 100 times compared with that of the device (OLED pair 1) which is not doped with CBP under the condition of non-encapsulation.
COMPARATIVE EXAMPLE 2 (device No. OLED Pair 2)
A single layer OLED was prepared in the same manner as the device of formula (2) above, but the organic light emitting layer of the single layer device was doped with only DMQA and not CBP (dual source evaporation). The structure of the device is shown in structural formula (4), and the luminance-voltage curve, the current density-voltage curve, the luminous efficiency-current density curve and the luminance-working time curve of the device are respectively shown in fig. 6, fig. 7 and fig. 9:
Glass/ITO/Teflon/Alq3DMQA 1 wt%/LiF/Al (4) from FIGS. 5 and 6, it can be seen that the maximum luminance of OLED pair 2 is 26000cd/m2The lighting voltage was 2.5V, and the maximum luminous efficiency was 12.5 cd/A.
Example 6 (device number OLED6)
By and above preparationA single-layer OLED is prepared by the same method of the device shown in the structural formula (2), wherein the doping concentration of CBP is 10 wt%, the doping concentration of DMQA is 1 wt%, and the brightness-voltage curve, the current density-voltage curve and the brightness-working time curve of the device are respectively shown in figure 8 and figure 9. As can be seen from FIG. 8, the emission luminance of OLED6 (25000 cd/m)2) There is not much change compared to the lighting voltage (2.5V) and OLED pair 2. However, from the lifetime comparison of fig. 9, OLED6, due to its doping with the bipolar dopant CBP, has a lifetime that is much higher than that of OLED pair 2 without the doping with CBP, and under the same conditions, OLED6 has a lifetime that is 3 times that of OLED pair 2.
Examples 7-10 (device No. OLED7-10)
Single-layer devices OLED7 and OLED8 were prepared in the same manner as in examples 1-5, single-layer devices OLED9 and OLED10 were prepared in the same manner as in example 6, and the anodes of these 4 devices were prepared by a spin coating method. The structures of 4 OLEDs are shown in table 4 below:
TABLE 4
| Example 7 | Example 8 | Example 9 | Example 10 | ||
| Device numbering | OLED7 | OLED8 | OLED9 | OLED10 | |
| Anode layer | PEDOT∶PSS | PANI | PEDOT∶PSS | PANI | |
| Buffer layer | PI | Teflon | |||
| Sheet Layer(s) Is provided with Machine for working Hair-like device Light (es) Layer(s) | Small molecular material Bipolar dopant Dye material | Gaq3∶B | Bphen∶EM2∶rubrene | Ga(Saph-q)∶EM4 | pentacene∶CBP∶DCM |
| Film thickness/ | 60 | ||||
| | 100∶50 | 100∶20∶2 | 100∶0.1 | 100∶0.01∶1 | |
| Evaporation total rate- nm/s | 0.5 | 0.6 | 0.4 | 0.2 | |
| Cathode layer | Ca | LiF | Ca | LiF | |
| Ag | Al | Ag | Al | ||
| Luminous brightness of device
/cd/ | 2000 | 6000 | 14000 | 8000 | |
| Color of emitted light of device | Yellow colour | Yellow colour | Yellow colour | Red wine | |
Examples 11 to 14 (device No. OLED11-14)
Single layer devices OLED11, OLED12, and OLED14 were prepared in the same manner as in example 6, wherein neither OLED11 nor OLED12 were prepared with buffer layers, and single layer device OLED13 was prepared in the same manner as in examples 1-5, wherein the buffer layer LiF of OLED13 was prepared by evaporation. The structures of 4 OLEDs are shown in table 5 below:
TABLE 5
| Example 11 | Example 12 | Example 13 | Example 14 | ||
| Device numbering | OLED11 | OLED12 | OLED13 | OLED14 | |
| Anode layer | ITO | ||||
| Buffer layer | LiF | Teflon | |||
| Sheet Layer(s) Is provided with Machine for working Hair-like device Light (es) Layer(s) | Small molecular material Bipolar dopant Dye material | Al(Saph-q)∶A∶DCM | Ga(Saph-q)∶EM1∶DCJTB | Alq3∶EM3 | Alq3∶EM5∶DMQA |
|
Film thickness/ | 60 | ||||
| | 100∶0.5∶1 | 100∶5∶2 | 100∶10 | 100∶8∶1 | |
| Evaporation total rate- nm/s | 0.6 | 0.4 | 0.5 | 0.3 | |
| Cathode layer | Mg∶Ag | LiF | Mg∶Ag | LiF | |
| Ag | Al | Ag | Al | ||
| Luminous brightness of device
/cd/ | 2000 | 2500 | 12000 | 26000 | |
| Color of emitted light of device | Red wine | Red wine | Green | Yellow green | |
Examples 15 and 16 (device Nos. OLED15 and 16)
Single layer devices OLED15, OLED16 were prepared in the same manner as in example 6. The structures of 2 OLEDs are shown in table 6 below:
TABLE 6
| Example 15 | Example 16 | ||
| Device numbering | OLED15 | OLED16 | |
| Anode layer | ITO | ||
| Buffer layer | PI | PMMA | |
| Sheet Layer(s) Is provided with Machine for working Hair-like device Light (es) Layer(s) | Small molecular material Bipolar dopant Dye material | Perylene, DCB and DCJTB | Bphen∶CPF∶rubrene |
|
Film thickness/ | 60 | ||
|
| 100∶1∶2 | 100∶90∶2 | |
| Evaporation total rate- nm/s | 0.7 | 0.4 | |
| Cathode layer | Mg∶Ag | Li | |
| Ag | Ag | ||
| Luminous brightness of device
/cd/ | 7000 | 4000 | |
| Color of emitted light of device | Red wine | Yellow colour | |
The synthesis of the ambipolar dopant DCB used in the preparation of the OLED15 can be carried out by condensation reactions between the corresponding aryl halides and carbazoles, as described in the literature (t. yamamoto, et al tetrahedron lett.1998, 84, 5583.; b.k. koene, et al chem. mater.1998, 10, 2235).
Synthesis of DCB:
in a 250ml three-necked flask, 100ml of anhydrous tetrahydrofuran was charged, 5.01g of carbazole (0.03mol) was added to dissolve, equimolar NaH was slowly added until no hydrogen gas was generated, then 1.75g (0.01mol) of p-xylylene dichloride was added, heated under reflux for 24 hours, cooled and filtered, then washed with 20ml of THF, and dried to obtain 3.62g of a white powdery solid with a yield of 80% (calculated as p-xylylene dichloride). Mass spectrum m/e 436. Elemental analysis: experimental determination C: 88.12%, H: 5.39%, N: 6.50 percent; theoretical value: c: 88.07%, H: 5.50%, N: 6.42 percent.
The ambipolar dopant CPF used in the preparation of the OLED15 was synthesized by copper catalyzed Ullman condensation according to literature methods (b.k.koene, et al.chem.mater.1998, 10, 2235). Synthesis of CPF:
the reaction raw materials are 9, 9-di (p-iodophenyl) fluorene and carbazole, and the catalyst is copper powder and potassium hydroxide which are subjected to condensation reaction in an o-dichlorobenzene solution. The yield was 65%. Mass spectrum: m/e, 648; elemental analysis: experimental determination C: 90.65%, H: 4.52%, N: 4.46 percent; theoretical value: c: 90.74%, H: 4.94%, N: 4.32 percent.
Although the present invention has been described in connection with the preferred embodiments, the present invention is not limited to the above-described embodiments and the accompanying drawings, and it is to be understood that various modifications and improvements can be made by those skilled in the art within the spirit of the present invention, and the scope of the present invention is outlined by the appended claims.
Claims (12)
1. A single-layer organic electroluminescent device, the device includes transparent substrate (1), first electrode layer (2) and second electrode layer (5), and insert the organic luminescent layer (4) of single-layer between said first electrode layer (2), second electrode layer (5), the organic luminescent layer (4) of single-layer adopts the small molecule material, characterized by that: the small molecule material is doped with a bipolar dopant.
2. The single-layer organic electroluminescent device according to claim 1, wherein the bipolar dopant is one of triphenylamine-oxadiazole, biphenyl-carbazole, or benzene-carbazole compounds.
3. The single-layer organic electroluminescent device according to claim 2, wherein the triphenylamine-oxadiazole compound is {4- [5- (4-tert-butyl-phenyl) - [1, 3, 4] oxadiazole-2-bi ] -phenyl } - (9-ethyl-9H-carbazolyl-3-bi) -triphenylamine, N '-bis- {4- [5- (4-tert-butyl-phenyl) - [1, 3, 4] oxadiazole-2-bi ] -phenyl } -9-ethyl-N, N' -biphenyl-9H-carbazolyl-3, 6-diamine, 1, 1, 1, 3, 3, 3, -hexafluoro-2, 2-bis [5- (4-N, N-diphenylanilino) -1, 3, 4-oxadiazole-2-p-phenyl ] propane, 1, 4-bis [5(4-N, N-diphenylanilino) -1, 3, 4-oxadiazole-2 ] benzene, 1, 3-bis [5(4-N, N-diphenylanilino) -1, 3, 4-oxadiazole-2 ] benzene, 1, 2-bis [5(4-N, N-diphenylanilino) -1, 3, 4-oxadiazole-2 ] benzene, or 1, 3, 5-tris [5(4-N, N-diphenylanilino) -1, 3, 4-oxadiazole-2 ] benzene, wherein the biphenyl-carbazole-based compound is 4, 4-N, N '-dicarbazole-biphenyl, wherein the benzene-carbazole compound is N, N' -dicarbazole-1, 4-dimethylene benzene or 9, 9-bis (4-dicarbazole-phenyl) fluorene.
4. The single-layer organic electroluminescent device according to claim 1, wherein the doping concentration of the bipolar dopant is 0.01 wt% to 90 wt% of the small molecule material.
5. The single-layer organic electroluminescent device as claimed in claim 4, wherein the doping concentration of the bipolar dopant is 5 wt% to 20 wt% of the small molecule material.
6. The single-layer organic electroluminescent device as claimed in claim 1, wherein the small molecule material is further doped with a dye.
7. The single-layer organic electroluminescent device as claimed in claim 6, wherein the dye is one of aromatic fused ring compounds, coumarin compounds or dipyran compounds.
8. A single-layer organic electroluminescent device as claimed in claim 1, wherein a buffer layer (3) is sandwiched between the first electrode layer (2) and the single-layer organic light-emitting layer (4).
9. Single layer organic electroluminescent device according to claim 8, characterized in that the buffer layer (3) is made of a polymer material with a uniform distribution of nanostructures on the film surface.
10. A single layer organic electroluminescent device as claimed in claim 9, wherein the polymer material is one of polytetrafluoroethylene, polyimide, polymethylmethacrylate or polyethylene terephthalate.
11. The single-layer organic electroluminescent device according to claim 1, wherein the small molecule material is one of metal organic complexes, aromatic condensed rings or phenanthroline compounds.
12. The single-layer organic electroluminescent device according to claim 11, wherein the metal-organic complex material is one of tris (8-hydroxyquinoline) aluminum, tris (8-hydroxyquinoline) gallium, (salicylaldehyde o-aminophenol) - (8-hydroxyquinoline) aluminum (III) or (salicylaldehyde o-aminophenol) - (8-hydroxyquinoline) gallium (III), the aromatic condensed ring compound is pentacene or perylene, and the phenanthroline compound is 4, 7-diphenyl-1, 10-phenanthroline.
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| CNB031264220A CN100426556C (en) | 2003-07-25 | 2003-09-28 | Single layer organic electro luminuous device |
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| CN03150370.5 | 2003-07-25 | ||
| CN03150370 | 2003-07-25 | ||
| CNB031264220A CN100426556C (en) | 2003-07-25 | 2003-09-28 | Single layer organic electro luminuous device |
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| CN100426556C CN100426556C (en) | 2008-10-15 |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104078612A (en) * | 2013-03-29 | 2014-10-01 | 海洋王照明科技股份有限公司 | White organic light-emitting diode and manufacturing method thereof |
| CN104124387A (en) * | 2013-04-28 | 2014-10-29 | 海洋王照明科技股份有限公司 | Flexible conductive electrode and preparation method thereof |
| CN105219163A (en) * | 2015-10-16 | 2016-01-06 | Tcl集团股份有限公司 | A kind of quantum dot ink of spray ink Printing and preparation method and quantum dot light emitting layer |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| KR100462723B1 (en) * | 1996-08-12 | 2004-12-20 | 더 트러스티즈 오브 프린스턴 유니버시티 | Flexible orgarnic light emitting device and method of preparing thereof |
| KR100683050B1 (en) * | 1999-06-28 | 2007-02-15 | 모토로라 인코포레이티드 | Organic electroluminescent device |
| JP3970495B2 (en) * | 2000-01-11 | 2007-09-05 | Ｔｄｋ株式会社 | Organic EL device |
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- 2003-09-28 CN CNB031264220A patent/CN100426556C/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104078612A (en) * | 2013-03-29 | 2014-10-01 | 海洋王照明科技股份有限公司 | White organic light-emitting diode and manufacturing method thereof |
| CN104124387A (en) * | 2013-04-28 | 2014-10-29 | 海洋王照明科技股份有限公司 | Flexible conductive electrode and preparation method thereof |
| CN105219163A (en) * | 2015-10-16 | 2016-01-06 | Tcl集团股份有限公司 | A kind of quantum dot ink of spray ink Printing and preparation method and quantum dot light emitting layer |
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