CN107123749B - A high color rendering index white light organic electroluminescent device and its preparation method - Google Patents

Abstract

The invention discloses a high color rendering index white light organic electroluminescent device and a preparation method thereof. The device comprises a substrate, an anode layer, an organic functional layer and a cathode layer from bottom to top, and the organic functional layer is sequentially from bottom to top It includes a hole transport layer, a blue light-emitting layer and an electron transport layer. The blue light-emitting layer is composed of one of the following two methods: ① A host-guest doped structure formed by doping a blue fluorescent light-emitting material with a host material. The doping mass ratio of the color fluorescent light-emitting material is 1% to 20%; ②The non-doped structure is formed by a single-layer host material close to the hole transport layer and a single-layer blue fluorescent light-emitting material close to the electron transport layer. The present invention only utilizes a blue fluorescent material to generate blue light, combines the hole transport layer and the main material to form the orange light and red light generated by the electro-exciter association, realizes white light emission with high color rendering index, and simplifies the device at the same time The structure and preparation process reduce the production cost and improve the spectral stability of the device.

Description

A high color rendering index white light organic electroluminescent device and its preparation method

technical field

The invention relates to the field of organic photoelectric technology in electronic components, in particular to a high color rendering index white light organic electroluminescent device and a preparation method thereof.

Background technique

White organic light-emitting devices (Organic light-emitting devices, OLEDs) is a new type of display technology, which is widely used in various fields of daily production and life such as flat panel display, solid-state lighting, and flexible transparent display, and can meet the needs of the world today. Energy saving, low-carbon environmental protection and green living requirements. The color rendering index is an evaluation index of the ability of the light source to express the color of the material itself. The closer the color rendering index is to 100, the better the color rendering of the light source. In OLED devices, in order to achieve white light, two luminescent dyes based on the principle of blue and yellow (or blue, orange) complementary colors, or three luminescent dyes based on the principle of red, green and blue three primary colors are usually used. In order to achieve a white light device with a high color rendering index, it is necessary to mix four luminescent dyes of red, green, yellow, and blue or more luminescent materials with different luminescent colors.

The first-generation OLED light-emitting materials are organic fluorescent materials, which can only use 25% of singlet excitons to emit light, while 75% of triplet excitons are inactivated in a non-radiative form, so the theoretical luminous efficiency is low. The second-generation OLED light-emitting material is a metal complex phosphorescent material. By introducing rare noble metals such as iridium (Ir) and platinum (Pt) to enhance spin-orbit coupling, the intersystem crossing between singlet and triplet states is realized, utilizing 25% The singlet excitons and 75% of the triplet excitons emit light, which can theoretically achieve 100% exciton utilization and are widely used. However, there is still a bottleneck problem of short lifetime of blue phosphorescent materials, which hinders its market development. In 2012, Adachi et al. from Kyushu University in Japan reported a thermally activated delayed fluorescence (TADF) material. The energy level difference between the singlet state and triplet state of this material molecule is very small, resulting in the occurrence of TADF at room temperature. The triplet-to-singlet intersystem anti-crossover can theoretically achieve 100% exciton utilization, and has become a more popular third-generation OLED light-emitting material. Especially the blue TADF luminescent material has high luminous efficiency, and it is also expected to solve the problem of short life of the blue phosphorescent material. Due to the quenching effect of conventional luminescent dyes in the aggregated state, the luminescence is reduced. Therefore, physical doping methods are needed to form a host-guest structure, reduce the concentration of luminescent materials, and overcome the problem of aggregation luminescence quenching. Therefore, in white OLED devices, multiple luminescent dyes are doped into the host material to form a single-layer light-emitting layer structure, or each light-emitting material is doped into the same or different hosts to form a multi-layer light-emitting layer structure, Realize high-performance light-emitting devices. However, this also brings many problems, such as the low doping ratio of multiple luminescent materials (especially low-energy red, orange and yellow luminescent materials) is difficult to accurately control, the spectral stability is not high, and the preparation process is complicated. , higher production costs, etc. For example, in order to improve the color rendering index, Jou et al. used three phosphorescent materials of red, green and yellow to dope one host material, and at the same time used two kinds of blue and green fluorescent materials to dope another host material. Among them, five light-emitting materials were combined to prepare a white light device with a double-emitting layer structure. Although the color rendering index reached 93 [J.Mater.Chem.2011,21,18523], the device structure and preparation process were very complicated and the repeatability was not high. Therefore, through device structure design, combined with new and efficient light-emitting materials, it provides an important research direction for the preparation of white OLEDs with simple structure and high color rendering index.

In the OLED device structure, the hole transport material can reduce the injection barrier of holes from the anode to the light-emitting layer, and transport the holes to the light-emitting layer. The hole transport material is usually an aromatic diamine compound or an aromatic triamine compound. Amine compounds or star-shaped triphenylamine compounds. Among them, the hole-transporting material TAPC with triphenylamine groups, due to the effect of triphenylamine groups, produces a peak at 580nm in the electroluminescence spectrum of TAPC under the action of an electric field, which belongs to the luminescence of electroexciter associations [Appl. Phys. Lett. 2000, 76, 2352]. Similar to this, the carbazole compound as the host material can also generate electroexciter associations under the action of an electric field, and obtain different luminescence peaks. Due to the low luminous efficiency of excimates, the research on the preparation of white light OLEDs by means of excimates has not attracted the attention of scholars, and related reports are scarce.

Contents of the invention

In order to solve the above-mentioned technical problems, the object of the present invention is to provide a high color rendering index white light organic electroluminescent device, which utilizes a novel, high-performance, low-cost blue fluorescent light-emitting material as the light-emitting material in the organic layer, Doping this blue fluorescent light-emitting material in the host material to form a blue light layer or a non-doped structure forms a blue light layer, and combines the hole transport layer and the host material to form the orange light and red light generated by the electroexcitative association , to achieve white light emission. By using only one blue fluorescent light-emitting material and a simple device structure, a white light device with high color rendering index can be realized, while the production cost can be reduced and the spectral stability of the device can be improved.

Another object of the present invention is to provide a method for preparing the above-mentioned high color rendering index white light organic electroluminescent device.

The technical problem proposed by the present invention is solved in the following way: a high color rendering index white light organic electroluminescent device comprises a substrate, an anode layer, an organic functional layer and a cathode layer from bottom to top, and is characterized in that: the organic The functional layer includes a hole transport layer, a blue light-emitting layer, and an electron transport layer from bottom to top. The blue light-emitting layer is composed of one of the following two methods: ①The main body material is doped with a blue fluorescent light-emitting material. The guest doping structure, the doping mass ratio of the blue fluorescent luminescent material is 1% to 20%, and the thickness of the blue luminescent layer is 10nm to 30nm; ② consists of a single-layer host material close to the hole transport layer and A non-doped structure formed by a single layer of blue fluorescent material close to the electron transport layer, the thickness of the host material is 5nm-10nm.

A method for preparing a white light organic electroluminescent device, comprising the following steps:

① Ultrasonic cleaning is performed on the substrate, and after cleaning, it is placed in an oven for drying;

② Move the substrate into the vacuum coating chamber, prepare the anode layer, the hole transport layer, the blue light-emitting layer, the electron transport layer and the cathode layer by dry method or wet method in the order from bottom to top, and obtain White light organic electroluminescent devices;

③ Encapsulating the prepared white organic electroluminescent device in a nitrogen atmosphere.

The material involved in the present invention is an organic semiconductor material with excellent conventional performance, and the selection range of the material is wide. The blue fluorescent light-emitting material with TADF characteristics is used, and the hole transport material and the host material in the device structure are combined to generate different electro-exciting groups. The light-emitting peak of the composite can realize a white light device with a high color rendering index, thus, a white light device can be obtained with the least amount of light-emitting materials. In addition, this device allows the blue light-emitting layer to be prepared with a non-doped structure, which can simplify the operation process and avoid the difficult-to-control host-guest doping process problem. The device of the invention has the advantages of high color rendering index, simple structure, good stability, high luminous efficiency, simple preparation process and low production cost, and opens up a unique approach from the perspective of material technology and device preparation.

Description of drawings

Fig. 1 is a high color rendering index white light organic electroluminescent device provided by the present invention and a schematic structural view of Examples 1, 2, and 3;

Fig. 2 is the structural representation of embodiment 4,5,6 provided by the present invention;

Figure 3 is the electroluminescence spectrum of the device in Example 1 provided by the present invention at different voltages, wherein the solid square curve represents the electroluminescence spectrum at a voltage of 14V, and the hollow circular curve represents the electroluminescence spectrum at a voltage of 15V Spectrum, the abscissa Wavelength represents the wavelength, in nm, and the ordinate Normalized EL intensity represents the normalized electroluminescence intensity.

Among them, a substrate 1 , an anode layer 2 , a hole transport layer 3 , a host material 4 , a blue fluorescent material 5 , an electron transport layer 6 , a cathode layer 7 , and an external power source 8 .

Detailed ways

The present invention will be further described below in conjunction with accompanying drawing:

As shown in the figure, a high color rendering index white light organic electroluminescence device of the present invention includes a substrate 1, an anode layer 2, an organic functional layer and a cathode layer 7 in order from bottom to top. The organic functional layer emits light under the driving of an applied voltage, and includes a hole transport layer 3 , a blue light emitting layer and an electron transport layer 6 in sequence from bottom to top. The blue light-emitting layer can be formed in one of the following two ways: ① A host-guest doped structure formed by doping the blue fluorescent light-emitting material 5 with the host material 4, and the doping mass ratio of the blue fluorescent light-emitting material 5 is 1% to 20%, and the thickness of the blue light-emitting layer is 10nm to 30nm; ② formed by a single-layer host material 4 close to the hole transport layer 3 and a single-layer blue fluorescent light-emitting material 5 close to the electron transport layer 6 The non-doped structure, the thickness of the host material is 5nm-10nm. The blue fluorescent light-emitting material with the characteristics of TADF is a pure organic molecule, does not contain rare and precious metals, and has the characteristics of high stability, simple synthesis, and low cost. It is an ideal choice for realizing blue light emission. Therefore, by using the orange light and red light generated by the excimer, combined with the blue light generated by the blue fluorescent light-emitting material, not only can obtain white light emission with high color rendering index, but also can reduce the number of light-emitting materials, simplify the device structure and The preparation process is also conducive to improving spectral stability and reducing production costs.

Preferably, the hole transport layer is made of a material that can form an electroexciter association under voltage driving and generate a luminescence peak in the orange light region of 560nm to 590nm, such as an aromatic triamine compound or a star. One or more than two kinds of triphenylamine compounds are mixed, more preferably, the aromatic triamine compound is two-[4-(N,N-bitolyl-amino)-phenyl]cyclohexane (TAPC ), the star-shaped triphenylamine compound is selected from one of the star-shaped triphenylamine compounds containing phenyl (TDAB series), triphenylamine (PTDATA series) or 1,3,5-triphenylbenzene (TDAPB series) in the molecular center a mixture of two or more.

The host material is a material that can form an electroexciter group association under high voltage and generate a luminescence peak in the red light region of 590nm-650nm. For example, carbazole compounds, more preferably, carbazole compounds are 1,3-di(carbazole-9-yl)benzene (MCP), 4,4',4"-tri(carbazole-9-yl) Triphenylamine (TCTA) or 4,4'-bis(carbazole-9-yl)biphenyl (CBP), 3,3-bis(9H-carbazole-9-yl)biphenyl (mCBP), 2,2 '-bis(4-carbazolephenyl)-1,1'-diphenyl (4CzPBP), polyvinylcarbazole (PVK) or a mixture of two or more.

Preferably, the blue fluorescent light-emitting material includes a conventional organic small molecule blue fluorescent light-emitting material or a blue fluorescent light-emitting material with thermally activated delayed fluorescence characteristics. The molecular structure of the blue fluorescent light-emitting material with thermally activated delayed fluorescence characteristics includes electron donor groups and electron acceptor groups, and the electron donor groups include carbazole group series, acridine group series or triphenylamine groups One or more than two of the series, electron acceptor groups include phthalonitrile group series, triphenyltriazine group series, phenylphosphine oxide group series, thiaxanthene oxidation series, thia Anthrone group series or diphenyl sulfone group series or a mixture of two or more.

Preferably, the materials used for the electron transport layer are metal complexes, oxadiazole compounds, quinoxaline compounds, nitrogen-containing heterocyclic compounds, phosphine oxide compounds, anthracene compounds, organosilicon materials, organoboron materials or One or more than two kinds of organic sulfur materials. Among them, the metal complexes can be 8-hydroxyquinoline aluminum (Alq ₃ ), bis(2-methyl-8-hydroxyquinoline) (p-phenylphenol) aluminum (BAlq), 8-hydroxyquinoline lithium (Liq ), bis(10-hydroxybenzo[h]quinoline)beryllium (Bebq ₂ ) or bis[2-(2-hydroxyphenyl-1)-pyridine]beryllium (Bepp ₂ ). Oxadiazole compounds can be 2-(4-diphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole 18 (PBD) or 1,3-bis[2- (4-tert-butylbenzene)-1,3,4-oxadiazole-5-yl]benzene (OXD-7). The nitrogen-containing heterocyclic compound can be 1,3,5-(triN-phenyl-2-benzimidazole-2)benzene 41 (TPBI), 4,7-biphenyl-1,10-o-diazepine Phenanthrene (Bphen), 2,9-dimethyl-4,7-biphenyl-1,10-phenanthrophenanthrene (BCP), 3-(4-diphenyl)-4-benzene-5-tert Butylbenzene-1,2,4-Benzenetriazole (TAZ), 3,5,3”,5”-tetrakis-3-pyridine-[1,1’; 3’,1”]terphenyl (B3PyPB) , 3-(diphenylphosphate chloride)-9-benzene-9H-carbazole (PPO1) or 3,6-bis(diphenylphosphate chloride)-9-benzene-9H-carbazole (PPO2). Phosphine oxide The base compound can be bis(2-(diphenylphosphino)phenyl)ether oxide (DPEPO) or 2,8-bis(xylylphosphonic acid)thiofluorene (PO15). Anthracene compounds can be 9,10-di -(2-naphthyl)anthracene (AND).Organoboron material can be three(2,4,6-trimethyl-3-(pyridine-3-yl)benzene)borane (3TPYMB).Organosulfur material can be For 2,8-two (xylyl phosphate) thiofluorene (PO15) and so on.

The substrate 1 is the support of the electrode and the organic thin film layer. It has good light transmission performance in the visible light region, has a certain ability to prevent moisture and oxygen penetration, and has good surface smoothness. It can be glass or flexible substrate. , The flexible substrate adopts one of polyester, polyimide compound or thinner metal.

The anode layer 2 is used as the connection layer for the forward voltage of the white light organic electroluminescence device, and it requires good electrical conductivity, visible light transparency and high work function. Inorganic metal oxides (such as indium tin oxide ITO), organic conductive polymers (such as PEDOT:PSS) or high work function metal materials (such as gold, copper, silver, platinum) are usually used.

Cathode layer 7 is used as the connecting layer of negative voltage of device, and it requires better electrical conductivity and lower work function, and cathode is usually made of low work function metal materials such as lithium, magnesium, calcium, strontium, aluminum, indium and other work functions. Low metals or their alloys with copper, gold, and silver; or a very thin buffer insulating layer (such as LiF, MgF ₂ ) and the aforementioned metals or alloys.

The preparation method of the above-mentioned white light organic electroluminescence device, it comprises the following steps:

①Use de-detergent, deionized water, acetone and ethanol solutions to ultrasonically clean the substrate in sequence, and put it in an oven for drying after cleaning.

② Move the substrate into the vacuum coating chamber, prepare the anode layer, the hole transport layer, the blue light-emitting layer, the electron transport layer and the cathode layer by dry method or wet method in the order from bottom to top, and obtain White light organic electroluminescent devices. The anode layer, the hole transport layer, the blue light-emitting layer, the electron transport layer and the cathode layer are directly prepared sequentially by a dry method, or are sequentially prepared on the substrate through a wet process after being diluted with an organic solvent. For example, the process can be: vacuum evaporation Plating, ion beam deposition, ion plating, DC sputtering coating, radio frequency sputtering coating, ion beam sputtering coating, ion beam assisted deposition, plasma enhanced chemical vapor deposition, high density inductively coupled plasma source chemical vapor deposition, catalyst Formed by one or several methods of chemical vapor deposition, magnetron sputtering, electroplating, spin coating, dip coating, inkjet printing, roller coating, and LB film, and the processes of each layer can be the same or different.

③ The prepared white organic electroluminescence device is packaged in a glove box, and the glove box is a nitrogen atmosphere.

The structure of the organic photoelectric device prepared by the present invention is exemplified as follows:

Glass/ITO/hole transport layer/host material layer/blue fluorescent light-emitting material layer/electron transport layer/cathode layer

Glass/ITO/hole transport layer/host material doped blue fluorescent light-emitting material layer/electron transport layer/cathode layer

Flexible substrate/ITO/hole transport layer/host material layer/blue fluorescent light-emitting material layer/electron transport layer/cathode layer

Flexible substrate/ITO/hole transport layer/host material doped blue fluorescent light-emitting material layer/electron transport layer/cathode layer

Example 1

As shown in Figure 1, the hole transport layer 3 in the device structure is TAPC, the host material 4 in the blue light-emitting layer is MCP, and the blue fluorescent light-emitting material 5 is a blue fluorescent light-emitting material DMACDPS with thermally activated delayed fluorescence characteristics (wherein The electron donor group is acridine series 9,9-dimethyl-9,10-dihydroacridine (DMAC), the electron acceptor group is diphenylsulfone series Diphenylsulphone (DPS)), and the doping mass ratio is guest material: host material =10%, the material used for the electron transport layer 6 is TPBi, and the cathode layer is Mg:Ag alloy, the ratio is 10:1. The entire device structure is described as:

Glass substrate/ITO/TAPC(40nm)/MCP:10%DMACDPS(20nm)/TPBi(40nm)/Mg:Ag(10:1, 200nm)

The preparation method is as follows:

(1) Use detergent, deionized water, acetone and ethanol solutions to ultrasonically clean the transparent conductive substrate ITO glass, and put it in an oven for drying after cleaning. Wherein the ITO film on the glass substrate is used as the anode layer of the device, the square resistance of the ITO film is 10Ω/sq, and the film thickness is 150nm.

(2) The dried substrate is moved into a vacuum chamber, and the ITO glass is subjected to oxygen plasma pretreatment for 15 minutes under an oxygen pressure environment of 10 Pa.

(3) Pass the treated transparent substrate into a high-vacuum organic evaporation chamber, and vapor-deposit each organic functional layer in sequence from bottom to top, including a hole transport layer, a blue light emitting layer, an electron transport layer and a cathode layer, The air pressure is below 4×10 ^-3 Pa. Among them, the evaporation rate of the hole transport layer TAPC and the electron transport layer TPBi is 1nm/s, the evaporation rate of the host material MCP in the blue light-emitting layer is 2nm/s, and the evaporation rate of the guest material DMACDPS is 0.02nm/s , the ratio of Mg:Ag in the cathode layer is 10:1, the rate of evaporating magnesium is 10nm/s, and the rate of evaporating silver is 1nm/s. The evaporation rate and thickness are monitored by a film thickness meter installed near the substrate.

(4) Transfer the prepared device to a glove box filled with nitrogen for packaging, and test the photoelectric properties of the device and the electroluminescent spectrum of the device. Table 1 shows the performance parameters of the electroluminescence spectrum of the device in Example 1 under voltages of 14V and 15V.

Table 1

Example 2

As shown in Figure 1, the hole transport layer 3 in the device structure is TAPC, the host material 4 in the blue light-emitting layer is MCP, and the blue fluorescent light-emitting material 5 is a blue fluorescent light-emitting material DMACDPS with thermally activated delayed fluorescence characteristics (wherein The electron donor group is acridine series 9,9-dimethyl-9,10-dihydroacridine (DMAC), the electron acceptor group is diphenylsulfone series Diphenylsulphone (DPS)), and the doping mass ratio is guest material: host material =20%, the material used for the electron transport layer 6 is TPBi, and the cathode layer is Mg:Ag alloy, the ratio is 10:1. The entire device structure is described as:

Glass substrate/ITO/TAPC(60nm)/MCP:20%DMACDPS(20nm)/TPBi(40nm)/Mg:Ag(10:1, 200nm)

The preparation steps of the device are similar to those in Example 1.

Example 3

As shown in Figure 1, the hole transport layer 3 in the device structure is TAPC, the host material 4 in the blue light-emitting layer is MCP, and the blue fluorescent light-emitting material 5 is a blue fluorescent light-emitting material DMACDPS with thermally activated delayed fluorescence characteristics (wherein The electron donor group is acridine series 9,9-dimethyl-9,10-dihydroacridine (DMAC), the electron acceptor group is diphenylsulfone series Diphenylsulphone (DPS)), and the doping mass ratio is guest material: host material =1%, the material used for the electron transport layer 6 is Bphen, and the cathode layer is Mg:Ag alloy with a ratio of 10:1. The entire device structure is described as:

Glass substrate/ITO/TAPC(30nm)/MCP:1%DMACDPS(20nm)/Bphen(40nm)/Mg:Ag(10:1, 200nm)

The preparation steps of the device are similar to those in Example 1.

Example 4

As shown in Figure 2, the hole transport layer 3 in the device structure is TAPC, the host material 4 is MCP, the thickness of the host material is 10nm, and the blue fluorescent light-emitting material 5 is a blue fluorescent light-emitting material with thermally activated delayed fluorescence characteristics DMACDPS (wherein the electron donor group is acridine series 9,9-dimethyl-9,10-dihydroacridine (DMAC), and the electron acceptor group is diphenylsulfone series Diphenylsulphone (DPS)), the material used for the electron transport layer 6 is DPEPO, the cathode layer is Mg:Ag alloy, the ratio is 10:1. The entire device structure is described as:

Glass substrate/ITO/TAPC(40nm)/MCP(10nm)/DMACDPS(15nm)/DPEPO(40nm)/Mg:Ag(10:1, 200nm)

The preparation steps of the device are similar to those in Example 1.

Example 5

As shown in Figure 2, the hole transport layer 3 in the device structure is TAPC, the host material 4 is MCP, the thickness of the host material is 5nm, and the blue fluorescent light-emitting material 5 is a blue fluorescent light-emitting material with thermally activated delayed fluorescence characteristics DMACDPS (wherein the electron donor group is acridine series 9,9-dimethyl-9,10-dihydroacridine (DMAC), and the electron acceptor group is diphenylsulfone series Diphenylsulphone (DPS)), the material used for the electron transport layer 6 is TPBi, the cathode layer is Mg:Ag alloy, the ratio is 10:1. The entire device structure is described as:

Glass substrate/ITO/TAPC(30nm)/MCP(5nm)/DMACDPS(10nm)/TPBi(40nm)/Mg:Ag(10:1, 200nm)

The preparation steps of the device are similar to those in Example 1.

Example 6

As shown in Figure 2, the hole transport layer 3 in the device structure is TAPC, the host material 4 is MCP, the thickness of the host material is 8nm, and the blue fluorescent light-emitting material 5 is a blue fluorescent light-emitting material with thermally activated delayed fluorescence characteristics DMACDPS (wherein the electron donor group is acridine series 9,9-dimethyl-9,10-dihydroacridine (DMAC), and the electron acceptor group is diphenylsulfone series Diphenylsulphone (DPS)), the material used for the electron transport layer 6 is DPEPO, the cathode layer is Mg:Ag alloy, the ratio is 10:1. The entire device structure is described as:

Glass substrate/ITO/TAPC(30nm)/MCP(8nm)/DMACDPS(20nm)/DPEPO(40nm)/Mg:Ag(10:1, 200nm)

The preparation steps of the device are similar to those in Example 1.

Claims (5)

1. a kind of high color rendering index (CRI) white light organic electroluminescent device successively includes substrate, anode layer, organic functions from the bottom to top Layer and cathode layer, it is characterised in that: the organic function layer successively includes hole transmission layer, blue light-emitting layer and electricity from the bottom to top Sub- transport layer, the blue light-emitting layer are made of one of following two mode: 1. by material of main part doped, blue fluorescence radiation material Expect the host-guest system structure that DMACDPS is formed, the doping mass ratio of the blue-fluorescence luminescent material is 1%~20%, institute State blue light-emitting layer with a thickness of 10nm~30nm；2. by the single layer material of main part close to hole transmission layer and close to electron-transport Layer single layer blue-fluorescence luminescent material DMACDPS formed undoped structure, the material of main part with a thickness of 5nm~ 10nm；The hole transmission layer uses two-[4- (N, N- ditolyl-amino)-phenyl] hexamethylenes, can under voltage driving Electroluminescent excimer is formed, and generates a luminescence peak in 560nm~590nm orange light region；The material of main part is adopted With 1,3- bis- (carbazole -9-yl) benzene, it is capable of forming electroluminescent excimer under high voltages, and in 590nm~650nm feux rouges Region generates a luminescence peak.

2. high color rendering index (CRI) white light organic electroluminescent device according to claim 1, it is characterised in that: the electronics passes The material that defeated layer uses is metal complex, furodiazole compound, quinoxaline compound, nitrogen-containing heterocycle compound, phosphine oxygen One or more of based compound, anthracene compound, organosilicon material, organic boron material or organo-sulfur materials.

3. high color rendering index (CRI) white light organic electroluminescent device according to claim 2, it is characterised in that: the metal Complex is 8-hydroxyquinoline aluminium, bis- (2- methyl -8-hydroxyquinoline) (p-phenyl phenol) aluminium, 8-hydroxyquinoline lithium, bis- (10- Hydroxy benzo [h] quinoline) beryllium or bis- [2- (2- hydroxy phenyl -1)-pyridine] berylliums, furodiazole compound is 2- (4- hexichol Base) -5- (4- 2-methyl-2-phenylpropane base) -1,3,4- oxadiazoles 18 or 1,3- bis- [2- (4- tert-butylbenzene) -1,3,4- oxadiazoles -5-yl] Benzene, nitrogen-containing heterocycle compound 1,3,5- (three N- phenyl -2- benzimidazolyl-2 radicals) benzene 41,4,7- phenylbenzene -1,10- neighbour's diaza Phenanthrene, 2,9- dimethyl -4,7- phenylbenzene -1,10- phenanthrolene, 3- (4- hexichol) -4- benzene -5- tert-butylbenzene -1,2,4- benzene Triazole, 3,5,3 ", 5 "-four -3- pyridines-[1,1 '；3 ', 1 "] terphenyl, 3- (diphenylphosphoric acid chlorine) -9- benzene -9H- carbazole, 3, Bis- (diphenylphosphoric acid the chlorine) -9- benzene -9H- carbazoles of 6-, phosphine oxo-compound be two (2- (diphenylphosphino) benzene) ether oxygen compounds or Person 2,8- bis- (diformazan benzenephosphonic acid) dibenzothiophen, anthracene compound 9,10- bis--(2- naphthalene) anthracene, and organic boron material is three (2,4,6- Trimethyl -3- (pyridine -3-yl) benzene) borine, organo-sulfur materials 2,8- bis- (diformazan benzenephosphonic acid) dibenzothiophen.

4. the preparation method of white light organic electroluminescent device described in claim any one of described in claim 1-3 comprising Following steps:

1. being cleaned by ultrasonic to substrate, it is put into baking oven after cleaning and is dried；

2. substrate is moved into vacuum film coating chamber, according to sequence from bottom to up, is prepared by dry or wet, successively made respectively Standby anode layer, hole transmission layer, blue light-emitting layer, electron transfer layer and cathode layer, are made white light organic electroluminescent device；

3. the white light organic electroluminescent device that preparation is completed is packaged in nitrogen atmosphere.

5. the preparation method of white light organic electroluminescent device according to claim 4, the step 2. in, anode layer, The directly successively dry process of hole transmission layer, blue light-emitting layer, electron transfer layer and cathode layer, or pass through organic solvent diluting It is sequentially prepared afterwards by wet processing on substrate；Preferably, the anode layer, hole transmission layer, blue light-emitting layer, electronics pass Defeated layer and cathode layer be respectively by vacuum evaporation, ionized cluster beam deposition, ion plating, DC sputtering deposition, radio-frequency sputtering plated film, Ion beam sputtering deposition, ion beam assisted depositing, plasma reinforced chemical vapour deposition, high density inductive coupling plasma Source chemical vapor deposition, catalyst chemical vapor deposition, magnetron sputtering, plating, spin coating, dip-coating, inkjet printing, roller coating or LB film One of formed.