TWI280269B - Organic light-emitting material and light-emitting device - Google Patents

Abstract

The present invention is an organic light-emitting material having the properties of high luminescent brightness, high luminescent efficiency, low driving voltage, high color purity and high thermal stability and a light-emitting device using the organic light-emitting material. The present invention mainly uses a hydrogen atom, a halogen atom, a cyano group, an alkyl group, a haloalkyl group, a cycloalkyl group, an alkoxy group, an amino-group, an aromatic group, an aromatic complex alkyl, and an aryl group as the substituent group, such that not only the glassy transition temperature of the material is increased and the molecular decomposition phenomenon does not easily occur, but also the light-emitting device produced by the organic light-emitting material has a high stability.

Description

Amendment

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a luminescent material and a luminescent element, and more particularly to an organic electroluminescent material and an electroluminescent device for use thereof. [Prior Art] The use of liquid crystal displays is becoming more and more popular, but there are still disadvantages such as insufficient viewing angle, fast response time, high speed animation, increased power consumption, and inability to easily manufacture large panels. Organic Light-Emitting Diode (abbreviated as 〇led) is a next-generation flat panel display with its advantages of self-illumination, no viewing angle, power saving, easy process, low cost, high response speed, and full color. And the corner of the plane light source illumination.发光 Generally, the structure of the light-emitting element of the single-layer polymer light-emitting diode is as shown in the first figure. The organic light-emitting diode 10 includes a transparent substrate 12, a transparent anode 14, an organic electroluminescent layer 16, and a cathode 18. . When a DC voltage is applied to the organic light-emitting diode 10, the hole is injected by the transparent anode 14, and electrons are injected from the cathode 18. At this time, the potential difference caused by the applied electric field causes the carrier to be in the organic electroluminescent layer. 16 moves, meets and recombines, and an exciton generated by the combination of electrons and holes can excite the luminescent molecules in the organic electroluminescent layer 16, and emit the excited luminescent molecules in the form of light. Energy, this luminescent molecule includes organic electroluminescent materials of small molecules and polymers. Research on organic materials for organic electroluminescent layers has been developing for a long time' 1 987, CW Tang and S. A. Vanslyke published an organic thin film layer and a hole containing electrons or electron transport for organic electroluminescent layers. The two-layer structure of the film layer allows the luminosity to be different depending on the energy level difference between the ground state and the excited state of the material (Appl·Phys· Lett, Vol. 51:913, 1987), which is a fluorescent light-emitting structure. In 1998, Baldo et al. doped the red fluorescent dye PtOEP into the matrix Alq3, and found that the energy transfer between Alq3 and PtOEP is 5,280,269. The correction efficiency is as high as about 90%, which makes the triplet energy transfer between the matrix Alq3 and PtOEP. This is achieved through the Dexter energy transfer process, which is a very important finding for making high efficiency EL components. Forrest, Burrow, 1999

Thompson and Baldo et al. also published an organic electroluminescent material designed by metal chelate of Ir(ppy)3 fac-tr is (2-phenyl pyridine) iridium structure, which can be used to make green light-emitting elements (Αρρ1· Phys. Lett 74) : 4, 1999), and because the light-emitting structure is a light-emitting light, the efficiency of light emission after the payment is greatly improved. In the past few years, Forrest et al. have proposed a number of related derivatives of Ir(ppy)3 and PtOEP and applied for related patents, such as US patents US6573651, 6303238, 6579232, etc., due to diphenylpyridinium Ir(ppy)3 The stability of the self is higher than that of Alq3, and it is suitable as the organic light-emitting diode material of the Dawning series, and the light-emitting mechanism belongs to the triplet light emission, and the performance and the luminous efficiency are better than the fluorescence. Therefore, the derivatives of Ir(PPy)3 have been paid more and more attention, and are widely used in organic electroluminescent materials and electroluminescent devices, but there are still some shortcomings, such as excessive light decay time, triplet quenching county Seriously, it is easy to cause problems such as short life of components and low color purity. In order to effectively solve the above disadvantages of Ir(ppy) 3, the excitation light material and the electroluminescence element are

The present invention proposes an organically effective overcoming the above-mentioned problems. [Inventive content] The main purpose of this test is to provide a system with high illuminance, high luminous efficiency, and enthusiasm. ο Half and heat recovery stability and other characteristics. Another object of the present invention is to provide a device having a 攸 攸 f 、 , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Its structure is · · Organic electroluminescent material, 1280269 correction

The group 1 is 1~3; Rl is an individual hydrogen atom, an alkyl group or a combination thereof; a group; R2 is an individual hydrogen atom, a sulfhydryl group or a group thereof.

;: "3;R; '/: \R6 ^ R? ^ t, L1 and II are soap buds or double buds. When η is 2, X=y=i L1 is the generation of A · early dentate base, M is b; when η is 2, x==2, when corpse is Μ, Ir is = 1Γ; when η is 2 When X^, y=〇, Ll is a double bud base, and the light material is in. When Γ, M is 1r. Therefore, the organic electric excitation has better performance in terms of initial efficiency and thermal stability, and the electroluminescent element completed by the strong electro-optical device can enhance the light efficiency of the device and have a reduced driving voltage and Improve thermal stability like I 棺田

An example of an Asahi, when a more purpose > skill (4) capacity' and its achieved effect r per aa u u [Embodiment] The present invention provides an electroluminescent device for the production of a branch of electrical excitation light Material and apply this material. The overall structure of the compound is as follows: 1280269 Amendment 〆, ' n is 1~3 ’· R1 is an individual independent oblique; ^ 2 ^ ^

a group consisting of; R2 is an individual; a group consisting of the original or its group; R3, r4 w 6 虱 atomic alkyl or a combination thereof is ... two single buds or "2 is a single bud base" ^: when ... two, 2"^ bud base, M*Ir; tnA7 T y-〇, l is single

Ir . ^ n A , field n is 2'X=1, when 0 is produced, L1 is a double bud base, Ma Ir, field n is 3, and x=y=〇, M is a bu. It can be seen from the domain that the structure of the present invention has different implementations, and the electrically activated precursor (4) can have the implementation structure shown in the following (4):

The luminescent material of the present invention may have an implementation structure as shown in the following (2-a): η is 3, x=0, y=〇' L1 and L2 are single bud groups. 8 1280269 Amendment L1 And L2, y=〇, L1 is a double bud group, or n is 2, x=y==1. For example, the luminescent material of the present invention may have the following

(3-a)

EXAMPLE 1 In order to explain the organic electroluminescent material of the present invention in detail and to understand its synthesis process, the above-mentioned compounds (i_a), (2_a) and (3-a) are exemplified for the synthesis method of the present invention.

First, in a 100 ml two-neck round bottom bottle, add 182 g (〇·〇1 mol) of 7,8-benzoquinone | acenaphthrenequinone, 2.37 g (〇·03 Moer) under nitrogen. Ammonium bicarbonate, 1.45 g (o.oii mol) of acetyaldehyde and 3 ml of acetic acid, followed by heating and refluxing under ι〇〇C for 12 hours, and then standing to cool to room. At the temperature, a pale yellow solid precipitates, and the solid in the reaction liquid is filtered off, and the solid is dried under vacuum to obtain 1.96 g (9.5 mmol) of the compound (A) in a yield of 95%. The formula is as shown in the following formula (Π). 1280269 Amendment

Then, the compound (Ay.5 g (7·3 mmol) was added to 3 μl of anhydrous sodium tetrahydrofuran (tetrahydr〇furan) under nitrogen to add 2 g of sodium hydride (8 8 mmol). After stirring for 2 hours at room temperature, 1.25 g (8.8 mol) of methyl moth (methyi i〇 (jide) was added, followed by heating under reflux for 6 hours, and allowed to cool to room temperature, and there was solid. Precipitation, filtration and drying, the compound (Β) 1.52 g (6.9 mmol), yield 95%, the reaction formula is as follows (羾)

After the synthesis (Β), the aforementioned compounds (1-a), (2-a), (3-a) can be synthesized as described below. First, in a 100 ml two-necked round bottom flask, 1.52 g (6.9 m mole) of the compound (β) and the crystallized water containing three gasified hydrazine (IrCb·3Η2〇) 0·81 g were taken under nitrogen. 2.3 millimoles) Add 2:1 of 2 -ethoxyethanol and water as a solvent, stir and reflux under heating for 24 hours, then let stand to cool to room temperature, solids will be precipitated, vacuum The pump extracts the solvent to obtain a solid of 0.83 g (0.8 mM) in a yield of 70%. This product is the compound (1 - a) described above, and the reaction formula is represented by the following formula (jy):

Ml (0.8 mmol) of compound (1-a) was placed in a 10 1280269 modified milliliter two-necked round bottom flask under nitrogen, then 10 equivalents of compound (B) and 4 equivalents of trifluoroacetate were added. The compound (CFsCOOAg) was heated and refluxed at 200 ° C for 12 to 15 hours, and then cooled to room temperature. The crude product was purified by a column chromatography to give a solid, 0.24 g (0.28 mmol), yield 70%. This product is the compound (2-a), and the reaction formula is as shown in the following formula (V):

The sublimation purification analysis result of this compound (2-a) was as follows: ipj-NMR (CDC13, 400 MHz) (5 = 7.90 (d, 3H); 7.80 (d, 6H); 7.60 (m, 6H); 3.63 (s , 9H); 2.42 (s, 9H). The DSC test has a melting point of 315 ° C, and its glass transition temperature is 125 ° C. Elemental analysis (theoretical value) C% = 65.13% (65.59%); H% = 3.87% (3.91%); N% = 9.77% (9.89 %). Mass analysis (theoretical value) Μ = 850·48 (850·24). Take another 11.11 g (0.8 mmol) under nitrogen. Compound (丨-a), placed in a 100 ml two-neck round bottom bottle, then added 1.5 equivalents of acetyl acetone and 7 equivalents of trifluoroacetate miscide (CF3CO〇Ag After heating under reflux for 12 to 15 hours, cooling to room temperature, the solid in the reaction liquid is filtered, and the solid is washed twice with water and n-hexane to obtain a crude product, and then the crude product is purified by a silica gel column. The solid is 〇.2 () g (0.28 mmol), the yield is 7〇%, the product is the aforementioned compound (3_a), and the reaction formula is as shown in the following formula (V!): Na2C03 Ethoxyethanol reflux / 12hr

(VI)

Compound 3_a 1280269 The results of purification of this compound (3-a) were analyzed as follows: H-NMR (CDC13, 400 MHz) δ = 7.96 (d, 2H); 7.65 (d, 4H); 3.63 (s, 6H); 6.1 (m, lH); 3.63 (s, 6H); 2.42 (s, 6H); 2.30 (s, 3H); 1.65 (s, 3H). The DSC test gave a melting point of 302 ° C and a glass transition temperature of 131 ° C. Elemental analysis (theoretical value) C%=57.89% (57.60%); Η%=4·06% (4·0%); Ν%=7·56% (7.66%). Mass analysis (theoretical value) Μ = 829 · 78 (730 · 19). Embodiment 2 The organic electroluminescent material of the present invention is more applicable to the manufacture of an electroluminescent device. The electroluminescent device of the present invention comprises a transparent substrate.

a transparent anode, an organic electroluminescent layer and a cathode, wherein the transparent anode is formed on the transparent substrate; the organic electroluminescent layer is formed on the transparent anode; and the cathode is formed on the organic electroluminescent layer . The transparent substrate can be a glass substrate, a plastic substrate or a flexible substrate, and the plastic substrate and the flexible substrate can be a polycarbonate (PC) substrate or a polyester ( P〇iyester, PET) substrate. The transparent anode may be formed on the transparent substrate by means of SpUttering or ion plating, and the material of the transparent anode may be an electrically conductive metal oxide such as indium tin oxide (ITO). ), aluminum zinc oxide (AZ〇) or indium zinc oxide (IZ0). The luminescent layer is composed of the organic electroluminescent material as shown in the above formula (1), wherein the organic electroluminescent material is more a dopant of the luminescent layer, and the doping concentration is about 〇〇丨wt%~5. 〇wt〇/c, and the luminescent layer matrix may further include an aromatic amine compound having an aromatic hydrocarbon group substituent or an aromatic polycyclic group substituent, an aromatic diamine compound or an aromatic triamine compound, and emitting light The glass transition temperature of the layer is greater than 10 °C. The various layers of the organic electroluminescent layer may be formed on the transparent anode by evaporation, spin coating, ink jet printing or printing. The organic electroluminescent material of the present invention as shown in the formula (I) can be formed by the following film forming method, such as vacuum evaporation method, molecular line evaporation method 12 1280269 amendment (MBE), immersion method, spin coating Method, casting, bar code, roll coating, and the like. The cathode may be formed by a vapor deposition method, an electron beam bonding method (E-beam) or a sputtering method, and the material may be conductivity of aluminum, calcium, aluminum lithium alloy, magnesium silver alloy or silver. material.

The process of manufacturing the electroluminescent device of the present invention will now be described with reference to an embodiment. First, a 100 mm X 100 mm glass substrate is used, and then a 15 nm thick indium tin oxide is bonded to the glass substrate, and a pattern of 10 mm X 10 mm light-emitting region is formed by yellow light, and vacuum is performed at a vacuum of 10_5 Pa. After evaporation, the first layer is first plated with a 50 nm thick hole transport material. The hole transport material can be NPB (N, N'-diphenyl-N, N'-b is-(1-naphthaleny 1)·[1 , 1 '-biphenyl ]-4,4'-diamine), whose structure is as follows, and the vaporization rate of the hole transport material is maintained at 0.2 nm/sec.

Next, the second layer is further plated with an organic electroluminescent matrix material CBP (4,4'-nitrogen, 4,4'-N, N'-dicarbazole-biphenyl) having a thickness of about 30 nm. The steaming rate is maintained at 0.2 nm/sec.

CBP is connected, and a third layer of BCP (2,9-dimethyl-4,7-diphenyl-l, 10-phenanthroline) is further plated on the third layer, and the above compound (3-a) is used as a light-emitting layer. The impurity has a thickness of about 10 nm and the steaming rate is maintained at 0.2 nm/sec. Then, the fourth layer is plated with Alq3 (trihydrocarbyl 13 1280269 modified in 8 quinolino aluminum), and its structure is as follows, which is an electron transporting layer having a thickness of about 40 nm and a steaming rate of 0.2. Nm/sec.

Finally, Alq3 was plated on the above electron transport layer with LiF (1.2 nm) and Al (150 nm) as a cathode. Thus, an electroluminescent device of the present invention is completed. The luminescence characteristics of the produced electroluminescent device were measured using a direct current (DC) voltage, and measured by Keithly 2000, the result showed that the luminescent color was red. In addition, the EL spectrum measurement system of the electroluminescence device utilizes the spectrometer of Otsuka Electronic Co., and uses the photodiode array as a detector, and the measured spectrum of the spectrum is referred to the second figure, which shows that the emission wavelength is 610 nm. The current-brightness-voltage value (IBV) of the electro-optic device is as shown in the third figure. When a voltage of 9 V is applied to the obtained electro-excitation element, a luminance of 18360 cd/m2 and a current density of 100 mA can be obtained. /cm2, luminous efficiency 8.7 lm/W and 22 cd/A, CIE = (0.61, 0.36). Hereinafter, the organic electroluminescent material of the present invention is compared with the conventional one, and a conventional organic electroluminescent material has a structure of the following formula (VE).

When the electroluminescent device uses a compound represented by the formula (W) as a material of the light-emitting layer, as shown in the third figure, when a voltage of 9 V is applied, a luminance of 16660 cd/m 2 and a current density of 170 mA/cm 2 can be obtained. Efficiency 6.3 lm/W and 18.5 cd/A, CIE = (0.63, 0.39). 14 1280269

The other conventional organic electroluminescent material is modified, and its structure is as follows:

When the electroluminescent element is made of a compound represented by the formula (M) as a material of the light-emitting layer, see the third figure, when a voltage of 9 V (four) is applied, a luminance of 1255 〇cd/m can be obtained. mA/cm2, luminous efficiency 5.3 lm/w and 15.4 cd/A, CIE = (〇.62, 0.36). When the electroluminescent element is made of the compound (2-a) proposed by the present invention as a material of the two light-emitting layers, a voltage of 9 V is applied to obtain a luminance of 155 〇cd/m, a current density of 15 mA/cm2, and a luminous efficiency i. 3 and 3 8 cd/A, CIE=(〇.6〇,〇·39) 〇

Comparing the above results, it is clear that the electroluminescence light produced by the organic electroluminescence material of the invention of the present invention is superior to the conventional organic electroluminescence light in terms of maximum brightness or luminous efficiency. An electroluminescent element produced from a material. In addition, the organic electroluminescent material of the present invention has a high glass transition temperature. Therefore, when the organic electroluminescent material of the present invention is sublimated at a low pressure and high temperature, w is separately reported, and thus the present invention has Electromechanical excitation materials have high thermal stability. As described above, the organic electroluminescent material of the present invention and its electroluminescent element can effectively enhance the luminance of the light, increase the luminous efficiency, lower the driving voltage, improve the color purity of the south, and improve the thermal stability. The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Therefore, any changes or modifications to the features and spirits described in the scope of the present application should be included in the scope of the invention. [Simple description of the diagram] 15 1280269 Revision This figure is a schematic block diagram of a conventional organic light-emitting diode. The second figure is a graph of EL spectrum at various voltages of an electroluminescent device according to an embodiment of the present invention. The third figure is a current-luminance-voltage curve of an electroluminescent device according to an embodiment of the present invention. [Main component symbol description] 10 organic light-emitting diode 12 transparent substrate 14 transparent anode 16 organic electroluminescent layer 18 cathode

16

Claims (1)

!28〇269 Amendment 10 Scope of application: 1 · An organic electroluminescent material whose structure is Wherein, η is 1 to 3; t is a group of independent hydrogen atoms, a hospital group or a combination thereof; a system consisting of a hydrogen atom, a burning group or a combination thereof. Independent hydrogen atom. The organic electroluminescent material according to item _ i: a group selected from the group consisting of a hydrogen atom independently, a carbon atom: a substituted alkyl group or a combination thereof. The organic electroluminescent material described in the above paragraph, wherein the organic electroluminescent material is selected from the group consisting of a separate hydrogen atom, a thiol group having 1 to 2 Μ unsubstituted or a combination thereof. Replacement of stone anatomic atoms or The organic electroluminescent material of claim 1 is 5, R, R6 and R7 are selected from the respective independent hydrogen atoms. The organic electroluminescent material according to the first aspect of the invention, wherein M is 6· The organic electroluminescence light as described in the scope of claim 2 1 is a single bud base. , A L and • The organic electroluminescent material pot L system described in the scope of claim 2 is a double bud base. "A L · and 8. = Please refer to the organic electroluminescence of winter, ', and '- in the fifth, sixth and seventh items of the patent scope, when η is 2, x = y = l, L丨 and L2 are single bud groups, M is ir. § η is 2, x==2, when corpse is L1 is a single bud base, M is Ir; when n is $, ' 17 1280269 y=0, L1 is a double bud base, M, and the modified 9·-type electroluminescent element comprises a snow: when n is 3 'x'〇, M is Ir. The excitation layer, the organic electro-excitation: the soil is located Between the electrodes _ organic electroluminescent material: the first 9 series contains one of the following structures MLxLy ' where Π is 1~3; 2^ individual hydrogen atoms, alkyl groups or combinations thereof. R is a hydrogen atom of the Qing, ^ no group, R, R4, R5, R6 deduct R7 A々乂^, ,, and the group of the mouth, and 10 as a separate hydrogen atom. • Affirmation of the scope of patents mentioned in item 9 of the singularity of Gongshui, a separate chlorine atom, with a pound, wherein the R1 is a group of burned bases or a combination thereof. The substitution of the counter atom is obtained by the electroluminescent element which is not substituted, wherein the 112 is a group consisting of a group or a combination thereof. The electroluminescent device of claim 9, wherein the & R, R and r are independent hydrogen atoms. = The electroluminescent device of item 9, wherein MM. Declaring the electroluminescent device described in Item 9 of the patent circumference, 苴 Ll 2 is a single bud base. 〃15. The electroluminescent device according to claim 9, wherein. And L2 is a double bud base. 〃 16. The electroluminescent device described in claim 13, claim 14, and claim 15, wherein when η is 2 ' x=y=l, and L2 is a single bud, M is 18 1280269 Ir, when η is 2, x=2, y=0, L丨 is a single bud base, mx=i, y=〇, l1 is a double bud base, ^Ir, and Μ is ir. Field n. The electroluminescent light-emitting layer as described in claim 9 further contains an aromatic amine compound. 18·^ The electroluminescent device described in claim 17 is a private amine compound having an aromatic hydrocarbon group substituent. 19·^ The electroluminescent device described in claim 17 of the patent scope is a compound having an aromatic polycyclic group. 2. The glass transition temperature of the electroluminescent layer of the electroluminescent device according to claim 17 is greater than 1 〇 (r. L. The electroluminescent element according to claim 9 of claim 4, electric The excitation light layer further comprises an aromatic diamine compound. 22 = The electroluminescent device according to claim 21, wherein the amine compound has an aromatic hydrocarbon group substituent. 23 = Patent Application No. 21 The electroluminescent device has an aromatic polycyclic substituent. The electroluminescent device according to claim 21, wherein the electroluminescent layer has a glass transition temperature of more than 1 〇. · 〇 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 The compound has an aromatic hydrocarbon group-based substituent. The electroluminescent device according to claim 25, wherein the triamine compound has an aromatic polycyclic substituent. 25 items of electricity The electroluminescent device, wherein the electroluminescent device is the organic electroluminescent device, wherein the electroluminescent device is the electroluminescent device. The doping substance of the layer. The modification 1 is 2, :0, wherein among them, among them, the organic one, the aromatic, the aromatic, the organic, the aromatic, the aromatic, the organic, the organic, the aromatic, the aromatic, the organic The electroluminescent device of claim 29, wherein the organic electroluminescent material has a doping concentration of from 1 to 50% by weight. 20 1280269 Amendment VII. Designated representative: (1) The representative representative of the case is: None. (2) A brief description of the symbol of the representative figure: 8. If there is a chemical formula in this case, please disclose the chemical formula that best shows the characteristics of the invention: