TW555831B - Electroluminance device - Google Patents

Abstract

An blue organic EL device includes an anode, a cathode and an EL element arranged between the two. The EL element includes a substance represented by the following chemical formula: in which m, n=1-3; the substitute R is selected from a group consisting of t-butyl, phenyl, methylphenyl, naphehyl and heterocyclic compound. The EL element is highly efficient, lower-voltage operative and easy to be synthesized.

Description

555831 V. Description of the invention [Application field of the invention] The present invention relates to an organic blue fluorescent material applied to an organic electroluminescence device, which has high fluorescence efficiency, low driving voltage, and is easy to synthesize. [Background of the Invention and Related Technology] Since Kodak developed the first high-efficiency green light organic electroluminescence device (Organic electroluminescence device) in 1987, the bow has taken the attention of all walks of life. The operating principle of the organic electroluminescence device is as shown in "Figure 1". An organic thin film or an organic electroluminescence element (hereinafter referred to as an EL element) is sandwiched between a cathode 3 and an anode 1. The current causes the two carriers of electrons and holes to meet and recombine in the organic layer to emit light. A two-layer element structure of a generally simple organic electroluminescence device is: on the anode 1 (an IT0 transparent conductive film on the surface of transparent glass 2), a hole transport layer is deposited on the anode, and the hole transport layer is 6 light-emitting layer (light emitting layer) 5 on top, this light-emitting layer has the ability to transport electrons and emit light; finally on the electron transfer layer 4 is re-steamed on the metal electrode 3 (roughly containing Mg, Li, A1 and other metal elements ) As the cathode. In addition, there is also a multilayer structure element (as shown in "Figure 2"). Other organic materials are mainly deposited between the electrode and the hole transfer material and the electron transfer material. ο 1 e Injection Layer (HIL) 7, Hole Transport Layer (HTL) 6, organic light emitting layer (EML) 5, and Electron Transport Layer 4 (Electron Transport Layer,

555831 V. Description of the invention (2) ETL) or Electron Injection Layer (EIL), etc., in order to improve the efficiency of carrier injection, thereby reducing the driving voltage and increasing the carrier recombination probability. EL elements have the characteristics of (1) high brightness, (2) self-luminous, (3) low driving voltage, (4) no viewing angle, and (5) a simple process, so they can be applied to flat-panel displays. However, until the development of EL elements, there are still many technical problems to be broken through, such as poor luminous efficiency, unsatisfactory brightness, and short life. The factors that affect the above problems are as follows: Imitation of a double-injector is moved between the layers, so the light emitting patent application hole injection part 2 releases the energy that can accumulate, which is very L 7L · type. In the light emitter, the electric V and the electric γ are accompanied by the seed, the organic material layer, and the injected electrode are implanted, and the energy excited by the encounter is then again the organic material. The ability of the electrode to implant into the plant or = is released. One of the important factors of brightness and luminous efficiency. Decide the EL element in the 8th 6 1 0 1 5 5 1 case, which will be disclosed, for example, the Republic of China layer material, in order to improve the carrier's injection. New electro-optic efficiency and brightness. Eight efficiency increase the impurities contained in the EL element, EL element; in the process of the element, in addition to the impurities contained in the plant will be released due to the thermal energy caused by the encounter and release, resulting in its luminous effect. It will also affect the crystallization of organic materials and decrease in brightness, until thermal decomposition occurs and affect the life of the device. Recrystallization)

Page 9 555831 V. Description of the invention (3) A '" 一 " " --- Knee a Γ f Currently applied organic light emitting diode (0LED) display, has been ^ m monochrome, multi-shirt And full-color, and other types, the π structure of full-color OLED is as shown in "Figure 3A ~ 3C", including:! Three-color light-emitting materials independent light-emitting type; mainly three light-emitting materials * 0EL2, 0EL3) precision It is coated in day pixels (pixels), and generates the required color light by generating three colors of R, G, and B.

志 a ί color conversion type; mainly use blue light-emitting material (B-0EL) to emit j-color light source, through the pre-made light color conversion film (F 丨), and transfer the blue two to red (R) green ( G) Two kinds of color light. The difference from the former is the blue light-emitting material 疋 comprehensive film, which does not need to make a pattern corresponding to pi χ e 1; and the * shape color filter film type; mainly uses white light-emitting material (W_〇EL ) Is a method of light that is matched with a color filter film (f 2) like LCD to achieve full color. Among them, the former two have developed rapidly and existing products have been publicly displayed. However, the method of using color conversion requires High-efficiency blue light materials', while general blue light materials have low efficiency and require high driving voltages, and even require tedious organic synthesis steps to reduce yields and increase production costs. Known blue light materials include, for example, 9, 10-di- (2-naphthyl) anthracene derivatives disclosed in published U.S. Patent No. 5 9 3 5 7 2 1 and U.S. Patent No. 5,972,247. 9, 10-bis (3 ', 5' -diaryl) phenylanthracene

d e r i v a t i v e s, but the luminous efficiency of these two disclosed blue light materials is not ideal. [Objective and Summary of the Invention]

Page 10 555831 V. Description of the invention (4) The main purpose of this patent is to provide a high-efficiency, low driving voltage and simple 50% blue light material. r H Sun and Moon is mainly to synthesize an asymmetric structure by adding the structure modification of 9 ′ 10—Qi anthracene (9, 10 — (diphenyl) anthracene) ”, a high fluorescent efficiency blue fluorescent material, and adding a three-dimensional structure to it. A steric-hindrance substitute group with a large barrier reduces its recrysta (recrysta 1 1 izati ο η) condition to obtain a blue fluorescent material with high efficiency and low driving voltage. The EL element disclosed in the present invention includes a substance represented by the following formula:

Where m, and the substituents R are the same or different and are selected from the group consisting of t-butyl, phenyl, methylphenyl (methy lpheny 1), naphthyl (naphenyl), And groups of heterocyclic bompounds. [Description of the preferred embodiment] Please refer to "Picture 4" of the organic electroluminescence disclosed in the present invention

Page 11 555831 V. Description of the invention (5) Device (EL device), including an anode 10, a cathode 20, and an organic element 30 (EL element) sandwiched between them; the anode 10 is ITO transparent conductive film is attached to glass or transparent plastic substrate 40 by sputtering or evaporation; cathode 20 is a metal electrode containing magnesium (Mg), lithium (Li), aluminum (A1), etc .; The EL element 30 includes a hole injection layer (11016-: [114 | 6 (: 1; 丨 〇1181)]: 301, a hole-transport layer 302, and light emission. Layers (light emitting layer) 303, and electron-transport layer 304 and other multilayer structures of organic electroluminescent elements (EL elements), which constitute a light emitting layer in an organic electroluminescence device structure (light emitting layer, EML). "9, 10- (diphenyl) anthracene)" is a kind of blue fluorescence materials with high fluorescence efficiency, but there will be more Crystallization (recrystallization) phenomenon. Correct the molecular structure of optical materials, synthesize an asymmetric molecular structure, and add a steric-hindrance substitute group to it to reduce its recrystallization condition, and obtain a high efficiency, low driving voltage, A new blue fluorescent material that is easy to synthesize, and then uses this new blue fluorescent material to make a blue EL element with good luminous efficiency. The EL element disclosed in the present invention is used to constitute an organic electroluminescence. A light emitting layer (EML) in a light emitting device includes a substance represented by the following formula (1):

Page 12 555831 V. Description of the invention (6)

n

Formula ⑴ wherein m, η di 1-3, and the substituent R are the same or different and are selected from the group consisting of t-butyl, phenyl, methylphenyl, and naphthalene The naphenyl group and the heterocyclic bompound group. In another preferred embodiment of the present invention, the EL element further includes a substance represented by the following formula (2):

Page 13 555831

Formula (2) wherein m, n = 1 to 3, the substituents R are the same or different, and the methyl group contains methyl, isopropyl, and th: t-butyl , Phenyl (naphthyl), naphthyl (naphenyl), and a group of heterocyclic bompounds. The following are examples of the operation of synthesizing the blue fluorescent material disclosed in the present invention with the following heterocycles: ΰ 物 < Synthesis Example 1 > Compound (A) 9- (4-third butyl-4 '- Synthesis of biphenyl) anthracene (9- (4'-t-butylbiphenyl) anthracene) (a) Synthesis of 4-tert-4'-biphenylmagnesiumbromide 8 · 4 Grams of 4-bromo-4'-tert-butyl-biphenyl and 1 g of magnesium are placed in a 150 ml reaction bottle, and 20 ml of tetraphdrofurane are added. , Heated at 80 degrees, stirred and reacted for four hours.

^ 55831

(b) 5 ~, white 3 ~ -2> 9-bromo anthracene, 0.13 g 1, bottle, add 50, burn ~ digas nickel (NiC12 (dppp)) and put in 250 ml reaction Dissolve (a), tetrahydrofuran in milliliters, and heat at 60 ° C for one hour, and then slowly dry it out, drip the solution, stir and react for 8 hours. The solution was distilled under reduced pressure and washed three times with 100 ml of methanol, and the solution was filtered. The solid was crystallized from toluene to obtain 5.0 g of a pale yellow solid with a yield of 68%. Its structure is as follows (3).

Formula (3) < Synthesis Example 2 > Compound (B) 9,-(4- (2,4,6-trimethylphenylbenzyl) phenylphenyl) anthracene (9-4- (2, 4, 6-Trimethylphenyi) — Synthesis of phenyl) anthracene

Page 15 555831 V. Description of the invention (9) (a) Synthesis of 4-1,3,5-trimethylphenyl-1-benzenemagnesium bromid e 7.8 g of 4-1,3,5-trimethylphenyl-1-bromobenzene (4-1,3,5-trimethylphenyl-l-benzylbromide) and 1 g of magnesium in 150 ml To the reaction flask, 20 ml of tetrahydrofurane was added, and the mixture was heated and stirred at 80 ° C for 4 hours. (b) 5 grams of 9-bromo anthracene and 0.13 grams of j 3-diphenylphosphine-nickel (NiC12 (dppp)) are placed in a 250 ml reaction bottle, and 50 liters of quart Hydrogen squeaking 'heated at 60 degrees for one hour' and slowly dropped (a) the solution, stirred and reacted for 8 hours. The solution was evaporated to dryness under reduced pressure, and 100 ml of methanol was added and washed three times. The solution was filtered, and the solid was recrystallized from methylbenzyl and methanol to obtain 4.2 g of a pale yellow solid with a yield of 60%. Its structural formula is expressed by the following formula (4).

Compound (B) Formula (4)

Page 16 55583l

Synthesis Example III> Synthesis of Compound (C) 9,-(3,5-diphenylphenyl) anthracene (3,5-diphenyl) phenyl) anthracene) (a) Synthesis of (3, 5-diphenyl) 3.8g of diphenylbenzylmagnesium bromide 8.8g of (3, 5-diphenyl) benzene bromide (3, 5-diphenylbenzylbromide) and 1.1g of magnesium (magnesium) were placed in 150ml reaction Add 20 ml of tetrahydrofurane to the bottle, stir and react for 4 hours. (B) 5 g of 9-Dirromo anthracene, 0.13 g of 1,3-diphenylpropane Burned-nickel dichloride (NiC12 (dppp)) was placed in a 250 ml reaction flask, 50 ml of tetrahydrofuran was added, and the reaction was heated at 60 degrees for one hour. The solution (a) was slowly dropped in, stirred and reacted for 8 hours. It was evaporated to dryness under reduced pressure, washed with 100 ml of methanol three times, and the solution was filtered. The solid was recrystallized from toluene and methanol to obtain 4.8 g of a pale yellow solid with a yield of 63%. Its structure is represented by the following formula (5).

Page 17 555831 V. Description of the invention (π)

Compound (C) Formula (5) < Synthesis Example 4 > Compound (D) Synthesis of 9- (4-third-butylphenyl) -anthracene ~ (4-t-butylphenyl) anthracene) (a) Synthesis of 4- T ~ butylbenzylmagnesium bromide) 1 g 4-t-butylbenzyzylbromide and 1 · ^ g magnesium in a 150 ml reaction bottle, force 20 ml of tetrahydrofurane was added, mixed and reacted for four hours. (b) 5 grams of 9-Dibromo anthracene, 0.13 grams ^ 3, diphenylphosphine-nickel dichloride (NiC12 (dppp)) are placed in a 250 ml reaction bottle, 50 ml of four Hydrogen bite, heated at 60 ° C for one hour, and slowly (a) the solution was added dropwise, stirred and reacted for 8 hours. The solution was evaporated under reduced pressure

Page 18 555831

V. Description of the invention (12) Distilled and dried, 100 ml of methanol was added and washed three times, the solution was filtered, benzene and methanol were recrystallized to obtain 4.1 g of a pale yellow solid with a yield of 75%. The structural formula is expressed by the following formula (6). ° ° #

Compound (D) Formula (6) < Comparative Synthesis Example 1 > is a synthesis of a known compound (E) 9- (biphenyl) anthracene (9- (biphenyl) anthracene) (a) Synthesis of 4-biphenyl bromide 4-biphenylmagnesiumbromide 6.6 g 4-bromo-biphenyl and 1 g magnesium were placed in a 150 ml reaction flask, and 20 ml tetrahydrofurane was added. , Heated at 80 degrees to stir and react for four hours. (b) 5 grams of 9-Dibromo anthracene, 0.13 grams of 1,3-diphenylphosphopropane-dichloronickel (NiC12 (dppp)) were placed in a 250 ml reaction flask, and 50 ml of tetrahydrofuran was added. , Heating at 60 degrees for one hour, slow

Page 19 555831 V. Description of the invention (13) Slowly drip (a) the solution, stir and react for 8 hours. The solution was evaporated to dryness under reduced pressure, 100 ml of methanol was added and washed three times, and the solution was filtered. The solid was recrystallized from toluene and methanol to obtain 4.3 g of a pale yellow solid with a yield of 68%. Its structure is represented by the following formula (7).

Compound (E) Formula ⑺ < Comparative Synthesis Example 2 > is a known compound (F) 9,10-di (3-methylphenyl) anthracene (9, 10-di- (3-methylphenyl) anthracene ) Synthesis (a) Synthesis of 3-methylphenylmagnesium bromide 6. 4 g of 3-methylphenylbromide and 1 g of magnesium were placed in 150 ml reaction Add 20 ml of tetrahydrofurane to the bottle and heat it at 80 ° C: mix and react for four hours. (1)) 5 grams of 9,10 dibromoanthracene (9,10- (111) 1′〇111〇 anthracene), 0.13 grams of 1,3-diphenylpropane-digas nickel

Page 20 555831 Description of the Five 'Invention (14) (NlCl2 (dppp)) was placed in a 250 ml reaction flask, 50 ml of tetrahydronaphthalene was added, and the reaction was heated at 60 degrees for one hour, and the (a) solution was slowly dropped. Into, stir and react for 8 hours. The solution was distilled to dryness under reduced pressure, and 100 ml of methanol was added and washed three times. The solution was filtered, and the solid was recrystallized from toluene and methanol to obtain 3.8 g of a pale yellow solid with a yield of 71%. Its structural formula is expressed by the following formula (8).

Compound (F) Formula (8) The following is an operation example of applying the compound synthesized by the present invention to the preparation of an organic electroluminescence device. The organic electroluminescence devices listed below all include: a hole injection layer ( hole-injection layer), hole-transport layer, light emitting layer, and electron-transport layer example. < Preparation example 1 > includes the following steps:

Page 21 555831 V. Description of the invention (15) (a) Indium-tin-oxide glass (ITO glass) is used as the anode substrate, and it is cleaned with a commercially available glass cleaning agent and then with deionized water. drying. (b) Copper Phthalcoyanine was selected as the hole injection layer material (150angstroms), and the steaming bell was on IT0 glass. (c) Distilling the hole-transport layer material on the hole injection layer-nitrogen, nitrogen-di- (1-naphthyl) -nitrogen, nitrogen biphenyl (N, Ν '-bis- (Ι-naphthyl) -Ν, Ν '-diphenylbenzidine) (600 angstroms) o (d) A light-emitting layer is further vapor-deposited on the hole-transporting layer. . (e) Electron-transport layer on the light-emitting layer, 350-8 angstroms (alumium-tris-8-hydroxy-quinoline) · (f) As a cathode, a magnesium-silver alloy was vapor-deposited on the electron transport layer. (g) The device is packaged in a dry glove box filled with nitrogen. The organic electroluminescence device prepared by using the first compound A proposed by the present invention and prepared according to the above steps has been measured for an EL spectrum with a wavelength of ax-440nm and CIE coordinate x = y = 0.17 (EL, IV, BV (see "Figure 5"), it can be seen that its wavelength is very close to the wavelength of blue light of 45nm 'and the brightness / voltage curve of this EL element is shown in "Figure 6", the current / voltage curve As shown in "Figure 7". < Preparation example two >

Page 22 555831 V. Description of the invention (16) Includes the following steps: (a) Select indium-tin-oxide glass (ITO glass) as the anode substrate, first clean it with a commercially available glass cleaning agent, and then use it. Wash with ion water and dry. (b) Copper phthalcoyanine was selected as the hole injection layer material (150angstroms) and evaporated on IT0 glass. (c) Steam hole-transport layer material-nitrogen, nitrogen-di- (1-naphthyl)-nitrogen, nitrogen biphenyl (N, N'-bis- (l-naphthyl) -N, N'-diphenylbenzidine) (4 0 0 angstroms) 〇 (d) Re-evaporate the light-emitting layer on the hole-transport layer. . (e) vapor-bond an electron-transport layer (eiectron-transport layer) on the light-emitting layer, and tri-8-hydroxyquinolinium aluminum compound (300 angstroms) (alumium-tris-8-hydroxy-quinoline) 〇 (f) As a cathode, a magnesium-silver alloy was vapor-deposited on the electron transport layer. (g) The device is packaged in a dry glove box filled with nitrogen. < Preparation example 3 > includes the following steps: (a) using indium-tin-oxide glass (IT0 glass) as the anode substrate, cleaning with a commercially available glass cleaning agent, and then using deionized water, drying.

Page 23 555831 V. Description of the invention (17) (b) Copper phthalcoyanine is used as a hole injection layer material (150angstroms) and is vapor-deposited on IT0 glass. (c) A hole-transmission layer (h0ie-tranSprt layer) material-nitrogen, nitrogen-di- (1-naphthyl) -nitrogen, nitrogen biphenyl (N, N'-bis- (l-naphthyl) -N, N'-diphenylbenzidine) (600 angstroms) 〇 (d) Re-evaporate the light-emitting layer on the hole transfer layer (light-emitting \ layer) using the aforementioned compound -C ( 150 angstroms). (e) Electron-transport layer, 350-8 angstroms (alumium-tris-8-hydroxy-quinoline) ° (f) is deposited on the light-emitting layer. As a cathode, a magnesium-silver alloy was vapor-deposited on the electron transport layer. (g) The device is packaged in a dry glove box filled with nitrogen. < Preparation Example 4 > includes the following steps: (a) selecting indium-tin-oxide glass (IT0 glass) as the anode substrate, cleaning it with a commercially available glass cleaning agent, and then using deionized water, drying. (b) Copper phthalcoyanine is used as a hole injection layer material (120angstroms) and is deposited on IT0 glass. (c) A hole-transport layer material-nitrogen, nitrogen-di- (1-naphthyl nitrogen, nitrogen biphenyl (N, N, -bis-)- (1-naphthyl) -N, N, _diphenylbenzidine)

Page 24 555831 V. Description of the invention (18) (400 angstroms) ° (d) Re-steaming the light-emitting layer on the hole transfer layer Select the aforementioned compound -D (150 angstroms). (e) Electron-transport layer, 350-angstroms (alumium-tris-8-hydroxy-quinoline) ° (f) on the light-emitting layer As a cathode, a magnesium-silver alloy was vapor-deposited on the electron transport layer. (g) The device is packaged in a dry glove box filled with nitrogen. < Preparation of Comparative Example 1 > includes the following steps:

(a) Indium-tin-oxide glass (IT0 glass) is used as the anode substrate, and it is washed with a commercially available glass cleaning agent, and then washed with deionized water, and dried. (b) Copper phthalcoyanine is used as the hole injection layer material (150angstroms), and steam is mined on IT0 glass. (c) A hole-transport layer material-nitrogen, nitrogen-di- (bnaphthyl) -nitrogen, nitrogen biphenyl (N, N,-bis- (l- naphthyl) -N, N'-diphenylbenzidine) (4 0 0 angstroms) 〇

(d) Re-steaming the light-emittint layer on the hole-transporting layer selects the aforementioned compound-E (150 angstroms). (e) An electron-transport layer was vapor-bonded on the light-emitting layer, and tri-8-hydroxyquinolin-Ming compound (300

Page 25 555831 V. Description of the invention (19) angstroms) (alumium-tris-8-hydroxy-quinoline) ○ (f) Steam-mineralized silver alloy is used as the cathode on the electron transport layer. (g) The components are packaged in a dry glove box filled with nitrogen. < Preparation of Comparative Example 2 > Including the following steps: (a) Indium-tin-oxide glass (IT0 glass) as the anode substrate, first washed with a commercially available glass cleaning agent, and then washed with deionized water, drying. (b) Copper ph t ha 1 coy an i ne is used as the hole injection layer material (150angstroms), and the bond is vapor-deposited on the ITO glass. (c) Distilling the hole-transport layer material on the hole injection layer-nitrogen, nitrogen-di- (1-naphthyl) -nitrogen, nitrogen biphenyl (N, Ν '-bis- (l-naphthyl) -N, N'-diphenylbenzidine) (400 angstroms). (d) Re-evaporate the light-emitting layer on the hole transfer layer using the aforementioned compound-F (150 angstroms). (e) An electron-transport layer is vapor-bonded on the light-emitting layer. The tri-8-hydroxyquinolinium aluminum compound (300 angstroms) (alumium-tris-8-hydroxy-quinoline) is 〇 (f) As a cathode, a magnesium-silver alloy was vapor-deposited on the electron transport layer. (g) The device is packaged in a dry glove box filled with nitrogen. Finally, based on the results of the above preparation examples, an organic electroluminescent device made of the blue fluorescent material synthesized by the present invention can be calculated.

Page 26 555831 V. Description of the invention (20) The comparison of luminous efficiency and wavelength of organic electroluminescence devices made of known blue fluorescent materials (compounds E, F) is as follows: Indication 0 Voltage (V) Efficiency (lm / W) * Maximum emission wavelength (nm) Compound A 1 7 1. 3 440 Compound B 7 1. 2 460 Compound C 8 1. 3 450 Compound D 10 1.1 [460 Known sapwood 1 Compound E 12 0. 9 ″ 460 Compound F 15 0.4 | 480 * Measuring area: 0 · 2 5 cm 2 P

Page 27 555831 Brief description of the drawings Figure 1 is a cross-sectional view of the basic structure of an organic electroluminescence device. Fig. 2 is a sectional view showing another structure of an organic electroluminescence device. Figures 3A to 3C are sectional views of the structure of three conventional organic light emitting diodes. Fig. 4 is a structural sectional view of an organic electroluminescence device of the present invention. Fig. 5 is a graph showing the wavelength distribution of an organic electroluminescent device manufactured in Preparation Example 1 of the present invention. Fig. 6 is a brightness / voltage curve of an organic electroluminescence device manufactured in Preparation Example 1 of the present invention. Fig. 7 is a current / electricity M curve of an organic electroluminescent device manufactured in Preparation Example 1 of the present invention. [Illustration of Symbols] 1 · · · · Anode 2 · · · · · Transparent glass 3 · · · · Cathode 4 · · · · · Electron transfer layer 5 · · · · Light emitting layer 6 · · · · Hole transport layer 7 ··· Hole Injection Layer (HIL) 0EL1, 0EL2, 0EL3 · · · · Three light emitting materials B_0EL · · · · Blue light emitting material F1 · · · · Light color conversion film

Page 28 555831 Brief description of drawings W_OEL · · · · White luminescent material F2 (EL el ement) 4 0 • • • • Glass or transparent plastic substrate 3 0 1 • • • • Hole injection layer (h 〇1 e-injection layer) 3 0 2 • • • Hole transfer layer ( h 〇1 e-transport layer) 3 0 3

Page 29

Claims (1)

555831 VI. Announcement of the scope of patent application 1 An organic electroluminescence device (EL device) comprising an anode, a cathode, and an organic element (EL element) sandwiched therebetween for emitting light, the organic electroluminescence The element system includes a substance represented by: Where m, n = 1 to 3, and the substituents R are the same or different and are selected from the group consisting of t-butyl, phenyl, methylphenyl, and naphthyl (Naphenyl) group. The organic electroluminescence device according to item 1 of the scope of patent application, wherein the substituent R is a third butyl (t-butyl). 3 An organic electroluminescence device (EL device) comprising an anode, a cathode, and an organic electroluminescent element (EL e 1 ement) sandwiched therebetween for emitting light. The organic electroluminescent element includes the following formula A substance represented: Page 30 555831 6. Scope of patent application Where m, n = 1 to 3, the substituents R are the same or different and are selected from the group consisting of methyl, isopropyl, t-butyl, and phenyl ) And naphthyl (η8ρ1ΐ6η7ΐ) group 0 4 The organic electroluminescence device as described in item 3 of the patent application scope, wherein the substituent R is a third butyl (t-butyl). & In the organic electroluminescence device as described in item 3 of the scope of patent application, wherein m = 1, n = l-3, the substituents R are the same or different and the t-butyl group contains t-butyl , Phenyl, methylphenyl, naphenyl, heterocyclic bompound group 0 Organic electroluminescence as described in item 5 of the scope of patent application wherein the substitution The radical R is a third butyl (t-buty 1). & Page 31