TWI487689B - White organic light-emitting device and manufacturing method thereof - Google Patents

Description

White light organic light-emitting element and preparation method thereof

The present invention relates to a white light organic light-emitting element and a method of producing the same. In particular, there are a white organic light-emitting element formed of a single luminescent material and a method of preparing the same.

In recent years, the development of organic light-emitting diodes (OLEDs) has been highly valued by academics and industry. The main reason is that the organic light-emitting diode has the advantages of being light and thin, self-luminous, wide viewing angle, short reaction time, high brightness, and the like, and has the potential to develop into a large-area display or a flexible thin film device. However, there are still many problems that need to be overcome in terms of component lifetime, efficiency, luminescent color purity, and the like. Conventional organic light-emitting materials or components, usually by the following ways to achieve the purpose of modulating the color of light: (1) co-evaporation of dopant materials, through the energy transfer mechanism to achieve color modulation; 2) via chemical synthesis, different functional groups are attached to the main chain of the luminescent molecule; (3) using a component containing two layers of luminescent materials, the carrier recombination zone is regulated by different voltages to achieve color modulation. The above method requires the use of two or more luminescent materials, or chemical synthesis or related reaction steps, which increases the difficulty of the process.

In addition to being applicable to displays, white light organic light-emitting technology has become increasingly important in lighting applications as its luminous efficiency continues to increase. At present, the white organic light-emitting diodes are mostly composed of the three primary colors of light (red, green, blue) or It is a mixture of two complementary colors. A common white light organic light emitting diode device comprises: (1) a plurality of light emitting layer devices formed by continuous evaporation, and each light emitting layer emits a single color light; (2) a single layer polymer mixing device, which will emit all the light The composition is mixed between the single layers; and (3) the guest illuminant capable of emitting different color lights is doped into the single layer structure of the main illuminant. The above method requires a plurality of types of vapor deposition sources in the process, and there are many kinds of materials that are contaminated with each other. Compared with a white organic light-emitting diode containing several kinds of luminescent components, a white light organic light-emitting diode using a single illuminant has the advantages of high stability and reproducibility, and simple process. Therefore, it is still necessary to develop an organic light-emitting technology in which a single material can emit white light.

The present invention provides a white organic light-emitting element comprising: an anode; an organic light-emitting layer on the anode; and a cathode on the organic light-emitting layer, wherein the organic light-emitting layer is substantially composed of 2, 2', 7, 7'-tetradecyl It consists of -9,9'-ring double bismuth (TPSBF).

The invention further provides a method for preparing a white organic light-emitting element, comprising the steps of: providing a substrate; forming an anode on the substrate; forming an organic light-emitting layer on the anode, wherein the organic light-emitting layer is substantially composed of 2, 2', 7, 7' - Tetrakidenyl-9,9'-cyclohexane (TPSBF) is formed, and a cathode is formed on the light-emitting layer.

The above and other objects, features and advantages of the present invention will become more <RTIgt;

100‧‧‧White organic light-emitting elements

110‧‧‧Base

120‧‧‧Anode

130‧‧‧Organic lighting unit

131‧‧‧ hole injection layer

132‧‧‧ hole transport layer

133‧‧‧ functional layer

135‧‧‧ Organic light-emitting layer

136‧‧‧Electronic transport layer

137‧‧‧electron injection layer

138‧‧‧ functional layer

140‧‧‧ cathode

200‧‧‧Manufacture method

210, 220, 230, 240 ‧ ‧ steps

Figure 1 shows 2,2',7,7'-tetradecyl-9,9'-cyclohexane (2,2',7,7'-tetra-(pyren-1-yl)-9, Molecular structure of 9'-spirobifluorene, TPSBF).

Figure 2 is a photoluminescence spectrum of 2,2',7,7'-tetradecyl-9,9'-cyclonic bifluoride film of different thickness.

Fig. 2A is an exploded view of the photoluminescence spectrum of a 2,2',7,7'-tetradecyl-9,9'-cyclohexane double iridium film (thickness: 30 nm).

Fig. 2B is an exploded view of the photoluminescence spectrum of the 2,2',7,7'-tetradecyl-9,9'-cyclohexane double ruthenium film (thickness: 50 nm).

Figure 2C is an exploded view of the photoluminescence spectrum of a 2,2',7,7'-tetradecyl-9,9'-cyclohexane bismuth film (thickness 70 nm).

Figure 3 is a schematic diagram of a white light organic light-emitting device.

Fig. 4 is a flow chart showing the process of manufacturing a white organic light emitting device.

FIG. 5 is a schematic diagram showing the configuration and energy level of the white organic light-emitting device 1.

Figure 6 shows the molecular structure of 2T-NATA, NPB and Alq ₃ .

Figure 7 is an electroluminescence spectrum of white organic light-emitting devices I, II and III.

Fig. 8A is a graph showing the electroluminescence efficiency-current density change of the white organic light-emitting device II.

Fig. 8B is a graph showing the power efficiency-current density change of the white organic light-emitting device II.

Fig. 8C is a current density-voltage change diagram of the white organic light-emitting device II.

Fig. 8D is a graph showing the electroluminescence luminance-current density change of the white organic light-emitting device II.

Figure 9 is an electroluminescence spectrum of a white organic light-emitting device IV-VII.

The white organic light-emitting device of the present invention will be described in detail below. It will be appreciated that the following description provides many different embodiments or examples to implement the invention. The specific elements and arrangements described below are intended to be illustrative of the invention and are merely illustrative and not limiting. Moreover, repeated numbers or labels may be used in different embodiments. These repetitions are merely for the purpose of simplicity and clarity of the invention and are not to be construed as a limitation of the various embodiments and/or structures discussed. Furthermore, when the first material layer is on or above the second material layer, the first material layer is in direct contact with the second material layer. Alternatively, it is also possible to have one or more layers of other materials interposed, in which case there may be no direct contact between the first material layer and the second material layer.

As used herein, the terms "about" and "about" are generally meant to be within 20%, preferably within 10%, and more preferably within 5% of a given value or range. The quantity given here is an approximate quantity, meaning that the meaning of "about" or "about" may be implied without specific explanation.

The invention provides a white organic light-emitting element and a preparation method thereof. The organic light-emitting layer of the above white organic light-emitting element is substantially composed of 2,2',7,7'-tetradecyl-9,9'-cyclocyclic guanidine (2,2',7,7'-tetra-(pyren) -1-yl)-9,9'-spirobifluorene, TPSBF), and can control 2,2',7,7'-tetradecyl-9,9'-rotation in organic light-emitting layer through different process conditions The shape of the ring double bismuth produces a white light organic light-emitting element which contains only a single luminescent material with high efficiency and high stability.

Figure 1 shows 2,2',7,7'-tetradecyl-9,9'-cyclohexane (2,2',7,7'-tetra-(pyren-1-yl)-9, Molecular structure of 9'-spirobifluorene, TPSBF). The 2,2',7,7'-tetradecyl-9,9'-cyclocyclic biguanide of the present invention can be obtained by Suzuki coupling reaction, and the related preparation method and characteristic analysis have been disclosed in ECS Journal of Solid State Science and Technology, 1 (3) R203-R107, 2012 and ChemPlus Chem Volume 78, issue 10, page 1288-1295, the disclosure of which is incorporated herein by reference in its entirety. For example, pyrene boronic acid can be combined with 2,2',7,7'-tetrabromo-9,9'-cyclocyclic guanidine (2,2',7,7'-Tetrabromo-9 , 9'-spirobifluorene) is dissolved in toluene (Toluene) and ethanol (Ethanol) mixed solvent, adding sodium carbonate solution (Na ₂ CO ₃ ) and a catalyst to carry out the reaction, and then extracting and purifying to obtain 2, 2', 7, 7'-tetradecyl-9,9'-coiled bivalve. Table 1 lists the physical properties associated with 2,2',7,7'-tetradecyl-9,9'-cyclohexane.

LUMO: lowest unoccupied molecular orbital

The above λ _max (UV), λ _max (PL) and Φ _F are 2,2′,7,7′-tetradecyl-9,9′-cyclohexafluorene dissolved in chloroform (CHCl ₃ ) at a concentration of Measured at 4×10 ^-3 M. The highest occupied molecular orbital and the lowest unoccupied molecular orbital were measured using a Rilken KeiKi AC-2 photoelectric spectrometer.

2,2',7,7'-tetradecyl-9,9'-cyclocyclic fluorene is composed of spirobifluorene as the structural center and carbon number 2,2',7,7' The position is attached to a pyrene group, and the core of the cyclodane has a rigid aromatic ring, which has excellent steric hindrance, reduces intermolecular action and provides high thermal stability, and has a high fluorescence luminous efficiency. Electron transport capability and reduction of crystallinity by forming a covalent bond with the cyclopentadienyl core, resulting in high luminous efficiency of the 2,2',7,7'-tetradecyl-9,9'-cyclocyclic bisulfonium material And high glass transfer temperature. Therefore, the molecular structure design of 2,2',7,7'-tetradecyl-9,9'-cyclohexane is not only excellent in charge transport and luminescence, but also in the preparation of organic light-emitting elements. Material stability for the process and subsequent applications.

The inventors prepared the above 2,2',7,7'-tetradecyl-9,9'-cyclohexane fluorene into films of different thicknesses and analyzed their photoluminescence (PL) spectra. It is found that there are three kinds of luminescence mechanisms in the 2,2',7,7'-tetradecyl-9,9'-cyclocyclic bifluorene film, which are: (a) the molecule itself emits light, mainly by intramolecular force The effect is that the emission band is between 440 nm and 470 nm (about blue light); (b) the molecular concentration and the light are mainly affected by the intermolecular force, and the emission band is about 490 nm to 510 nm (about green light). (c) Molecular emission with longer conjugate wavelength, mainly affected by the interaction between layers, and its emission band is about 540nm~560 Nm (approximately yellow-green light). Therefore, as long as the coating parameters of the organic light-emitting layer are precisely controlled, and the content of the shorter wavelength band and the longer wavelength band in the organic light-emitting layer is adjusted, 2, 2', 7, 7'-tetradecyl-9 can be achieved. The 9'-ring double bismuth single material emits white light.

Fig. 2 is a photoluminescence spectrum (illumination wavelength of 358 nm) of 2,2',7,7'-tetradecyl-9,9'-cyclohexane bismuth film with thicknesses of 30 nm, 50 nm and 70 nm, respectively. Comparing the photoluminescence spectra of different 2,2',7,7'-tetradecyl-9,9'-cyclocyclic bifluorene film thicknesses, each photoluminescence spectrum should include at least three overlapping peaks, and The main emission wavelengths are located at 456nm, 500nm and 550nm, respectively, and the thickness of the 2,2',7,7'-tetradecyl-9,9'-cyclohexane double ruthenium film is gradually increased, and the long-wavelength of the light is also increased. gradually increase.

Assuming that each of the light-emitting bands has a Gaussian distribution, the above-mentioned photoluminescence spectrum is further decomposed into three light-emitting wavelength waveforms. Fig. 2A-2C is an exploded view of the photoluminescence spectrum of the 2,2',7,7'-tetradecyl-9,9'-cyclohexane double iridium film with thicknesses of 30 nm, 50 nm and 70 nm, respectively. It can be found from the above waveform decomposition diagram that the signal intensity of the longer wave grows with the thickness of the 2,2',7,7'-tetrameryl-9,9'-spin bicyclic film, making 2,2',7 , 7'-tetramercapto-9,9'-spin-ring double-twist film release phenomenon with red film shift due to the increase of film thickness, and the intensity of light observed at different emission wavelengths, according to deposition The thickness of the condition or sample (2,2',7,7'-tetradecyl-9,9'-cyclocyclic bifluorene film) varies. Therefore, the illumination pattern of the 2,2',7,7'-tetradecyl-9,9'-spin-ring double oxime can be controlled by different process conditions, and even a wide spectrum can be obtained under specific process conditions. White light spectrum.

FIG. 3 is a schematic diagram of a white light organic light emitting device 100 according to an embodiment of the present disclosure. The white light organic light emitting element 100 includes a substrate 110 and an anode 120 Formed on the substrate 110, the organic light emitting unit 130 is formed on the anode 120, and the cathode 140 is formed on the organic light emitting unit 130. Wherein, the organic light emitting unit 130 includes an organic light emitting layer 135 consisting essentially of 2,2',7,7'-tetradecyl-9,9'-cyclohexane. In other words, the organic light-emitting layer 135 is basically composed only of 2,2',7,7'-tetradecyl-9,9'-cyclohexane, that is, the organic light-emitting layer 135 does not substantially include other light-emitting components. Or it can affect and change the doping of the 2,2',7,7'-tetradecyl-9,9'-cyclocyclic bifluorene type.

The organic light emitting unit 130 may additionally include a hole injection layer (HIL) 131 and/or a hole transporting layer (HTL) 132 and/or another layer between the anode 120 and the organic light emitting layer 135 or A multi-layered functional layer 133 (for example, a functional layer, a buffer layer or an electron blocking layer having both a hole injection function and a hole transmission function). In some embodiments, the organic light emitting unit 130 may additionally include a hole injection layer 131 on the anode 120 and a hole transport layer 132 on the hole injection layer 131.

The organic light emitting unit 130 may additionally include an electron transport layer (ETL) 136 and/or an electron injection layer (EIL) 137 and/or another layer or layers between the organic light emitting layer 135 and the cathode 140. The functional layer 138 (for example, a hole blocking layer or a functional layer having both an electron transport function and an electron injecting function) is located between the organic light emitting layer 135 and the cathode 140. In some embodiments, the organic light emitting unit 130 may additionally include an electron transport layer 136 on the organic light emitting layer 135 and an electron injection layer 137 on the electron transport layer 136.

FIG. 4 is a flow chart of a process for fabricating a white light organic light emitting device 200 according to an embodiment of the present disclosure. It must be understood that additional The steps are before, during, and after the manufacturing method 200, and in the embodiments of the present disclosure, some of the steps described below may also be replaced or removed.

According to the white light organic light emitting device manufacturing method 200 of Fig. 4, step 210 is to provide a substrate. The substrate may use various rigid and flexible substrates commonly used in organic light-emitting elements, such as a glass substrate, a plastic substrate, or a metal substrate, but is not limited thereto. In an embodiment, the substrate is a glass substrate. In one embodiment, the substrate may be first ultrasonically cleaned and treated with oxygen plasma (O ₂ plasma) prior to use.

According to the white light organic light emitting device manufacturing method 200 of Fig. 4, the subsequent step 220 is to form an anode. Taking FIG. 3 as an example, the anode 120 is formed on the substrate 110. The anode is a connection layer of forward voltage, which should have good electrical conductivity, visible light transparency and high work function. The material of the anode 120 includes a metal, a transparent conductive oxide, a conductive polymer or a composite thereof and a laminated structure, or other materials known in the art. The anode 120 may have a single layer or a multilayer structure of two or more layers. For example, the anode material can include, but is not limited to, a transparent conductive oxide. Wherein, the transparent conductive oxide may be at least one selected from the group consisting of indium (In), tin (Sn), zinc (Zn), gallium (Ga), cerium (Ce), cadmium (Cd), magnesium (Mg), and cerium (Be). ), silver (Ag), molybdenum (Mo), vanadium (V), copper (Cu), iridium (Ir), rhenium (Rh), ruthenium (Ru), tungsten (W), cobalt (Co), nickel (Ni ), oxides of manganese (Mn), aluminum (Al) and lanthanum (La). The material of the anode 120 preferably includes indium tin oxide (ITO) or indium zinc oxide (IZO), and a substrate coated with a transparent conductive oxide may be used to omit the step of forming the anode 120. In one embodiment, the substrate is a glass substrate coated with indium tin oxide.

The anode 120 can be formed by any of the following methods: physical vapor deposition (PVD), such as: metal evaporation or sputtering, chemical vapor deposition (CVD), metal organic chemical vapor deposition (MOCVD), plasma-assisted chemistry Vapor deposition (PECVD), atmospheric pressure chemical vapor deposition (APCVD), low pressure chemical vapor deposition (LPCVD), high density plasma chemical vapor deposition (HDPCVD), atomic layer chemical vapor deposition (ALCVD), but are not limited thereto.

According to the white light organic light emitting device manufacturing method 200 of FIG. 4, the organic light emitting unit is formed in the subsequent step 230. Taking FIG. 3 as an example, the organic light emitting unit 130 is formed on the anode 120.

The organic light emitting unit 130 includes an organic light emitting layer 135 which is substantially composed of 2,2',7,7'-tetradecyl-9,9'-cyclocyclic double fluorene.

The organic light emitting unit 130 may additionally include a hole injection layer 131 and/or a hole transport layer 132 and/or other one or more functional layers 133 (eg, a functional layer having both a hole injection function and a hole transfer function, buffering) A layer or an electron blocking layer) is located between the anode 120 and the organic light-emitting layer 135.

In order to facilitate the injection of the hole into the organic light-emitting layer, the material of the hole injection layer is preferably a material having a large work function. The material of the hole injection layer 131 may be selected from known hole injection materials, and specific examples thereof include: DNTPD (N1, N1'-(biphenyl-4, 4'-diyl) bis (N1-phenyl-N4, N4-di- M-tolylbenzene-1,4-diamine)), 4,4'4"-tris(N,N-diphenylamino)triphenylamine (TDATA), 4,4',4"-three [2- Naphthylphenylamino]triphenylamine (4,4',4"-Tris[N-(2-naphthyl)-N-phenylamino]triphenylamine, 2T-NATA), polyaniline/dodecylbenzene Polyaniline/Dodecylbenzenesulfonic acid, Pani/DBSA), poly(3,4-ethylenedioxythiophene)/poly(4-styrene sulfate),Poly(3,4-ethylenedioxythiophene)/Poly(4-styrenesulfonate), PEDOT/PSS], polyaniline/camphoric acid (PolyaniIine/Camphor) Sulfonic acid, Pani/CSA) or polyaniline/poly (4-styrenesulfonate), PANI/PSS, etc., but is not limited thereto.

The material of the hole transport layer 132 may be a known hole transport material, and specific examples thereof include a diamine compound, an aromatic amine compound, a triarylamine derivative, and a diphenylnaphthyl group. Indole phenylenediamine (NPB) series, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD ), bisphenol phenol (Spiro-NPB), poly(3,4-ethylenedioxythiophene)/poly(4-styrene sulfonate) [Poly(3,4-ethylenedioxythiophene)/Poly(4-styrenesulfonate) , PEDOT/PSS], but not limited to this.

The organic light emitting unit 130 may additionally include an electron transport layer 136 and/or an electron injection layer 137 and/or another one or more functional layers 138 (eg, a hole blocking layer or a functional layer having both an electron transport function and an electron injection function) ) is located between the organic light-emitting layer 135 and the cathode 140.

Specific examples of the material of the electron injecting layer 137 may include: metals such as magnesium (Mg), calcium (Ca), sodium (Na), potassium (K), titanium (Ti), indium (In), ytterbium (Y), Lithium (Li), gallium (Ga), aluminum (Al), silver (Ag), tin (Sn), lead (Pb) or alloys thereof; materials of a multilayer structure such as LiF/Al or LiO ₂ /Al, The same material as the hole injection layer 131 may be used, but is not limited thereto.

The material of the electron transport layer 136 is a material capable of receiving electrons from the electron injection layer 137 and transporting the electrons to the light emitting layer 135, and is more suitably a material having high electron mobility. Specific examples thereof include: an aluminum complex of 8-hydroxyquinoline, a complex containing tris(8-hydroxyquinoline)aluminum (Alq ₃ ), an organic group compound, and a hydroxyflavone-metal complex. Compounds, etc., but are not limited thereto.

The organic light emitting unit 130 can be formed by a deposition method, for example, by any of the following methods: physical vapor deposition (PVD), such as metal evaporation or sputtering, chemical vapor deposition (CVD), metal organic chemical vapor deposition. Method (MOCVD), plasma assisted chemical vapor deposition (PECVD), atmospheric pressure chemical vapor deposition (APCVD), low pressure chemical vapor deposition (LPCVD), high density plasma chemical vapor deposition (HDPCVD), atomic layer chemistry Gas phase deposition (ALCVD), but is not limited thereto. The organic light-emitting unit 130 can also be formed by a method such as a spin coating method, a dip coating method, or an inkjet printing method.

In some embodiments, the method of forming the organic light-emitting layer 135 is vapor deposition, and the color light can be adjusted by adjusting parameters such as coating rate, coating thickness, and evaporation source preheating conditions.

In some embodiments, the organic light-emitting layer 135 may have a thickness of 10 nm to 100 nm, for example, a thickness of 10 nm to 90 nm, and further, for example, a thickness of 30 nm to 70 nm. If the thickness of the excitation layer is less than 5 nm, the 2,2',7,7'-tetradecyl-9,9'-cyclohexane molecule may be in a particulate phase on the substrate, which may cause unevenness of the film layer, or The direct contact between the electron transport layer and the electromotive transport layer causes exciton attenuation; if the thickness of the excitation light layer is greater than 100 nm, the light color may deviate from the white light region, or the exciton recombination region may be decoupled from the light emitting layer, resulting in a decrease in efficiency.

In some embodiments, the organic light-emitting layer 135 can be deposited by a deposition rate between 0.01 nm/sec and 0.5 nm/sec, for example, a coating rate of between 0.01 nm/sec and 0.4 nm/sec, for example: The coating rate is between 0.02 nm/sec and 0.35 nm/sec. In some embodiments, the slower the evaporation rate, 2, 2', 7, 7'-four The longer the heating time of the thiol-9,9'-ring ring is, the more time it takes to form molecular aggregation, which can gradually increase the luminous intensity of the longer band. On the contrary, the faster the evaporation rate, the 2,2',7,7'-tetradecyl-9,9'-cyclohexane fluorene molecular aggregation behavior is less obvious, and the longer wavelength luminescence intensity is weaker. If the evaporation rate is less than 0.01 nm/sec, the machine cannot detect it; and the evaporation rate of more than 0.5 nm/sec may exceed the material cracking temperature, resulting in material denaturation.

In some embodiments, the vapor deposition source may be preheated at a temperature between 300 ° C and 550 ° C prior to evaporation of the organic light emissive layer 135 . For example, the preheating temperature is between 350 ° C and 540 ° C, and for example: the preheating temperature is between 400 ° C and 530 ° C. In some embodiments, the preheated evaporation source has a similar effect as slowing the coating rate, and the temperature of the 2,2',7,7'-tetradecyl-9,9'-ring bimetallic material is heated by preheating. To near or above its sublimation temperature (about 450 ° C), it helps the 2,2',7,7'-tetradecyl-9,9'-cyclocyclic bisulfon molecule to be arranged and aggregated, and its molecular group After the enlargement is carried out, evaporation is performed to increase the luminous intensity of the longer wavelength band. If the preheating temperature is less than 300 °C, the 2,2',7,7'-tetradecyl-9,9'-cyclohexane bismuth material can not be effectively heated to be close to or higher than its sublimation temperature; and the heating temperature is higher than 550 °C. Then, the 2,2',7,7'-tetradecyl-9,9'-cyclohexane double oxime formed an aggregated molecular group that is too large, which is not conducive to evaporation, and may exceed the material cracking temperature, resulting in material denaturation.

In some embodiments, the organic light-emitting layer 135 may have an emission peak between 450 nm and 620 nm, for example, an emission peak between 450 nm and 600 nm, and another example, an emission peak between 470 nm and 570 nm. In an embodiment, the organic light-emitting layer 135 has an emission peak of between 440 nm and 470 nm. In another embodiment, the organic light-emitting layer 135 has an emission peak of between 470 nm and 490 nm. In still another embodiment, the organic light-emitting layer 135 has a wavelength between 490 nm and 520 nm. The luminescence peak. In still another embodiment, the organic light-emitting layer 135 has an emission peak of between 540 nm and 560 nm.

According to the white light organic light emitting device manufacturing method 200 of Fig. 4, the cathode is formed in the subsequent step 240. Taking FIG. 3 as an example, a cathode 140 is formed on the organic light emitting unit 130.

The material of the cathode 140 should have good electrical conductivity and a low work function, and specific examples thereof may include a metal, a transparent conductive oxide, a conductive polymer or a composite thereof and a laminated structure, or other materials known in the art. The cathode 140 may have a single layer or a multilayer structure of two or more layers. For example, the material of the cathode 140 may include, but is not limited to, magnesium (Mg), calcium (Ca), sodium (Na), potassium (K), titanium (Ti), indium (In), yttrium (Y), lithium. (Li), gallium (Ga), aluminum (Al), tin (Sn), lead (Pb), the above alloy with copper (Cu), gold (Au) or silver (Ag), buffer insulation layer [eg: fluorine Lithium (LiF)] and combinations thereof. The cathode is preferably formed of aluminum (Al) or lithium fluoride/aluminum (LiF/Al). In some embodiments, the cathode material comprises lithium fluoride/aluminum (LiF/Al).

The cathode 140 can be formed by any of the following methods: physical vapor deposition (PVD), such as: metal evaporation or sputtering, chemical vapor deposition (CVD), metal organic chemical vapor deposition (MOCVD), plasma assisted chemistry. Vapor deposition (PECVD), atmospheric pressure chemical vapor deposition (APCVD), low pressure chemical vapor deposition (LPCVD), high density plasma chemical vapor deposition (HDPCVD), atomic layer chemical vapor deposition (ALCVD), but not Limited to this.

In some embodiments, the anode, the organic light emitting element, and the cathode are formed by continuous evaporation.

In summary, according to the white light organic light-emitting element provided by the present invention, the light-emitting layer is mainly composed of 2,2',7,7'-tetradecyl-9,9'-cyclodane. The 2,2',7,7'-tetradecyl-9,9'-cyclohexane big molecule fluorescent luminescent material has three main emission bands of about 440 nm to 470 nm, 490 nm to 510 nm, and 540 nm to 560 nm. And 2,2',7,7'-tetradecyl-9,9'-cyclohexane has different light-releasing behaviors under different aggregation patterns, and can form a single layer without doping other materials. A white light organic light-emitting element of a single material, in a preferred embodiment, has a maximum luminance of more than 45,000 cd/m ² , preferably more than 55,000 cd/m ² , and a luminous efficiency of more than 5.5 cd/A, preferably higher than 6 cd. /A.

[Preparation Example] Synthesis of 2,2',7,7'-tetradecyl-9,9'-cyclocyclic guanidine

4.06 mmol (1.00 g) of pyrene boronic acid and 0.79 mmol (0.51 g) of 2,2',7,7'-tetrabromo-9,9'-cyclocyclic guanidine (2,2',7 , 7'-Tetrabromo-9, 9'-spirobifluorene) was dissolved in a mixed solvent of toluene and ethanol (Ethanol) in a volume ratio of 5:3, and 4.80 mmol (2.40 ml) of a 2 M sodium carbonate solution was added ( Na ₂ CO ₃ ) and 47 mg (4.0 mol%) of tetrakis(triphenylphosphine)palladium, Pd(PPh ₃ ) ₄ ], were heated under reflux under a nitrogen atmosphere. After 24 hours of reaction, the heating was stopped and 100 ml of water was added, and after cooling, the product was extracted with chloroform, and finally washed and purified to obtain 2,2',7,7'-tetradecyl-9,9'-cyclocyclobiguanide.

[Example 1]

A glass substrate is used which is covered with a sheet resistance of about 10 Ω. Cm, indium tin oxide (ITO) having a thickness of 170 nm. Prior to deposition, the substrate was ultrasonically cleaned prior to isopropanol and deionized water followed by oxygen plasma (O ₂ plasma). The substrate is then placed in a deposition chamber, and 2T-NATA, NPB, 2,2', 7,7'-tetradecyl-9,9'-rings are sequentially placed under a pressure of 10 ^-6 torr. Bismuth, Alq ₃ , lithium fluoride (LiF) and aluminum (Al) are evaporated onto the substrate without breaking the vacuum, and the structure is ITO (170 nm) / 2T-NATA (15 nm) / NPB (65 nm) / TPSBF ( White light organic light-emitting device I of 30 nm)/Alq ₃ (30 nm)/LiF (0.8 nm)/Al (200 nm), wherein 2,2',7,7'-tetradecyl-9,9'-ring ring It is formed by vapor deposition at a fixed coating rate of 0.1 nm/sec. FIG. 5 is a schematic diagram showing the configuration and energy level of the white organic light-emitting device 1. Figure 6 shows the molecular structures of 2T-NATA, NPB, and Alq ₃ , which serve as a hole injection layer, a hole transport layer, and an electron transport layer of the white organic light-emitting device, respectively, and ITO and LiF/Al serve as anodes, respectively. cathode.

[Example 2]

A glass substrate is used which is covered with a sheet resistance of about 10 Ω. Cm, indium tin oxide (ITO) having a thickness of 170 nm. Prior to deposition, the substrate was ultrasonically cleaned prior to isopropanol and deionized water followed by oxygen plasma (O ₂ plasma). The substrate is then placed in a deposition chamber, and 2T-NATA, NPB, 2,2', 7,7'-tetradecyl-9,9'-ring is sequentially placed under a pressure of 10 ^-6 torr. Bismuth, Alq ₃ , lithium fluoride (LiF) and aluminum (Al) are evaporated onto the substrate without breaking the vacuum, and the structure is ITO (170 nm) / 2T-NATA (15 nm) / NPB (65 nm) / TPSBF ( White light organic light-emitting device II of 50 nm)/Alq ₃ (30 nm)/LiF (0.8 nm)/Al (200 nm), wherein 2,2',7,7'-tetradecyl-9,9'-ring ring It is formed by vapor deposition at a fixed coating rate of 0.1 nm/sec.

[Example 3]

A glass substrate is used which is covered with a sheet resistance of about 10 Ω. Cm, indium tin oxide (ITO) having a thickness of 170 nm. Prior to deposition, the substrate was ultrasonically cleaned prior to isopropanol and deionized water followed by oxygen plasma (O ₂ plasma). The substrate is then placed in a deposition chamber, and 2T-NATA, NPB, 2,2', 7,7'-tetradecyl-9,9'-ring is sequentially placed under a pressure of 10 ^-6 torr. Bismuth, Alq ₃ , lithium fluoride (LiF) and aluminum (Al) are evaporated onto the substrate without breaking the vacuum, and the structure is ITO (170 nm) / 2T-NATA (15 nm) / NPB (65 nm) / TPSBF ( White light organic light-emitting device III of 70 nm)/Alq ₃ (30 nm)/LiF (0.8 nm)/Al (200 nm), wherein 2,2',7,7'-tetradecyl-9,9'-ring ring It is formed by vapor deposition at a fixed coating rate of 0.1 nm/sec.

Fig. 7 is an electroluminescence (EL) spectrum of white organic light-emitting devices I, II and III, and Table 2 lists various properties of white organic light-emitting devices I, II and III.

Here, η _ext , ηc ^* , ηL ^* and ηp ^* are the maximum values of the respective devices, and ηc, ηL and ηp are measured values of the respective devices at a current density of 20 mA/cm ² . The electroluminescence CIE coordinates were measured at a voltage of 7V.

From the above results, it is known that after the 2,2',7,7'-tetradecyl-9,9'-cyclohexane is produced as an organic light-emitting element, the electroluminescence spectrum of the element is 2, 2', 7, The photoluminescence spectrum of 7'-tetradecyl-9,9'-cyclonic bifluorene film is wider, and the luminescence intensity with wavelength between 500nm and 600nm increases with the increase of coating thickness. When the fixed coating rate is 0.1 nm/sec, the organic light-emitting devices prepared by vapor-depositing 2,2',7,7'-tetradecyl-9,9'-cyclohexane double iridium thicknesses of 30 nm, 50 nm and 70 nm are all obtained. White light can be emitted, especially the CIE chromaticity of the white organic light-emitting device II is (0.29, 0.36), and FIG. 8A is an electroluminescence efficiency-current density change diagram of the white organic light-emitting device II, which is shown at 5.4 mA/cm ² At the current density, the electroluminescence efficiency is up to 6.51 cd/A; the 8B is the power efficiency-current density change diagram of the white organic light-emitting device II and the 8C is the current density and voltage change of the white organic light-emitting device II The figure shows that the power efficiency is up to 4.07 lm/W at a voltage of 4.5 V; the 8D is a graph of the electroluminescence brightness-current density change of the white organic light-emitting device II, which is shown at a voltage of 12V. The electroluminescence brightness is up to 57,680 cd/m ² .

[Embodiment 4]

A glass substrate is used which is covered with a sheet resistance of about 10 Ω. Cm, indium tin oxide (ITO) having a thickness of 170 nm. Prior to deposition, the substrate was ultrasonically cleaned prior to isopropanol and deionized water followed by oxygen plasma (O ₂ plasma). The substrate is then placed in a deposition chamber, and 2T-NATA, NPB, 2,2', 7,7'-tetradecyl-9,9'-ring is sequentially placed under a pressure of 10 ^-6 torr. Bismuth, Alq ₃ , lithium fluoride (LiF) and aluminum (Al) are evaporated onto the substrate without breaking the vacuum, and the structure is ITO (170 nm) / 2T-NATA (15 nm) / NPB (65 nm) / TPSBF ( White light organic light-emitting device IV of 30 nm)/Alq ₃ (30 nm)/LiF (0.8 nm)/Al (200 nm), wherein 2,2',7,7'-tetradecyl-9,9'-ring ring It is formed by vapor deposition at a fixed coating rate of 0.02 nm/sec.

[Embodiment 5]

A glass substrate is used which is covered with a sheet resistance of about 10 Ω. Cm, indium tin oxide (ITO) having a thickness of 170 nm. Prior to deposition, the substrate was ultrasonically cleaned prior to isopropanol and deionized water followed by oxygen plasma (O ₂ plasma). The substrate is then placed in a deposition chamber, and 2T-NATA, NPB, 2,2', 7,7'-tetradecyl-9,9'-ring is sequentially placed under a pressure of 10 ^-6 torr. Bismuth, Alq ₃ , lithium fluoride (LiF) and aluminum (Al) are evaporated onto the substrate without breaking the vacuum, and the structure is ITO (170 nm) / 2T-NATA (15 nm) / NPB (65 nm) / TPSBF ( White light organic light-emitting device V of 30 nm)/Alq ₃ (30 nm)/LiF (0.8 nm) / Al (200 nm), wherein 2,2',7,7'-tetradecyl-9,9'-ring ring It is formed by vapor deposition at a fixed coating rate of 0.15 nm/sec.

[Embodiment 6]

A glass substrate is used which is covered with a sheet resistance of about 10 Ω. Cm, indium tin oxide (ITO) having a thickness of 170 nm. Prior to deposition, the substrate was ultrasonically cleaned prior to isopropanol and deionized water followed by oxygen plasma (O ₂ plasma). The substrate is then placed in a deposition chamber, and 2T-NATA, NPB, 2,2', 7,7'-tetradecyl-9,9'-ring is sequentially placed under a pressure of 10 ^-6 torr. Bismuth, Alq ₃ , lithium fluoride (LiF) and aluminum (Al) are evaporated onto the substrate without breaking the vacuum, and the structure is ITO (170 nm) / 2T-NATA (15 nm) / NPB (65 nm) / TPSBF ( White light organic light-emitting device VI of 30 nm)/Alq ₃ (30 nm)/LiF (0.8 nm)/Al (200 nm), wherein 2,2',7,7'-tetradecyl-9,9'-ring ring It is formed by vapor deposition at a fixed coating rate of 0.35 nm/sec.

[Embodiment 7]

A glass substrate is used which is covered with a sheet resistance of about 10 Ω. Cm, indium tin oxide (ITO) having a thickness of 170 nm. Prior to deposition, the substrate was ultrasonically cleaned prior to isopropanol and deionized water followed by oxygen plasma (O ₂ plasma). The substrate is then placed in a deposition chamber, and 2T-NATA, NPB, 2,2', 7,7'-tetradecyl-9,9'-ring is sequentially placed under a pressure of 10 ^-6 torr. Bismuth, Alq ₃ , lithium fluoride (LiF) and aluminum (Al) are evaporated onto the substrate without breaking the vacuum, and the structure is ITO (170 nm) / 2T-NATA (15 nm) / NPB (65 nm) / TPSBF ( White light organic light-emitting device VII of 30 nm)/Alq ₃ (30 nm)/LiF (0.8 nm) / Al (200 nm), wherein 2,2',7,7'-tetradecyl-9,9'-ring ring The vapor deposition source was preheated at a temperature of 480 ° C for 25 minutes, and then vapor deposited at a fixed coating rate of 0.02 nm / sec.

[Embodiment 8]

A glass substrate is used which is covered with a sheet resistance of about 10 Ω. Cm, indium tin oxide (ITO) having a thickness of 170 nm. Prior to deposition, the substrate was ultrasonically cleaned prior to isopropanol and deionized water followed by oxygen plasma (O ₂ plasma). The substrate is then placed in a deposition chamber, and 2T-NATA, NPB, 2,2', 7,7'-tetradecyl-9,9'-ring is sequentially placed under a pressure of 10 ^-6 torr. Bismuth, Alq ₃ , lithium fluoride (LiF) and aluminum (Al) are evaporated onto the substrate without breaking the vacuum, and the structure is ITO (170 nm) / 2T-NATA (15 nm) / NPB (65 nm) / TPSBF ( White light organic light-emitting device of 30 nm)/Alq ₃ (30 nm)/LiF (0.8 nm)/Al (200 nm), wherein 2,2',7,7'-tetradecyl-9,9'-ring ring is First, after the evaporation source is not preheated, the deposition rate is fixed at 0.02 nm/sec to one-half of the film thickness, and the evaporation is stopped. Then, the evaporation source is preheated at a temperature of 480 ° C for 25 minutes, and then at a fixed coating rate. It is formed by vapor deposition at 0.02 nm/sec.

Figure 9 is an electroluminescence spectrum of a white organic light-emitting device IV-VII. From the results, it can be seen that the 2,2',7,7'-tetradecyl-9,9'-cyclohexane is vapor-deposited at different rates. It does have a significant impact on the color of the component. The slower the evaporation rate, the longer the heating time of the 2,2',7,7'-tetradecyl-9,9'-ring bisulfon in the heating source, the more time it takes to produce the material aggregation behavior, and thus the influence Finally, the emission spectrum of the organic light-emitting device produced has a red shift phenomenon (light color is shifted from blue light to yellow light). The preheated evaporation source (for example, preheating TPSBF) has a similar effect, as long as the material is The material is heated to near or above the sublimation temperature, so that the material is pre-aligned and aggregated in the heating source, so that the molecular group becomes larger and then evaporated, and the film layer must exhibit a longer wavelength yellow light spectrum. Since the 2,2',7,7'-tetradecyl-9,9'-cyclobiguanide molecule has the characteristics of emitting shorter waves and longer waves in different aggregation modes, therefore, as long as the organic light-emitting layer is precisely controlled The coating parameters of the short-wave and longer-wavelength in the organic light-emitting layer can be achieved by a single material of 2,2',7,7'-tetradecyl-9,9'-spin-ring double bond. The purpose of white light.

Although the present invention has been disclosed above in several preferred embodiments, it is not intended to limit the invention. The scope of the present invention is defined by the scope of the appended claims, unless otherwise claimed.

110‧‧‧Base

120‧‧‧Anode

130‧‧‧Organic lighting unit

131‧‧‧ hole injection layer

132‧‧‧ hole transport layer

135‧‧‧ Organic light-emitting layer

136‧‧‧Electronic transport layer

137‧‧‧electron injection layer

140‧‧‧ cathode

Claims (12)

A white light organic light-emitting element comprises: an anode; an organic light-emitting layer is disposed on the anode, wherein the organic light-emitting layer is substantially composed of 2, 2', 7, 7'-tetradecyl-9, 9'-ring double The composition of ruthenium (TPSBF) and a cathode are located on the organic light-emitting layer. The white light organic light emitting device of claim 1, further comprising: a hole injection layer and/or a hole transport layer interposed between the anode and the organic light emitting layer. The white light organic light-emitting device of claim 1, further comprising: an electron injection layer and/or an electron transport layer interposed between the organic light-emitting layer and the cathode. The white light organic light emitting device of claim 1, further comprising: a hole injection layer on the anode between the anode and the organic light emitting layer; and a hole transport layer located in the electricity a hole injection layer between the hole injection layer and the organic light-emitting layer; and an electron transport layer on the organic light-emitting layer between the organic light-emitting layer and the cathode. The white light organic light-emitting device of claim 4, wherein the hole injection layer is 2T-NATA, the hole transport layer is NPB, and the electron transport layer is Alq ₃ . The white light organic light-emitting device of claim 1, wherein the organic light-emitting layer has an emission peak of between 470 nm and 570 nm. The white light organic light-emitting device according to claim 1, wherein the organic light-emitting layer has an emission peak of 440 nm to 470 nm and 540 nm to 560 nm. The white light organic light-emitting device according to claim 1, wherein the organic light-emitting layer has a thickness of between 5 nm and 100 nm. A method for preparing a white light organic light emitting device, comprising the steps of: providing a substrate; forming an anode on the substrate; forming an organic light emitting layer on the anode, wherein the organic light emitting layer is substantially 2, 2', 7, 7'-tetradecyl-9,9'-cyclocyclic bisulfonium (TPSBF) is formed, and a cathode is formed on the luminescent layer. The method for preparing a white organic light-emitting device according to claim 9, wherein the organic light-emitting layer has a thickness of between 5 nm and 100 nm. The method for producing a white light organic light-emitting device according to claim 9, wherein the organic light-emitting layer is deposited by a fixed plating rate of between 0.01 nm/sec and 0.5 nm/sec. The method for preparing a white organic light-emitting device according to claim 11, further comprising preheating a vapor deposition source at a temperature between 300 ° C and 550 ° C before evaporating the organic light-emitting layer.