阅读说明：本技术 有机配体修饰的稀土氧化物纳米片复合材料、制法，oled发光膜和oled器件及应用 (Organic ligand modified rare earth oxide nanosheet composite material, preparation method, OLED (organic light emitting diode) light emitting film, OLED device and application ) 是由 杨薇 虞再道 姜丽丽 杨樾 陈超中 于 2021-09-15 设计创作，主要内容包括：本申请涉及能源与光照技术领域,公开了一种有机配体修饰的稀土氧化物纳米片复合材料、制法,OLED发光膜和OLED器件及应用。有机配体修饰的稀土氧化物纳米片复合材料,在稀土氧化物纳米片溶胶中加入有机配体进行超声配位,得到有机配体修饰的稀土氧化物纳米片复合材料；稀土氧化物纳米片溶胶与有机配体的摩尔比为1：(3-9)。本申请主要是通过稀土氧化物纳米片溶胶作为OLED发光膜材料,利用有机配体进一步优化发光性能,将该带有电荷的复合材料进行电镀,得到均匀的OLED发光膜。本申请不仅能保持稀土发光中心优异的色彩纯度,还能有效改善有机配合物在有机溶液中易溶出、团聚、猝灭等问题；并且其光漂白性进一步得到改善。(The application relates to the technical field of energy and illumination, and discloses an organic ligand modified rare earth oxide nanosheet composite material, a preparation method, an OLED luminescent film, an OLED device and application. Adding an organic ligand into rare earth oxide nanosheet sol for ultrasonic coordination to obtain an organic ligand modified rare earth oxide nanosheet composite material; the molar ratio of the rare earth oxide nanosheet sol to the organic ligand is 1: (3-9). The method mainly comprises the steps of taking rare earth oxide nanosheet sol as an OLED luminescent film material, further optimizing the luminescent performance by utilizing an organic ligand, and electroplating the composite material with charges to obtain the uniform OLED luminescent film. The method not only can keep the excellent color purity of the rare earth luminescent center, but also can effectively solve the problems that the organic complex is easy to dissolve out, agglomerate, quench and the like in an organic solution; and its photobleachability is further improved.)

1. The preparation method of the organic ligand modified rare earth oxide nanosheet composite material is characterized by comprising the following steps of: adding an organic ligand into the rare earth oxide nanosheet sol for ultrasonic coordination, and performing ultrasonic treatment for 20-40min at the power of 40-60% to obtain a rare earth oxide nanosheet composite material modified by the organic ligand; wherein the molar ratio of the rare earth oxide nanosheet sol to the organic ligand is 1: (3-9).

2. The method for preparing an organic ligand-modified rare earth oxide nanosheet composite of claim 1, wherein the organic ligand is selected from one of potassium (3, 5-dimethylpyrazolyl) borate, α -thiopheneacetone, and 2-thiophenecarbonyltrifluorpropanone.

3. The method for preparing the organic ligand modified rare earth oxide nanosheet composite material of claim 1, wherein the method for preparing the rare earth oxide nanosheet sol comprises:

1) grinding the rare earth oxide and the bromide and calcining at the temperature of 700-1000 ℃ for 12-24h to prepare the rare earth bromide;

2) carrying out microwave intercalation treatment on the rare earth bromide by using an intercalation agent to obtain a rare earth oxide intercalation intermediate;

3) dispersing the rare earth oxide intercalation intermediate into an organic solvent for stripping to obtain a rare earth oxide nanosheet;

4) centrifugally separating the stripped rare earth oxide intercalation intermediate, and taking supernatant to obtain rare earth oxide nanosheet sol.

4. The method for preparing an organic ligand-modified rare earth oxide nanosheet composite according to claim 3, wherein in 1), the bromide is selected from potassium bromide and/or ammonium bromide.

5. The method of making an organic ligand-modified rare earth oxide nanosheet composite of claim 3, wherein the rare earth oxide comprises at least two of yttrium metal oxide, europium metal oxide, terbium metal oxide, cerium metal oxide, and gadolinium metal oxide.

6. The method for preparing an organic ligand modified rare earth oxide nanosheet composite material according to claim 5, wherein in 1), the molar ratio of rare earth oxide to bromide is 1: (2-3).

7. The method for preparing an organic ligand-modified rare earth oxide nanosheet composite as claimed in claim 1, wherein in 1), the milling is performed by a method selected from ball milling.

8. The preparation method of the organic ligand modified rare earth oxide nanosheet composite material according to claim 1, wherein in 2), the specific operation of microwave intercalation is: dispersing the rare earth bromide into an organic solution, adding an intercalation agent, heating for 2-5 min by using power of 700 plus 800W microwave, cooling and stirring, filtering, washing for many times by using deionized water, and drying at the temperature of 60-100 ℃ for 12-24h to obtain a rare earth oxide intercalation intermediate.

9. The method of making an organic ligand-modified rare earth oxide nanosheet composite of claim 8, wherein the intercalant comprises sodium benzoate and/or sodium dodecylbenzenesulfonate.

10. The method for preparing an organic ligand-modified rare earth oxide nanosheet composite as claimed in claim 8, wherein the organic solvent is selected from one or more of n-butanol, ethanol and water.

11. The method for preparing an organic ligand modified rare earth oxide nanosheet composite material according to claim 1, wherein in 3), the exfoliation method employed comprises ultrasonic exfoliation and/or ball milling exfoliation.

12. The method for preparing an organic ligand modified rare earth oxide nanosheet composite material as claimed in claim 11, wherein in 3), the ultrasonic power used for ultrasonic stripping is 1000-1500W, and the ultrasonic time is 20-40 min.

13. An organic ligand modified rare earth oxide nanosheet composite, characterized by being prepared by the method for preparing an organic ligand modified rare earth oxide nanosheet composite according to any one of claims 1 to 12; wherein the organic ligand modified rare earth oxide nanosheet composite has a positive charge.

14. The organic ligand-modified rare earth oxide nanosheet composite of claim 13, wherein the organic ligand-modified rare earth oxide nanosheet composite includes a host element and a guest element, the host element being at least one of yttrium and gadolinium; the guest element is at least one of europium element, terbium element and cerium element; the molar ratio of the host element to the guest element is (19-99): 1.

15. the organic ligand-modified rare earth oxide nanosheet composite of claim 13, wherein the organic ligand-modified rare earth oxide nanosheet composite has a length of 10-500 nm, a width of 10-500 nm, and a thickness of 0.8-9 nm.

16. An OLED luminescent film is characterized in that the preparation method comprises the step of forming a film on a substrate by carrying out layer-by-layer self-assembly, electroplating, spin coating or lifting on the organic ligand modified rare earth oxide nanosheet composite material disclosed by claim 13 to obtain the OLED luminescent film.

17. The OLED luminescent film of claim 16, wherein the method of making the OLED luminescent film further comprises: and carrying out OLED packaging on the OLED luminescent film in a protective atmosphere.

18. An OLED device comprising the OLED luminescent film of claim 16.

19. Use of the organic ligand-modified rare earth oxide nanosheet composite of claim 13 in the preparation of an OLED luminescent film material.

Technical Field

The invention relates to the technical field of energy and illumination, in particular to an organic ligand modified rare earth oxide nanosheet composite material, a preparation method, an OLED luminescent film, an OLED device and application.

Background

The OLED is a self-luminous material, has the advantages of large luminous visual angle range, low energy consumption, low cost, no toxic substance doped in the manufacturing process and the like, and has potential to replace the traditional lighting system. The light emitting principle is that under the action of external voltage, the anode injects holes, the holes enter the hole transport layer, and meanwhile, the cathode injects electrons, and the electrons enter the electron transport layer. When the hole and the electron are excited to form an exciton after meeting in the organic light emitting layer, the exciton in an excited state is unstable, and an energy difference generated by radiation transition to a ground state is released in the form of light.

At present, besides the excellent light emitting performance of the OLED compared with that of the LED, the OLED also has the defect of not negligible color purity, which results in difficulty in displaying vivid and rich colors, and meanwhile, the conventional organic light emitting compound is easy to undergo photobleaching, resulting in a light emitting life far shorter than that of the LED. The materials of OLEDs therefore still have much room for improvement.

Disclosure of Invention

In order to obtain excellent color purity and long service life, the application provides an organic ligand modified rare earth oxide nanosheet composite material, a preparation method, an OLED luminescent film, an OLED device and application.

In a first aspect, the application provides a method for preparing an organic ligand modified rare earth oxide nanosheet composite material, which adopts the following technical scheme:

a preparation method of an organic ligand modified rare earth oxide nanosheet composite material comprises the following steps: adding an organic ligand into the rare earth oxide nanosheet sol for ultrasonic coordination, and performing ultrasonic treatment for 20-40min at the power of 40-60% to obtain a rare earth oxide nanosheet composite material modified by the organic ligand; wherein the molar ratio of the rare earth oxide nanosheet sol to the organic ligand is 1: (3-9).

By adopting the technical scheme, the rare earth oxide nanosheet sol is subjected to organic coordination, and as the organic ligand has a wide and strong absorption band in a near ultraviolet region, the matching degree of the three-stage energy level of the organic ligand and the lowest excited state energy level of the rare earth luminescence center is better, and at the moment, the organic ligand modification can be performed on the rare earth oxide nanosheet sol under the action of ultrasonic waves by controlling the molar ratio of the rare earth oxide nanosheet sol to the organic ligand; compared with the rare earth complex, the preparation method is low in preparation cost and simple and feasible, and the organic ligand modified rare earth oxide nanosheet composite material prepared at the same time has the advantages of being difficult to agglomerate, capable of quenching luminescence, capable of realizing efficient utilization of rare earth atoms and the like; therefore, the prepared organic ligand modified rare earth oxide nanosheet composite material has more excellent color purity and longer luminescence life.

Preferably, the organic ligand is selected from one of potassium (3, 5-dimethylpyrazolyl) borate, alpha-thiopheneacetone and 2-thiophenecarboxyltrifluoroacetone.

Preferably, the preparation method of the rare earth oxide nanosheet sol comprises the following steps:

1) grinding the rare earth oxide and the bromide and calcining at the temperature of 700-1000 ℃ for 12-24h to prepare the rare earth bromide;

2) carrying out microwave intercalation treatment on the rare earth bromide by using an intercalation agent to obtain a rare earth oxide intercalation intermediate;

3) dispersing the rare earth oxide intercalation intermediate into an organic solvent for stripping to obtain a rare earth oxide nanosheet;

4) centrifugally separating the stripped rare earth oxide intercalation intermediate, and taking supernatant to obtain rare earth oxide nanosheet sol.

Preferably, in 1), the bromide is selected from potassium bromide and/or ammonium bromide.

Preferably, the bromide is further selected to be potassium bromide.

Preferably, the rare earth oxide includes at least two of yttrium metal oxide, europium metal oxide, terbium metal oxide, cerium metal oxide, and gadolinium metal oxide.

Preferably, in 1), the molar ratio of the rare earth oxide to the bromide is 1: (2-3).

Preferably, in 1), the grinding mode is selected from ball milling.

Preferably, in 2), the specific operation of microwave intercalation is: dispersing the rare earth bromide into an organic solution, adding an intercalation agent, heating for 2-5 min by using power of 700 plus 800W microwave, cooling and stirring, filtering, washing for many times by using deionized water, and drying at the temperature of 60-100 ℃ for 12-24h to obtain a rare earth oxide intercalation intermediate.

Preferably, the intercalating agent comprises sodium benzoate and/or sodium dodecylbenzenesulfonate.

Preferably, the organic solvent is selected from one or more of n-butanol, ethanol and water.

Preferably, in 3), the peeling method includes ultrasonic peeling and/or ball milling peeling.

Preferably, in 3), the ultrasonic power used for ultrasonic stripping is 1000-1500W, and the ultrasonic time is 20-40 min.

By adopting the technical scheme, the preparation method is simple and environment-friendly; the rare earth oxide nanosheet sol tape with positive charges is prepared, and a microwave method is used in the intercalation (ion exchange) process, so that the time is greatly saved.

In a second aspect, the present application provides an organic ligand modified rare earth oxide nanosheet composite material, which adopts the following technical scheme:

an organic ligand modified rare earth oxide nanosheet composite material is prepared by adopting a preparation method of the organic ligand modified rare earth oxide nanosheet composite material; wherein the organic ligand modified rare earth oxide nanosheet composite has a positive charge.

Preferably, the organic ligand modified rare earth oxide nanosheet composite material comprises a host element and a guest element, wherein the host element is at least one of yttrium element (Y) and gadolinium element (Gd); the guest element is selected from at least one of europium element (Eu), terbium element (Tb) and cerium element (Ce); the molar ratio of the host element to the guest element is (19-99): 1.

preferably, the organic ligand for modifying the rare earth oxide nanosheet composite material has a wide and strong absorption band in a near-ultraviolet region, and the matching degree of the three-level energy level of the organic ligand and the lowest excited state energy level of the rare earth luminescent center is good.

Preferably, the length of the organic ligand modified rare earth oxide nanosheet composite material is 10-500 nm, the width of the organic ligand modified rare earth oxide nanosheet composite material is 10-500 nm, and the thickness of the organic ligand modified rare earth oxide nanosheet composite material is 0.8-9 nm.

By adopting the technical scheme, the excellent color purity of the rare earth luminescent center can be maintained, and the problems of easy dissolution, agglomeration, quenching and the like of the organic complex in an organic solution can be effectively solved; and its photobleachability is further improved.

In a third aspect, the present application provides an OLED light-emitting film, which adopts the following technical scheme:

the preparation method of the OLED luminescent film comprises the step of forming a film on a substrate in a layer-by-layer self-assembly, electroplating, spin coating or lifting mode on the organic ligand modified rare earth oxide nanosheet composite material to form the OLED luminescent film.

By adopting the technical scheme, the rare earth oxide nanosheet composite material modified by the organic ligand has positive charges, and the OLED luminescent film can be prepared by multiple assembling modes such as layer-by-layer self-assembly, electroplating, spin coating or lifting, so that the color purity and the service life of the OLED during luminescence are improved.

Preferably, the preparation method of the OLED light-emitting film further includes: and carrying out OLED packaging on the OLED luminescent film in a protective atmosphere.

Preferably, the protective atmosphere is selected from inert gas atmospheres.

Preferably, the inert gas in the inert gas atmosphere is one of argon (Ar), helium (He), neon (Ne), krypton (Kr), and xenon (Xe).

By adopting the technical scheme, the rare earth oxide nanosheet composite material modified by the organic ligand is charged, and the phenomenon of falling off in the experimental process can be effectively avoided after OLED packaging treatment is carried out in the inert gas atmosphere by adopting an electroplating method.

In a fourth aspect, the present application provides an OLED device, which adopts the following technical solution:

an OLED device comprises the OLED light-emitting film.

In a fifth aspect, the application provides an application of the organic ligand modified rare earth oxide nanosheet composite material in preparing an OLED luminescent film material.

In summary, the present application has the following beneficial effects:

1. the method not only can keep the excellent color purity of the rare earth luminescent center, but also can effectively solve the problems that the organic complex is easy to dissolve out, agglomerate, quench and the like in an organic solution; and the photobleaching property of the rare earth oxide nanosheet composite material modified by the organic ligand is further improved.

2. The preparation method is low in preparation cost, simple and feasible, short in time consumption, and capable of obtaining the OLED luminescent film of the organic ligand modified rare earth oxide nanosheet composite material in an electroplating mode.

3. According to the method, the rare earth oxide nanosheet composite material modified by the organic ligand is charged, and the phenomenon of falling off in the experimental process can be effectively avoided after OLED packaging treatment is further performed by adopting an electroplating method.

4. The OLED luminescent film prepared from the organic ligand modified rare earth oxide nanosheet composite material is different from powder luminescent films prepared by other technologies, and an additional curing agent is not required to be added in the preparation method of the OLED luminescent film, so that the OLED luminescent film can be applied to OLEDs with different morphologies and flexibility, and is wide in application.

5. According to the organic ligand modified rare earth oxide nanosheet composite material obtained by the application, the research of OLEDs with different light effects can be effectively promoted by regulating and controlling the types of rare earth elements and the types of organic ligands.

Drawings

Fig. 1 is a schematic flow chart illustrating a process for preparing an OLED light-emitting film according to an exemplary embodiment of the present disclosure.

FIGS. 2a to 2c are each a rare earth (Y) in example a of the present application₁₉(Eu)) oxide, rare earth (Y)₁₉(Eu)) intercalation intermediate and rare earth (Y)₁₉(Eu)) SEM image of oxide nanoplates. Wherein, FIG. 2a shows rare earth (Y)₁₉(Eu)) bromide SEM picture; FIG. 2b shows rare earth (Y)₁₉(Eu)) SEM picture of oxide intercalation intermediate; FIG. 2c shows rare earth (Y)₁₉(Eu)) oxide nanosheet SEM image.

FIG. 3 shows the rare earth element (Y) in example a of the present application₁₉(Eu)) sol diagram of an oxide nanoplate composite.

FIG. 4 shows rare earth (Y) in example 2 of the present application₉₉(Tb)) oxide nanosheet composite material preparation OLED luminescent film preparation scheme.

FIG. 5 shows the rare earth (Gb) obtained in example 3 of the present application₂₀(Ce)) oxide nanosheet composite material is applied to an OLED.

FIG. 6 is a graph comparing fluorescence spectra of example 1 and comparative example 1 of the present application.

FIG. 7 is a graph comparing the fluorescence spectra of the test sample 6 of the present application and the comparative sample 2.

Fig. 8 is a schematic diagram of the luminescent properties of the europium oxide nanosheet solution of example 1 herein, the europium complex solution of comparative example 1 under an ultraviolet lamp, wherein fig. 8a is a solution of europium oxide nanosheets; FIG. 8b shows a europium complex solution.

Description of reference numerals: 1. an Al layer; 2. a LiF layer; 3. a TPBI layer; 4. an OLED light emitting film layer; 5. a PEDOT layer; 6. an ITO layer.

Detailed Description

The present application is described in further detail below with reference to figures 1-8 and examples.

The raw materials used in the examples of the present application are commercially available products unless otherwise specified.

Examples a-d: organic ligand modified rare earth oxide nanosheet composite material

Example a

An organic ligand modified rare earth oxide nanosheet composite, see fig. 1, comprising the steps of:

1) according to the molar ratio of 19: 1 adding yttrium metal oxide and europium metal oxide, and mixing to obtain rare earth oxide containing yttrium and europium; mixing rare earth oxide containing yttrium europium with potassium bromide according to the molar ratio of 1:2, grinding for 2 hours, calcining at 700 ℃ for 12 hours to obtain rare earth (Y)₁₉(Eu)) bromide cake product.

2) The obtained rare earth (Y)₁₉(Eu)) bromide blocky product (0.1 mg) is added into 500mL deionized water, 1.4 mg sodium benzoate is added as an intercalation agent, microwave 800W heating is carried out for 2min, cooling and stirring are carried out, 20 times of repetition are carried out, suction filtration is carried out, deionized water is used for cleaning for 3 times, drying is carried out for 12h at the temperature of 100 ℃, and rare earth (Y) is obtained₁₉(Eu)) oxide intercalation intermediate.

3) Drying the rare earth (Y) obtained in step 2)₁₉Adding (Eu)) oxide intercalation intermediate into n-butanol, and performing ultrasonic treatment at 1200W power for 20 min to obtain rare earth (Y)₁₉(Eu)) oxide nanoplates (see fig. 2 a-2 c).

4) Subjecting the rare earth (Y) obtained by the ultrasonic stripping in step 3) to₁₉(Eu)) oxide nanosheets were centrifuged, and the supernatant was collected, as shown in FIG. 3, to give rare earth (Y)₁₉(Eu)) oxide nanosheet sol.

5) Organic ligand (2-thenoyltrifluoroacetone) and rare earth (Y) are mixed according to the molar ratio of 3:1₁₉(Eu)) oxide nanosheet sol, performing ultrasonic coordination for 40min at the rated power of 40% to obtain rare earth (Y) modified by organic ligand₁₉(Eu)) oxide nanoplate composite.

Example b

An organic ligand modified rare earth oxide nanosheet composite material comprises the following steps:

1) according to a molar ratio of 99: 1 adding yttrium metal oxide and terbium metal oxide, and mixing to obtain rare earth oxide containing yttrium and terbium; mixing rare earth oxide containing yttrium and terbium and ammonium bromide according to the molar ratio of 1:2, grinding for 2h, placing into a muffle furnace, and calcining at 900 ℃ for 12h to obtain rare earth (Y)₉₉(Tb)₁) Bromide cake product.

2) The obtained rare earth (Y)₉₉(Tb)₁) Adding the bromide blocky product (0.1 mg) into 400mL of deionized water, adding 1.4 mg of sodium benzoate as an intercalation agent, heating for 5min under the microwave of 700W, cooling and stirring, repeating for 20 times, performing suction filtration, washing for 4 times with deionized water, and drying for 24h at the temperature of 60 ℃.

3) Drying the rare earth (Y) obtained in step 2)₉₉Adding (Tb)) oxide intercalation intermediate into ethanol, and performing ultrasonic treatment at 1200W power for 30 min to prepare rare earth (Y)₉₉(Tb)) oxide nanoplates.

4) Subjecting the rare earth (Y) obtained by the ultrasonic stripping in step 3) to₉₉(Tb)) oxide nanosheet is centrifugally separated, and the supernatant is taken to prepare rare earth (Y)₉₉(Tb)) an oxide nanoplate sol.

5) Organic ligand (2-thenoyltrifluoroacetone) and rare earth (Y) are mixed according to the molar ratio of 6:1₉₉(Tb)₁) Mixing oxide nanosheet sol, performing ultrasonic treatment for 20 min at 40% rated power, and performing ultrasonic coordination to obtain rare earth (Y) modified by organic ligand₉₉(Tb)₁) An oxide nanoplate composite.

Example c

An organic ligand modified rare earth oxide nanosheet composite material comprises the following steps:

1) according to the molar ratio of 20: 1 addition ofMixing cerium metal oxide and gadolinium metal oxide to obtain rare earth oxide containing cerium and gadolinium, ball milling the rare earth oxide containing cerium and gadolinium and potassium bromide in a molar ratio of 1:3 for 2h, calcining in a tube furnace at 1000 deg.C for 24h to obtain rare earth (Gd)₂₀(Ce)) bromide bulk product.

2) The rare earth (Gd) obtained in the step 1)₂₀(Ce)) bromide chunk product (0.2 mg) was added to 200mL deionized water, followed by 2.4 mg sodium benzoate as an intercalating agent, heated at 750W for 3mins with microwave, cooled and stirred, repeated 20 times, filtered with suction and washed 3 times with deionized water, and dried at 80 ℃ for 20 h.

3) Drying the rare earth (Gd) obtained in step 2)₂₀(Ce)) oxide intercalation intermediate is added into deionized water, ultrasonic treatment is carried out for 40min at 1200W power, and rare earth (Gd) is prepared₂₀(Ce)) oxide nanoplates.

4) Subjecting the rare earth (Gd) obtained by the ultrasonic stripping in step 3)₂₀(Ce)) oxide nanosheet is centrifugally separated, and the supernatant is taken to prepare rare earth (Gd)₂₀(Ce)) an oxide nanoplatelet sol.

5) Organic ligand (alpha-thiophene acetylacetone) and rare earth (Gd) are mixed according to the molar ratio of 9:1₂₀(Ce)) oxide nanosheet sol is mixed, ultrasonic processing is carried out for 40min at 60% of power for coordination modification, and rare earth Gd modified by organic ligand is obtained after ultrasonic coordination₂₀(Ce)) oxide nanoplate composites.

Example d

An organic ligand modified rare earth oxide nanosheet composite, differing from example b in that: in 3), the intercalation is carried out by ball milling instead of ultrasonic exfoliation. Wherein the ball milling speed is 600 rpm/min, and the ball milling time is 2 h.

Examples 1 to 4: OLED luminescent film

Example 1

An OLED luminescent film, comprising the steps of:

the organic ligand (2-thenoyltrifluoroacetone) modified rare earth (Y) prepared in example a₁₉(Eu)) oxide nanoplate composite, method of electroplatingAnd preparing the organic ligand modified rare earth oxide nanosheet OLED luminescent film (called OLED luminescent film for short).

Example 2

An OLED luminescent film, comprising the steps of:

the organic ligand (2-thenoyltrifluoroacetone) modified rare earth (Y) prepared in example b₉₉(Tb)₁) The oxide nanosheet composite, see fig. 4, is prepared by electroplating to obtain an OLED light-emitting film.

Example 3

An OLED luminescent film, comprising the steps of:

the organic ligand (alpha-thiophene acetylacetone) modified rare earth Gd prepared in the example c₂₀(Ce)) oxide nanosheet composite material, and preparing the OLED luminescent film by layer-by-layer self-assembly.

Example 4

An OLED luminescent film, comprising the steps of:

the organic ligand (alpha-thiophene acetylacetone) modified rare earth Gd prepared in the example c₂₀(Ce)) oxide nanosheet composite material, and preparing the OLED luminescent film by a spin coating method.

Example 5

An OLED luminescent film, which is different from example 1 in that: based on the OLED luminescent film prepared in example 1, the preparation method further comprises the following steps: the encapsulation of the OLED is performed under the action of an inert gas, such as argon.

Example 6

An OLED luminescent film, which is different from example 2 in that: 2-Thienoyltrifluoroacetone coordinated terbium Tb oxide nanosheets (Tb (TTA))₃）。

Application examples 1-2: OLED device

Application example 1

Referring to fig. 5, the rare earth nanosheet (i.e., OLED) is composed of an Al layer 1, a LiF layer 2, a TPBI layer 3, an OLED light emitting film layer 4, a PEDOT layer 5 and an ITO layer 6 in sequence from the cathode to the anode. The OLED light-emitting film layer 4 was the OLED light-emitting film obtained in example 2.

Application example 2

An OLED device, which differs from application example 1 in that: the above-mentioned OLED light-emitting film layer was the OLED light-emitting film obtained in example 5.

Comparative example

Comparative example 1

An OLED luminescent film, which is different from example 1 in that: different organic ligands, europium complex replaces organic ligand (2-thenoyl trifluoroacetone) modified rare earth (Y)₁₉(Eu)) oxide nanosheet composite, and fabrication of an OLED luminescent film.

The preparation method of the europium complex comprises the following steps: dissolving 1 mg of europium nitrate into 100 mL of deionized water, adding an organic ligand 2-thiophene formyl trifluoroacetone according to a molar ratio of 1:3, and adding diluted ammonia water to adjust the pH value to 6-7 to obtain the europium complex.

Comparative example 2

An OLED luminescent film, which is different from example 2 in that: using rare earths (Y)₉₉(Tb)₁) Oxide nanosheet sol replaces organic ligand (2-thenoyltrifluoroacetone TTA) modified rare earth (Y)₉₉(Tb)₁) Oxide nanosheet composite material and the preparation of OLED luminescent film.

Performance detection analysis

Test one: fluorescence intensity measurement

Test subjects: the OLED luminescent film of example 1 was used as a test sample 1; the OLED luminescent film of comparative example 1 was used as a control sample 1;

the test method comprises the following steps: the fluorescence properties of example 1 and comparative example 1 were measured using a spectrofluorometer and recorded in figure 6.

As can be seen by combining example 1 and comparative example 1 with FIG. 6, the fluorescence intensity of the europium complex is lower than that of the europium oxide nanosheet Y under the condition of the same luminescence center (europium Eu)₁₉(Eu) O-TTA, i.e. rare earth (Y) modified by organic ligand (2-thenoyltrifluoroacetone)₁₉(Eu)) oxide nanoplate composite.

The fluorescence intensity performance of the rare earth oxide nanosheet composite materials obtained in examples 2-6 is tested to be substantially consistent with that of example 1.

And (2) test II: color purity

Test subjects: the OLED luminescent film of example 6 was used as a test sample 6; a zinc complex (Zn (phen) coordinated with 1, 10-phenanthroline₃) As comparative sample 2.

The test method comprises the following steps: respectively detecting 1, 10-phenanthroline coordinated zinc complex (Zn (phen) by using a fluorescence spectrophotometer₃) With (Tb (TTA) of example 6₃) And is recorded in figure 7.

As can be seen by combining test sample 6 and comparative sample 2 with FIG. 7, the central ion-luminescent rare earth oxide nanosheets (Tb (TTA))₃) Has high light color purity (half-peak width less than 10 nm), and zinc complex (Zn (phen)₃) The half-wave width of (a) is much larger than the half-peak width of the test sample 6, resulting in lower color purity. The maximum quantum efficiency of the organic fluorescent material is not more than 25% due to the limitation of the spin selection rule, compared with the light emission of the rare earth complex, the light emission of the rare earth complex is from the energy transfer of singlet excitons to triplet states through intersystem crossing and further to central ions. The light-emitting mechanism can effectively utilize singlet excitons and triplet excitons generated in the electroluminescent process, and finally leads to the radiative transition of rare earth ions. The rare earth nanosheet modified by the organic ligand is the same as the rare earth complex, and the theoretical upper limit of the internal quantum efficiency of the rare earth nanosheet can reach 100%.

The color purity performance of the rare earth oxide nanosheet composite materials obtained in examples 1-5 was tested to be substantially consistent with that of example 6.

And (2) test II: service life

Test subjects: the OLED luminescent film of example 1 was used as a test sample 1; the OLED luminescent film of comparative example 1 was used as a control sample 1;

the test method comprises the following steps: the example 1 and the comparative example 1 were left under an ultraviolet lamp for 5 months, and then the luminescence properties of the example 1 and the comparative example 1 were examined.

Combining example 1 and comparative example 1 and combining fig. 8, it can be seen that the europium oxide nanosheet solution (fig. 8 a) and the europium complex solution (fig. 8 b) with the same luminescent properties still maintain excellent luminescent properties after being placed under an ultraviolet lamp for 5 months, while the luminescent properties of the europium complex solution are obviously weakened compared with those of the nanosheets, which indicates that the europium oxide nanosheets are not easy to agglomerate and have photobleaching resistance, and therefore have more excellent luminescent lives.

Through testing, the service life performance of the rare earth oxide nanosheet composite materials obtained in examples 2-6 is substantially consistent with that of example 1.

The specific embodiments are merely illustrative of the present application and are not restrictive of the present application, and those skilled in the art can make modifications of the embodiments as required without any inventive contribution thereto after reading the present specification, but only protected by the patent laws within the scope of the claims of the present application.