WO2022016464A1

WO2022016464A1 - Method for preparing optically active material, and use thereof

Info

Publication number: WO2022016464A1
Application number: PCT/CN2020/103858
Authority: WO
Inventors: 孟鸿; 艾琳
Original assignee: 北京大学深圳研究生院
Priority date: 2020-07-23
Filing date: 2020-07-23
Publication date: 2022-01-27

Abstract

A method for preparing an optically active material, the method comprising the following steps: S1, preparing a metal dot nanorod, involving: dissolving a metal salt in a solvent, adding an alkyl acid and a ligand thereto, and performing a water bath one-pot process to prepare and obtain a metal dot nanorod material; and S2, compounding with an adhesive material, involving: mixing the metal dot nanorod material with an adhesive material, and spin-coating and spreading same to obtain an optically active material. The metal dot nanorod is prepared into a backlight film, and the backlight film is integrated in a backlight LCD module. By using the optical activity of the metal dot nanorod, the light utilization rate of a backlight is increased, and the excitation light intensity is used at 100%, such that the light utilization rate is increased and the display brightness is improved. The optically active material is a favorable alternative material for a new generation of display screen backlights.

Description

A kind of preparation method and application of optically active material

technical field

The invention relates to the field of backlight luminescent materials, in particular to a preparation method and application of an optically active material.

Background technique

LCD displays generally use white backlight and three-color color filters as the color display mechanism. When controlling color grayscale, the incident light needs to be rotated by the upper and lower polarizers, but the intensity of the incident light at this time is when it passes through the lower polarizer. The direct loss is 50%, and the loss after passing through each film layer is more serious, and the final light output rate is less than 5%, resulting in the brightness of the LCD display screen has always been a thorny problem in the field. Especially now that the demand for large-screen high-definition display, the resolution is constantly increasing, and the aperture ratio is gradually decreasing. How to improve the brightness is the focus of attention of various enterprises.

The existing solution is to use quantum dot nanorods as a backlight film. Since the anisotropic rods have optical rotation, the incident light does not need to undergo downward polarization treatment, and the light intensity is not lost, which greatly improves the brightness. The brightness of LCD displays has always been criticized by the industry and buyers due to the presence of toxic elements such as lead and mercury in quantum dots.

SUMMARY OF THE INVENTION

In view of the above shortcomings of quantum dot nanorod materials, the present invention provides a preparation method and application of an optically active material.

The technical scheme of the present invention is achieved by the following manner: a preparation method of an optically active material is provided, comprising the following steps:

S1. Preparation of metal dot nanorods: Dissolve metal salt in solvent, add alkyl acid and ligand, and prepare metal dot nanorod material by one-pot water bath method;

S2. Compounding with glue material: mixing the metal dot nanorod material with the glue material, spin coating and spreading to obtain the optically active material.

In a preferred embodiment of the present invention, in the step S1, the metal salt is at least one of copper salts, gold salts, silver salts, platinum salts, iron salts, zinc salts, nickel salts, and cobalt salts; The solvent is at least one of ethanol, toluene, paraffin, dibenzyl ether, dimethylformamide, dimethyl sulfoxide, and tetrahydrofuran.

In a preferred embodiment of the present invention, in the step S1, the alkyl acid is at least one of citric acid, serine, and tryptophan.

In a preferred embodiment of the present invention, in the step S1, the ligand is at least one of POSS, POSS whose amino group is substituted by a thiol group, and a POSS derivative.

In a preferred embodiment of the present invention, in the step S1, the molar ratio of the ligand to the metal salt is 5:1 to 10:1.

In a preferred embodiment of the present invention, in the step S2, the glue material is PSA glue material or PMMA glue material.

In a preferred embodiment of the present invention, in the step S2, the metal dot nanorod material and the glue material are mixed after being heated and melted.

In a preferred embodiment of the present invention, in the step S2, the metal dot nanorod material is mixed with a polymer, and then UV-cured after spreading.

The present invention also provides an LCD module, comprising a backlight film, and the backlight film is made of the aforementioned optically active material.

The beneficial effects are as follows:

The invention constructs metal point nanorods, has excellent fluorescence performance, good optical activity, low metal point toxicity, simple synthesis, stable material, can be mass-produced, and is especially suitable for commercial application. Anisotropic growth makes it have better optical rotation. It is used for LCD backlight film, which greatly improves the light utilization rate, improves the brightness of the display screen, reduces energy consumption, and becomes a favorable replacement material for the backlight of a new generation of display screens.

Description of drawings

Fig. 1 is the preparation process schematic diagram of metal nanorods;

Fig. 2 is the luminescence spectrum of metal dot nanorods of different sizes;

Fig. 3 is the optical rotation schematic diagram of metal dot nanorod;

4 is a schematic diagram of a film material of a metal dot nanorod optically active material;

FIG. 5 is a structural comparison diagram of an LCD module, 5(a) is an LCD module with a lower polarizer, and 5(b) is an LCD module using an optically active material backlight film.

detailed description

In order to make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

In order to improve the brightness of the LCD display, starting from the light utilization rate, the optically active material is used as the backlight luminescent material, which reduces the loss of 50% of the polarization effect of the lower polarizer on the incident light, greatly improves the light utilization rate of the backlight, and reduces the energy loss. , enhance light efficiency and reduce costs.

The invention comprises a one-pot method for preparing metal dot nanorods (usually <1000 nm) of different sizes, preparing the metal dot nanorods into a backlight film, and integrating the backlight film in a backlight LCD module. Using the optical rotation properties of metal dot nanorods, the light utilization rate of the backlight is improved, and the excitation light intensity is 100% used, which improves the light utilization rate and the display brightness, especially the large-size TV brightness can be greatly improved. Its detailed preparation method is as follows:

1. Preparation of metal dot nanorods of different sizes

The metal salt is dissolved in a solvent, an alkyl acid and a ligand are added, and a metal dot nanorod material is prepared by a water bath one-pot method.

The metal salt used is at least one of copper salt, gold salt, silver salt, platinum salt, iron salt, zinc salt, nickel salt and cobalt salt, and the metal salt can be used alone or mixed and added. The solvent used is at least one in ethanol, toluene, paraffin, dibenzyl ether, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), and the solvent can be used alone, or Can be mixed and added. The metal salt is dissolved in the solvent to form a reaction bottom liquid of 0.01M-0.5M, and the preferred concentration range is 0.05-0.2M. During the preparation of the reaction bottom liquid, auxiliary means such as ultrasound and stirring can be used to promote the dissolution of the metal salt to form the reaction bottom liquid.

Then add citric acid and ligand to the reaction bottom liquid, the molar ratio of ligand to metal salt is 5:1~10:1, and the water bath 50-120 ℃ one-pot stirring for 10~40min can get different sizes and different metal centers. Metal dot nanorod material (the preparation path is shown in Figure 1), the metal salt can be copper chloride, chloroauric acid, silver nitrate, copper nitrate, copper acetate, copper acetylacetonate, copper sulfate, ferric chloride, ferric nitrate, chloride One of zinc, zinc nitrate, platinum chloride, nickel chloride, cobalt acetate and silver acetate. Citric acid can also be substituted with amino acids such as serine and tryptophan. The ligand is at least one of POSS, POSS in which the amino group is substituted by a thiol group, and a POSS derivative.

In the preparation process of the above-mentioned metal dots, it is more important to change the size of the rod by changing the ratio of the ligand, and the molar ratio of the ligand to the metal salt is 5:1 to 10:1. For example, citric acid: POSS=1:5, 1:10, 1:20 can obtain metal rods with lengths of 50 nanometers, 100 nanometers, and 200 nanometers, respectively. Under excitation at 365 nm, the fluorescence is blue, green, and red, respectively. The luminescence spectra of metal dot nanorods of different sizes are shown in Figure 2. And among the metal nanoparticles of the same scale, the luminescence peak position is further controllable with the change of the metal species.

2. Preparation of metal dot nanorod backlight film

Due to the anisotropy of the metal dot nanorods, the material has optically active properties, which can emit polarized light under ultraviolet excitation, as shown in Figure 3. Therefore, the lower polarizer filter is no longer needed when used for LCD backlighting.

The optically active material is obtained by mixing the metal dot nanorod material with the glue material, and spin coating and spreading. The adhesive material used is polymethyl methacrylate (PMMA) adhesive material or pressure sensitive adhesive (PSA) adhesive material. The method of mixing the metal dot nanorod material with the glue material includes, but is not limited to, hot-melt method and ultraviolet curing method.

The general process of the hot-melting method includes: the metal dot nanorod material and the glue material are mixed after heating and melting, and the spreading method is preferably spin coating, which is convenient for forming.

The general process of the ultraviolet curing method includes: mixing the metal dot nanorods with the polymer monomer, and then performing ultraviolet curing after spreading to obtain the photosensitizing material. The polymer monomers are multifunctional monomers, mainly polyhydric alcohol acrylates. The spreading method is preferably spin coating spreading, which is convenient for UV curing.

3. Backlight LCD module with metal dot nanorods

Integrate the backlight film into the backlight structure and form a module, as shown in Figure 5. 5(a) is an LCD module with a lower polarizer, and 5(b) is an LCD module using an optically active material backlight film. The backlight film emits polarized light under ultraviolet excitation, so the entire LCD backlight does not need a lower polarizer to filter light.

This patent constructs metal dot nanorods, which have excellent fluorescence properties, good optical activity, low metal dot toxicity, simple synthesis, stable materials, mass production, and are especially suitable for commercial applications. Anisotropic growth makes it have better optical rotation. It is used for LCD backlight film, which greatly improves the light utilization rate, improves the brightness of the display screen, reduces energy consumption, and becomes a favorable replacement material for the backlight of a new generation of display screens.

Although the embodiments of the present invention have been shown and described above, it should be understood that the above-mentioned embodiments are exemplary and should not be construed as limiting the present invention. Embodiments are subject to variations, modifications, substitutions and variations.

Claims

A preparation method of an optically active material, comprising the steps of:

S1. Preparation of metal dot nanorods: Dissolve metal salt in solvent, add alkyl acid and ligand, and prepare metal dot nanorod material by one-pot water bath method;

S2. Compounding with glue material: mixing the metal dot nanorod material with the glue material, spin coating and spreading to obtain the optically active material.
The method for preparing an optically active material according to claim 1, wherein in the step S1, the metal salt is copper salt, gold salt, silver salt, platinum salt, iron salt, zinc salt, nickel salt, cobalt salt At least one of the salts; the solvent is at least one of ethanol, toluene, paraffin, dibenzyl ether, dimethylformamide, dimethyl sulfoxide, and tetrahydrofuran.
The method for preparing an optically active material according to claim 1, wherein in the step S1, the alkyl acid is at least one of citric acid, serine and tryptophan.
The method for preparing an optically active material according to claim 1, wherein in the step S1, the ligand is at least one of POSS, POSS in which the amino group is substituted by a sulfhydryl group, and a POSS derivative.
The method for preparing an optically active material according to claim 1, wherein in the step S1, the molar ratio of the ligand to the metal salt is 5:1 to 10:1.
The method for preparing an optically active material according to claim 1, wherein, in the step S2, the glue material is a PSA glue material or a PMMA glue material.
The method for preparing an optically active material according to claim 1, wherein in the step S2, the metal dot nanorod material and the glue material are heated and melted and then mixed.
The method for preparing an optically active material according to claim 1, characterized in that, in the step S2, the metal dot nanorod material is mixed with a polymer, and then UV-cured after spreading.
An LCD module is characterized in that it includes a backlight film, and the backlight film is made of the optically active material in claims 1-8.