WO2022000369A1

WO2022000369A1 - Preparation method for and use of photosensitive material

Info

Publication number: WO2022000369A1
Application number: PCT/CN2020/099736
Authority: WO
Inventors: 孟鸿; 艾琳; 刘振国; 后藤修; 何谷峰
Original assignee: 北京大学深圳研究生院
Priority date: 2020-07-01
Filing date: 2020-07-01
Publication date: 2022-01-06

Abstract

A preparation method for a photosensitive material, comprising dissolving a metal salt in a solvent, adding a ligand, and preparing a metal dot material by using a one-pot method; and then mixing same with a polymer monomer, spreading, and then performing ultraviolet light curing, so as to obtain the photosensitive material. As metal dots are stable, easy to synthesize, and can be mass-produced, and the structure is controllable, the coverage of a photosensitive region is wide, the toxicity is low, and the nanoscale size thereof can match with a flexible substrate, in the case of being dominant in all aspects, the effect of sensitization can be achieved by using a thin metal cluster layer to cover above the photosensitive layer, and in combination with the high carrier mobility of the photosensitive layer and the high light absorption rate of the sensitive layer, the light response capability of a device is greatly improved, and the demand for current large-size display is satisfied.

Description

A kind of preparation method and application of photosensitizing material

technical field

The invention relates to the field of photosensitive materials, in particular to a preparation method and application of a photosensitive material.

Background technique

LCD large-screen high-definition display has recently been fiercely competitive among major companies. In order to add luster to it, the current strategy is to adopt the "principle of increasing the volume without increasing the price" to develop additional functions for it to increase its user experience. At present, the main strategy is to attach small-sized ambient light sensing, color temperature sensing, tactile response or voice control to the large-screen display. The ambient light sensing uses a triode TFT photosensitive sensor to make the entire screen have photosensitive ability, and then can use The laser pointer can operate it at a long distance, improve the human-computer interaction ability of the display, and make it more intelligent and convenient.

At present, the main core photosensitive layers of TFT photosensitive devices are mostly inorganic a-Si, etc. and inorganic oxide IZGO, etc. Most of them have strong photosensitive ability in the ultraviolet region, low responsivity in the visible light region, and the energy band is determined, the controllability is poor, and the adjustment Only doping methods can be used, the method is single, the selectivity of doping elements is small, and it is almost impossible to adjust the industrial chain; the new generation of photosensitive substances to take over are organic substances, which have a wide variety of organic substances and controllable structures. The ability of light absorption in the light region can be adjusted, but organic compounds have a long synthesis cycle, high toxicity and low yield, which limit their large-scale application and production.

SUMMARY OF THE INVENTION

In view of the above shortcomings of photosensitive materials in the field of TFT photosensors, the present invention provides a preparation method and application of a photosensitization material.

The technical scheme of the present invention is realized in the following ways:

The application provides a preparation method of a photosensitizing material, comprising the following steps:

S1. Preparation of metal dots: dissolving metal salts in a solvent, adding ligands, and preparing metal dots using a one-pot method;

S2. Compounding with polymer materials: mixing the metal dot material with polymer monomers, and performing UV curing after spreading to obtain the photosensitizing material.

In a preferred embodiment of the present application, in the step S1, the metal salt is at least one of copper salt, gold salt, silver salt, iron salt, and zinc salt; the solvent is dibenzyl ether solvent, At least one of paraffin, dibenzyl ether, oleic acid, and dodecylamine.

In a preferred embodiment of the present application, in the step S1, the ligand is hexyl mercaptan, octyl mercaptan, dodecyl mercaptan, hexadecyl mercaptan, or alkyl acrylate at least one of them.

In a preferred embodiment of the present application, in the step S1, the ligand is alkyl thiol acrylate, and the molecular formula is:

Wherein, R is a straight-chain alkane or branched-chain alkane with a carbon chain length ranging from 1 to 4 carbons.

In a preferred embodiment of the present application, in the step S1, the ligand is at least one of the following aromatic ligands:

In a preferred embodiment of the present application, in the step S2, the polymer monomer is a polyhydric alcohol acrylate.

The present application also provides a photosensitive TFT device, comprising a photosensitive layer made of a photosensitive material, and the photosensitive layer is made of the aforementioned photosensitive material. This new type of metal dot-sensitized photosensitive TFT device structure utilizes the strong photosensitive properties of metal dots combined with the high carrier mobility of the TFT inorganic/organic photosensitive layer to greatly improve the ambient light sensing capability of the display and meet the needs of large-size TVs. The needs of laser pointer touch interaction.

The present application also provides a flexible wearable device, including the aforementioned photosensitive TFT device.

In a preferred embodiment of the present application, the photosensitive TFT device is a flexible and bendable film material.

The beneficial effects are as follows:

The present invention mainly uses metal dots to match inorganic and organic photosensitive materials. Because the metal dots are stable, easy to synthesize, and can be mass-produced, the structure is controllable, the photosensitive area covers a wide range, and the toxicity is low. Substrate matching, in the case of dominant in all aspects, use a thin metal cluster layer to cover the photosensitive layer, which can play the role of sensitization, combined with the high carrier mobility of the photosensitive layer and the sensitization layer. The high absorbance greatly improves the light response capability of the device and meets the current demand for large-scale displays.

Description of drawings

Fig. 1 is a schematic diagram of the preparation process of thiol-modified metal dots;

Figure 2 shows the absorption spectra of different kinds of metal dots;

3 is a schematic structural diagram of a photosensitive TFT device;

FIG. 4 is a schematic diagram of a metal dot flexible film material;

FIG. 5 is a graph showing the comparison results of the photoresponsivity.

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.

The photosensitive layer of small-sized optical sensing devices is generally inorganic, of a single type, with a fixed optical sensing band gap and poor controllability, and it is generally difficult to meet the optical sensing order of magnitude of large-sized displays in the visible light region. . The invention uses ultra-small-sized metal dots as the photosensitive layer on the photosensitive layer. The metal dots have stable structure, simple synthesis, mass production, controllable structure, wide photosensitive area coverage, and low toxicity. The nanoscale scale can be matched with flexible substrates. In the case of dominance in all aspects, a thin metal cluster layer is used to cover the photosensitive layer, which can play a sensitizing effect, combined with the high carrier migration of the photosensitive layer. The high absorption rate of the sensitization layer and the high light absorption rate of the sensitization layer greatly improve the photoresponse capability of the device and meet the current demand for large-scale display of the photoresponse order of magnitude.

The invention includes one-pot preparation of metal dots of different sizes (usually < 20 nm), construction of a photosensitive TFT device structure, photosensitive performance testing, and integration of TFT in a large-sized display screen. The photosensitive performance is enhanced by the plasmon resonance absorption characteristics of metal dots, making it have high sensitivity, high responsivity and practical application value in the visible light region. Its detailed preparation method is as follows:

1. Preparation of metal dots of different sizes

The metal salt is dissolved in the solvent, the ligand is added, and the metal dot material is prepared by a water bath one-pot method.

The metal salts used are at least one of copper salts, gold salts, silver salts, iron salts, and zinc salts, and the metal salts can be used alone or mixed and added. The solvent used is at least one of dibenzyl ether solvent, paraffin, dibenzyl ether, oleic acid, and dodecylamine, and one solvent can be used alone or mixed and added. The metal salt is dissolved in the solvent to form a reaction bottom liquid of 0.01M-1M, preferably in the concentration range of 0.05-0.5M. In the process of preparing the reaction bottom liquid, auxiliary means such as ultrasound can be used to promote the dissolution of the metal salt.

The dodecyl mercaptan ligand is then added dropwise to the reaction bottom liquid, and the molar ratio of the ligand to the metal salt is 7:1 to 20:1, and the water bath is stirred at 30°C to 100°C for 5 to 30 minutes in one pot to obtain For metal point materials with different sizes and different metal centers, the preparation paths are shown in Figure 1.

The metal salt may be at least one of copper chloride, chloroauric acid, silver nitrate, copper nitrate, copper acetate, copper acetylacetonate, copper sulfate, ferric chloride, ferric nitrate, zinc chloride, zinc nitrate, and silver acetate. The dodecyl mercaptan ligand can also be replaced with saturated hexyl mercaptan, octyl mercaptan and hexadecyl mercaptan; it can also be unsaturated acrylic acid alkyl mercaptan, wherein R is the carbon chain length 1～ Straight or branched alkanes with 4 carbons. The ligand structures are shown below, from top to bottom, they are hexanethiol, octanethiol, dodecylthiol, hexadecylthiol, and alkyl acrylate:

In addition, the ligand structure is not limited to aliphatic alkyl thiols, but can also be aromatic ligands. The specific aromatic thiol ligand structures are shown below:

In the preparation process of the above metal dots, it is more important that the absorption of different types of metal dots covers the entire visible light region. The nanoparticle plasmonic absorption peak is at 500-530 nm. The specific absorption spectrum coverage is shown in Figure 2.

And among them, the absorption peak position of the same metal nanoparticle is further controllable with the change of size. The general rule is that with the increase of size, the absorption peak position gradually redshifts, so the absorption of metal dots is extremely controllable.

2. Composite with polymer materials

The photosensitive material is obtained by mixing the metal dot material with the polymer monomer, and after spreading it out, and then curing with ultraviolet light. 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. Fabrication of ambient light-sensing TFT devices sensitized by metal dots

The metal electrode Cu is sputtered on the glass substrate, and then a layer of SiO2 is plated as an insulating protective layer, and the amorphous Si and n+Si layers are used as the channel photosensitive layer and the ohmic contact layer. A layer of photosensitive layer is spin-coated on the track, that is, metal dots and polymer composite materials, and finally a polyester package is made for the overall photosensitive TFT device. The TFT device can be all existing TFT device structures, such as the photosensitive device shown in Figure 3. TFT film structure.

The photosensitive layer is a composite of metal dot materials and polymer materials, and the polymer monomers are multifunctional monomers, mainly polyhydric alcohol acrylates. Mix the metal dots with the monomer, spin-coat the mixture on the photosensitive layer, and then perform UV curing. Because the metal dots are ultra-small and compounded with polymers, they can be made into flexible and bendable membranes. The flexible base is PET compatible and can be used as a flexible wearable material. As shown in Figure 4.

Finally, when fabricating flexible devices, TFT is integrated into a system and applied to the field of flexible wear, such as directly covering the finger joints. Since the structure of the TFT photosensitive device integrates the high carrier mobility of the photosensitive layer and the high absorbance of the photosensitization layer, compared with the traditional structure, the photoresponse and photosensitivity of the device have absolute advantages. The performance comparison is shown in Figure 5.

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 method for preparing a photosensitizing material, comprising the steps of:

S1. Preparation of metal dots: dissolving metal salts in a solvent, adding ligands, and preparing metal dots using a one-pot method;

S2. Compounding with polymer materials: mixing the metal dot material with polymer monomers, and performing UV curing after spreading to obtain the photosensitizing material.
The method for preparing a photosensitizing material according to claim 1, wherein in the step S1, the metal salt is at least one of copper salt, gold salt, silver salt, iron salt, and zinc salt; The solvent is at least one of dibenzyl ether solvent, paraffin, dibenzyl ether, oleic acid and dodecylamine.
The method for preparing a photosensitizing material according to claim 1, wherein in the step S1, the ligand is hexyl mercaptan, octyl mercaptan, dodecyl mercaptan, hexadecyl thiol At least one of alcohol and alkyl thiol acrylate.
The method for preparing a photosensitizing material according to claim 1, wherein in the step S1, the ligand is an acrylic acid alkyl thiol ester, and the molecular formula is:

Wherein, R is a straight-chain alkane or branched-chain alkane with a carbon chain length ranging from 1 to 4 carbons.
The preparation method of photosensitizing material according to claim 1, is characterized in that, in described step S1, described ligand is at least one in following aromatic ligand:
The method for preparing a photosensitizing material according to claim 1, wherein in the step S2, the polymer monomer is a polyhydric alcohol acrylate.
A photosensitive TFT device, characterized in that it comprises a photosensitive layer made of a photosensitive material, and the photosensitive layer is made of the photosensitive material of claims 1-6.
A flexible wearable device, comprising the photosensitive TFT device of claim 7.
The flexible wearable device according to claim 8, wherein the photosensitive TFT device is a flexible and bendable film.