Stretching color-changing film, light-emitting device thereof and preparation method of light-emitting device

Abstract

The invention relates to a tensile color-changing film and a luminescent device and a preparation method thereof, and belongs to the field of luminescent materials and devices. Various luminescent materials with different forbidden bandwidths are made into a mixed component film, effective fluorescence resonance energy transfer (FRET) is allowed by the distance among the various luminescent materials, and the efficiency of the FRET process among the luminescent materials in the film can be changed by stretching when the luminescent materials are deposited on a stretchable flexible substrate, so that the dynamic emission spectrum of the film is changed, and the luminescence efficiency of the film is improved. And the stretching discoloring effect is achieved. When the stretching color-changing film is used as a light-emitting layer of the light-emitting device and a stretchable flexible material is used as a substrate of the light-emitting device, the dynamic electro-emission spectrum of the device can be changed through stretching. The tensile color-changing film disclosed by the invention is simple in structure, wide in applicable material system range and good in compatibility with existing various solution process film manufacturing equipment. The light-emitting device based on the stretching color-changing film is compatible with an existing device structure and process, and the production limitation is small.

Description

Technical Field

[0001] The present invention belongs to the field of luminescent materials and devices, and in particular relates to a stretched color-changing film, a luminescent device thereof, and a preparation method thereof. Background Art

[0002] Vision is an important way for humans to obtain information, and color is an important physical quantity that the human eye can intuitively perceive. The development of new luminescent materials and devices has important practical significance. Thin-film luminescent devices have the advantages of active luminescence, large viewing angle, diverse manufacturing processes, solution processing, flexibility, and a wide range of application scenarios.

[0003] Flexible luminescence and sensing are important technical components of wearable displays and smart displays. Flexible luminescent materials with stretchable color-changing functions have sensing functions in addition to the luminescence function, providing an effective way to make the equipment lighter, thinner and more integrated. Currently, common stretchable color-changing materials often use liquid crystal layers or photonic crystal layers to achieve the color-changing function. The product structure and manufacturing process of these color-changing solutions are relatively complex, and some solutions have a small operating temperature range, which is not conducive to the commercial application of the product.

[0004] Fluorescence resonance energy transfer (FRET) can occur between different luminescent materials, and its efficiency is related to the degree of spectral overlap between the materials and the distance between the luminophores. When luminescent materials with different bandgap widths form a mixed system, if the distance between the luminophores is relatively close, an effective FRET process will occur. When stretching causes the distance between the luminophores to increase, the efficiency of each FRET process in the film can be greatly reduced, causing the dynamic emission spectrum of the film to change accordingly, thereby realizing the stretch color change function. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects and shortcomings of the prior art and to provide a stretch-chromic film, a light-emitting device and a preparation method thereof, which are mainly used in light-emitting materials and devices to realize lightweight, thin and integrated stretch-chromic functions.

[0006] The stretched color-changing film and the light-emitting device thereof provided by the present invention mainly adjust the efficiency of the FRET process between the light-emitting materials in the film by changing the distance between the light-emitting bodies during the stretching process, thereby realizing the dynamic change of the emission spectrum of the film, which has certain significance for the development and commercialization of wearable displays and smart displays.

[0007] To achieve the above object, the technical solution of the present invention is: a stretched color-changing film, comprising a plurality of luminescent materials with different bandgap widths.

[0008] In one embodiment of the present invention, the bandgap width of the luminescent material is between 380 and 750 nm, and visible light can be emitted under optical excitation or electrical excitation; the luminescent material includes one of an organic luminescent material or an inorganic luminescent material.

[0009] In one embodiment of the present invention, the plurality of light-emitting materials with different bandgap widths are uniformly distributed in the film, and the distance between the light-emitting materials allows effective FRET.

[0010] In one embodiment of the present invention, when the stretched color-changing film is deposited on a stretchable flexible substrate, the changed spacing between the luminophores after stretching can change the efficiency of each FRET process in the film, thereby changing the dynamic emission spectrum of the film.

[0011] The present invention also provides a light-emitting device based on a stretched color-changing film, comprising the stretched color-changing film as its light-emitting layer; the device comprises a DC device or an AC device.

[0012] In one embodiment of the present invention, a functional layer is further included; the functional layer includes one of an anode, a hole injection layer, a hole transport layer, an electron blocking layer, an electron transport layer, a cathode, a conductive layer, an ion conductor layer, and a dielectric layer.

[0013] In one embodiment of the present invention, the valence band energy level structure of each functional layer matches the valence band energy level structure of an adjacent functional layer, and the conduction band energy level structure of each functional layer matches the conduction band energy level structure of an adjacent functional layer.

[0014] In one embodiment of the present invention, when a stretchable flexible material is used as its substrate, the dynamic electroemission spectrum of the device can be changed by stretching; the stretchable flexible material includes one of a hydrogel material, polydimethylsiloxane (PDMS), polyester (PET), polyimide (PI), polyethylene naphthalate (PEN), and a textile material.

[0015] The present invention also provides a method for preparing the stretched color-changing film as described above, comprising the following steps: Step A1, fully and evenly mixing solutions containing a plurality of luminescent materials with different bandgap widths to form a mixed component solution; the mixing method includes one of stirring, shaking, ultrasound, and washing; Step A2, preparing a flexible substrate for carrying the stretched color-changing film; the stretchable flexible material includes one of a hydrogel material, polydimethylsiloxane (PDMS), polyester (PET), polyimide (PI), polyethylene naphthalate (PEN), and a textile material; Step A3, pre-treating the flexible substrate in step A2 before use; the pre-treatment method includes cutting, physical extrusion, scrubbing, rinsing, ultrasound, baking, drying, heating, vacuum treatment, etching, plasma cleaning, ultraviolet ozone treatment, acid washing, alkaline washing, silanization treatment, hydroxylation treatment, amination treatment, carboxylation treatment, methylation treatment, and hydroformylation treatment; Step A4, making the mixed component solution described in step A1 into a solid film and depositing it on the pretreated flexible substrate; the film-making method includes one of the Langmuir-Blodgett method, spin coating, inkjet printing, doctor blade coating, spray coating, electrophoretic deposition, bubble printing, electrostatic adsorption, and heating annealing.

[0016] The present invention also provides a method for preparing the light-emitting device based on the stretched color-changing film as described above, comprising the following steps: Step B1, preparing a flexible substrate for supporting the light-emitting device based on the stretchable color-changing film; the stretchable flexible material includes one of a hydrogel material, polydimethylsiloxane (PDMS), polyester (PET), polyimide (PI), polyethylene naphthalate (PEN), and a textile material; Step B2, pre-treating the flexible substrate in step B1 before use; the pre-treatment method includes cutting, physical extrusion, scrubbing, rinsing, ultrasound, baking, drying, heating, vacuum treatment, etching, plasma cleaning, ultraviolet ozone treatment, acid washing, alkaline washing, silanization treatment, hydroxylation treatment, amination treatment, carboxylation treatment, methylation treatment, and hydroformylation treatment; Step B3, sequentially depositing the pre-functional layers required before the light-emitting layer; the deposition method includes one of sputtering, chemical vapor deposition, vacuum evaporation coating, Langmuir-Blodgett method, spin coating, inkjet printing, scraping, spraying, electrophoretic deposition, bubble printing, and electrostatic adsorption; Step B4, preparing a stretched color-changing film on the front functional layer as a light-emitting layer; Step B5, sequentially depositing other functional layers required after the light-emitting layer; the deposition method includes one of sputtering, chemical vapor deposition, vacuum evaporation coating, Langmuir-Blodgett method, spin coating, inkjet printing, scraping, spraying, electrophoretic deposition, bubble printing, and electrostatic adsorption.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1) The stretchable color-changing film of the present invention is applicable to a wide range of material systems.

[0018] 2) The stretch-chromic film of the present invention has a simple structure, a convenient manufacturing process, and can be prepared by a solution processing technology, and has good compatibility with various existing solution process film-making equipment.

[0019] 3) The stretched color-changing film of the present invention has a wide operating temperature range.

[0020] 4) The light-emitting device based on the stretched color-changing film of the present invention has a sensing function in addition to the light-emitting function, which is conducive to the lightweight, thinning and integration of the equipment.

[0021] 5) The light-emitting device based on the stretched color-changing film of the present invention actively emits light, has a large viewing angle, has a variety of manufacturing processes, can be processed by solution, can be flexible, and has a wide range of application scenarios.

[0022] 6) The light-emitting device based on the stretched color-changing film of the present invention is compatible with the existing light-emitting device structure and process, and has little production limitation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the production process of the stretched color-changing film according to an embodiment of the present invention.

[0024] Figure 2 This is a schematic diagram of the structure of a DC light-emitting device based on a stretched color-changing film according to an embodiment of the present invention.

[0025] Among them, 101 is the solvent of the solution; 102 is a luminescent material X; 103 is a luminescent material Y; 104 is a luminescent material Z; 105 is a flexible substrate carrying the stretched color-changing film; 106 is a container for a solution; 201 is the cathode of the device; 202 is an electron transport layer of the device; 203 is the light-emitting material Y in the light-emitting layer of the device; 204 is the light-emitting material Z in the light-emitting layer of the device; 205 is the light-emitting material X in the light-emitting layer of the device; 206 is a hole transport layer of the device; 207 is a hole injection layer of the device; 208 is the anode of the device; 209 is a flexible substrate of the device; 210 is a DC driving power supply of the device. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings.

[0027] Example 1 The present embodiment provides a stretchable color-changing film, and its preparation process is as follows: Figure 1 As shown, proceed as follows: S11: preparing the luminescent material X102, the luminescent material Y103 and the luminescent material Z104 together into a mixed component solution; S12: pre-treating the flexible substrate for carrying the stretched color-changing film by cutting, solvent cleaning, drying, plasma cleaning, etc.; S13: Forming the mixed component solution described in step S11 into a solid film.

[0028] Example 2 This embodiment provides a DC light-emitting device based on a stretched color-changing film, and its structural schematic diagram is as follows: Figure 2 As shown, the preparation process is carried out according to the following steps: S21: depositing the anode 208 of the device on the flexible substrate 209; S22: depositing a hole injection layer 207 on the anode of the device; S23: depositing a hole transport layer 206 on the hole injection layer of the device; S24: depositing a mixed component film including the luminescent material X205, the luminescent material Y203, and the luminescent material Z204 onto the hole transport layer of the device as a luminescent layer; S25: depositing an electron transport layer 202 on the light-emitting layer of the device; S26: depositing a cathode 201 on the electron transport layer of the device.

[0029] Afterwards, a DC driving power supply 210 of the device may be connected between the cathode and the anode to fully realize its working function.

[0030] This patent is not limited to the above-mentioned optimal implementation mode. Anyone can derive other various forms of stretched color-changing films and their light-emitting devices and preparation methods under the inspiration of this patent. All equal changes and modifications made according to the scope of the patent application of the present invention should be covered by this patent.

[0031] The above are preferred embodiments of the present invention. Any changes made according to the technical solution of the present invention, as long as the resulting functions do not exceed the scope of the technical solution of the present invention, belong to the protection scope of the present invention.

Claims

1. A stretched color-changing film, characterized in that: Includes a variety of luminescent materials with different bandgap widths.

2. A stretched color-changing film according to claim 1, characterized in that: The light-emitting material has a bandgap width between 380 and 750 nm and can emit visible light under optical or electrical excitation.

3. A stretched color-changing film according to claim 1 or 2, characterized in that: The plurality of light-emitting materials with different bandgap widths are uniformly distributed in the film, and the distances between the light-emitting materials allow efficient fluorescence resonance energy transfer (FRET).

4. A stretched color-changing film according to claim 1 or 2, characterized in that: When deposited on a stretchable flexible substrate, the changed spacing between the luminophores after stretching can change the efficiency of each fluorescence resonance energy transfer (FRET) process in the film, thereby changing the dynamic emission spectrum of the film.

5. A light-emitting device based on a stretched color-changing film, characterized in that: The method comprises using the stretched color-changing film as described in any one of claims 1 to 4 as the light-emitting layer.

6. A light-emitting device based on a stretched color-changing film according to claim 5, characterized in that: It also includes a functional layer; the functional layer includes one of an anode, a hole injection layer, a hole transport layer, an electron blocking layer, an electron transport layer, a cathode, a conductive layer, an ion conductor layer, and a dielectric layer.

7. A light-emitting device based on a stretched color-changing film according to claim 6, characterized in that: The valence band energy level structure of each functional layer matches the valence band energy level structure of the adjacent functional layer, and the conduction band energy level structure of each functional layer matches the conduction band energy level structure of the adjacent functional layer.

8. The light-emitting device based on a stretched color-changing film according to claim 5, characterized in that: When a stretchable flexible material is used as a substrate of a light-emitting device, the dynamic electroemission spectrum of the light-emitting device can be changed by stretching.

9. A method for preparing a stretched color-changing film according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step A1, fully and evenly mixing solutions containing a plurality of luminescent materials with different bandgap widths to form a mixed component solution; the mixing method includes one of stirring, shaking, ultrasound, and washing; Step A2, preparing a flexible substrate for supporting the stretched color-changing film; Step A3, pre-treating the flexible substrate described in step A2 before use; Step A4: Form the mixed component solution described in step A1 into a solid film and deposit it on the pretreated flexible substrate.

10. A method for preparing a light-emitting device based on a stretched color-changing film according to any one of claims 5 to 8, characterized in that: The following steps are involved: Step B1, preparing a flexible substrate for supporting the light-emitting device based on the stretchable color-changing film; Step B2, pre-treating the flexible substrate described in step B1 before use; Step B3, sequentially depositing the pre-functional layers required before the light-emitting layer; Step B4, preparing a stretched color-changing film on the front functional layer as a light-emitting layer; Step B5: sequentially depositing other functional layers required after the light-emitting layer.

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