Flexible circularly polarized light-emitting device and preparation method and application thereof

Abstract

The application relates to a flexible circularly polarized light-emitting device, a preparation method thereof and application, and relates to the material field. The flexible circularly polarized light-emitting device comprises a flexible polymer wrapped perovskite film, and a liquid crystal polymer film or a patterned liquid crystal polymer film is arranged on the flexible polymer wrapped perovskite film. The flexible circularly polarized light-emitting device has excellent circular polarization characteristics and bending performance, and the preparation method is simple, low in cost, easy to realize fine patterning preparation, and has a very good application prospect in the field of anti-counterfeiting.

Description

Technical Field

[0001] This invention relates to the field of materials, and more particularly to flexible materials. Background Technology

[0002] Circularly polarized luminescence has broad application prospects in fields such as 3D display, information anti-counterfeiting and encryption, and photocatalytic asymmetric synthesis. Currently, the main methods for achieving circularly polarized luminescence include supramolecular self-assembly, small organic molecules, organic polymers, and inorganic materials. However, these reported materials still have shortcomings; the circularly polarized luminescence obtained through these materials exhibits a small luminescence asymmetry factor (only around 10). -3 Their low fluorescence quantum yield (on orders of magnitude) and low fluorescence quantum yield will limit their further applications.

[0003] Flexible devices offer advantages such as light weight and bendability, making them suitable for wearable and portable devices, which will broaden their application scenarios and scope. Therefore, there is an urgent need for a flexible circularly polarized luminescent material with high luminescence quantum yield and high asymmetry factor. Summary of the Invention

[0004] The purpose of this invention is to provide a flexible circularly polarized light-emitting device and its fabrication method, wherein the flexible circularly polarized light-emitting device can solve the problems in the prior art;

[0005] The present invention also aims to provide a flexible polymer-encapsulated perovskite thin film and its preparation method, wherein the flexible polymer-encapsulated perovskite thin film is used to prepare a flexible circularly polarized light-emitting device.

[0006] The present invention also aims to provide a method for preparing a liquid crystal polymer film, wherein the prepared liquid crystal polymer film is used to prepare a flexible circularly polarized light-emitting device;

[0007] Another objective of this invention is to provide an application for a flexible circularly polarized light-emitting device.

[0008] The technical problem solved by this invention can be achieved by the following technical solutions:

[0009] A flexible polymer-coated perovskite film, characterized by comprising a flexible substrate on which a polymer-coated perovskite layer is disposed. The thickness of the polymer-coated perovskite layer is 100–1000 nm. The flexible substrate is either a PET substrate or a PEN substrate.

[0010] A method for preparing a flexible polymer-coated perovskite film is characterized by placing a flexible substrate on a spin coater, using a 200 μL pipette to draw 80 μL of perovskite precursor solution onto the flexible substrate, and starting spin coating at 3000 rpm for 30 s. After the spin coating process is completed, the substrate is removed and placed on a heating stage for annealing at 70°C for 10 min. After annealing, a flexible polymer-coated perovskite film is obtained.

[0011] A method for preparing a liquid crystal polymer film, characterized by comprising the following steps:

[0012] Step 1: Clean the quartz substrate sequentially with deionized water, ethanol and acetone using ultrasonic cleaning for 25 min-35 min.

[0013] Step 2: Treat the quartz substrate washed in Step 1 with ultraviolet ozone for 15-25 minutes;

[0014] Step 3: In an air environment, spin-coat the photoalignment agent SD1 solution onto the quartz substrate and heat-anneal at 100°C for 10 min to remove DMF;

[0015] Step 4: Attach two optical tapes to both sides of the quartz substrate, cover it with another quartz substrate, and then irradiate it with ultraviolet polarized light for 5 minutes.

[0016] Step 5: Add dopants S-5011 or R-5011 with different chiralities to liquid crystal polymer monomers RM257 and LC242, and add photoinitiator Irgacure 184. Stir at 140°C for 2 hours. The liquid crystal mixture containing S-5011 or R-5011 is injected into the space between the quartz substrates through capillary action. Irradiate with 365nm ultraviolet light for 10 minutes. Finally, peel off the quartz substrates to obtain the liquid crystal polymer film.

[0017] A method for preparing patterned liquid crystal polymer films is characterized by adding dopants S-5011 or R-5011 with different chiralities to liquid crystal polymer monomers RM257 and LC242, and adding photoinitiator Irgacure 184. The mixture is stirred at 140°C for 2 hours, and the liquid crystal mixture containing S- or R-5011 is poured into a liquid crystal cell through capillary action. The liquid crystal cell is cooled to room temperature, irradiated with 365nm ultraviolet light for 10 minutes, and then placed on a 140°C heating stage until the unpolymerized areas become transparent. The cell is then irradiated with 365nm ultraviolet light for another 10 minutes. Finally, the liquid crystal cell is peeled off to obtain a patterned liquid crystal polymer film.

[0018] A flexible circularly polarized light-emitting device is characterized by comprising a flexible polymer-encapsulated perovskite film, wherein a liquid crystal polymer film or a patterned liquid crystal polymer film is disposed on the flexible polymer-encapsulated perovskite film.

[0019] A method for fabricating a flexible circularly polarized light-emitting device, characterized by comprising the following steps:

[0020] Step 1: First, ultrasonically clean the PET or PEN substrate in soapy water, deionized water and ethanol for 15-25 minutes in sequence. After cleaning, dry it with high-purity nitrogen.

[0021] Step 2: Treat the dried PET or PEN substrate from Step 1 with ultraviolet ozone for 15-25 minutes;

[0022] Step 3: Transfer the PET or PEN substrate into a nitrogen glove box and place it on a spin coater;

[0023] Step 4: Use a 200μL pipette to draw 80μL of perovskite precursor solution and drop it onto the substrate. Start spin coating at 3000rpm for 30s. After spin coating, remove the substrate and place it on a heating stage for annealing at 70℃ for 10min. After annealing, a flexible polymer-coated perovskite film is obtained.

[0024] Step 5: Treat the quartz substrate with ultraviolet ozone for 20 minutes;

[0025] Step 6: In an air environment, spin-coat the photoaligning agent SD1 solution onto the substrate and heat-anneal at 100°C for 10 min to remove DMF;

[0026] Step 7: Attach two optical tapes to both sides of the quartz substrate, making sure they are tightly bonded to the other quartz substrate;

[0027] Step 8: Irradiate one side of the quartz glass with ultraviolet polarized light for 5 minutes;

[0028] Step 9: Add dopants S-5011 or R-5011 with different chiralities to liquid crystal polymer monomers RM257 and LC242, and add photoinitiator Irgacure 184 and stir at 140℃ for 2 hours;

[0029] Step 10: Using a capillary tube, the liquid crystal polymer monomer containing S- or R-5011 is injected into the quartz assembled in Step 7 via capillary action.

[0030] Step 11: Irradiate with 365nm ultraviolet light for 10 minutes;

[0031] Step 12: Peel off the quartz substrate to obtain a liquid crystal polymer film;

[0032] Step 13: Adhere the liquid crystal polymer film obtained in step 12 to the flexible polymer-encapsulated perovskite film obtained in step 4 to obtain a flexible circularly polarized light-emitting device.

[0033] A method for fabricating a patterned flexible circularly polarized light-emitting device, characterized by comprising the following steps:

[0034] Step 1: First, ultrasonically clean the PET or PEN substrate in soapy water, deionized water and ethanol for 15-25 minutes in sequence. After cleaning, dry it with high-purity nitrogen.

[0035] Step 2: Treat the dried PET or PEN substrate from Step 1 with ultraviolet ozone for 15-25 minutes;

[0036] Step 3: Transfer the PET or PEN substrate into a nitrogen glove box and place it on a spin coater;

[0037] Step 4: Use a 200μL pipette to draw 80μL of perovskite precursor solution and drop it onto the substrate. Start spin coating at 3000rpm for 30s. After spin coating, remove the substrate and place it on a heating stage for annealing at 70℃ for 10min. After annealing, a flexible polymer-coated perovskite film is obtained.

[0038] Step 5: Add dopants S-5011 or R-5011 with different chiralities to the liquid crystal polymer monomers RM257 and LC242, and add photoinitiator Irgacure 184. Stir at 140°C for 2 hours. Fill the liquid crystal mixture containing S- or R-5011 into the liquid crystal cell through capillary action. Cool the liquid crystal cell to room temperature, irradiate it with 365nm ultraviolet light for 10 minutes, and then place it on a 140°C heating stage until the unpolymerized area becomes transparent. Then irradiate it with 365nm ultraviolet light for another 10 minutes. Finally, peel off the liquid crystal cell to obtain a patterned liquid crystal polymer film.

[0039] Step 6: The patterned liquid crystal polymer film obtained in Step 5 is attached to the flexible polymer-encapsulated perovskite film obtained in Step 4 to obtain a flexible circularly polarized light-emitting device.

[0040] The application of the flexible circularly polarized light-emitting device is characterized by its ability to be used as a flexible label with anti-counterfeiting function.

[0041] Beneficial effects:

[0042] This invention achieves a high-quality flexible circularly polarized light-emitting device by combining a chiral liquid crystal polymer with selective reflectivity with a polymer-encapsulated perovskite nanocrystalline film exhibiting high luminescence performance. The flexible circularly polarized light-emitting device of this invention possesses excellent circular polarization characteristics and bending performance, and its fabrication method is simple, low-cost, and easily achievable through fine patterning, making it highly promising for applications in the anti-counterfeiting field.

[0043] This invention utilizes a flexible polymer-encapsulated perovskite film to achieve a high luminescence quantum yield of 96.2%. This flexible film exhibits excellent bending ability and fatigue resistance, maintaining its original performance even after 1000 cyclic bending cycles at a bending radius of 1 mm.

[0044] This invention combines a flexible polymer-encapsulated perovskite film and a liquid crystal polymer film to fabricate a circularly polarized light-emitting device. It utilizes the unique selective reflection of circularly polarized light by the liquid crystal polymer and the high luminescence capability of the polymer-encapsulated perovskite film to achieve g lum Circularly polarized light emission with a value of 1.8.

[0045] The present invention is based on a device (PeLCP) of perovskite-liquid crystal polymer encapsulated by a flexible polymer, which has excellent storage stability and can maintain its original performance after being placed in air for a year. It also has excellent bending performance, and its circular polarization light emission capability remains at the original level after being cyclically bent 1000 times with a bending radius of 2mm.

[0046] This invention designs patterns on liquid crystal polymer films to fabricate patterned PeLCP devices, thereby realizing flexible labels with anti-counterfeiting functions. Attached Figure Description

[0047] Figure 1 This describes the fabrication process of left-handed pentagram patterned thin films (L-LCP) and their right-handed complementary patterned thin films (R-LCP);

[0048] Figure 2 The images show the effects of observing the flexible multilayer patterned device with the naked eye and with the aid of a quarter-wave plate and a linear polarizer.

[0049] Figure 3 Circular dichroism spectral curves of liquid crystal polymer films with different chiralities;

[0050] Figure 4 CPL curves for flexible PeLCP devices with different chirities;

[0051] Figure 5 The curves show the CPL variation of flexible PeLCP devices under different bending radii. Detailed Implementation

[0052] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific illustrations.

[0053] Regarding flexible polymer-encapsulated perovskite films and their preparation methods

[0054] A flexible polymer-coated perovskite film includes a flexible substrate on which a polymer-coated perovskite layer is disposed. The thickness of the polymer-coated perovskite layer is 100–1000 nm.

[0055] The method for preparing flexible polymer-coated perovskite films involves placing a flexible substrate on a spin coater, applying 80 μL of perovskite precursor solution to the substrate using a 200 μL pipette, and then starting spin coating at 3000 rpm for 30 seconds. After spin coating, the substrate is removed and annealed on a heating stage at 70°C for 10 minutes. The resulting flexible polymer-coated perovskite film is then obtained. Before spin coating the flexible substrate, it can be cleaned, dried with high-purity nitrogen, and then treated with ultraviolet ozone to ensure a clean surface.

[0056] The preferred steps for preparing flexible polymer-encapsulated perovskite thin films are as follows:

[0057] Step 1: Clean the flexible substrate (preferably PET substrate or PEN substrate) sequentially in soapy water, deionized water and ethanol by ultrasonic cleaning for 15 min-30 min, preferably 20 min. After cleaning, dry it with high-purity nitrogen.

[0058] Step 2: Treat the dried flexible substrate from Step 1 with ultraviolet ozone for 15-30 minutes, preferably 20 minutes;

[0059] Step 3: Transfer the flexible substrate into a nitrogen glove box and place it on a spin coater;

[0060] Step 4: Using a 200 μL pipette, drop 80 μL of the perovskite precursor solution onto the substrate and begin spin coating at 3000 rpm for 30 seconds. After spin coating, remove the sample and place it on a heating stage for annealing at 70°C for 10 minutes. After annealing, a flexible polymer-coated perovskite film is obtained. The concentration of the perovskite precursor solution is 0.01-2 mol / L.

[0061] Preparation methods of liquid crystal polymer films

[0062] The preferred steps for preparing liquid crystal polymer films are as follows:

[0063] Step 1: Clean the quartz substrate sequentially in deionized water, ethanol and acetone using ultrasonic cleaning for 25 min-35 min, preferably 30 min;

[0064] Step 2: Treat the quartz substrate washed in Step 1 with ultraviolet ozone for 15 min-25 min, preferably 20 min;

[0065] Step 3: In an air environment, spin-coat the photoalignment agent SD1 solution onto the quartz substrate and heat-anneal at 100°C for 10 min to remove DMF;

[0066] Step 4: Attach two optical tapes to both sides of the quartz substrate, cover it with another quartz substrate, and then irradiate it with ultraviolet polarized light for 5 minutes.

[0067] Step 5: Add dopants S-5011 or R-5011 with different chiralities to liquid crystal polymer monomers RM257 and LC242, and add photoinitiator Irgacure 184. Stir at 140°C for 2 hours. The liquid crystal mixture containing S-5011 or R-5011 is injected into the space between the quartz substrates through capillary action. Irradiate with 365nm ultraviolet light for 10 minutes. Finally, peel off the quartz substrates to obtain the liquid crystal polymer film.

[0068] Methods for preparing patterned liquid crystal polymer films

[0069] Different chiral dopants S-5011 or R-5011 were added to the liquid crystal polymer monomers RM257 and LC242, along with the photoinitiator Irgacure 184. The mixture was stirred at 140°C for 2 hours, and the liquid crystal mixture containing S- or R-5011 was injected into a liquid crystal cell via capillary action. The liquid crystal cell was cooled to room temperature and irradiated with 365nm ultraviolet light for 10 minutes. It was then placed on a 140°C heating stage until the unpolymerized areas became transparent, followed by another 10 minutes of irradiation with 365nm ultraviolet light. Finally, the liquid crystal cell was peeled off to obtain a patterned liquid crystal polymer film. The liquid crystal cell can be fabricated using a quartz substrate used in the liquid crystal polymer film preparation process. Figure 1 The preparation process of left-handed pentagram patterned thin film (L-LCP) and its right-handed complementary patterned thin film (R-LCP) is described.

[0070] Flexible circularly polarized light-emitting devices and their fabrication methods

[0071] A flexible circularly polarized light-emitting device includes a flexible substrate, on which a polymer-coated perovskite layer is disposed, and a chiral liquid crystal polymer layer is disposed on the polymer-coated perovskite layer. Preferably, the polymer-coated perovskite layer is a flexible polymer-coated perovskite thin film, and the chiral liquid crystal polymer layer is preferably a liquid crystal polymer thin film.

[0072] The flexible substrate can be either a PET substrate or a PEN substrate. The polymer can be one or more of PS, PVDF, PMMA, PAN, and PVDC. The perovskite material can be ABX3; wherein A includes CH3NH3. + HC(NH2)2 + Cs+ and Rb + One or more of the following; B includes Pb 2+ Sn 2+ and Sr 2+ One or more of the following; X includes Br - I - and Cl - One or more of the following. The chiral liquid crystal polymer is S(R)-5011 doped with LC242 and RM257. The chiral liquid crystal includes, but is not limited to, polymer-stabilized cholesteric phase, blue phase liquid crystal, and liquid crystal polymer. The thickness of the chiral liquid crystal polymer layer is preferably 5-30 μm. The chiral liquid crystal polymer layer may consist of two or more layers.

[0073] The preferred method for fabricating a flexible circularly polarized light-emitting device includes the following steps:

[0074] Step 1: First, ultrasonically clean the PET or PEN substrate in soapy water, deionized water and ethanol for 20 minutes in sequence. After cleaning, dry it with high-purity nitrogen.

[0075] Step 2: Irradiate the dried PET or PEN substrate from Step 1 under ultraviolet light for 20 minutes;

[0076] Step 3: Transfer the PET or PEN substrate into a nitrogen glove box and place it on a spin coater;

[0077] Step 4: Using a 200μL pipette, drop 80μL of the perovskite precursor solution onto the substrate and begin spin coating at 3000rpm for 30s. After spin coating, remove the sample and place it on a heating stage for annealing at 70℃ for 10min. After annealing, a uniform, flexible polymer-coated perovskite luminescent film is obtained. The concentration of the perovskite precursor solution is 0.01-2mol / L; the thickness of the perovskite layer is 100-1000nm.

[0078] Step 5: Irradiate the quartz substrate under ultraviolet light for 20 minutes;

[0079] Step 6: In an air environment, spin-coat the photoaligning agent SD1 solution onto the substrate and heat-anneal at 100°C for 10 min to remove DMF;

[0080] Step 7: Attach two optical tapes to both sides of the quartz substrate, making sure they are tightly bonded to the other quartz substrate;

[0081] Step 8: Irradiate one side of the quartz glass with ultraviolet polarized light for 5 minutes;

[0082] Step 9: Add dopants S-5011 or R-5011 with different chiralities to liquid crystal polymer monomers RM257 and LC242, and add photoinitiator Irgacure 184 and stir at 140℃ for 2 hours;

[0083] Step 10: Using a capillary tube, the liquid crystal polymer monomer containing S- or R-5011 is injected into the quartz assembled in Step 7 via capillary action.

[0084] Step 11: Irradiate with 365nm ultraviolet light for 10 minutes;

[0085] Step 12: Peel off the quartz substrate to obtain a separate liquid crystal polymer (LCP) film;

[0086] Step 13: Adhere the LCP film obtained in Step 12 to the flexible polymer-encapsulated perovskite light-emitting film obtained in Step 4 to obtain a flexible circularly polarized light-emitting device.

[0087] Patterned flexible circularly polarized light-emitting devices and their fabrication methods

[0088] A patterned flexible circularly polarized light-emitting device includes a flexible substrate, on which a polymer-coated perovskite layer is disposed, and a chiral liquid crystal polymer layer is disposed on the polymer-coated perovskite layer. The polymer-coated perovskite layer is preferably a flexible polymer-coated perovskite thin film, and the chiral liquid crystal polymer layer is preferably a patterned liquid crystal polymer thin film. The pattern of the liquid crystal polymer layer can be used for anti-counterfeiting purposes, serving as a flexible anti-counterfeiting label or for manufacturing flexible anti-counterfeiting labels. The method for forming the patterned liquid crystal polymer layer involves: polymerizing the liquid crystal under different phase states (isotropic and anisotropic) using ultraviolet light; then placing the liquid crystal on a 140°C heating stage to make it isotropic, and then polymerizing it again using ultraviolet light.

[0089] Patterned liquid crystal polymer films can consist of two or more layers. When there are two layers, the preparation method is as follows: two liquid crystal polymer films with complementary patterns and chirality are combined with a polymer-coated perovskite film to form a patterned flexible circularly polarized light-emitting device. Figure 2This invention provides an embodiment of the effect of observing a flexible multilayer patterned device directly with the naked eye and observing it with the aid of a quarter-wave plate and a linear polarizer. When the angle between the quarter-wave plate and the linear polarizer is 45° and 225°, the pentagram pattern area containing S-5011 exhibits an extinction effect, that is, the brightness of the pentagram area reaches its darkest point, while the brightness of the pentagram complementary pattern area containing R-5011 reaches its brightest point. When the angle between the quarter-wave plate and the linear polarizer is 135° and 315°, the pentagram complementary pattern area containing R-5011 exhibits an extinction effect, that is, the brightness of the pentagram complementary area reaches its darkest point, while the brightness of the pentagram pattern area containing S-5011 reaches its brightest point. When the angle between the quarter-wave plate and the linear polarizer is 0°, 90°, 180°, and 270°, half of the brightness of both the pentagram area and its complementary area can be transmitted, thus showing the effect of the pattern being hidden.

[0090] Circular dichroism performance test of the liquid crystal polymer film of the present invention

[0091] The testing instrument was a JASCO-1500CD spectrometer.

[0092] Scan range: 350-800nm

[0093] Scan speed: 500 nm / min

[0094] LCP films were excited using 365nm light, and CPL measurements were performed. A positive CD signal was obtained when the chiral molecule was S-5011, and a negative CD signal was obtained when the chiral molecule was R-5011, exhibiting mirror symmetry. Figure 3 The CD spectrum of the LCP thin film is shown.

[0095] Circular polarization performance test of the flexible circularly polarized light-emitting device of the present invention

[0096] The testing instrument was a JASCO CPL-300 spectrometer.

[0097] Scan range: 450-700nm

[0098] Data interval: 0.5nm

[0099] CPL measurements were performed using PeLCP devices excited with 365nm light. The L-PeLCP device with S-5011 chiral molecules produced a negative CPL signal, while the R-PeLCP device with R-5011 chiral molecules produced a positive CPL signal. Figure 4 This is the CPL curve of a flexible circularly polarized light-emitting device.

[0100] Bending performance test of the flexible circularly polarized light-emitting device of the present invention

[0101] The testing instrument was a JASCO CPL-300 spectrometer.

[0102] Scan range: 450-700nm

[0103] Data interval: 0.5nm

[0104] Figure 5 The curves show the CPL variation of a flexible circularly polarized light-emitting device under different bending radii.

[0105] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for fabricating a flexible circularly polarized light-emitting device, characterized in that, Includes the following steps: Step 1: First, ultrasonically clean the PET or PEN substrate in soapy water, deionized water and ethanol for 15-25 minutes in sequence. After cleaning, dry it with high-purity nitrogen. Step 2: Treat the dried PET or PEN substrate from Step 1 with ultraviolet ozone for 15-25 minutes; Step 3: Transfer the PET or PEN substrate into a nitrogen glove box and place it on a spin coater; Step 4: Using a 200 μL pipette, draw 80 μL of perovskite precursor solution and drop it onto the substrate. Begin spin coating at 3000 rpm for 30 s. After spin coating, remove the substrate and place it on a heating plate for annealing at 70°C. o C, annealing time is 10 min, after which a flexible polymer-encapsulated perovskite film is obtained; Step 5: Add dopants S-5011 or R-5011 with different chiralities to the liquid crystal polymer monomers RM257 and LC242, and add photoinitiator Irgacure 184. Stir at 140℃ for 2 h. The liquid crystal mixture containing S- or R-5011 is poured into the liquid crystal cell by capillary action. Cool the liquid crystal cell to room temperature, irradiate it with 365 nm ultraviolet light for 10 min, and then place it on a 140℃ heating stage until the unpolymerized area becomes transparent. Then irradiate it with 365 nm ultraviolet light for 10 min. Finally, peel off the liquid crystal cell to obtain a patterned liquid crystal polymer film. Step 6: The patterned liquid crystal polymer film obtained in Step 5 is attached to the flexible polymer-encapsulated perovskite film obtained in Step 4 to obtain a flexible circularly polarized light-emitting device.

2. A flexible circularly polarized light-emitting device, characterized in that, The flexible circularly polarized light-emitting device described in claim 1 was prepared using the same method.

3. The application of the flexible circularly polarized light-emitting device according to claim 2, characterized in that, Used as a flexible label with anti-counterfeiting features.

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