Flexible laser based on D-J-2D perovskite material and application

Abstract

The invention relates to a flexible laser based on a D-J-2D perovskite material and application. The flexible laser comprises a flexible substrate; the two-photon 3D printing polymer microcavity is arranged on the flexible substrate; the D-J quasi 2D perovskite gain dielectric film covers the polymer microcavity, and the film is prepared by the following method: dissolving PbBr2, CsBr, PDABr and HDABr in DMSO (dimethylsulfoxide) to obtain a perovskite precursor solution with the concentration of 0.4 M; the preparation method comprises the following steps: dissolving tributyl phosphine oxide in ethyl acetate to obtain an EA-coated TBPO solution; the PET substrate is sequentially subjected to deionized water, acetone and isopropanol ultrasonic cleaning and nitrogen blow-drying and then subjected to plasma treatment; filtering the precursor solution, spin-coating the precursor solution on a PET substrate, and dropwise adding an EA-TBPO solution during spin-coating; and performing low-temperature annealing to form the crystallized D-J phase perovskite thin film. The invention provides a laser which is high in stability, low in power consumption and resistant to mechanical stress.

Description

Technical Field

[0001] The present invention belongs to the field of laser technology, and in particular relates to a flexible laser based on DJ quasi-2D perovskite material and its application. Background Art

[0002] Traditional lasers are mostly based on rigid substrates, such as silicon wafers and glass. These rigid lasers have significant limitations in their application scenarios and are unable to meet the demand for flexible and bendable devices in emerging fields such as wearable devices and flexible electronics. In recent years, flexible lasers have become a research hotspot. Using flexible substrates instead of rigid substrates provides new possibilities for expanding laser applications.

[0003] In the research of flexible lasers, material selection and microcavity fabrication are crucial. Perovskite materials are widely used in optoelectronic devices due to their excellent optical properties, such as high fluorescence quantum yield, wide spectral tunability, and high carrier mobility. However, current flexible lasers based on perovskites still face some challenges. For example, perovskite materials have poor stability and are prone to degradation under environmental factors such as humidity and oxygen. They are also easily affected by stress when bent, which reduces the luminous efficiency of the perovskite light-emitting layer. Among them, Dion-Jacobson quasi-2D perovskites show great potential in optoelectronic devices due to their unique crystal structure and optical properties. DJ-type quasi-2D perovskites exhibit enhanced structural robustness and more efficient charge transfer because diammonium cations electrostatically connect adjacent inorganic layers without forming a van der Waals gap. At the same time, this layered structure with alternating organic and inorganic layers imparts a certain degree of mechanical flexibility to the material. At present, the mainstream method for preparing DJ-type quasi-2D perovskite laser gain medium films is to use the overheating method. This method using high temperature and high pressure is not suitable for large-scale manufacturing and is not suitable for combination with flexible substrates.

[0004] Therefore, how to achieve low-temperature preparation of highly stable DJ-phase perovskite films, efficiently couple them with flexible microcavities, and provide a low-threshold, bend-resistant flexible perovskite laser is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0005] The first object of the present invention is to provide a flexible laser based on DJ quasi-2D perovskite material to address the problems in the prior art.

[0006] To this end, the above-mentioned purpose of the present invention is achieved through the following technical solutions: A flexible laser based on DJ quasi-2D perovskite material, comprising: Flexible substrate; a two-photon 3D-printed polymer microcavity disposed on the flexible substrate; A DJ quasi-2D perovskite gain medium film covering the polymer microcavity is prepared by the following method: Step S1, precursor solution preparation: PbBr2, CsBr, PDABr and HDABr are dissolved in DMSO to obtain a perovskite precursor solution with a concentration of 0.2M-1.0mol / ml; Step S2, preparation of anti-solvent: dissolving tri-n-butylphosphine oxide in ethyl acetate at a concentration of 0.02 mol / ml to obtain EA@TBPO solution; Step S3, substrate treatment: the PET substrate is sequentially cleaned with deionized water, acetone, and isopropyl alcohol by ultrasonic cleaning, dried with nitrogen, and then plasma treated; Step S4, thin film deposition: the precursor solution of step S1 is filtered and spin-coated on a PET substrate, and the EA@TBPO solution is added dropwise during the spin coating; Step S5, low temperature annealing: annealing the spin-coated sample at a low temperature to form a crystallized DJ phase perovskite film.

[0007] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions: As a preferred technical solution of the present invention: the polymer microcavity adopts NanoscribeIP-dip photoresist, is 3D printed into a circular shape and has a size of micrometer level.

[0008] As a preferred technical solution of the present invention: the flexible substrate is polyethylene terephthalate.

[0009] As a preferred technical solution of the present invention: in step S1, PbBr2, CsBr, PDABr and HDABr are dissolved in DMSO in a molar ratio of (8-16): (8-16): (1-2): (1-2).

[0010] As a preferred technical solution of the present invention: in step S1, the molar ratio of PbBr2, CsBr, PDABr and HDABr is 16:16:1:1, wherein the organic ammonium ions of PDABr and HDABr account for 5.88% of the total cations.

[0011] As a preferred technical solution of the present invention: TBPO in the EA@TBPO solution and Pb in the perovskite precursor solution 2+ The molar ratio is 1:20.

[0012] The second object of the present invention is to provide an application of a flexible laser based on DJ quasi-2D perovskite material to address the problems in the prior art.

[0013] To this end, the above-mentioned purpose of the present invention is achieved through the following technical solutions: The application of the flexible laser based on DJ quasi-2D perovskite material, the laser is applied to flexible optoelectronic systems, and WGM laser output is achieved under 400nm femtosecond laser pumping, with a threshold of ≤2.16μJ / cm 2 , net modal gain ≥1704cm at 10 times the threshold -1 .

[0014] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions: As a preferred technical solution of the present invention: the flexible optoelectronic system includes a wearable biosensor, a flexible display backplane or a micro-spectral analysis module, and the laser is integrated into the system as a low-power light source.

[0015] Compared with the prior art, the flexible laser based on DJ quasi-2D perovskite material and its application of the present invention have the following beneficial effects: in the present invention, the defect passivation effect of TBPO additive in ethyl acetate anti-solvent is used to realize the preparation of high-crystalline DJ phase perovskite film at low temperature, which solves the damage of traditional high-temperature and high-pressure process to flexible substrate; the introduction of TBPO additive can realize the interaction between P=O bond in TBPO and Pb 2+ The vacancies and the P=O bonds form hydrogen bonds with the NH bonds in the DJ organic macromolecules, which solves the contradiction between stability and flexibility, improves the crystallization and optical properties of the film, and further enhances the stability of the DJ quasi-two-dimensional perovskite material; the present invention can realize the mode selection of the laser by changing the size of the microcavity of two-photon 3D printing, and realize multi-mode or single-mode laser output.

[0016] The present invention prepares a high-performance flexible laser by combining a polymer microcavity with a flexible substrate based on an ultra-stable DJ phase perovskite thin film gain medium and using 3D printing technology. By using two-photon 3D printing of the microcavity, whispering gallery mode (WGM) lasing is achieved. The flexible laser of the present invention exhibits excellent laser performance and strong mechanical toughness, and has great potential for applications in fields such as wearable electronics, optical communications, and robotic systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Figure (a) is the SEM image before TBPO treatment. Figure 1 Figure (b) is the SEM image after TBPO treatment. Figure 1 Figure (c) is the AFM image before TBPO treatment. Figure 1 Figure (d) shows the AFM image after TBPO treatment;

[0018] Figure 2Figure (a) is a comparison of the original fluorescence spectrum before TBPO treatment and the fluorescence spectrum after TBPO treatment. Figure 2 Figure (b) shows the fluorescence spectrum of the original sample before TBPO treatment. Figure 2 Figure (c) shows the fluorescence spectrum of the sample after TBPO treatment. Figure 2 Figure (d) shows the pump intensity-dependent emission spectrum of the film before TBPO treatment and the relationship between PL intensity and FWHM and pump density. Figure 2 Figure (e) shows the pump intensity-dependent emission spectrum of the film after TBPO treatment and the relationship between PL intensity and FWHM and pump density. Figure 2 Figure (f) shows the optical gain parameters before and after TBPO treatment;

[0019] Figure 3 Figure (a) shows ring structures of different sizes fabricated on a 100μm×100μm square flexible base. Figure 3 Figure (b) shows lasers with ring structures of different sizes;

[0020] Figure 4 Figure (a) shows the pump density-dependent laser spectrum in a 3μm ring. Figure 4 In, Figure 4 Figure (b) shows the relationship between laser intensity and FWHM and pump density. Figure 4 Figure (c) shows the stability test at 1.5 times the threshold intensity. Figure 4 Figure (d) shows the transition from spontaneous emission to WGM lasing. First-order coherence measurements at different delay times using a Michelson interferometer (I) and (II) are performed below (III) and above (IV) threshold fluorescence images.

[0021] Figure 5 Figure (a) shows the image of the flexible laser at different bending degrees. Figure 5 Figure (b) shows the laser intensity and quality factor test under different bending degrees; Figure 5 Figure (c) shows the mechanical durability test of the flexible perovskite laser, with a bending degree of 8 mm. DETAILED DESCRIPTION

[0022] The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

[0023] The present invention aims to provide an ultra-stable DJ-phase perovskite flexible laser combined with a two-photon 3D-printed microcavity. By optimizing material properties and flexible microcavity preparation, the advantages of the DJ-phase perovskite gain medium are fully utilized on a flexible substrate, thereby improving the laser's luminous efficiency, stability, and overall performance to meet the needs of different application scenarios.

[0024] In this application, DJ specifically refers to Dion-Jacobson.

[0025] The present invention uses the additive tri-n-butylphosphine oxide (TBPO) to improve the optical and material properties of the DJ quasi-2D perovskite thin film gain medium and combines it with a 3D-printed polymer microcavity to realize the preparation of a flexible perovskite laser device in the WGM mode.

[0026] The specific invention points are as follows:

[0027] 1. In order to solve the problem of difficulty in preparing high-performance DJ-type perovskite gain media on a large scale, TBPO additives were introduced to react with Pb via the P=O bond in TBPO. 2+ The vacancies and P=O bonds form hydrogen bonds with the NH bonds in the DJ organic macromolecules, which improves the crystallization and optical properties of the film and further enhances the stability of the DJ quasi-two-dimensional perovskite material.

[0028] 2. To achieve low-temperature integration with a flexible substrate, the present invention adopts a full solution method. By introducing TBPO into an ethyl acetate (EA) antisolvent to act as a surface defect passivator, EA@TBPO solution is added dropwise during the spin-coating process and annealed at low temperature (70°C). This prevents the flexible substrate from being damaged by high temperature, achieving perfect compatibility with the flexible substrate.

[0029] 3. To improve the performance of 3D-printed polymer microcavities combined with a flexible substrate (polyethylene terephthalate), rings of different sizes were prepared by varying the two-photon printing power. This ring structure exhibited a good interface match with the DJ-phase quasi-two-dimensional perovskite thin film gain medium, allowing the growth of a high-performance laser gain medium within the ring.

[0030] 4. The laser threshold based on flexible substrate is as low as 2.16μJ / cm 2 , the net modal gain can reach 1704cm at 10 times the threshold -1 This is the most excellent material among DJ phase perovskite gain media and all flexible perovskite laser devices, as well as the most powerful flexible laser.

[0031] 5. In the present invention, nanoscrible IP-dip is used as a two-photon 3D printing photoresist, and the 3D printed circular microcavity structure is at the micron level.

[0032] 6. By changing the size of the microcavity of two-photon 3D printing, the laser mode can be selected to achieve multi-mode or single-mode laser output.

[0033] 7. By pumping the circular intracavity laser gain medium with 1Khz400nm femtosecond light, low-threshold and high-gain laser emission is achieved. At twice the threshold, stable lasing for more than 12 hours can be achieved.

[0034] 8. Under different bending degrees, the flexible laser can still maintain efficient light emission, and after 3,000 bending tests, it can still achieve efficient laser output, demonstrating excellent mechanical toughness and stability.

[0035] The present invention discloses a flexible laser based on DJ quasi-2D perovskite materials and its application. The flexible laser is based on an ultra-stable DJ phase perovskite thin film gain medium and uses 3D printing technology to combine a polymer microcavity with a flexible substrate to prepare a high-performance flexible laser. The present invention realizes whispering gallery mode (WGM) laser through two-photon 3D printing of microcavities. This flexible laser exhibits excellent laser performance and strong mechanical toughness, which highlights their great potential in technical applications such as wearable electronics, optical communications and robotic systems. The flexible laser based on DJ quasi-2D perovskite materials of the present invention is particularly suitable for application scenarios such as wearable devices, flexible displays, and biomedical testing that have special requirements for device flexibility and thinness.

[0036] Example 1

[0037] Experimental materials: lead bromide (PbBr2), cesium bromide (CsBr), 1,3-diaminopropane dihydrobromide (PDABr), 1,6-hexanediamine hydrobromide (HDABr), dimethyl sulfoxide (DMSO), ethyl acetate (EA), and tri-n-butylphosphine oxide (TBPO).

[0038] Experimental methods:

[0039] Preparation of precursor solution: 0.4 mmol of PbBr2 (146.8 mg), 0.4 mmol of CsBr (84.8 mg), 0.025 mmol of PDABr (5.9 mg), and 0.025 mmol of HDABr (6.9 mg) were dissolved in 1 ml of DMSO and stirred for 2 hours using a stirring bar until dissolved.

[0040] Preparation of EA@TBPO solvent: 0.02 mmol TBPO (4.36 mg) was dissolved in 1 ml EA solution and stirred with a stirring bar for 1 h until dissolved.

[0041] Substrate Treatment: PET substrates were used to prepare perovskite films. First, the PET substrates were ultrasonically treated in deionized water, acetone, and isopropanol for 5 minutes. Then, in this invention, a nitrogen stream was used to dry the PET substrates. The cleaned substrates were then treated with plasma for 15 minutes.

[0042] Laser preparation: The precursor solution and EA@TBPO solution were filtered through a poly(hexamethylene adipamide) membrane filter, 75 μL of the precursor solution was dropped onto the flexible substrate and spin-coated for 60 seconds. 200 μL of EA@TBPO solution was added after 30 seconds, and then the substrate was transferred to a heating stage and annealed at 80°C for 10 minutes.

[0043] Control group: The precursor solution and EA solution were filtered through a poly(hexamethylene adipamide) membrane filter, 75 μL of the precursor solution was dropped onto the flexible substrate and spin-coated for 60 s. 200 μL of EA solution was added after 30 s, and then the substrate was transferred to a heating stage for annealing at 80 °C for 10 min.

[0044] Experimental results: Figure 1 : Scanning electron microscopy (SEM) and atomic force microscopy (AFM) tests were performed on the control group and the DJ quasi-2D perovskite film after TBPO treatment. It can be seen that after TBPO treatment, the surface of the perovskite film has dense grains and a smooth film surface.

[0045] Figure 2 : Fluorescence (PL) and fluorescence lifetime (TRPL) tests of the film after TBPO treatment. The fluorescence of the film was enhanced and the fluorescence lifetime was extended after TBPO treatment, indicating that the defects of the perovskite film were significantly suppressed.

[0046] Figure 3 In this paper, a flexible laser device is fabricated by constructing a whispering gallery mode (WGM) cavity on a polyethylene terephthalate (PET) substrate using two-photon 3D printing technology. These WGM cavities exhibit excellent mechanical strength. Figure 3 As shown in Figure (a), in the present invention, ring structures of different sizes (6μm, 5μm, 4μm, 3μm) were fabricated on a 100μm×100μm square flexible substrate, and the perovskite film was deposited into the ring by spin coating. Figure 3 As shown in Figure (b), by reducing the microcavity size (5μm~3μm), the number of WGM modes in the gain region can be reduced to a single mode, thereby achieving single-mode lasing.

[0047] Figure 4 :Under ambient conditions, under single-photon excitation (using 400 nm femtosecond laser pulses) and in a stripe pumping configuration, the emission spectrum evolves from spontaneous emission to amplified spontaneous emission (ASE). Figure 4Figure (a) shows the emission spectra of the original perovskite film under different excitation intensities. At low pump density, a broad spontaneous emission spectrum centered at 523 nm is observed, with a maximum FWHM of approximately 26 nm. As the pump density increases, a clear narrow emission peak appears at 539 nm, and the FWHM decreases by 6 nm, indicating the onset of amplified spontaneous emission (ASE). Figure 4 Figure (b) shows the relationship between PL intensity and FWHM and pump density, showing that the ASE threshold is 11.6 μJ / cm 2 In contrast, the TBPO-treated perovskite film exhibits ASE behavior centered at 541 nm, as Figure 4 As shown in (c). After TBPO treatment, the ASE threshold of the quasi-2D perovskite film is reduced to 3.2 μJ / cm 2 ,like Figure 4 As shown in Figure (d), it is reduced by nearly 70%.

[0048] Figure 5 :like Figure 5 As shown in Figure (a), in order to evaluate the mechanical reliability of the flexible laser under stress, the laser threshold and quality factor at different bending degrees (from 8mm to 2mm) are measured. Figure 5 As shown in Figure (b). Figure 5 As shown in Figure (b), under mild bending (length of 10-8mm), the threshold of the flexible laser decreases from 2.16μJ / cm 2 Increased to 2.82 μJ / cm 2 , the quality factor decreases to 2557. However, under severe bending (length 6-2 mm), the threshold rises sharply to 8.88 μJ / cm 2 , the quality factor dropped to 1353. This nonlinear degradation may be due to structural changes caused by excessive mechanical deformation in the microcavity. The flexible laser still retains >80% of its initial intensity after 3,000 bending cycles, such as Figure 5 As shown in Figure (c), it exhibits excellent robustness under mechanical stress.

[0049] In the existing technology, the minimum threshold of quasi-2D DJ laser gain medium is 5.5μJ / cm 2 The quasi-2D DJ laser gain medium produced by the method of the present invention has a minimum ASE threshold of 3.2μJ / cm 2 The minimum threshold of single-mode laser is 2.16μJ / cm 2 Compared with ordinary perovskite gain media, it has extremely low threshold and high stability.

[0050] The above-mentioned specific implementation methods are used to illustrate the present invention and are only preferred embodiments of the present invention, rather than limiting the present invention. Any modifications, equivalent substitutions, improvements, etc. made to the present invention within the spirit of the present invention and the scope of protection of the claims shall fall within the scope of protection of the present invention.

Claims

1. A flexible laser based on DJ quasi-2D perovskite material, characterized in that: include: Flexible substrate; a two-photon 3D-printed polymer microcavity disposed on the flexible substrate; A DJ quasi-2D perovskite gain medium film covering the polymer microcavity is prepared by the following method: Step S1, precursor solution preparation: PbBr2, CsBr, PDABr and HDABr are dissolved in DMSO to obtain a perovskite precursor solution with a concentration of 0.2M-1.0mol / ml; Step S2, preparation of anti-solvent: dissolving tri-n-butylphosphine oxide in ethyl acetate at a concentration of 0.02 mol / ml to obtain EA@TBPO solution; Step S3, substrate treatment: the PET substrate is sequentially cleaned with deionized water, acetone, and isopropyl alcohol by ultrasonic cleaning, dried with nitrogen, and then plasma treated; Step S4, thin film deposition: the precursor solution of step S1 is filtered and spin-coated on a PET substrate, and the EA@TBPO solution is added dropwise during the spin coating; Step S5, low temperature annealing: annealing the spin-coated sample at a low temperature to form a crystallized DJ phase perovskite film.

2. The flexible laser based on DJ quasi-2D perovskite material according to claim 1, characterized in that: The polymer microcavity is 3D printed using Nanoscribe IP-dip photoresist and is circular in shape with a size of micrometers.

3. The flexible laser based on DJ quasi-2D perovskite material according to claim 1, characterized in that: The flexible substrate is polyethylene terephthalate.

4. The flexible laser based on DJ quasi-2D perovskite material according to claim 1, characterized in that: In step S1, PbBr2, CsBr, PDABr and HDABr are dissolved in DMSO at a molar ratio of (8-16): (8-16): (1-2): (1-2).

5. The flexible laser based on DJ quasi-2D perovskite material according to claim 1, characterized in that: In step S1, the molar ratio of PbBr2, CsBr, PDABr and HDABr is 16:16:1:1, wherein the organic ammonium ions of PDABr and HDABr account for 5.88% of the total cations.

6. The flexible laser based on DJ quasi-2D perovskite material according to claim 5, characterized in that: The TBPO in the EA@TBPO solution and the Pb in the perovskite precursor solution 2+ The molar ratio is 1:

20.

7. Application of a flexible laser based on a DJ quasi-2D perovskite material according to any one of claims 1 to 6, characterized in that: The laser is applied to flexible optoelectronic systems and realizes WGM laser output under 400nm femtosecond laser pumping, with a threshold of ≤2.16μJ / cm 2 , net modal gain ≥1704cm at 10 times the threshold -1 .

8. The application of the flexible laser based on DJ quasi-2D perovskite material as claimed in claim 7, characterized in that: The flexible optoelectronic system includes a wearable biosensor, a flexible display backplane or a micro-spectral analysis module, and the laser is integrated into the system as a low-power light source.

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