Laser molecule with cascade excited state double proton transfer activity, single crystal material as well as preparation method and application of laser molecule and single crystal material

Abstract

The invention discloses a laser molecule with cascade excited state double proton transfer activity, a single crystal material and a preparation method and application of the laser molecule and the single crystal material. According to the invention, the laser molecule with a specific structure and cascade excited state double proton transfer activity is designed, so that the J-type aggregate can be spontaneously formed; by utilizing the intermolecular coupling effect of J-type aggregation, the excited state energy of the tautomer B is effectively reduced, and two times of proton transfer are promoted to be completely completed in thermodynamics. The thorough cascade excited state double-proton transfer process can avoid excited state particle shunting loss and promote excitons to release energy through an excited radiation channel, so that the utilization rate of the excitons is remarkably improved, sufficient population inversion intensity and optical gain are guaranteed, and the photoelectric conversion efficiency is improved. Finally, the core problems that an existing near-infrared organic solid laser is low in exciton utilization rate and insufficient in optical gain are solved, and ultralow-threshold near-infrared laser emission is achieved.

Description

Technical Field

[0001] This invention relates to the field of near-infrared solid-state laser technology, specifically to a laser molecule, single-crystal material, and its preparation method and application that have cascaded excited-state dual proton transfer activity. Background Technology

[0002] Near-infrared solid-state lasers, with their unique advantages of low waveguide loss rate and strong tissue penetration, have significant application value in key fields such as optical communication, biomedical technology, and information security systems. Their performance improvement depends on the laser gain medium. Organic semiconductor molecules, due to their abundant excited-state processes, large stimulated emission cross-section, tunable molecular structure, and good processability, have become a major research direction for near-infrared laser gain media. In 2010, Toshikuni Kaino et al. achieved 820 nm near-infrared laser emission with a threshold of 128 μJ·cm⁻¹ based on an LDS821@PVP planar waveguide. -2 In 2018, Adachi et al. developed a donor-acceptor-donor (DAD) type boron difluoride curcumin derivative with thermally activated delayed fluorescence (TADF) properties, achieving tunable near-infrared laser emission in the 740-799 nm range in 4,4'-bis(9-carbazole)biphenyl (CBP) films, with a threshold of approximately 7 μJ·cm⁻¹. -2 In 2021, María A. Díaz-García et al. reported that the longest emission wavelength of a tetrazier benzoxene compound was close to 800 nm, with a threshold of approximately 600 μJ·cm⁻¹. -2 However, near-infrared organic materials generally suffer from high non-radiative transition rates, resulting in low exciton utilization. This means that existing near-infrared organic solid-state lasers have always faced core technical bottlenecks such as insufficient optical gain and excessively high threshold, which severely limits their practical applications.

[0003] To overcome this bottleneck, energy level engineering has become a key strategy for realizing low-threshold near-infrared lasers, with the core objective of minimizing competitive decay pathways and improving exciton utilization in stimulated emission channels. Among these, laser molecules with excited-state intramolecular proton transfer (ESIPT) activity are a preferred choice for near-infrared laser gain media due to their ability to form four-level systems and reduce self-absorption losses. Building upon this, laser molecules with cascaded excited-state double proton transfer (ESDPT) activity can construct a more stable six-level gain system by sequentially triggering two proton transfers through two adjacent intramolecular hydrogen bonds, potentially extending the laser wavelength to the communication wavelength region and further optimizing laser performance. However, although existing laser molecules with cascaded ESDPT activity contain two adjacent intramolecular hydrogen bonds, the excited-state energy of the tautomer B (TB) is too high, making it thermodynamically difficult to completely complete the two proton transfers, or even prevent the second transfer from occurring. This problem directly causes excited-state particle shunting, significantly reduces the exciton utilization rate of the stimulated emission channel, and thus weakens the population inversion intensity and optical gain, severely restricting the application of laser molecules with cascaded ESDPT activity in high-gain near-infrared lasers. Summary of the Invention

[0004] The purpose of this invention is to address the technical problems of existing near-infrared organic solid-state lasers, such as low exciton utilization, high laser threshold, and insufficient optical gain due to the fast nonradiative transition rates of organic materials. It also addresses the limitations of existing laser molecules with cascaded ESDPT activity, which suffer from excessively high TB ​​excited-state energies, preventing complete two-proton transfer and resulting in weak population inversion intensity. This invention provides a laser molecule, single-crystal material, and its preparation method and applications that possess cascaded excited-state two-proton transfer activity. This invention is based on an aggregate strategy, through… J By reducing the excited state energy of the TB form through aggregation coupling, not only can a complete cascaded ESDPT process be obtained, thereby tailoring and optimizing the two-proton transfer six-level system, but also significantly improve exciton utilization, ensure sufficient population inversion intensity and optical gain, and ultimately effectively achieve ultra-low laser threshold.

[0005] This invention is achieved through the following technical solution:

[0006] The first aspect of this invention provides a laser molecule with cascaded excited-state two-proton transfer activity, the structure of which is shown in formula (I):

[0007] .

[0008] A second aspect of this invention provides a method for preparing the laser molecule with cascaded excited-state two-proton transfer activity as described in the first aspect, comprising the following steps:

[0009] The laser molecule with cascade excited-state biproton transfer activity was obtained by reacting 1-(1,8-dihydroxynaphth-2-yl)acetone with 4-(dimethylamino)benzaldehyde under alkaline conditions via a Claisen-Schmidt condensation reaction.

[0010] The structure of 1-(1,8-dihydroxynaphth-2-yl)acetone is shown in formula (II): The structure of 4-(dimethylamino)benzaldehyde is shown in formula (III): .

[0011] Further, 1-(1,8-dihydroxynaphth-2-yl)ethyl ketone and a base were added to an organic solvent and stirred until homogeneous at 25-40 °C. 4-(dimethylamino)benzaldehyde was added to the resulting mixture, and a Claisen-Schmidt condensation reaction was carried out at 60-80 °C to obtain the laser molecule with cascade excited-state biproton transfer activity.

[0012] Further, the molar ratio of 1-(1,8-dihydroxynaphth-2-yl)ethyl ketone to 4-(dimethylamino)benzaldehyde is (0.8-1.2):1.

[0013] Furthermore, the molar ratio of 1-(1,8-dihydroxynaphth-2-yl)ethyl ketone to base is 1:(3-7).

[0014] Furthermore, the base is sodium tert-butoxide; the organic solvent is ethanol.

[0015] Sodium tert-butoxide possesses both strong basicity and weak nucleophilicity: its strong basicity allows it to efficiently abstract the α-hydrogen from 1-(1,8-dihydroxynaphth-2-yl)acetone, ensuring the efficiency of enol anion generation; its weak nucleophilicity prevents the base itself from acting as a nucleophile to attack the carbonyl group in the raw materials or products, thus reducing side reactions.

[0016] Furthermore, the Clayson-Schmidt condensation reaction also includes acidification, extraction, and column chromatography separation steps.

[0017] A third aspect of this invention provides a method for preparing a single-crystal material of laser molecules with cascaded excited-state biproton transfer activity as described in the first aspect, comprising the following steps:

[0018] (1) Dissolve laser molecules with cascaded excited state biproton transfer activity in a good solvent to obtain a laser molecule solution;

[0019] (2) Drop the laser molecule solution into a poor solvent, mix and shake well, and then let it stand;

[0020] (3) The mixed solution after standing is dropped onto the substrate. After the solvent evaporates, the single crystal material of the laser molecule with cascaded excited state biproton transfer activity is obtained.

[0021] This invention utilizes solvent polarity differences to regulate the precipitation rate of laser molecules, achieving controllable single-crystal growth. A good solvent allows for the full dissolution of target molecules, while the addition of a poor solvent reduces solubility, causing molecules to slowly precipitate from the solution. By controlling the solvent evaporation rate, molecules can be ordered according to a specific stacking pattern, ultimately forming a single-crystal structure. Specifically, laser molecules with cascaded excited-state proton transfer activity spontaneously form during single-crystal growth. J Type aggregate, J These aggregates exhibit a unique molecular stacking pattern, with molecular dipole moments arranged head-to-tail. This stacking mode generates unique intermolecular coupling. This coupling effectively modulates the electronic energy level structure of the molecules, particularly significantly reducing the excited-state energy of the TB (proton divertor). When the excited-state energy of TB decreases, it is thermodynamically more conducive to the occurrence of the second proton transfer, thereby driving the cascaded ESDPT process to complete completely and avoiding the shunting loss of excited-state particles. This lays the molecular structural foundation for subsequently improving exciton utilization and enhancing population inversion intensity.

[0022] Furthermore, in step (1), the good solvent is tetrahydrofuran (THF).

[0023] Further, in step (1), the concentration of laser molecules with cascade excited state biproton transfer activity in the molecular solution is 3-7 mmol / L.

[0024] Furthermore, in step (2), the volume ratio of the molecular solution to the poor solvent is 1:(3-5).

[0025] Furthermore, in step (2), the undesirable solvent is n-hexane.

[0026] The fourth aspect of this invention provides a single-crystal material of laser molecules with cascaded excited-state biproton transfer activity prepared by the preparation method described in the third aspect.

[0027] The single-crystal material of laser molecules with cascaded excited-state two-proton transfer activity provided by this invention exhibits molecular characteristics... J This type of aggregation endows materials with unique optical properties and thorough cascaded ESDPT performance, which is the core material basis for realizing ultra-low threshold near-infrared laser emission and can provide key support for the research and development of high-performance near-infrared organic solid-state lasers (such as electrically pumped near-infrared organic solid-state lasers).

[0028] The fifth aspect of this invention provides the application of a single-crystal material of a laser molecule with cascaded excited-state dual proton transfer activity as described in the first aspect or the laser molecule with cascaded excited-state dual proton transfer activity as described in the fourth aspect in a near-infrared organic solid-state laser.

[0029] The sixth aspect of the present invention provides a near-infrared organic solid-state laser comprising a single-crystal material of laser molecules having cascaded excited-state biproton transfer activity as described in the fourth aspect.

[0030] This invention provides a method based on J The core of this ultra-low threshold near-infrared organic single-crystal laser, driven by aggregation and exhibiting complete cascaded two-proton transfer activity, lies in its use of a single-crystal material containing laser molecules with cascaded excited-state two-proton transfer activity as both the gain medium and optical resonator of the near-infrared organic solid-state laser. As the gain medium, its... J The fully cascaded ESDPT process driven by the aggregation type can provide high exciton utilization and sufficient optical gain; as an optical resonator, its regular single crystal morphology can realize low-loss total internal reflection transmission of light, which meets the conditions for laser oscillation.

[0031] Compared with the prior art, the above-described technical solution of the present invention has the following advantages:

[0032] 1. This invention designs laser molecules with specific structures possessing cascaded excited-state two-proton transfer activity, enabling them to form J Type aggregates, utilizing J The intermolecular coupling of the aggregated type effectively reduces the TB excited state energy, thermodynamically promoting the complete completion of the two proton transfers. This solves the technical problem of incomplete two-proton transfer and weak population inversion intensity caused by excessively high TB ​​excited state energy in existing laser molecules with cascaded ESDPT activity.

[0033] 2. The molecular preparation of the present invention adopts the Claisen-Schmidt condensation reaction, and the single crystal preparation adopts a simple solvent evaporation method. The entire preparation process does not require complex equipment and harsh reaction conditions. It is simple to operate, low in cost, and has a clear range of process parameters with good repeatability, which is conducive to industrial production.

[0034] 3. The single-crystal material of laser molecules with cascaded excited-state two-proton transfer activity provided by this invention has... J The clustering characteristics can be used to achieve a complete cascaded ESDPT process by reducing the excited state energy of the TB form. This process can effectively avoid excited state particle shunting loss, prompting more excitons to release energy through stimulated emission channels, thereby significantly improving exciton utilization, ensuring sufficient population inversion intensity and optical gain, and finally solving the core problems of low exciton utilization and insufficient optical gain of existing near-infrared organic solid-state lasers, realizing ultra-low threshold near-infrared laser emission. Attached Figure Description

[0035] Figure 1The images shown are optical microscope images, SEM images, and XRD patterns of the DDMC single-crystal microrods prepared in Example 2; the upper left and upper right images are optical microscope images, the lower left image is an SEM image, and the lower right image is an XRD pattern.

[0036] Figure 2 The images show TEM images and corresponding SAED spectra of the single DDMC single-crystal microrods prepared in Example 2.

[0037] Figure 3 This is a molecular packing diagram of the single DDMC single-crystal microrod prepared in Example 2.

[0038] Figure 4 The absorption spectra of DDMC in single-molecule and aggregated states are obtained from simulation calculations and experiments; the left figure shows the absorption spectrum obtained from simulation calculations, and the right figure shows the absorption spectrum obtained from experiments.

[0039] Figure 5 This is a schematic diagram of the energy levels for laser molecular biproton transfer with cascaded ESDPT activity.

[0040] Figure 6 The results show the calculated relative excited-state energies for the second proton transfer process in DDMC single molecules and aggregates.

[0041] Figure 7 The diffuse reflectance absorption, fluorescence spectrum, and femtosecond fluorescence decay curve of the DDMC single-crystal microrod prepared in Example 2 are shown in the figure. The left figure shows the diffuse reflectance absorption and fluorescence spectrum, and the right figure shows the femtosecond fluorescence decay curve.

[0042] Figure 8 The DDMC single-crystal microrod prepared in Example 2 J A schematic diagram of a high-gain cascaded ESDPT six-level system driven by aggregation.

[0043] Figure 9 The images show optical imaging of the micro-region excitation sites and characterization of the optical waveguide performance of the DDMC single-crystal microrods prepared in Example 2; the left image is the optical imaging of the micro-region excitation sites, and the right image is the micro-region emission spectrum and optical waveguide loss fitting curve of different excitation sites.

[0044] Figure 10 The images show the PL spectrum and threshold performance characterization of the DDMC single-crystal microrods prepared in Example 2; the left image shows the PL spectrum under different laser pump intensities, and the right image shows the variation of laser intensity-half-maximum width with pump intensity and the threshold fitting graph.

[0045] Figure 11 This is a graph showing the laser threshold-emission wavelength data for reported near-infrared organic single-crystal lasers. Detailed Implementation

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0047] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0048] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the materials and reagents used are commercially available.

[0049] Example 1

[0050] A laser molecule DDMC with cascaded excited-state two-proton transfer activity ( The preparation method of ) includes the following steps:

[0051]

[0052] First, 1-(1,8-dihydroxynaphthyl-2-yl)acetone (505 mg, 2.5 mmol) and sodium tert-butoxide (t-BuONa, 1201 mg, 12.5 mmol) were added to ethanol (C2H5OH, 30 mL) and stirred for 1 h at room temperature (rt) in a 250 mL round-bottom flask. Then, 4-(dimethylamino)benzaldehyde (373 mg, 2.5 mmol) was added to the resulting mixture, and the reaction was stirred at 70 °C for 48 h. After the reaction was complete, the ethanol in the system was evaporated to dryness, and the residue was dissolved in water; the solution was then acidified to neutral, extracted with ethyl acetate, and the organic phase was collected. The ethyl acetate in the organic phase was evaporated to dryness, and the residue was purified by column chromatography (eluent: petroleum ether / dichloromethane = 3 / 1) to give a laser-induced molecular product (0.11 g, yield 13%) with cascade excited-state biproton transfer activity, named DDMC.

[0053] The characterization data for DDMC are as follows: 1 H NMR (400 MHz, CDCl3) δ 18.02 (s, 1H), 10.67 (s,1H), 7.96 (d, J = 15.1 Hz, 1H), 7.62 (d, J= 9.1 Hz, 1H), 7.56 (d, J = 8.9Hz, 2H), 7.44 (t, J = 7.9 Hz, 1H), 7.37 (d, J = 15.1 Hz, 1H), 7.14 (d, J =7.5 Hz, 1H), 7.09 (d, J = 9.1 Hz, 1H), 6.84 (dd, J = 7.9, 0.8 Hz, 1H), 6.66(d, J = 8.9 Hz, 2H), 3.03 (s, 6H).

[0054] Example 2

[0055] A method for preparing DDMC single-crystal microrods includes the following steps:

[0056] (1) Dissolve the DDMC powder prepared in Example 1 in THF to obtain a DDMC molecular solution with a concentration of 5 mmol / L;

[0057] (2) Add 200 μL of DDMC molecular solution to 800 μL of n-hexane, shake vigorously until well mixed, and then let stand.

[0058] (3) After standing for 30 min, the mixed solution was dropped onto the glass substrate. As the solvent evaporated, DDMC single crystal microrods of different lengths were obtained.

[0059] Figure 1 The optical microscope image, scanning electron microscope (SEM) image, and X-ray diffraction (XRD) pattern of the DDMC single crystal microrods prepared in Example 2 are shown. The characterization results show that the DDMC single crystal microrods have a regular morphology, a smooth surface, and excellent crystallinity.

[0060] Figure 2 The images show transmission electron microscopy (TEM) images and corresponding selected area electron diffraction (SAED) patterns of a single DDMC single-crystal microrod prepared in Example 2; the diffraction points marked in the patterns correspond to the crystal plane (002), and their interplanar spacing is shown in the figures. d The value is 7.3 Å, which indicates that the DDMC single-crystal microrods are oriented along the

[001] direction.

[0061] Figure 3The molecular packing pattern of DDMC single-crystal microrods shown indicates that DDMC molecules are arranged in an ordered manner in two parallel dimer forms: 1-2 dimers with a slip angle of 20° and 2-3 dimers with a slip angle of 48°. This packing pattern is a perfect match. J Structural characteristics of aggregates.

[0062] Figure 4 To simulate and experimentally determine the absorption spectra of DDMC in both single-molecule and aggregate states, the simulation results show that the dipole-dipole interactions between the 1-2 dimer and the 2-3 dimer reach 4260 cm⁻¹. -1 and 1853 cm -1 This demonstrates a significant J The coupling characteristics are evident. Furthermore, compared to the single-molecule state (corresponding to the DDMC molecules prepared in Example 1), the simulated and experimental absorption spectra of the DDMC aggregate state (corresponding to the DDMC single-crystal microrods prepared in Example 2) both exhibit a significant redshift. This spectral characteristic further indicates that… J The existence of aggregates.

[0063] A schematic diagram of the energy levels of laser-induced molecular two-proton transfer with cascaded ESDPT activity is shown below. Figure 5 As shown, the calculated results of the relative excited state energies of the second proton transfer process in DDMC single molecules and aggregates are as follows: Figure 6 As shown, in DDMC single molecules, the second proton transfer process is thermodynamically difficult to occur spontaneously due to the excessively high TB* energy; however, in DDMC aggregates (corresponding to the DDMC single-crystal microrods prepared in Example 2), the TB* energy is significantly reduced, allowing the second proton transfer process to occur smoothly. This theoretical calculation result directly confirms... J Type aggregation can effectively drive a thorough cascaded ESDPT process.

[0064] The diffuse reflectance absorption, fluorescence spectrum, and femtosecond fluorescence decay curve of the DDMC single-crystal microrods prepared in Example 2 are shown below. Figure 7 As shown, no emission signals corresponding to N* and TA* were detected in DDMC single-crystal microrods. This spectral characteristic directly confirms that DDMC single-crystal microrods... J This type of aggregation can trigger a complete cascaded ESDPT process. This complete cascaded ESDPT process ensures that all particles undergoing radiative transitions participate in the stimulated emission channels of TB* and TB, significantly improving exciton utilization while guaranteeing sufficient population inversion intensity (Δ). N Based on this, and combining molecular stacking and energy level modulation characteristics, a high-gain cascaded ESDPT six-level system was finally constructed, such as... Figure 8 As shown.

[0065] The optical imaging image of the micro-region excitation site and the characterization image of the optical waveguide performance of the DDMC single-crystal microrod prepared in Example 2 are shown below. Figure 9 As shown, the left figure presents the optical imaging results of micro-region excitation at different sites (1-6) of the DDMC single-crystal microrod; the right figure shows the emission spectrum at the same endpoint after micro-region excitation at different sites of the DDMC single-crystal microrod. By fitting the change in the ratio of spectral intensity between the excitation point and the endpoint with the transmission distance, the optical waveguide loss rate of the DDMC single-crystal microrod can be calculated to be only 0.032 dB / μm. This result confirms that the DDMC single-crystal microrod possesses excellent optical waveguide transmission performance and can be used to construct a low-loss, high-quality optical resonator.

[0066] Figure 10 The photoluminescence (PL) spectra of a single DDMC single-crystal microrod with a length of 35 μm prepared in Example 2 are presented under 532 nm pulsed laser excitation, corresponding to different pump intensities: when the pump intensity increases from 410 nJ·cm... -2 Increased to 1310 nJ·cm -2 At approximately 870 nm, a significant laser emission signal appears, with its intensity increasing nonlinearly with increasing pump intensity, while the full width at half maximum (FWHM) narrows sharply. Combining the spectral intensity and FWHM curves with pump intensity, the laser threshold of this system is determined to be as low as 486 nJ·cm⁻¹. -2 .

[0067] The DDMC single-crystal microrods prepared in Example 2 were used in a near-infrared organic single-crystal laser. Figure 11 This paper summarizes the threshold and corresponding emission wavelength data of currently reported near-infrared organic single-crystal lasers. The organic materials used are DP-DHAQ (dinaphthalenedicarbamate derivative), DMHP (dimethylphenthiazine derivative), DEPHP (diethylphenoxazine derivative), TPE-SP (tetraphenylphenyl-spiropyran derivative), DMHC (dimethylnaphthalenedicarbamate derivative), DDMP (dimethylpyrazine derivative), DPHP (dipyrrolopyrazine derivative), and DDMC. The results show that the near-infrared organic single-crystal laser based on DDMC single-crystal microrods of this invention has reached the lowest reported laser threshold among similar near-infrared organic single-crystal lasers.

[0068] In summary, this invention provides a near-infrared laser-active material with ultra-low threshold characteristics, specifically having... J A cascaded ESDPT single-crystal material exhibiting aggregated characteristics. This material... J The aggregation effect can induce a complete cascaded ESDPT process by lowering the excited state energy; this process not only significantly improves exciton utilization but also ensures sufficient population inversion intensity (Δ).N By combining optical gain with optical gain, a near-infrared organic single-crystal laser with an ultra-low threshold was successfully constructed.

[0069] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art should understand that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A laser molecule with cascaded excited-state two-proton transfer activity, characterized in that, The structure is shown in equation (I): 。 2. A method for preparing a laser molecule with cascaded excited-state two-proton transfer activity as described in claim 1, characterized in that, The process includes the following steps: reacting 1-(1,8-dihydroxynaphth-2-yl)acetone with 4-(dimethylamino)benzaldehyde under alkaline conditions via a Claisen-Schmidt condensation reaction to obtain the laser molecule with cascade excited-state biproton transfer activity.

3. The preparation method according to claim 2, characterized in that, 1-(1,8-dihydroxynaphth-2-yl)ethyl ketone and a base were added to an organic solvent and stirred until homogeneous at 25-40 °C. 4-(dimethylamino)benzaldehyde was added to the resulting mixture, and a Claisen-Schmidt condensation reaction was carried out at 60-80 °C to obtain the laser molecule with cascade excited-state biproton transfer activity.

4. The preparation method according to claim 3, characterized in that, The molar ratio of 1-(1,8-dihydroxynaphth-2-yl)ethyl ketone to 4-(dimethylamino)benzaldehyde is (0.8-1.2):1; the molar ratio of 1-(1,8-dihydroxynaphth-2-yl)ethyl ketone to the base is 1:(3-7); the base is sodium tert-butoxide; and the organic solvent is ethanol.

5. A method for preparing a single-crystal material of laser molecules with cascaded excited-state two-proton transfer activity, characterized in that, Includes the following steps: (1) Dissolve the laser molecule with cascaded excited state biproton transfer activity as described in claim 1 in a good solvent to obtain a laser molecule solution; (2) Drop the laser molecule solution into a poor solvent, mix and shake well, and then let it stand; (3) The mixed solution after standing is dropped onto the substrate. After the solvent evaporates, the single crystal material of the laser molecule with cascaded excited state biproton transfer activity is obtained.

6. The preparation method according to claim 5, characterized in that, In step (1), the good solvent is tetrahydrofuran; the concentration of laser molecules with cascade excited state biproton transfer activity in the molecular solution is 3-7 mmol / L.

7. The preparation method according to claim 5, characterized in that, In step (2), the volume ratio of the laser molecular solution to the undesirable solvent is 1:(3-5); the undesirable solvent is n-hexane.

8. A single-crystal material of laser molecules with cascaded excited-state biproton transfer activity, prepared by the preparation method according to any one of claims 5-7.

9. The application of a single-crystal material of a laser molecule with cascaded excited-state two-proton transfer activity as described in claim 1 or the laser molecule with cascaded excited-state two-proton transfer activity as described in claim 8 in a near-infrared organic solid-state laser.

10. A near-infrared organic solid-state laser, characterized in that, A single-crystal material comprising the laser molecules with cascaded excited-state biproton transfer activity as described in claim 8.

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