Preparation of a Single-Component Organic Solid Luminescent Material and Method for Controlling Its Luminescent Color

Abstract

The present invention relates to the field of material preparation and characterization, and discloses a method for preparing a single-component organic solid luminescent material and regulating its luminescent color. The regulating method includes: first preparing an amorphous nanoparticle suspension of the single-component organic solid luminescent material; then regulating the ratio of the amorphous phase to the crystalline phase in the nanoparticles by regulating the amorphous-crystalline phase transition process and degree in the nanoparticle suspension, so as to control the luminescent color of the organic solid luminescent material. The nanoparticles can be extracted from the suspension by freeze-drying, suction filtration or centrifugal separation means to obtain the single-component organic solid luminescent material. The present invention can prepare single-component organic solid luminescent materials with specific luminescent properties according to actual needs, and the prepared luminescent materials have good light transmittance, uniform and stable properties, can realize in-situ tracking and detection of the phase transition of the nanoparticles in the suspension, and have various, simple and convenient regulating means, and can be prepared at low cost and on a large scale.

Description

Technical Field

[0001] The present invention relates to the fields of material preparation and characterization, and particularly relates to a method for regulating the emission color of a single-component organic solid luminescent material. Background Art

[0002] In typical application fields of organic solid luminescent materials such as information display and sensing, it is usually required that organic solid luminescent materials exhibit different emission colors to meet the actual application requirements. For example, the display of color pictures requires at least three organic solid luminescent materials of red, green, and blue to restore colors. The traditional methods for regulating the emission color of organic solid luminescent materials need to design and synthesize the materials at the molecular level to obtain organic solid luminescent materials with new emission colors (Dyes Pigm., 2021, 192, 109439; Sci. Adv., 2021, 7, 1794); or mix two or more organic solid luminescent materials in a specific ratio to obtain a composite material with a new emission color (Science, 1995, 267, 1332; Adv. Mater., 2013, 25, 1713). It can be seen that the traditional methods for regulating the color of organic solid luminescent materials need to introduce a new material of another component to replace the original material, thus increasing the application cost. Moreover, the emission colors of the amorphous and crystalline phases of many organic solid luminescent materials often have significant differences. For example, amorphous-phase ETTDA emits yellow fluorescence, while crystalline-phase ETTDA emits green fluorescence. Therefore, regulating the ratio of the amorphous and crystalline phases can achieve the regulation of the emission color of a single-component organic solid luminescent material.

[0003] At present, the means for regulating the amorphous-crystalline phase transition process of organic materials mainly include the solvent evaporation method, the melting-cooling method, and the solvent fumigation method. The solvent evaporation method is to first dissolve an organic solid functional material in a volatile solvent. The rapid evaporation of the solvent induces the solute to first precipitate in an amorphous state, and then the solute molecules rearrange to transform into a crystalline phase solid (Sci. Rep., 2016, 6, 22918.). The melting-cooling method is to heat a solid functional material to its melting point, and then induce the molten functional material to precipitate in an amorphous or crystalline state by cooling (Chem. Asian J., 2019, 14, 755.). The solvent fumigation method is to first spread the prepared amorphous micro- and nano-sized solid particles on a glass substrate, and then place the glass substrate carrying the amorphous micro- and nano-sized particles in a device containing a volatile solvent. The solvent fumigation method is used to promote the amorphous-crystalline phase transition of the micro- and nano-sized particles (Angew. Chem. Int. Ed., 2015, 54, 7976). The above-mentioned means for regulating the amorphous-crystalline phase transition are single, difficult to control, and costly. Therefore, they are not suitable for controllably preparing solid functional materials with a specific amorphous-crystalline phase composition, especially nano-materials. Summary of the Invention

[0004] An object of the present invention is to provide a new method with diverse and simple means of regulation, which can be applied to regulate the emission color of single-component organic solid luminescent materials and the preparation of nano-materials, based on the disadvantages of few means, high cost, difficult control, and difficulty in applying to the preparation of nano-materials for regulating the emission color of single-component organic solid luminescent materials in the prior art.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A method for regulating the emission color of a single-component organic solid luminescent material, comprising the following steps:

[0007] (1) Prepare an amorphous nano-particle suspension of the single-component organic solid luminescent material;

[0008] (2) Regulate the ratio of the amorphous phase to the crystalline phase in the nano-particles by regulating the amorphous-crystalline phase transition process and degree in the nano-particle suspension, and control the emission color of the organic solid luminescent material. After regulating the amorphous-crystalline phase transition of the nano-particles, the nano-particles can be separated and collected from the suspension, and the preparation of organic solid luminescent nano-materials with a specific emission color can be achieved.

[0009] Preferably, the preparation of the amorphous nano-particle suspension is carried out by an ultrasonic-assisted microfluidic reactor.

[0010] Preferably, the method for regulating the rate of the amorphous-crystalline phase transition in the nanoparticle suspension includes: changing the suspension temperature, or changing the nanoparticle concentration, or changing the nanoparticle particle size, or stirring the suspension at different rates, or adding electrolytes or surfactants with different concentrations to the suspension. The electrolytes are preferably sodium chloride, potassium chloride, potassium bromide, sodium sulfate, etc., and the surfactants are preferably sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, cetyltrimethylammonium bromide, polyethylene glycol, etc.

[0011] Preferably, the single-component organic solid luminescent material includes tetrakis(4-diethylaminophenyl)ethylene (ETTDA), tetraphenylethylene (TPE), 1-(4-bromophenyl)-1,2,2-triphenylethylene, 1,1-bis(4-methoxyphenyl)-2-(4-bromophenyl)-2-phenylethylene, 1,1-bis(4-diethylaminophenyl)-2-(4-bromophenyl)-2-phenylethylene, triphenylamine (TPA), salicylaldehyde azine (SAA), and hexaphenylsilole (HPS).

[0012] Preferably, the method for preparing the amorphous nanoparticle suspension of the single-component organic solid luminescent material is as follows: adding a good solvent to the single-component organic solid luminescent material, and ultrasonically dissolving it at room temperature; then transferring it to a syringe and loading it on syringe pump 1, and taking another syringe filled with a poor solvent and loading it on syringe pump 2; controlling the ratio of the poor solvent to the good solvent to be 5-40:1, controlling the total flow rate to be 5-20 mL / min, and the power of the auxiliary ultrasonic wave to be 5-40 W.

[0013] The suspension prepared by the present invention has good light transmittance, stable macroscopic properties, and can be compatible with various common spectral characterization methods. Therefore, the in-situ tracking and detection of the phase transition of the nanoparticles in the suspension can be realized. The photophysical or photochemical property evolution process occurring during the phase transition of the nanoparticles is revealed. This has important scientific research significance for understanding the property differences and underlying mechanisms of the same substance in the amorphous and crystalline phases. For production practice, this method can easily monitor the phase transition of the prepared nanoparticles, and continuous qualitative or quantitative analysis of the relative abundances of the amorphous and crystalline phases of the nanoparticles can be achieved.

[0014] Preferably, the good solvent includes one or more of acetone, acetonitrile, ethanol, methanol, isopropanol, and tetrahydrofuran, and the poor solvent includes one or more of water, n-hexane, cyclohexane, and petroleum ether.

[0015] Preferably, the single-component organic solid luminescent material is tetra-(4-diethylaminophenyl)ethylene. When the temperature of the suspension is 4 - 20°C, the concentration of nanoparticles is 50.2 - 66.7 mg / L, the particle size of nanoparticles is 100 - 170 nm, without additional stirring, without additional electrolyte, and without additional surfactant, tetra-(4-diethylaminophenyl)ethylene emits yellow fluorescence at 0 - 15 min; emits yellow-green fluorescence at 15 - 60 min; and emits green fluorescence after 60 min. When the additional stirring rate is 600 - 1200 rpm, tetra-(4-diethylaminophenyl)ethylene can be adjusted from yellow luminescence to green luminescence within 30 - 120 min. When the concentration of the electrolyte added to the suspension is 5 - 20 mM, tetra-(4-diethylaminophenyl)ethylene can be adjusted from yellow luminescence to green luminescence within 10 - 120 min. When the concentration of the surfactant added to the suspension is 3 - 5 mM, tetra-(4-diethylaminophenyl)ethylene can be adjusted from yellow luminescence to green luminescence within 30 - 120 min.

[0016] The application of the above-mentioned regulation method can be used to regulate the luminescence color of single-component organic solid luminescent materials, prepare single-component organic solid luminescent materials with specific amorphous-crystalline phase compositions or specific color fluorescence, and in-situ track and detect the phase transition of nanoparticles in the suspension.

[0017] A preparation method of a single-component organic solid luminescent material includes the following steps:

[0018] (S1) Prepare an amorphous nanoparticle suspension of the single-component organic solid luminescent material;

[0019] (S2) Regulate the ratio of the amorphous phase to the crystalline phase in the nanoparticles by regulating the amorphous-crystalline phase transition process and degree in the nanoparticle suspension;

[0020] (S3) Extract the nanoparticles from the suspension by freeze-drying, suction filtration, or centrifugal separation means to obtain the single-component organic solid luminescent material

[0021] The organic solid luminescent material obtained by the above-mentioned preparation method.

[0022] The present invention uses an ultrasonic-assisted microfluidic reaction method to prepare an amorphous nanoparticle suspension. During this process, the nanoparticles precipitate rapidly at ultra-high supersaturation. When the solute precipitates rapidly in an environment of ultra-high supersaturation, it will precipitate in its metastable state, that is, in the amorphous state. Subsequently, as the supersaturation decreases, the crystallization rate also decreases, and at this time, an amorphous-crystalline phase transformation occurs. That is, the amorphous nanoparticles in the suspension will undergo an amorphous-crystalline phase transformation and gradually turn into crystalline-phase nanoparticles. Therefore, the amorphous-crystalline phase transformation process of the nanoparticles in the suspension can be regulated by changing the suspension temperature, nanoparticle concentration, nanoparticle size, stirring rate, electrolyte concentration in the suspension, and surfactant concentration in the suspension.

[0023] Specifically, the present invention has found that for the amorphous-crystalline phase transformation process of nanoparticles, an increase in the suspension temperature has a promoting effect, while a decrease in the suspension temperature has an inhibitory effect; a high nanoparticle concentration has a promoting effect, while a low nanoparticle concentration has an inhibitory effect; a large nanoparticle particle size has a promoting effect, while a small nanoparticle particle size has an inhibitory effect. Applying stirring to the suspension can promote the amorphous-crystalline phase transformation of the nanoparticles in the suspension, and the higher the stirring rate, the more obvious the promoting effect. The presence of electrolytes such as NaCl in the suspension can promote the amorphous-crystalline phase transformation of the nanoparticles in the suspension, and the higher the concentration, the more obvious the promoting effect. When there are surfactants such as sodium dodecyl sulfate (SDS) in the suspension, it has a promoting effect at low concentrations, and can inhibit the amorphous-crystalline phase transformation of the nanoparticles in the suspension at high concentrations.

[0024] After regulating the amorphous-crystalline phase transformation of the nanoparticles in the suspension through the above conditions, the nanoparticles that have undergone phase transformation to a certain specific degree can be separated from the suspension and collected, and thus a nanomaterial with a specific amorphous-crystalline phase composition and emitting specific-color fluorescence can be obtained. At present, the ultrasonic microfluidic reaction method has been able to achieve ton-level continuous preparation of nanoparticle suspensions, and the means adopted in the present invention to regulate the amorphous-crystalline phase transformation are diverse, simple, and easy to operate.

[0025] Preferably, the methods for separating and collecting the organic aggregation-induced emission material nanoparticles from the suspension include freeze-drying, suction filtration, and centrifugal separation.

[0026] Compared with the prior art, implementing the present invention has the following beneficial effects:

[0027] (1) The present invention provides a method for regulating the luminescence color of a single-component organic solid luminescent material, which can prepare a single-component organic solid luminescent material with specific luminescence properties according to actual needs. Moreover, the prepared luminescent material has good light transmittance, uniform and stable properties, and can realize in-situ tracking and detection of the phase transformation of the nanoparticles in the suspension.

[0028] (2) The present invention first prepares an amorphous nanoparticle suspension of an organic solid light-emitting material, regulates the process and degree of the amorphous-crystalline phase transition of the nanoparticles by controlling the conditions of the suspension, and then extracts the nanoparticles from the suspension by means such as freeze-drying, suction filtration and centrifugal separation, so as to realize the preparation of a nano-organic solid light-emitting material with a specific amorphous-crystalline phase composition. The preparation method is simple, and low cost and large-scale preparation can be achieved.

[0029] (3) The method provided by the present invention regulates the amorphous-crystalline phase transition of the nanoparticles by controlling the conditions of the nanoparticle suspension of the organic solid light-emitting material: changing the suspension temperature, nanoparticle concentration, nanoparticle particle size, stirring rate, electrolyte concentration in the suspension and surfactant concentration in the suspension. The regulation means are diverse, simple and convenient. Description of the Drawings

[0030] Figure 1 It is a schematic diagram and a physical diagram of the device for preparing an amorphous nanoparticle suspension by an ultrasonic-assisted microfluidic reactor;

[0031] Figure 2 It is the molecular structure of ETTDA (a) and the particle size distribution and photo of the prepared amorphous ETTDA nanoparticle suspension (b);

[0032] Figure 3 It is the X-ray diffraction pattern of the amorphous phase ETTDA powder (a), and the fluorescence emission spectra of the amorphous phase ETTDA powder and the amorphous phase ETTDA nanoparticle suspension (b);

[0033] Figure 4 It is the fluorescence change photo of the ETTDA nanoparticle suspension at different times during the regulation of the amorphous-crystalline phase transition of the nanoparticles (a) and the fluorescence spectra of the ETTDA nanoparticle suspension before and after regulation (b); the X-ray diffraction pattern of the crystalline phase ETTDA powder (c), and the fluorescence emission spectra of the crystalline phase ETTDA powder and the ETTDA nanoparticle suspension after regulation (d);

[0034] Figure 5 It is the means for regulating the amorphous-crystalline phase transition of the nanoparticles: suspension temperature (a), nanoparticle concentration (b), nanoparticle particle size (c), applied stirring speed (d);

[0035] Figure 6 It is the means for regulating the amorphous-crystalline phase transition of the nanoparticles: NaCl concentration in the suspension (a), SDS concentration in the suspension (b);

[0036] Figure 7To in-situ observe the phase transition process of ETTDA nanoparticles using conventional detection methods: ultraviolet-visible absorption (a), fluorescence spectrum (b), fluorescence quantum yield (c), femtosecond transient absorption (d);

[0037] Figure 8 Photographs of the filter cakes obtained by filtering ETTDA nanoparticles at different amorphous-crystalline phase transition stages. The filter cake emitted bright yellow light at 0 min, yellow light at 30 min, yellow-green light at 60 min, and green light at 90 min after regulation;

[0038] Figure 9 Regulation effects on the amorphous-crystalline phase transition of nanoparticles of hexaphenylsilole (a), tetraphenylethylene (b), and 1,1-bis(4-methoxyphenyl)-2-(4-bromophenyl)-2-phenylethylene (c);

[0039] Figure 10 Evolution of the relative abundance of the amorphous-crystalline phase of ETTDA nanoparticles over time;

[0040] Figure 11 Organic solid luminescent materials that can use the regulation method of the present invention. Detailed implementation manners

[0041] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0042] Example 1

[0043] As Figure 1 shown, in this example, an ultrasonic-assisted microfluidic reactor was used to prepare amorphous nanoparticles of tetra-(4-diethylaminophenyl)ethylene (ETTDA) that emit yellow fluorescence. The main process is as follows:

[0044] (1) Weigh 5 mg of ETTDA solid and place it in a beaker. Add 5 mL of a good solvent (acetone), and ultrasonically treat it at room temperature for about 5 minutes to fully dissolve ETTDA;

[0045] (2) Transfer the solution containing 5 mL of ETTDA to a syringe and load it on a precision syringe pump (syringe pump 1). Take another syringe containing a poor solvent (water) and load it on another precision syringe pump (syringe pump 2);

[0046] (3) Control the flow rates of the two precision syringe pumps, control the ratio of the poor solvent to the good solvent to be 14:1, control the total flow rate to be 15 mL / min, and the power of the auxiliary ultrasound to be 10 W to prepare a suspension of amorphous ETTDA nanoparticles.

[0047] In the ETTDA nanoparticle suspension prepared in Example 1, the proportion of the amorphous phase was 96.9%, and the proportion of the crystalline phase was only 3.1%. As Figure 10 shown, over time, the relative abundance of the amorphous phase of the ETTDA nanoparticles gradually decreased, while the relative abundance of the crystalline phase gradually increased. After 24 h of preparation of the nanoparticle suspension, the relative abundance of the amorphous phase decreased to 31.9%, while the relative abundance of the crystalline phase increased to 68.1%.

[0048] Example 2

[0049] The ETTDA nanoparticles prepared in Example 1 were observed. As Figure 2 shown, the prepared nanoparticles had uniform particle sizes, were well-dispersed, had no visible aggregation, and the particle size was about 100 nm. ETTDA is a solid luminescent material. Its amorphous phase ETTDA emits bright yellow fluorescence, while the crystalline phase ETTDA emits green fluorescence. The fluorescence spectrum of the nanoparticle suspension prepared in Example 1 was consistent with the fluorescence spectrum of the amorphous ETTDA powder ( Figure 3 a in Figure 3 and b in

[0050] ), emitting bright yellow fluorescence.

[0051] For the amorphous ETTDA nanoparticles with a particle size of about 100 nm obtained in Example 1, the amorphous-crystalline phase transition process was regulated under the following conditions: the suspension temperature was controlled at 20 °C, the concentration was 66.7 mg / L, no stirring was carried out, and no additional electrolyte and surfactant were added. As Figure 4 a in Figure 4 and Figure 4 c in Figure 4 shown, within 0 min to 90 min, the fluorescence emission of the suspension changed from bright yellow light (near the fluorescence emission peak of 546.5 nm) to green light (near the fluorescence emission peak of 511 nm). Specifically, from 0 to 15 min, ETTDA emitted yellow fluorescence; from 15 to 60 min, ETTDA emitted yellow-green fluorescence; after 60 min, ETTDA emitted green fluorescence. And the fluorescence emission of the regulated ETTDA nanoparticle suspension was consistent with the fluorescence spectrum of the crystalline phase ETTDA powder ( c in

[0052]

[0053] For the amorphous ETTDA nanoparticles obtained in Example 1, the amorphous-crystalline phase transition process was regulated under the conditions described in Example 2, but the suspension temperature was controlled at 4 °C, 20 °C, 45 °C, and 75 °C. Under these conditions, the phase transition process of the ETTDA nanoparticles in the suspension was as Figure 5As shown in a. When the temperature of the suspension is lower than room temperature (20 °C), the blue-shift rate of the fluorescence emission peak of the ETTDA nanoparticle suspension slows down, that is, the phase transition process of the ETTDA nanoparticles in the suspension is inhibited. When the temperature of the suspension is higher than room temperature (20 °C), the blue-shift rate of the fluorescence emission peak of the ETTDA nanoparticle suspension increases, that is, heating can promote the amorphous-phase transition process of the ETTDA nanoparticles in the suspension. Specifically, at 15 min, the ETTDA nanoparticles in the suspensions at 4 °C and 20 °C emit yellow fluorescence, the ETTDA nanoparticles in the 45 °C suspension emit yellow-green fluorescence, while the 75 °C suspension emits green fluorescence.

[0054] Example 5

[0055] The amorphous ETTDA nanoparticles obtained in Example 1 were used to regulate their amorphous-crystalline phase transition process under the conditions described in Example 2, but the concentration of ETTDA nanoparticles in the suspension was controlled to be 66.7 mg / L (undiluted), 50.2 mg / L (diluted to 75%), 33.4 mg / L (diluted to 50%), and 16.7 mg / L (diluted to 25%). Under these conditions, the phase transition process of ETTDA nanoparticles in the suspension is as Figure 5 shown in b. It can be seen that the lower the concentration of ETTDA nanoparticles in the suspension, the slower the blue-shift rate of the fluorescence emission peak of the ETTDA nanoparticle suspension, indicating that the phase transition process of the ETTDA nanoparticles in the suspension is inhibited. Conversely, the higher the concentration, the faster the blue-shift rate of the fluorescence emission peak, indicating that the phase transition process of the ETTDA nanoparticles in the suspension is promoted. Specifically, at 90 min, the nanoparticles at 16.7 mg / L (diluted to 25%) emit yellow fluorescence, the ETTDA nanoparticles at 33.4 mg / L (diluted to 50%) emit yellow-green fluorescence, while the ETTDA nanoparticles at 66.7 mg / L (undiluted) and 50.2 mg / L (diluted to 75%) emit green fluorescence.

[0056] Example 6

[0057] The steps described in Example 1 were used, but the total flow rate was controlled to be 7.5 mL / min and the power of the auxiliary ultrasound was 25 W to prepare an amorphous ETTDA nanoparticle suspension. The particle size of the ETTDA nanoparticle suspension prepared under these conditions is about 50 nm.

[0058] Example 7

[0059] The steps described in Example 1 were used, but the total flow rate was controlled to be 7.5 mL / min and no auxiliary ultrasound was used to prepare an amorphous ETTDA nanoparticle suspension. The particle size of the ETTDA nanoparticle suspension prepared under these conditions is about 150 nm.

[0060] Example 8

[0061] For the ETTDA nanoparticle suspensions with different particle sizes prepared in Example 1, Example 6, and Example 7, the amorphous-crystalline phase transition process was regulated using the regulation conditions in Example 2, and the results are as Figure 5 shown in c. It can be seen that the smaller the particle size of the ETTDA nanoparticles in the suspension, the slower the blue shift rate of the fluorescence emission peak of the ETTDA nanoparticle suspension, indicating that the phase transition process of the ETTDA nanoparticles in the suspension is inhibited. On the contrary, the larger the particle size, the faster the blue shift rate of the fluorescence emission peak, indicating that the phase transition process of the ETTDA nanoparticles in the suspension is promoted. Specifically, at 45 min, the 50-nm ETTDA nanoparticles emit yellow fluorescence, the 100-nm ETTDA nanoparticles emit yellow-green fluorescence, and the 170-nm ETTDA nanoparticles emit green fluorescence.

[0062] Example 9

[0063] For the ETTDA nanoparticle suspension prepared in Example 6, the amorphous-crystalline phase transition process was regulated using the conditions described in Example 2, but electromagnetic stirring was applied to it, and the rotation speed was controlled at 0 rpm (no stirring), 600 rpm, and 1200 rpm. Under these conditions, the phase transition process of the ETTDA nanoparticles in the suspension is as Figure 5 shown in d. It can be seen that the higher the stirring speed, the faster the blue shift rate of the fluorescence emission peak of the ETTDA nanoparticle suspension, indicating that the phase transition process of the ETTDA nanoparticles in the suspension is promoted. This is because the shear force generated by stirring the suspension promotes the collision of the nanoparticles in the suspension and induces crystallization. Specifically, at 60 min, when the rotation speed is 0 rpm (no stirring), the ETTDA nanoparticles emit yellow fluorescence, while when the stirring speed is 600 rpm, they emit yellow-green fluorescence, and when the stirring speed is 1200 rpm, the ETTDA nanoparticles emit green fluorescence.

[0064] Example 10

[0065] For the ETTDA nanoparticle suspension prepared in Example 1, the amorphous-crystalline phase transition process was regulated using the conditions described in Example 2, but NaCl was added to the suspension, and the concentration of NaCl in the suspension was controlled at 0 mM (no NaCl), 5 mM, and 20 mM. Under these conditions, the phase transition process of the ETTDA nanoparticles in the suspension is as Figure 6As shown in a. It can be seen that the higher the NaCl concentration in the suspension, the faster the blue shift rate of the fluorescence emission peak of the ETTDA nanoparticle suspension, indicating that the phase transition process of the ETTDA nanoparticles in the suspension is promoted. This is because the addition of NaCl compresses the double-layer thickness of the ETTDA nanoparticles, promoting the occurrence of the crystallization process. Specifically, at 15 min, the ETTDA nanoparticles emit yellow fluorescence at 0 mM (without NaCl), yellow-green fluorescence at 5 mM NaCl added, and green fluorescence at 20 mM NaCl added.

[0066] Example 11

[0067] For the ETTDA nanoparticle suspension prepared in Example 1, the amorphous-crystalline phase transition process was regulated under the conditions described in Example 2, but sodium dodecyl sulfate (SDS), a surfactant, was added to the suspension, and the concentration of SDS in the suspension was controlled at 0 mM (without SDS), 1 mM, 3 mM, and 5 mM. Under these conditions, the phase transition process of the ETTDA nanoparticles in the suspension Figure 6 As shown in b. It can be seen that the higher the SDS concentration in the suspension, the phenomenon that the blue shift rate of the fluorescence emission peak of the ETTDA nanoparticle suspension first increases and then decreases. It shows that a small amount of SDS in the suspension can promote the phase transition of the ETTDA nanoparticles. This is because a small amount of SDS exhibits its characteristics as an electrolyte and will also compress the double-layer thickness of the ETTDA nanoparticles. When the SDS concentration is 5 mM, the SDS in the suspension forms micelles due to exceeding the critical micelle concentration, and these micelles separate the ETTDA nanoparticles, reducing the probability of collision of the nanoparticles, thereby inhibiting the amorphous-crystalline phase transition of the ETTDA nanoparticles. Specifically, at 60 min, the ETTDA nanoparticles emit yellow-green fluorescence at 0 mM (without SDS), green fluorescence at 1 mM and 3 mM SDS added, and yellow fluorescence at 5 mM SDS added.

[0068] Example 12

[0069] For the ETTDA nanoparticle suspension prepared in Example 1, the amorphous-crystalline phase transition process was regulated under the conditions described in Example 2. Since the material prepared by the method provided by the present invention has good light transmittance and uniform and stable properties, it is very suitable for in-situ detection of the amorphous-crystalline phase transition process of the amorphous nanoparticle suspension of the organic aggregation-induced emission material. Therefore, conventional detection means such as ultraviolet-visible absorption, fluorescence spectroscopy, fluorescence quantum yield, and femtosecond transient absorption were used to conduct in-situ detection of the phase transition process of the ETTDA nanoparticles. As Figure 7As shown, the absorption spectrum, fluorescence spectrum, quantum yield, and the evolution of the excited state process during the amorphous-crystalline phase transition of amorphous nanoparticles of organic aggregation-induced emission materials were successfully observed in situ using the method provided by the present invention.

[0070] Example 13

[0071] For the ETTDA nanoparticle suspension prepared in Example 1, the amorphous-crystalline phase transition process was regulated under the conditions described in Example 2. The suspension was filtered through a 50-nm microporous filter membrane at 0 min, 30 min, 60 min, and 90 min during the regulation. The emitted colors of the obtained filter cakes were bright yellow, yellowish green (more yellow), yellowish green (more green), and green ( Figure 8 ), specifically, the filter cakes obtained by filtration at 0 - 15 min emitted yellow fluorescence; the filter cakes obtained by filtration at 15 - 60 min emitted yellowish green fluorescence; and the filter cakes obtained by filtration after 60 min emitted green fluorescence. This indicates that the content of the amorphous phase component in the ETTDA nanomaterial obtained by filtration gradually decreased, while the content of the crystalline phase component gradually increased. That is, a solid material with a specific amorphous-crystalline phase state can be obtained by the novel method for regulating the amorphous-crystalline phase transition of nanoparticles described in the present invention.

[0072] Example 14

[0073] The steps described in Example 1 were adopted, but ETTDA was replaced with hexaphenylsilole (HPS) to prepare an amorphous HPS nanoparticle suspension. The amorphous-crystalline phase transition process was regulated under the conditions described in Example 2. Figure 9 a in it shows that the fluorescence emission peak wavelength of the prepared HPS nanoparticle suspension was 510 nm, and it blue-shifted to 487 nm after regulation. That is, the method described in the present invention can be applied to regulate the amorphous-crystalline phase transition of HPS and prepare a nano-HPS material with a specific amorphous-crystalline phase state composition.

[0074] Example 15

[0075] The steps described in Example 1 were adopted, but ETTDA was replaced with tetraphenylethylene (TPE) to prepare an amorphous TPE nanoparticle suspension. The amorphous-crystalline phase transition process was regulated under the conditions described in Example 2. Figure 9 b in it shows that by using the method of the present invention, the amorphous-crystalline phase transition process of TPE nanoparticles can also be regulated, and a nano-TPE material with a specific amorphous-crystalline phase state can be prepared.

[0076] Example 16

[0077] The steps described in Example 1 were adopted, but ETTDA was replaced with 1,1-bis(4-methoxyphenyl)-2-(4-bromophenyl)-2-phenyl ethylene to prepare an amorphous 1,1-bis(4-methoxyphenyl)-2-(4-bromophenyl)-2-phenyl ethylene nanoparticle suspension. The amorphous-crystalline phase transition process was regulated under the conditions described in Example 2. Figure 9 It is illustrated in c that by using the method of the present invention, the amorphous-crystalline phase transition process of 1,1-bis(4-methoxyphenyl)-2-(4-bromophenyl)-2-phenyl ethylene nanoparticles can also be regulated, and a nano 1,1-bis(4-methoxyphenyl)-2-(4-bromophenyl)-2-phenyl ethylene material with a specific amorphous-crystalline phase state can be prepared.

[0078] Example 17

[0079] The steps described in Example 1 were adopted, but ETTDA was replaced with 1-(4-bromophenyl)-1,2,2-triphenylethylene, 1,1-bis(4-diethylaminophenyl)-2-(4-bromophenyl)-2-phenyl ethylene, triphenylamine (TPA), salicylaldehyde azine (SAA), and hexaphenyl silole. It was found that the results were similar to those observed in the ETTDA NPs suspension. Therefore, it was speculated that a similar amorphous-crystalline phase transition also occurred in the NPs of TPE and its derivatives.

[0080] The above-disclosed are only the preferred embodiments of the present invention. Of course, the scope of the rights of the present invention cannot be limited thereby. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A method for regulating the emission color of a single-component organic solid light-emitting material, characterized in that, It includes the following steps: (1) Prepare an amorphous nanoparticle suspension of a single-component organic solid luminescent material through an ultrasonic-assisted microfluidic reactor: Add a good solvent to the single-component organic solid luminescent material and ultrasonically dissolve it at room temperature; then transfer it to a syringe and load it on syringe pump 1. Take another syringe filled with a poor solvent and load it on syringe pump 2. Control the ratio of the poor solvent to the good solvent to be 5 - 40:1, the total flow rate to be 5 - 20 mL / min, and the power of the auxiliary ultrasound to be 5 - 40 W; (2) Regulate the ratio of the amorphous phase to the crystalline phase in the nanoparticles by regulating the amorphous-crystalline phase transition process and degree in the nanoparticle suspension, and control the luminescent color of the organic solid luminescent material; The single-component organic solid luminescent material includes tetra-(4-diethylaminophenyl)ethylene, tetraphenylethylene, 1-(4-bromophenyl)-1,2,2-triphenylethylene, 1,1-bis(4-methoxyphenyl)-2-p-bromophenyl-2-phenylethylene, 1,1-bis(4-diethylaminophenyl)-2-p-bromophenyl-2-phenylethylene, triphenylamine, salicylaldehyde azine, and hexaphenylsilole; The method for regulating the amorphous-crystalline phase transition process and degree in the nanoparticle suspension includes: changing the suspension temperature, or changing the nanoparticle concentration, or changing the nanoparticle particle size, or stirring the suspension at different rates, or adding electrolytes or surfactants with different concentrations to the suspension.

2. The regulation method according to claim 1, characterized in that, The good solvent includes one or more of acetone, acetonitrile, ethanol, methanol, isopropanol, and tetrahydrofuran, and the poor solvent includes one or more of water, n-hexane, cyclohexane, and petroleum ether.

3. The regulation method according to claim 1, wherein The single-component organic solid luminescent material is tetra-(4-diethylaminophenyl)ethylene. When the suspension temperature is 4 - 20 °C, the nanoparticle concentration is 50.2 - 66.7 mg / L, and the nanoparticle particle size is 100 - 170 nm, tetra-(4-diethylaminophenyl)ethylene emits yellow fluorescence at 0 - 15 min; emits yellow-green fluorescence at 15 - 60 min; and emits green fluorescence after 60 min.

4. The regulation method according to claim 3, characterized in that, When stirring is additionally carried out at a rate of 600 - 1200 rpm, tetra-(4-diethylaminophenyl)ethylene is adjusted from yellow luminescence to green luminescence within 30 - 120 min; when an electrolyte with a concentration of 5 - 20 mM is additionally added to the suspension, tetra-(4-diethylaminophenyl)ethylene is adjusted from yellow luminescence to green luminescence within 10 - 120 min; when a surfactant with a concentration of 3 - 5 mM is additionally added to the suspension, tetra-(4-diethylaminophenyl)ethylene is adjusted from yellow luminescence to green luminescence within 30 - 120 min.

5. Use of the regulation method according to claim 1, characterized in that It can be applied to regulate the luminescent color of single-component organic solid luminescent materials, prepare single-component organic solid luminescent materials with specific amorphous-crystalline phase compositions or specific color fluorescence, and in-situ track and detect the phase transition of nanoparticles in the suspension.

6. A preparation method of a single-component organic solid luminescent material, characterized in that, It includes the following steps: (S1) Prepare an amorphous nanoparticle suspension of a single-component organic solid luminescent material; (S2) Regulate the ratio of the amorphous phase to the crystalline phase in the nanoparticles and control the luminescence color of the organic solid luminescent material by regulating the amorphous-crystalline phase transition process and degree in the nanoparticle suspension; (S3) Extract the nanoparticles from the suspension by freeze-drying, suction filtration or centrifugal separation to obtain a single-component organic solid luminescent material; The single-component organic solid luminescent material includes tetra-(4-diethylaminophenyl)ethylene, tetraphenylethylene, 1-(4-bromophenyl)-1,2,2-triphenylethylene, 1,1-bis(4-methoxyphenyl)-2-p-bromophenyl-2-phenylethylene, 1,1-bis(4-diethylaminophenyl)-2-p-bromophenyl-2-phenylethylene, triphenylamine, salicylaldehyde azine and hexaphenylsilole; The method for regulating the amorphous-crystalline phase transition process and degree in the nanoparticle suspension includes: changing the suspension temperature, or changing the nanoparticle concentration, or changing the nanoparticle particle size, or stirring the suspension at different rates, or adding electrolytes or surfactants with different concentrations to the suspension.

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