Acid stimuli-responsive metal-organic hybrid perovskite optical waveguide material and preparation method thereof

Abstract

The invention discloses an acid stimuli-responsive metal-organic hybrid perovskite optical waveguide material and a preparation method thereof. The method specifically comprises the following steps: mixing hydrochloric acid or hydrobromic acid, 3-chloro-4-hydroxypyridine and metal halide salt, adding water, ultrasonically dissolving, heating or not heating, and separating out crystals after the solvent is volatilized, thereby obtaining the acid stimuli-responsive metal-organic hybrid perovskite optical waveguide crystal material. The material has fluorescence-phosphorescence dual emission, presents luminescence conversion of different colors under ultraviolet irradiation after being fumigated by different acids, and prolongs afterglow time after stopping light excitation. And information encryption is realized by using different luminescence colors and afterglow time after different acid fumigation materials are used. The invention provides a new thought and approach for preparing novel intelligent materials and optical information encryption devices with excellent optical characteristics.

Description

Technical Field

[0001] The present invention belongs to the technical field of stimulus-responsive functional materials, and particularly relates to an acid-stimulus-responsive metal-organic hybrid perovskite optical waveguide material and a preparation method thereof. Background Art

[0002] Stimulus-responsive luminescent materials are intelligent materials whose structure, spectrum, luminescence color, etc. change under external actions (heat, light, acid-base, pressure), and show great application potential in the fields of sensing, anti-counterfeiting, intelligent detection, molecular computers, etc. However, currently, stimulus-responsive intelligent materials are mainly composed of amorphous materials, and there are problems such as lack of theoretical design. Crystalline materials can study their structural transformation at the molecular level through single-crystal X-ray diffraction technology, which is conducive to studying their structure-activity relationship and building a bridge between the microscopic structure and macroscopic properties of crystalline materials. In addition, most crystalline materials are small in size, and it is difficult to observe the macroscopic properties of a single crystal. There is an urgent need to grow large-sized single crystals through a suitable preparation method. Summary of the Invention

[0003] The purpose of the present invention is to provide an acid-stimulus-responsive metal-organic hybrid perovskite optical waveguide material and a preparation method thereof. The present invention adopts an easy-to-operate solvent evaporation method, and the synthesized series of metal-organic hybrid perovskite materials have the advantages of adjustable energy levels and low optical loss coefficients, integrating logic, controllability, and diversity into large-sized single crystals. The present invention provides new ideas and approaches for the preparation of new intelligent materials with excellent optical properties and optical information encryption devices.

[0004] The preparation method of the acid-stimulus-responsive metal-organic hybrid perovskite optical waveguide material is as follows: Mix hydrochloric acid or hydrobromic acid, 3-chloro-4-hydroxypyridine, and metal halide salts, add water and dissolve them by ultrasonic treatment, and then heat or not heat. After the solvent evaporates, crystals are precipitated, and thus the acid-stimulus-responsive metal-organic hybrid perovskite optical waveguide crystal material is obtained.

[0005] The metal halide salt is cadmium chloride or cadmium bromide.

[0006] The molar ratio range of the 3-chloro-4-hydroxypyridine, metal halide salt, and hydrochloric acid or hydrobromic acid is 1:3.5 - 4.5:1.2 - 7.2, preferably 1:4:1.2 - 7.2.

[0007] The heating temperature is 45°C - 60°C.

[0008] The crystal material has a one-dimensional morphology, and the size includes micron level, millimeter level, and centimeter level.

[0009] The described acid-responsive metal-organic hybrid perovskite optical waveguide material has fluorescence-phosphorescence dual emission. After being fumigated with different acids, it shows luminescence transitions of different colors under ultraviolet light irradiation, and the afterglow time is prolonged after the light excitation is stopped.

[0010] Application of the above-prepared acid-responsive metal-organic hybrid perovskite optical waveguide material in information encryption. Information encryption is achieved by using different luminescence colors and afterglow times after fumigating the material with different acids.

[0011] In the present invention, a series of novel metal-organic hybrid perovskite crystal materials are synthesized by self-assembling 3-chloro-4-hydroxypyridine with metal halides. The self-assembly of 3-chloro-4-hydroxypyridine with metal halides can effectively promote the intersystem crossing between singlet and triplet states to achieve fluorescence-phosphorescence dual emission. Through acid stimulation, the molecular structure and stacking form of the metal-organic hybrid perovskite crystal can be effectively regulated. The prepared one-dimensional crystals at the micron scale and large size exhibit light response characteristics in a wide wavelength range (130 nm) and low-loss active optical waveguide characteristics. And through halide ion substitution and doping, white light emission based on blue fluorescence and orange-red phosphorescence is achieved. The present invention not only realizes the structural transformation of the metal-organic hybrid perovskite based on acid stimulation to obtain fluorescence-phosphorescence dual emission, but also realizes low-loss multi-color (including white light emission) optical waveguide characteristics, and demonstrates the potential application of this type of novel metal-organic hybrid perovskite material in the field of information encryption. Brief Description of the Drawings

[0012] Figure 1 Structural diagrams of metal-organic hybrid perovskite crystals prepared in Examples 1, 2, and 3.

[0013] Figure 2 Acid-responsive optical waveguide images and optical loss coefficient fitting curves of the micron-scale metal-organic hybrid perovskite crystal materials prepared in Examples 1, 2, and 3.

[0014] Figure 3 Acid-responsive images and potential information encryption applications of the centimeter-scale metal-organic hybrid perovskite crystal materials prepared in Examples 1, 2, and 3. Detailed Description of the Invention Example 1

[0015] Dissolve 12.9 mg of 3-chloro-4-hydroxypyridine, 73.2 mg of cadmium chloride, and 100 μL of 36 wt% concentrated hydrochloric acid in 10 mL of deionized water. After ultrasonic treatment for 10 minutes, transfer the solution into a 20 mL glass bottle. Seal the glass bottle with plastic wrap and then pierce 6 pinholes in the plastic wrap. Then heat the reaction mixture to 45 °C and maintain this temperature for 24 hours. After the solvent has evaporated, one-dimensional rod-shaped crystals can be obtained. Isolate the single crystal and perform washing and drying treatments in sequence to obtain the target product.

[0016] Single crystal X-ray diffraction analysis of the single crystal product shows that the metal-organic hybrid perovskite belongs to the triclinic system, space group P-1, and Cd 2+ and Cl - form an octahedral structure through six coordination and extend infinitely along the a-axis. The inorganic chain structure and organic molecules can be regarded as a core-shell structure and are assembled through strong hydrogen bond and halogen bond interactions.

[0017] Steady-state spectroscopy and time-resolved spectroscopy analysis show that when excited at 320 nm, the main fluorescence emission peak and main phosphorescence emission peak of this metal-organic hybrid perovskite are located at 370 nm and 500 nm, respectively. This metal-organic hybrid perovskite exhibits a light blue emission under ultraviolet light excitation. After the light excitation is stopped, it can emit a green phosphorescence afterglow visible to the naked eye for about 1 second, and the luminescence lifetime is 13.42 ms. After fumigation with acid, the luminescence of this metal-organic hybrid perovskite undergoes a red shift, and under ultraviolet light excitation, a luminescence transition from blue to cyan to green occurs. After the light excitation is stopped, the afterglow time is extended to about 2 seconds, and the luminescence lifetime is 46.09 ms. Spectral analysis shows that when excited with the optimal excitation wavelength, after acid fumigation, the main fluorescence emission peak redshifts from 320 nm to 500 nm.

[0018] Optical waveguide characterization shows that this metal-organic hybrid perovskite crystal exhibits obvious optical waveguide phenomena, and multi-color optical waveguide responses at the micron scale can be achieved through acid stimulation. Among them, the brightest cyan light shows the most obvious optical waveguide phenomenon, and the optical waveguide loss coefficient is 0.0016 dB / μm, which is lower than that of most molecular optical waveguide materials. Example 2

[0019] Dissolve 12.9 mg of 3-chloro-4-hydroxypyridine, 73.2 mg of cadmium chloride, and 100 μL of 36 wt% concentrated hydrobromic acid in 10 mL of deionized water. After ultrasonic treatment for 10 minutes, transfer the solution into a 20 mL glass bottle. Seal the glass bottle with plastic wrap and then pierce 6 pinholes in the plastic wrap. Then heat the reaction mixture to 45 °C and maintain this temperature for 24 hours. After the solvent has evaporated, one-dimensional rod-shaped crystals can be obtained. Isolate the single crystal and perform washing and drying treatments in sequence to obtain the target product.

[0020] Single crystal X-ray diffraction analysis of the single crystal product reveals that the metal-organic hybrid perovskite belongs to the triclinic system, space group P-1, and Cd 2+ and Cl - as well as Br - form an octahedral structure through six coordination, extending infinitely along the a-axis. The inorganic chain structure and organic molecules can be regarded as a core-shell structure, assembled through strong hydrogen bond and halogen bond interactions.

[0021] X-ray photoelectron spectroscopy and elemental analysis show that in this halogen ion-doped metal-organic hybrid perovskite, the molar ratio of Cl - and Br - is 1:1.

[0022] Steady-state spectroscopy and time-resolved spectroscopy analysis show that when excited at 405 nm, the fluorescence emission peaks of this halogen ion-doped metal-organic hybrid perovskite are located at 465 nm and 560 nm, and the phosphorescence emission peak is located at 620 nm. This halogen ion-doped metal-organic hybrid perovskite exhibits white light emission under ultraviolet light excitation.

[0023] Optical waveguide characterization shows that this halogen ion-doped metal-organic hybrid perovskite has white light optical waveguide properties, and its optical waveguide loss coefficient is 0.016 dB / μm, which is lower than that of most molecular optical waveguide materials. Example 3

[0024] Dissolve 12.9 mg of 3-chloro-4-hydroxypyridine, 137.6 mg of cadmium chloride, and 500 μL of 36 wt% concentrated hydrobromic acid in 10 mL of deionized water. After ultrasonic treatment for 10 minutes, place it in a 20 mL glass bottle; seal the glass bottle with plastic wrap, and then pierce 6 pinholes in the plastic wrap; then heat the reaction mixture to 45 °C and maintain this temperature for 24 hours. After the solvent evaporates, one-dimensional rod-shaped crystals can be obtained. Separate the single crystal and perform washing and drying treatments in sequence to obtain the target product.

[0025] Single crystal X-ray diffraction analysis of the single crystal product reveals that the metal-organic hybrid perovskite belongs to the triclinic system, space group P-1, and Cd 2+ and Br - form an octahedral structure through six coordination, extending infinitely along the a-axis. The inorganic chain structure and organic molecules can be regarded as a core-shell structure, assembled through strong hydrogen bond and halogen bond interactions.

[0026] Steady-state spectroscopy and time-resolved spectroscopy analysis show that when excited at 395 nm, the fluorescence emission peak and phosphorescence emission peak of this metal-organic hybrid perovskite are located at 465 nm and 580 nm. The metal-organic hybrid perovskite exhibits white light emission under ultraviolet light excitation.

[0027] Optical waveguide characterization shows that the halide-ion-doped metal-organic hybrid perovskite has white-light optical waveguide properties, with an optical waveguide loss coefficient of 0.0023 dB / μm, which is lower than that of most molecular optical waveguide materials. Application Example 1

[0028] Using the metal-organic hybrid perovskite crystal prepared by evaporation at room temperature in Example 1, potential applications in information encryption can be achieved, such as Figure 3 As shown, the one-dimensional centimeter-sized crystal prepared in Example 1 exhibits a light blue emission under ultraviolet light irradiation. After stopping the light excitation, a green afterglow visible to the naked eye can be emitted for about 1 second. After fumigation with hydrochloric acid, the crystal shows a luminescence transition from blue to cyan to green (I-II-III) under ultraviolet light irradiation. After stopping the light excitation, the green afterglow is extended to about 2 seconds. After fumigation with bromic acid, the crystal shows white-light emission (Br) under ultraviolet light irradiation. Taking advantage of the acid-stimulus response characteristics, spatial information encryption applications can be designed using I, II, and III with different luminescence colors and afterglow times.

Claims

1. A method for preparing an acid-stimulated metal-organic hybrid perovskite optical waveguide material, characterized in that: The specific operation of the preparation method is: mixing hydrochloric acid or hydrobromic acid, 3-chloro-4-hydroxypyridine and metal halide, adding water for ultrasonic dissolution and then heating or not heating, and precipitating crystals after the solvent evaporates, so as to obtain the acid-stimulated responsive metal-organic hybrid perovskite optical waveguide crystal material.

2. The preparation method according to claim 1, characterized in that: The metal halide salt is cadmium chloride or cadmium bromide.

3. The preparation method according to claim 1, characterized in that: The molar ratio of the 3-chloro-4-hydroxypyridine, the metal halide, and the hydrochloric acid or the hydrobromic acid is in the range of 1:3.5-4.5:1.2-7.

2.

4. The preparation method according to claim 1, characterized in that: The heating temperature is 45°C-60°C.

5. The preparation method according to claim 1, characterized in that: The crystalline material has a one-dimensional morphology, and its size includes micrometer level, millimeter level and centimeter level.

6. The preparation method according to claim 1, characterized in that: The acid-stimulated metal-organic hybrid perovskite optical waveguide material has fluorescence-phosphorescence dual emission, and after being fumigated with different acids, it exhibits luminescence transitions of different colors under ultraviolet light irradiation, and after stopping light excitation, the afterglow time is prolonged.

7. Application of the acid-stimulated metal-organic hybrid perovskite optical waveguide material prepared by the method according to any one of claims 1 to 6 in information encryption, characterized in that: Information encryption is achieved by utilizing the different luminescent colors and afterglow times of materials fumigated with different acids.

Images