Three-dimensional electrofluorescence color change material and preparation method and application thereof

Abstract

The invention discloses a three-dimensional electrofluorescence color change material and a preparation method and application thereof, DMAPbBr3 single crystal prepared by the method is a low-temperature ferroelectric material, and the electrofluorescence color change effect is observed in the material. When an electric field is applied, the fluorescence color of DMAPbBr3 changes from peach color to pink, which may be attributed to the interaction between fluorescence characteristics and ferroelectricity. The discovery of the electrofluorescence color change property shows that DMAPbBr3 is a potential photoelectric information material, possibly has a certain quantum effect, and possibly has application potential in the field of quantum information.

Description

Technical Field

[0001] The present invention relates to the field of optoelectronic materials, and in particular to a three-dimensional electroluminescent color-changing material and a preparation method and application thereof. Background Art

[0002] Ferroelectric materials play a key role in numerous applications, including capacitors, nonvolatile memories, ultrasound transducers, sensors, and actuators. When combined with other material properties, ferroelectrics can offer significant advantages in areas such as photovoltaics, spintronics, and optomechanical actuators. In addition, the study of ferroelectric materials with fluorescent properties is also a fascinating topic, as the introduction of spontaneous electric polarization provides new ways to manipulate light-matter interactions. The combination of fluorescence and ferroelectricity has great potential in future multifunctional optoelectronic applications, including integrated optical sensors.

[0003] Although hybrid halide perovskites with coexistence of ferroelectric polarization and fluorescence have been reported, such as (C4H9NH3)2PbCl4, zinc-based organic-inorganic hybrid RMPZnS2 and SMP2ZnS3, (S)- and ®-3-(fluoropyrrolidine)MnBr3, (C9H14N)2CdBr4, (3-pyrrolidine)(CdCl3) and (3-pyrrolidine)MnCl3, the interaction between light and ferroelectricity in fluorescent ferroelectric materials remains unclear. Summary of the invention

[0004] The present invention provides a three-dimensional electroluminescent color-changing material and a preparation method and application thereof. The DMAPbBr3 single crystal (DMA = (CH3)2NH2+) prepared by the method is a low-temperature ferroelectric material. The electroluminescent color-changing effect observed in the material indicates that the material is a potential optoelectronic information material and may have some quantum effect and may have application potential in the field of quantum information.

[0005] To achieve the above object, the technical solution adopted by the present invention is: A three-dimensional electroluminescent color-changing material, characterized in that the chemical formula of the three-dimensional electroluminescent color-changing material is (C2H8N)PbBr3.

[0006] Furthermore, the three-dimensional electroluminescent color-changing material undergoes a first-order phase transition at 252±10K, and the crystallographic space group changes from a high-temperature P63 / mmc to a low-temperature P21 space group.

[0007] Furthermore, the three-dimensional electroluminescent color-changing material is a ferroelectric below 252K, and the spontaneous polarization value is 0.2-0.3 μC·cm −2 , the coercive field is 2-5 kV / cm.

[0008] Furthermore, the three-dimensional electroluminescent color-changing material has pink fluorescence below 252K, and the pink fluorescence emission mainly comes from the self-trapped exciton recombination luminescence of the PbBr6 octahedron; the peak value of its fluorescence spectrum is 690±50 nm, and the half-peak width is 100-250nm;.

[0009] A method for preparing a three-dimensional electroluminescent color-changing material, the method comprising the following steps: 1) PbBr2, DMF and hydrobromic acid aqueous solution are added into a reaction container successively to obtain a mixture; wherein the molar ratio of PbBr2, DMF and hydrobromic acid aqueous solution is 1:(20-200):(1-200); 2) heating the reaction vessel to 30-90°C and stirring the mixture in the vessel for 0.5-24h to form a mixed solution; 3) The mixed solution is naturally cooled to room temperature and volatilized at room temperature, and irregular solid particles are grown as a precursor after 1-30 days; 4) dissolving the solid particles obtained in step (3) in DMF to form a transparent solution, and volatilizing the transparent solution at room temperature to grow a DMAPbBr3 single crystal after 1-14 days; wherein the mass ratio of the solid particles to DMF is 1:(5-100).

[0010] Furthermore, the purity of the PbBr2 is greater than 98%.

[0011] Furthermore, the purity of the DMF is analytically pure.

[0012] Furthermore, the mass fraction of the hydrobromic acid aqueous solution is 40 wt%.

[0013] A three-dimensional electroluminescent color-changing material is used in optoelectronic information material fields such as non-volatile memory, sensors, capacitors, optical modulators, electromagnetic non-destructive testing, and battery technology, as well as quantum information fields such as quantum communication, quantum state storage and transmission, quantum imaging, quantum sensors, and quantum networks.

[0014] Compared with the prior art, the present invention has the following advantages or technical effects: The dimethylamine ions in the DMAPbBr3 single crystal are obtained by the reaction of DMF and hydrobromic acid, rather than directly derived from dimethylamine, which increases the solubility of PbBr2 in the reaction solution and promotes the growth of DMAPbBr3 single crystals.

[0015] For the first time, it was discovered that DMAPbBr3 single crystal is a ferroelectric below 260K.

[0016] The electroluminescent color change characteristics in DMAPbBr3 single crystals were discovered for the first time.

[0017] The ferroelectricity and electroluminescent color-changing properties of DMAPbBr3 single crystals indicate that DMAPbBr3 single crystals are a new type of non-volatile memory material, optical information storage material, and photoelectric conversion material with great potential. The coupling of electrons and photons may also produce peculiar quantum effects, which may be applied in the field of quantum information. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The DMAPbBr3 single crystal is grown; Figure 2 The measured and calculated powder X-ray diffraction pattern of DMAPbBr3 single crystal at room temperature. The inset is a schematic diagram of its crystal structure at room temperature. Figure 3 The absorption and photoelectric generation spectra of DMAPbBr3 single crystal measured at room temperature. The inset is the band gap obtained by fitting the Tauc formula. Figure 4 is the DSC curve of DMAPbBr3 single crystal; Figure 5 Ferroelectric hysteresis loop of DMAPbBr3 single crystal measured at 206K and 50Hz; Figure 6 This is the luminescence image of DMAPbBr3 single crystal excited by 365nm UV flashlight from 303K to 213K; Figure 7 Schematic diagram of the structure of DMAPbBr3 single crystal at 100K; Figure 8 The fluorescence spectra of DMAPbBr3 single crystal excited by ultraviolet light at 100K, 200K and 300K; Fig. 9 The CIE chromaticity diagram (CIE1931) corresponding to the fluorescence spectrum of DMAPbBr3 single crystal at 100K, 200K, and 300K; Fig.10 This is the luminescence image of DMAPbBr3 single crystal excited by ultraviolet flashlight at 213K and bias voltage of 0V; Fig.11 This is the luminescence image of DMAPbBr3 single crystal excited by ultraviolet flashlight at 213K and bias voltage of 600V; Fig.12 The CIE chromaticity diagram corresponding to the luminescence diagram of DMAPbBr3 single crystal when the bias voltage is 0V and 600V; Fig.13 This is a graph showing the proportional changes in the red, green and blue RGB values ​​of the DMAPbBr3 single crystal when the bias voltage is 0V and 600V. DETAILED DESCRIPTION

[0019] In order to better understand the content of the present invention, the technical solution of the present invention is further described below in conjunction with specific embodiments, but the protection content of the present invention is not limited to the following embodiments. Example

[0020] 2 g of PbBr2 (lead bromide, purity > 99%, Aladdin Reagent Co., Ltd.), 20 ml of DMF (N,N-dimethylformamide solution, purity 99.8%, Aladdin Reagent Co., Ltd.) and 20 ml of HBr (hydrobromic acid aqueous solution, mass fraction 40 wt%, Aladdin Reagent Co., Ltd.) were slowly added to a beaker in sequence to obtain a mixture.

[0021] The mixture was heated to 50°C and stirred for 30 min to form a mixed solution.

[0022] The mixed solution was naturally cooled to room temperature and allowed to stand at room temperature for one week to form irregular solid particles as a precursor.

[0023] The obtained precursor particles were dissolved in DMF to prepare a saturated solution, which was then evaporated at room temperature for a week, and finally a large crystal of DMAPbBr3 several millimeters in size was grown. Figure 1 shown.

[0024] The chemical composition of the DMAPbBr3 single crystal prepared by the above method is (C2H8N)PbBr3. Figure 2 The powder X-ray diffraction pattern of the crystal at room temperature is measured and calculated; Figure 3 The absorption and photoelectric generation spectra of the crystal were measured at room temperature. It can be seen that the grown DMAPbBr3 single crystal is pure phase, and the space group of the crystal at room temperature is P63 / mmc. The optical band gap of the grown DMAPbBr3 single crystal is about 2.95eV, and it has a fluorescence emission peak with a half-peak width of about 200nm near the wavelength of 672nm under 365nm ultraviolet light at room temperature.

[0025] Figure 4 DSC curve of DMAPbBr3 single crystal, the temperature change rate is 10K·min -1 .Depend on Figure 6 and Figure 7 It can be seen that DMAPbBr3 single crystal undergoes a first-order phase transition at around 252 K, and the crystallographic space group changes from the high-temperature P63 / mmc to the low-temperature P21 space group. Figure 5 Ferroelectric hysteresis loop of DMAPbBr3 single crystal measured at 206K and 50Hz. The hysteresis loop shows that DMAPbBr3 single crystal is a ferroelectric. At 206K, its saturation polarization value is about 0.25μC·cm−2 , the coercive field is about 3.2 kV / cm.

[0026] Figure 8 The fluorescence spectra of DMAPbBr3 single crystal excited by ultraviolet light at 100K, 200K, and 300K are shown in Figure 2. Fig. 9 The CIE chromaticity diagram corresponding to the fluorescence spectrum of DMAPbBr3 single crystal at 100K, 200K, and 300K shows that the material crystal has a strong pink fluorescence emission below 252K. Therefore, DMAPbBr3 single crystal at 213K was selected for further testing. Fig.10 and Fig.11 These are the luminescence photos of DMAPbBr3 single crystal excited by ultraviolet flashlight at 213K and bias voltage of 0V and 600V respectively. From the figure, it can be seen that the crystal emits peach light at 0V and pink light at 600V. Fig.12 The CIE chromaticity diagram corresponding to the luminescence diagram of DMAPbBr3 single crystal at 0V and 600V, Fig.13 The figure shows the change in the ratio of red, green and blue RGB values ​​of DMAPbBr3 single crystal when the bias voltage is 0 V and 600 V. The change in RGB value shows that the blue fluorescence component of DMAPbBr3 increases when voltage is applied. The blue fluorescence corresponds to the emission of free excitons caused by the energy gap of DMAPbBr3 single crystal, and the green and red fluorescence corresponds to the emission of self-trapped excitons of PbBr6 octahedron. Therefore, in DMAPbBr3 crystal, the electric field can adjust the ratio of self-trapped exciton emission and free exciton emission.

[0027] In summary, the DMAPbBr3 single crystal prepared by the above method undergoes a first-order phase transition at around 252 K, and the crystallographic space group changes from the high-temperature P63 / mmc to the low-temperature P21 space group. Below 252 K, it is a ferroelectric with a spontaneous polarization value of about 0.25μC·cm −2 , the coercive field is about 3.2 kV / cm, and its temperature-dependent dielectric curve is step-shaped, proving that it is a non-intrinsic ferroelectric. The crystal of this material has a strong pink fluorescence below 252 K, and the pink fluorescence emission mainly comes from the self-trapped exciton recombination luminescence of the PbBr6 octahedron. By applying an external electric field to the crystal, the fluorescence of the crystal changes from pink to pink, indicating that the blue free exciton emission of the crystal is significantly enhanced under the action of the electric field.

[0028] This electroluminescent color change property suggests that there may be some quantum channels in DMAPbBr3 single crystals, which changes the passage path of excitons. The ferroelectric properties, fluorescence properties, and electroluminescent color change properties of DMAPbBr3 single crystals indicate that DMAPbBr3 single crystals have great application potential in the fields of optoelectronic information materials and quantum information.

[0029] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solution disclosed in the present invention, technicians in this field can make some substitutions and deformations to some technical features therein according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. A three-dimensional electroluminescent color-changing material, characterized in that: The chemical formula of the three-dimensional electroluminescent color-changing material is (C2H8N)PbBr3.

2. A three-dimensional electroluminescent color-changing material according to claim 1, characterized in that: The three-dimensional electroluminescent color-changing material undergoes a first-order phase transition at 252±10K, and the crystallographic space group changes from a high-temperature P63 / mmc to a low-temperature P21 space group.

3. The three-dimensional electroluminescent color-changing material according to claim 1, characterized in that: The three-dimensional electroluminescent color-changing material is a ferroelectric below 252K, and the spontaneous polarization value is 0.2-0.3 μC·cm −2 , the coercive field is 2-5 kV / cm.

4. The three-dimensional electroluminescent color-changing material according to claim 1, characterized in that: The three-dimensional electroluminescent color-changing material has pink fluorescence below 252K, and the pink fluorescence emission mainly comes from the self-trapped exciton complex luminescence of the PbBr6 octahedron; the peak value of its fluorescence spectrum is 690±50 nm, and the half-peak width is 100-250nm.

5. A method for preparing the three-dimensional electroluminescent color-changing material according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: 1) PbBr2, DMF and hydrobromic acid aqueous solution are added into a reaction container successively to obtain a mixture; wherein the molar ratio of PbBr2, DMF and hydrobromic acid aqueous solution is 1:(20-200):(1-200); 2) heating the reaction vessel to 30-90°C and stirring the mixture in the vessel for 0.5-24h to form a mixed solution; 3) The mixed solution is naturally cooled to room temperature and volatilized at room temperature, and irregular solid particles are grown as a precursor after 1-30 days; 4) dissolving the solid particles obtained in step (3) in DMF to form a transparent solution, and volatilizing the transparent solution at room temperature to grow a DMAPbBr3 single crystal after 1-14 days; wherein the mass ratio of the solid particles to DMF is 1:(5-100).

6. The method for preparing a three-dimensional electroluminescent color-changing ferroelectric material according to claim 5, characterized in that: In step (1), the purity of PbBr2 is greater than 98%.

7. The method for preparing a three-dimensional electroluminescent color-changing ferroelectric material according to claim 5, characterized in that: In step (1), the purity of the DMF is analytically pure.

8. The method for preparing a three-dimensional electroluminescent color-changing ferroelectric material according to claim 5, characterized in that: In step (1), the mass fraction of the hydrobromic acid aqueous solution is 40 wt%.

9. An application of the three-dimensional electroluminescent color-changing material according to claims 1-4, characterized in that: The three-dimensional electroluminescent color-changing material is used in the fields of non-volatile memory, sensors, capacitors, optical modulators, electromagnetic non-destructive testing, and battery technology, as well as quantum communication, quantum state storage and transmission, quantum imaging, quantum sensors and quantum networks.

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