A second-order nonlinear optical material and preparation method thereof

Abstract

The present invention discloses a second-order nonlinear optical material [Zn@Cu(pvb)2]·DMF, and the preparation steps are as follows: Step 1, put trans-2-(4-pyridyl)-4-vinylbenzoic acid, Zn(NO3)2·6H2 and Cu(NO3)2·3H2O into a reaction vessel; Step 2, add DMF and ethanol into the reaction vessel, after ultrasonic treatment, heat at 120 °C for 48 hours; Step 3, cool down to room temperature to generate green crystals, and obtain the product after washing, filtering and drying with DMF and ethanol respectively. By changing the ratio of Zn and Cu metal elements, the breaking of symmetry is enhanced, thereby synthesizing [Zn@Cu(pvb)2]·DMF with an improved second-order nonlinear coefficient, and further controlling the ratio to regulate its second-order nonlinear optical properties.

Description

Technical Field

[0001] The invention belongs to the technical field of second-order nonlinear optical materials, in particular to a second-order nonlinear optical material and a preparation method thereof. Background Art

[0002] With the advancement of laser technology, the requirements for new optical materials, one of its components, are higher. Frequency doubling crystals are one of them. Common ones include ferroelectric crystals such as potassium dihydrogen phosphate (KDP), lithium niobate (LiNbO3), barium metaborate (BBO), and oxides, as well as semiconductor crystals such as zinc selenide (ZnSe) and silver gallium selenide (AgGaSe). Many of the former have been commercialized, but their effective second-order nonlinear coefficients are small, the fundamental frequency light conversion efficiency is low, and they cannot efficiently generate second harmonics. The latter will have dissipation due to the influence of resonance conditions. Metal-Organic Frameworks (MOFs) materials are highly designable materials. They can form non-centrosymmetric structures by designing organic ligands and metal ion types and bonding methods. They have second-order nonlinear optical properties and can be applied to the field of nonlinear optics.

[0003] However, in recent years, there has been little research on the second-order nonlinear optical properties of metal-organic framework materials, and the second-order nonlinear coefficients of current metal-organic framework materials are also low, and they cannot efficiently generate second harmonics (doubled frequency light), thus limiting their application in this field. Summary of the invention

[0004] The purpose of the present invention is to provide a second-order nonlinear optical material and a preparation method thereof, so as to solve the problem that the second-order nonlinear coefficient of the frequency doubling crystal in the existing commercial second-order nonlinear optical material is small, which limits the application in this field.

[0005] In order to achieve the above-mentioned purpose, the technical solution of the present invention is as follows: a second-order nonlinear optical material, whose chemical formula is as follows: [Zn@Cu(pvb)2]·DMF.

[0006] A method for preparing a second-order nonlinear optical material comprises the following steps: Step 1, placing trans-2-(4-pyridyl)-4-vinylbenzoic acid, Zn(NO3)2·6H2 and Cu(NO3)2·3H2O into a reaction container;

[0007] Step 2, DMF and ethanol are added to a reaction container, and after ultrasonic treatment, heating is carried out at 120° C. for 48 hours;

[0008] Step 3, cooling to room temperature to generate green crystals, which are then washed and filtered with DMF and ethanol respectively, and dried to obtain [Zn@Cu(pvb)2]·DMF.

[0009] Further, in step 1, 0.1 mmol of trans-2-(4-pyridyl)-4-vinylbenzoic acid, 0.015 mmol to 0.4 mmol of Zn(NO3)2·6H2 and 0.01 mmol to 0.035 mmol of Cu(NO3)2·3H2O.

[0010] Further, in step 2, 2 ml of DMF and 2 ml of ethanol.

[0011] Furthermore, in step 2, the ultrasonic treatment time is 10 minutes.

[0012] Furthermore, in step 3, the temperature is lowered to room temperature at 5° C. per hour.

[0013] The following beneficial effects were achieved by adopting the above scheme: by changing the ratio of Zn and Cu metal elements, the symmetry breaking was enhanced, thereby synthesizing [Zn@Cu(pvb)2]·DMF with a greatly improved second-order nonlinear coefficient, and its second-order nonlinear optical properties can be regulated by further controlling the ratio.

[0014] (2) The compound [Zn@Cu(pvb)2]·DMF of the present invention as a frequency doubling crystal in the second-order nonlinear optical material has a higher second-order nonlinear coefficient, which is 20 times that of the general standard sample-urea crystal, and compared with the conventional frequency doubling crystals on the market, it is 46 times that of KDP, 3 to 7 times that of LiNbO3, and 7 times that of BBO, which can be explained that it has a higher conversion efficiency than these frequency doubling crystals. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 For example 1 [Zn 0.75 @Cu 0.25 (pvb)2]·DMF second harmonic intensity as a function of excitation light wavelength (left) and Log-log plot of second harmonic intensity versus excitation light power.

[0016] Figure 2 For example 2 [Zn 0.3 @Cu 0.7 (pvb)2]·DMF second harmonic intensity as a function of excitation light wavelength (left) and Log-log plot of second harmonic intensity versus excitation light power.

[0017] Figure 3 For example three [Zn 0.8 @Cu 0.2 (pvb)2]·Log-log plot of the second harmonic intensity of DMF as a function of the excitation light wavelength (left) and the second harmonic intensity as a function of the excitation light power (right).

[0018] Figure 4 This is a structural diagram of the second-order nonlinear optical material of this application. DETAILED DESCRIPTION

[0019] The following is further described in detail through specific implementation methods:

[0020] The present application provides a second-order nonlinear optical material, whose chemical formula is as follows: [Zn@Cu(pvb)2]·DMF, whose structural formula is as shown in the attached Figure 4 shown.

[0021] A method for preparing a second-order nonlinear optical material comprises the following steps:

[0022] Step 1, placing trans-2-(4-pyridyl)-4-vinylbenzoic acid, Zn(NO3)2·6H2 and Cu(NO3)2·3H2O in a reaction vessel;

[0023] Step 2, DMF and ethanol are added to a reaction container, and after ultrasonic treatment, heating is carried out at 120° C. for 48 hours;

[0024] Step 3, cooling to room temperature to generate green crystals, which are then washed and filtered with DMF and ethanol respectively, and dried to obtain [Zn@Cu(pvb)2]·DMF.

[0025] The present application embodiment is implemented as follows:

[0026] Embodiment 1: A method for preparing a second-order nonlinear optical material, comprising the following steps:

[0027] Step 1, 0.022 g (0.1 mmol) of trans-2-(4-pyridyl)-4-vinylbenzoic acid (Hpvb), 11.18 mg (0.0375 mmol) of Zn(NO3)2·6H2O and 3.03 mg (0.0125 mmol) of Cu(NO3)2·3H2O were placed in a 20 ml reaction glass bottle.

[0028] Step 2: Add 2 ml of DMF and 2 ml of ethanol to the reaction glass bottle, sonicate for 10 minutes, and then heat at 120°C for 48 hours.

[0029] Step 3, finally cooling to room temperature at 5°C per hour to generate green crystals, which were then washed and filtered with DMF and ethanol respectively, and finally dried to obtain [Zn 0.75 @Cu 0.25 (pvb)2]·DMF.

[0030] In this embodiment, as shown in the attached Figure 1 As shown, [Zn 0.75 @Cu 0.25(pvb)2]·DMF second harmonic intensity as a function of excitation light wavelength (left) and Log-log plot of second harmonic intensity versus excitation light power.

[0031] The compounds of the present invention [Zn 0.75 @Cu 0.25 (pvb)2]·DMF, as a frequency doubling crystal among second-order nonlinear optical materials, has a higher second-order nonlinear coefficient, which is 25 times that of the MOFs described in CN106192011B, 20 times that of the general standard sample - urea crystal, and compared with the conventional frequency doubling crystals on the market, it is 46 times that of KDP, 3 to 7 times that of LiNbO3, and 7 times that of BBO, which shows that it has a higher conversion efficiency than these frequency doubling crystals.

[0032] Embodiment 2

[0033] A method for preparing a second-order nonlinear optical material comprises the following steps:

[0034] Step 1, 0.022 g (0.1 mmol) of trans-2-(4-pyridyl)-4-vinylbenzoic acid (Hpvb), 4.47 mg (0.015 mmol) of Zn(NO3)2·6H2O and 8.47 mg (0.035 mmol) of Cu(NO3)2·3H2O were placed in a 20 ml reaction glass bottle.

[0035] Step 2, add 2 ml of DMF and 2 ml of ethanol to a glass bottle, ultrasonicate for 10 minutes, and then heat at 120°C for 48 hours.

[0036] In step 3, the temperature was finally lowered to room temperature at 5°C per hour to generate green crystals, which were then washed and filtered with DMF and ethanol, respectively, and finally dried to obtain [Zn 0.3 @Cu 0.7 (pvb)2]·DMF.

[0037] In this embodiment, as shown in the attached Figure 2 As shown, [Zn 0.3 @Cu 0.7 (pvb)2]·DMF second harmonic intensity as a function of excitation light wavelength (left) and Log-log plot of second harmonic intensity as a function of excitation light power

[0038] Embodiment three:

[0039] A method for preparing a second-order nonlinear optical material comprises the following steps:

[0040] Step 1, 0.022 g (0.1 mmol) of trans-2-(4-pyridyl)-4-vinylbenzoic acid (Hpvb), 11.92 mg (0.04 mmol) of Zn(NO3)2·6H2O and 2.42 mg (0.01 mmol) of Cu(NO3)2·3H2O were placed in a 20 ml reaction glass bottle.

[0041] Step 2, add 2 ml of DMF and 2 ml of ethanol to the reaction glass bottle, ultrasonicate for 10 minutes, then heat at 120 ° C for 48 hours, and finally cool to room temperature at 5 ° C per hour to generate green crystals, which are then washed and filtered with DMF and ethanol respectively, and finally dried to obtain [Zn 0.8 @Cu 0.2 (pvb)2]·DMF.

[0042] In this embodiment, as shown in the attached Figure 3 As shown, [Zn 0.8 @Cu 0.2 (pvb)2]·Log-log plot of the second harmonic intensity of DMF as a function of the excitation light wavelength (left) and the second harmonic intensity as a function of the excitation light power (right).

[0043] Conclusion: As attached Figure 1-Figure 3 It can be seen that [Zn 0.75 @Cu 0.25 The intensity of the doubled frequency light obtained by (pvb)2]·DMF under 950nm wavelength excitation is more than one hundred times that of Examples 2 and 3 under the same experimental conditions. The effective second-order nonlinear coefficient is calculated to be ~4 times that of Example 2, ~41 times that of Example 3, and ~20 times that of urea.

[0044] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for preparing a second-order nonlinear optical material, characterized in that: The steps include: In step 1, 0.022 g of trans-2-(4-pyridyl)-4-vinylbenzoic acid Hpvb, 11.18 mg of Zn(NO3)2·6H2O and 3.03 mg of Cu(NO3)2·3H2O were placed in a 20 ml reaction glass bottle; Step 2, add 2 ml of DMF and 2 ml of ethanol to the reaction glass bottle, sonicate for 10 minutes, and then heat at 120° C. for 48 hours; Step 3, finally cooling to room temperature at 5°C per hour to generate green crystals, which were then washed and filtered with DMF and ethanol respectively, and finally dried to obtain [Zn 0.75 @Cu 0.25 (pvb)2]·DMF.

2. A method for preparing a second-order nonlinear optical material, characterized in that: The steps include: In step 1, 0.022 g of trans-2-(4-pyridyl)-4-vinylbenzoic acid Hpvb, 4.47 mg of Zn(NO3)2·6H2O and 8.47 mg of Cu(NO3)2·3H2O were placed in a 20 ml reaction glass bottle; Step 2, add 2 ml of DMF and 2 ml of ethanol into a glass bottle, sonicate for 10 minutes, and then heat at 120° C. for 48 hours; Step 3, finally cooling to room temperature at 5°C per hour to generate green crystals, which were then washed and filtered with DMF and ethanol respectively, and finally dried to obtain [Zn 0.3 @Cu 0.7 (pvb)2]·DMF.

3. A method for preparing a second-order nonlinear optical material, characterized in that: The steps include: In step 1, 0.022 g of trans-2-(4-pyridyl)-4-vinylbenzoic acid Hpvb, 11.92 mg of Zn(NO3)2·6H2O and 2.42 mg of Cu(NO3)2·3H2O were placed in a 20 ml reaction glass bottle; Step 2, add 2 ml of DMF and 2 ml of ethanol to the reaction glass bottle, sonicate for 10 minutes, and then heat at 120° C. for 48 hours; Step 3, finally cooling to room temperature at 5°C per hour to generate green crystals, which were then washed and filtered with DMF and ethanol respectively, and finally dried to obtain [Zn 0.8 @Cu 0.2 (pvb)2]·DMF.

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