CN116444524A - Small-molecule thermoelectric performance auxiliary agent with side chain containing quaternary ammonium salt group, and preparation method and application thereof - Google Patents

Abstract

The invention discloses a small molecule thermoelectric performance additive with a side chain containing a quaternary ammonium salt group, a preparation method and an application thereof, and belongs to the field of organic semiconductor materials. The invention introduces a quaternary ammonium salt group into the side chain of the small molecule, and realizes the improvement of the performance of the existing organic polymer thermoelectric material. The compound provided by the invention has good solubility and a high degree of miscibility with polymers, which is beneficial to the solution processing of devices.

Description

A kind of small molecule thermoelectric performance additive containing quaternary ammonium salt group in side chain and preparation method thereof and application

technical field

The invention relates to the field of organic semiconductor materials, in particular to a small molecule thermoelectric performance additive with a side chain containing a quaternary ammonium salt group, a preparation method and application thereof.

Background technique

The thermoelectric effect can realize the mutual conversion of heat energy and electric energy, and has great potential in waste heat recovery and green refrigeration applications. Compared with inorganic thermoelectric materials, organic polymer thermoelectric materials have a wide range of sources, strong molecular modification, and good solubility. They can be prepared in large areas by solution methods such as spray coating and roll-to-roll, and they also have intrinsic flexibility. Can meet the requirements of wearable devices. However, the performance of current organic polymer thermoelectric materials still lags behind that of inorganic materials, and a method to improve the performance of existing organic polymer thermoelectric materials is urgently needed.

Quaternary ammonium salts are compounds in which all four hydrogen atoms in ammonium ions are replaced by hydrocarbon groups. In recent years, more and more attention has been paid to the use of quaternary ammonium salt compounds to construct organic polymer thermoelectric materials, but the currently reported In most thermoelectric materials, quaternary ammonium salt compounds are mainly used as host molecules or dopants (Adv. Additives There are relatively few additives to improve the performance of polymer thermoelectric materials. The development of this type of third-component additive can further improve the performance of existing organic polymer thermoelectric materials, and has important research significance and practical value for the development of organic polymer thermoelectric devices.

Contents of the invention

The invention provides a small molecule thermoelectric performance additive with a side chain containing a quaternary ammonium salt group and its preparation method and application. Improved performance of polymer thermoelectric materials.

The present invention firstly provides a kind of compound, its structural formula is as shown in formula I:

In the formula I, R and R' are all selected from C1-C50 straight chain or branched chain alkyl, C1-C50 alkoxy, C7-C50 aralkyl and C5-C50 heteroalkyl any;

X is selected from any one of hydrogen, fluorine, chlorine, bromine and iodine; _X is selected from any one of chlorine, bromine and iodine.

In the above compound, the heteroatom in the heteroalkyl group is at least one of oxygen, sulfur and selenium; the number of substitutions of the heteroatom is 1-10;

In the aralkyl, the alkyl is any one of C1-C50 alkyl, C1-C50 alkylcarbonyl, acyloxy, nitrile and C1-C50 alkoxy; the aralkyl The number of alkyl substituents is an integer of 1-4.

In the above compound, in the formula I, R and R' are selected from any one of C1-C16 straight chain or branched chain alkyl; R and R' are the same or different;

Specifically, in the formula I, R and R' are selected from any one of C1-C10 straight chain or branched chain alkyl groups; R and R' are the same or different;

More specifically, R is n-octyl; R' is methyl; X is selected from any one of hydrogen, fluorine, chlorine, bromine, and iodine; X _is selected from any one of chlorine, bromine, and iodine.

The present invention also provides a preparation method of the above-mentioned compound, comprising the steps of:

Under an inert atmosphere, the compound shown in formula II and the compound shown in formula III are subjected to a substitution reaction in an organic solvent to obtain the compound shown in formula I;

In the formula II and formula III, R, R', X and _X1 are the same as those in the compound shown in the above formula I.

In the above preparation method, the molar ratio of the compound represented by formula II to the compound represented by formula III is 1:10-20; specifically, it can be 1:10;

The organic solvent is at least one of toluene, xylene, chlorobenzene and o-dichlorobenzene;

The inert atmosphere is nitrogen and/or argon atmosphere;

The temperature of the substitution reaction is 90-110°C, specifically 100°C; the time is 24-72h, specifically 24h.

In the above preparation method, after the substitution reaction, there are steps of suction filtration and washing the solid with chloroform.

The application of the above compounds as general-purpose performance aids for organic polymer thermoelectric materials also belongs to the protection scope of the present invention.

In the above application, the organic polymer is a conjugated polymer.

Specifically, the organic polymer is Among them, n is 10-99.

In the above application, the molar ratio of the compound represented by formula I to the repeating unit of the organic polymer is 1:15-45; specifically, it may be 1:30.

The application of the above compound (compound represented by formula I) as an additive in improving the thermoelectric performance of an organic polymer.

The improved thermoelectric properties of the organic polymer are p-type thermoelectric properties.

The organic polymer is a conjugated polymer.

Specifically, the organic polymer is Among them, n is 10-99.

The present invention has following beneficial effect:

(1) The raw materials used in the synthesis are convenient and easy to get, and are easy to industrialized production;

(2) The small-molecule thermoelectric performance additives containing quaternary ammonium salt groups in the side chain of the present invention can improve the p-type thermoelectric performance of existing organic polymer materials;

(3) The compound itself has good solubility and a high degree of miscibility with polymers, which is beneficial to the solution processing of devices.

Description of drawings

Fig. 1 is the preparation method flowchart of DPPNMe ₃ Br in embodiment 1;

Fig. 2 is the ¹ H-NMR figure of DPPNMe ₃ Br in embodiment 1;

Fig. 3 is the ¹³ C-NMR figure of DPPNMe ₃ Br in embodiment 1;

Fig. 4 is based on the DPPNMe ₃ Br promotion polymer PDPP-EDOT thermoelectric performance effect of embodiment 2;

Figure 5 is a synthetic route diagram of the polymer PDPP-EDOT.

Detailed ways

The present invention will be further described in detail below in conjunction with specific embodiments, and the given examples are only for clarifying the present invention, not for limiting the scope of the present invention.

The experimental methods in the following examples are conventional methods unless otherwise specified.

Quantitative experiments in the following examples were all set up to repeat the experiments three times, and the results were averaged.

The materials and reagents used in the following examples can be obtained from commercial sources unless otherwise specified.

The structural formula of the raw material compound 1 used in the following embodiment 1 is It was purchased from Solon Organic Optoelectronics Technology (Beijing) Co., Ltd.

_NMe3 was purchased from Beijing Bailingwei Technology Co., Ltd.

Example 1

The synthesis of the compound shown in formula I (in formula I, R is n-octyl, R' is methyl, X is a bromine atom, X ₁ is a bromine atom; define this compound as DPPNMe ₃ Br) specific reaction steps conditions are as follows:

The chemical reaction flow chart is shown in Fig. 1. The specific method is as follows: Compound 1 (0.2 mmol) was dissolved in 50 mL of toluene, NMe ₃ (2 mmol) was added, nitrogen was introduced, heated to 100° C. for 24 hours, and the reaction was stopped. After suction filtration, the obtained solid was washed with chloroform to obtain DPPNMe ₃ Br (0.178 mmol, yield: 88%).

The structure confirmation data are as follows: ¹ H NMR (400MHz, Dimethylsulfoxide-d ₆ ): δ=8.53(d,2H),7.58(d,2H),3.92(t,4H),3.29(m,4H),3.04(s ,18H),1.70-1.59(m,8H),1.35-1.26(m,16H).

Figure 2 and Figure 3 are the ¹ H-NMR chart and ¹³ C-NMR chart of DPPNMe ₃ Br respectively.

Example 2

The small molecule DPPNMe ₃ Br prepared in Example 1 above was dissolved in dimethyl sulfoxide at room temperature, and the concentration of the solution was 4 mg/mL. Mix 10 μL of the above _DPPNMe3Br solution with 300 μL of the polymer PDPP-EDOT in o-dichlorobenzene (4 mg/mL) so that the molar ratio of the compound _DPPNMe3Br to the repeating unit of the polymer PDPP-EDOT is 1:30 (The repeating unit is the smallest unit with the same chemical composition in the polymer, and the amount of its substance can be obtained by dividing the polymer mass by the relative molecular mass of the repeating unit) to obtain a mixed solution. The above-mentioned mixed solution was drop-coated on the glass substrate containing the gold electrode through a pipette gun, and the solution was dried in a vacuum drying oven at 60° C., and the thickness of the obtained film was about 2 microns. After heating at 120°C for 1 hour, it can be used for thermoelectric performance test.

The above-mentioned o-dichlorobenzene solution with a concentration of 4 mg/mL polymer PDPP-EDOT was drop-coated on the glass substrate containing the gold electrode through a pipette gun, and the solution was dried in a vacuum drying oven at 60 °C, and the thickness of the obtained film was about 2 Microns. After heating at 120°C for 1 hour, it can be used for thermoelectric performance test.

The thermoelectric performance test method is as follows:

Conductivity (σ) and Seebeck test (S) were performed on the same film substrate, and the conductivity was tested in a vacuum environment using a four-probe method. The Seebeck coefficient can be calculated by S=ΔV/ΔT, where ΔV is the thermal voltage between the two electrodes of the device when a temperature difference of ΔT is applied. ΔT is introduced by a semiconductor heating module, and ΔV is measured in vacuum by a commercial voltmeter. The temperature difference is measured by an infrared camera. The thermoelectric performance (PF) can be calculated from the electrical conductivity and Seebeck coefficient by the following formula

PF=σS ²

The results are shown in Figure 4. It can be seen from Figure 4 that DPPNMe ₃ Br improves the thermoelectric performance of the polymer PDPP-EDOT at 130°C from 94μWm ^-1 K ^-2 to 571μWm ^-1 K ^-2 .

The synthetic method of above-mentioned polymer PDPP-EDOT is as follows:

The synthetic route diagram of polymer PDPP-EDOT is shown in Figure 5, and the specific method is as follows: compound 2 (150mg, 0.16mmol) (preparation method refers to literature Wang, Z, Liu, Z, Ning, L, et al., ChargeMobility Enhancement for Conjugated Dpp-Selenophene Polymer by SimplyReplacing One Bulky Branching Alkyl Chain with Linear One at Each DppUnit. Chemistry of Materials 2018,30:3090.), 5,7-bis(trimethyltin-based)- 2,3-Dihydrothiophene[3,4-b][1,4]dioxane (74.8mg, 0.16mmol) (Beijing Yinuokai Technology Co., Ltd.), tris(dibenzylideneacetone) Dipalladium (3.0 mg, 0.0032 mmol) (Beijing Yinuokai Technology Co., Ltd.) and tris(o-methylphenyl) phosphine (7.6 mg, 0.025 mmol) (Beijing Yinuokai Technology Co., Ltd.) were dissolved in toluene (9 mL) In a mixed solvent with N,N-dimethylformamide (1 mL). Oxygen in the system was removed by cyclic freezing pumping method. The reaction system was stirred at 110° C. for 3 hours under nitrogen atmosphere. The system was then poured into methanol and stirred for 30 minutes, filtered and the solid collected. The obtained solid was subjected to Soxhlet extraction with methanol, acetone, n-hexane and chloroform in sequence (the temperature of the oil bath was 100° C., the time was 12 hours, and the amount of solvent was 80 mL) to remove existing oligomers and other impurities. The insoluble dark blue solid was collected and dried under vacuum at 50°C for 48 hours to obtain the purified polymer PDPP-EDOT.

In the structural formula of the polymer PDPP-EDOT, n is 10-99.

Claims (10)

1. A compound has a structural formula shown in formula I:

in the formula I, R, R' is selected from any one of C1-C50 linear or branched alkyl, C1-C50 alkoxy, C7-C50 aralkyl and C5-C50 heteroalkyl;

x is selected from any one of hydrogen, fluorine, chlorine, bromine and iodine; x is X ₁ Selected from any one of chlorine, bromine and iodine.

2. A compound according to claim 1, characterized in that: the heteroatom in the heteroalkyl is at least one of oxygen, sulfur and selenium; the heteroatom substitution number is 1-10;

in the aralkyl, the alkyl is any one of C1-C50 alkyl, C1-C50 alkylcarbonyl, acyloxy, nitrile group and C1-C50 alkoxy; the number of alkyl substituents in the aralkyl group is an integer of 1 to 4.

3. A compound according to claim 1, characterized in that: in the formula I, R, R' is selected from any one of C1-C16 linear or branched alkyl; r and R' are the same or different.

4. A compound according to claim 1, characterized in that: in the formula I, R, R' is selected from any one of C1-C10 linear or branched alkyl; r and R' are the same or different;

specifically, R is n-octyl; r' is methyl; x is selected from any one of hydrogen, fluorine, chlorine, bromine and iodine; x is X ₁ Selected from any one of chlorine, bromine and iodine.

5. A process for the preparation of a compound as claimed in any one of claims 1 to 4 comprising the steps of:

in an inert atmosphere, carrying out substitution reaction on a compound shown in a formula II and a compound shown in a formula III in an organic solvent to obtain a compound shown in a formula I;

said formula IIAnd of the formula III R, R', X and X ₁ The same as in the compound represented by formula I as defined in any one of claims 1 to 4.

6. The method of manufacturing according to claim 5, wherein: the molar ratio of the compound shown in the formula II to the compound shown in the formula III is 1: 10-20 parts;

the organic solvent is at least one of toluene, dimethylbenzene, chlorobenzene and o-dichlorobenzene;

the inert atmosphere is nitrogen and/or argon atmosphere;

the temperature of the substitution reaction is 90-110 ℃ and the time is 24-72 h.

7. Use of a compound according to any one of claims 1 to 4 as a universal performance aid for organic polymeric thermoelectric materials.

8. The use according to claim 7, characterized in that: the organic polymer is a conjugated polymer.

9. The use according to claim 8, characterized in that: the organic polymer isWherein n is 10 to 99.

10. The use according to any one of claims 7-9, characterized in that: in said applications, the molar ratio of the compound according to any one of claims 1 to 4 to the repeating units of the organic polymer is from 1:15 to 45.