CN-121975096-A - Narrow-band gap polymer small molecule receptor material and preparation method and application thereof

Abstract

The invention discloses a narrow-band gap polymer small molecule acceptor material shown in a formula I, a preparation method and application thereof, wherein benzotriazole is used as an electron-withdrawing unit of a central core to enhance the electron-pushing effect in molecules, a selenophene unit is embedded into a conjugated framework to expand conjugation by utilizing the strong electron delocalization capability of the selenophene unit, the absorption spectrum is widened, a cyano-indenone end group is connected with a pi bridge through a gamma site, and the problem of regional isomerism caused by uncertain connecting sites is avoided while the conjugation continuity is ensured. The polymer acceptor material obtained based on the strategy effectively overcomes the limitation of narrow absorption range of the existing polymer acceptor, shows strong near infrared light absorption characteristic, widens the absorption spectrum to 940nm, has a corresponding optical band gap as narrow as 1.32eV, and can realize high short-circuit current density of 25.2 mA cm ‑2 and energy conversion efficiency of 15% by taking the polymer acceptor material as an acceptor.

Inventors

• FU HUITING
• LI YUXIANG
• GUO SHIWEN
• PAN XIANGYU
• HAN DONG

Assignees

• 南京大学
• 南京大学深圳研究院

Dates

Publication Date

20260505

Application Date

20260209

Claims (10)

1. 1. The narrow-bandgap polymer small molecule acceptor material is characterized by having a chemical structure shown in a formula I: ; Wherein X 1 、X 2 、X 3 is independently selected from S or Se, and at least one of X 1 、X 2 is Se; Y 1 and Y 2 are independently selected from H or halogen; r 1 、R 2 、R 3 is independently selected from any one of C 1 ~C 28 straight-chain alkoxy, C 3 ~C 30 branched-chain alkoxy, C 1 ~C 28 straight-chain alkylthio, C 3 ~C 30 branched-chain alkylthio, C 1 ~C 28 straight-chain alkyl, C 3 ~C 30 branched-chain alkyl.
2. 2. The narrow bandgap polymeric small molecule acceptor material of claim 1, wherein X 1 and X 2 are both Se and X 3 is S.
3. 3. The narrow bandgap polymeric small molecule acceptor material of claim 1, wherein said X 1 、X 2 、X 3 is Se.
4. 4. The narrow bandgap polymeric small molecule acceptor material of claim 1, wherein R 1 、R 2 、R 3 is independently selected from any one of C 1 ~C 28 straight chain alkyl, C 3 ~C 30 branched alkyl.
5. 5. The narrow bandgap polymeric small molecule acceptor material of claim 1, wherein said small molecule acceptor material has the structural formula: Or (b) 。
6. 6. A method for preparing a narrow bandgap polymer small molecule acceptor material according to any one of claims 1 to 5, comprising the steps of: (1) Adding a Wilsmeier reagent into a 1, 2-dichloroethane or trichloromethane solution of a compound a in a nitrogen atmosphere at a temperature of minus 10-0 ℃, stirring and reacting for 1-2 hours at a temperature of 20-30 ℃, heating to 70-90 ℃ and continuously reacting for 12-16 hours, cooling after the reaction is finished, quenching by ice water, fully stirring, extracting by an organic solvent, drying, filtering, concentrating under reduced pressure to obtain a crude product, and separating by column chromatography to obtain a compound b; (2) Dissolving the compound b and the compound C obtained in the step (1) in chloroform, adding pyridine after degassing treatment, stirring and reacting for 12-16 hours at 65-75 ℃ under the protection of nitrogen, concentrating under reduced pressure after the reaction is finished to obtain a crude product, and separating by column chromatography to obtain a compound d; (3) Placing the compound d obtained in the step (2), the compound e and a palladium catalyst in a sealed reaction container, adding anhydrous toluene under the protection of nitrogen, stirring and reacting for 48-72 hours at 120-140 ℃, cooling the reaction liquid, and then carrying out methanol precipitation, filtration, column chromatography, reduced pressure concentration, secondary methanol precipitation and suction filtration drying to obtain a polymer f, wherein the synthetic route is as follows: 。
7. 7. the preparation method of the narrow bandgap polymer small molecule acceptor material according to claim 6, wherein in the step (2), the molar ratio of the compound c to the compound b is 3-4:1.
8. 8. The preparation method of the narrow-bandgap polymer small-molecule acceptor material according to claim 6, wherein in the step (3), the molar ratio of the compound d to the compound e is 1:1, and the palladium catalyst is used in an amount of 6-10% of the molar fraction of the compound d.
9. 9. An application of the narrow bandgap polymer small molecule acceptor material in preparation of photoelectric functional devices.
10. 10. The use according to claim 9, wherein the photovoltaic device is a polymer solar cell, wherein the narrow bandgap polymeric small molecule is used as acceptor material, mixed with a polymer donor material for the preparation of a photoactive layer of an organic solar cell.

Description

Narrow-band gap polymer small molecule receptor material and preparation method and application thereof Technical Field The invention belongs to the technical field of organic photovoltaics, and particularly relates to a narrow-band-gap polymer small-molecule receptor material, and a preparation method and application thereof. Background In recent years, the energy conversion efficiency of organic solar cells has achieved a significant breakthrough thanks to the continual innovation of non-fullerene small molecule acceptor materials. However, bulk heterojunction structures based on small molecular receptors are easy to aggregate and crystallize under long-term illumination or high temperature conditions, so that the morphology stability of an active layer is reduced, and meanwhile, a thin film of the bulk heterojunction structures is easy to crack under mechanical stress, so that ageing and failure of a device are accelerated. In contrast, all-polymer solar cells (all-PSCs) in which both the donor and acceptor are polymeric materials exhibit significant advantages in that by virtue of the lower diffusion rate of the polymer molecules and tight inter-chain entanglement, the system has more excellent morphological stability and mechanical flexibility, thus having outstanding potential in future industrial production and flexible wearable electronic device applications. Nevertheless, all-PSC development has long been limited by the scarcity of high performance polymer acceptor materials, which has been relatively slow. In recent years, the strategy of "polymerizing small molecule acceptors" has been widely demonstrated as an effective way to build high performance n-type polymer semiconductors, injecting new viability for all-PSCs. The polymer small molecule acceptor material developed based on the strategy has the advantages of high light absorption capacity, high electron mobility, low energy loss and the like of a small molecule system, and meanwhile has good stability of the polymer, so that the efficient and stable organic solar cell device is realized by assistance. However, the absorption range of the existing poly-small molecule receptor is relatively narrow, and particularly the photon capturing capability of the poly-small molecule receptor in the near infrared region is weak, so that the short-circuit current density of all-PSC is generally low, and the overall photovoltaic performance still significantly lags behind a small molecule system. Therefore, how to continuously regulate and optimize the optical characteristics of the material on a molecular level, develop a novel narrow band gap poly-small molecule receptor, widen the spectral response range of the novel narrow band gap poly-small molecule receptor, and become a core subject and a difficult point for promoting all-PSC performance breakthrough. Disclosure of Invention The invention aims at providing a narrow band gap polymer small molecule acceptor material with strong near infrared light absorption characteristic, a second aim of the invention is to provide a preparation method of the narrow band gap polymer small molecule acceptor material, and a third aim of the invention is to provide application of the narrow band gap polymer small molecule acceptor material. The narrow band gap polymer small molecule acceptor material has a chemical structure shown in a formula I: ; Wherein X 1、X2、X3 is independently selected from S or Se, and at least one of X 1、X2 is Se; Y 1 and Y 2 are independently selected from H or halogen; r 1、R2、R3 is independently selected from any one of C 1~C28 straight-chain alkoxy, C 3~C30 branched-chain alkoxy, C 1~C28 straight-chain alkylthio, C 3~C30 branched-chain alkylthio, C 1~C28 straight-chain alkyl, C 3~C30 branched-chain alkyl. Preferably, both X 1 and X 2 are Se, X 3 is S, and the structural formula is: 。 preferably, each of the X 1、X2、X3 is Se, and the structural formula is: 。 Preferably, R 1、R2、R3 is independently selected from any one of a linear alkyl group of C 1~C28, a branched alkyl group of C 3~C30. Preferably, Y 1 and Y 2 are both H. Preferably, the R 1 is selected from the group consisting of linear alkyl groups of C 10~C12. Preferably, R 2 is selected from branched alkyl of C 23 -25. Preferably, the R 3 is selected from the group consisting of linear alkyl groups of C 1~C3. Preferably, the small molecule acceptor material has a structural formula: Or (b) 。 The preparation method of the narrow-band gap polymer small molecule receptor material comprises the following steps: (1) Adding a Wilsmeier reagent into a 1, 2-dichloroethane or trichloromethane solution of a compound a in a nitrogen atmosphere at a temperature of minus 10-0 ℃, stirring and reacting for 1-2 hours at a temperature of 20-30 ℃, heating to 70-90 ℃ and continuously reacting for 12-16 hours, cooling after the reaction is finished, quenching by ice water, fully stirring, extracting by an organic solvent, drying, filtering, concentrating