Organic micromolecule semiconductor bifunctional material, preparation method and application thereof

Abstract

The invention relates to an organic micromolecule semiconductor bifunctional material, a preparation method and application thereof, and the organic micromolecule semiconductor bifunctional material is used for an electron donor or an electron acceptor in a photoactive layer material of an organic photovoltaic cell, and is added into an active layer according to a corresponding proportion, so that the performance of an organic photovoltaic device can be remarkably improved, and enhanced photoelectric conversion efficiency can be obtained. According to the compound, an indacene fused ring is used as an electron donating unit, a thiophene ring is used as a bridging unit, and a wide-band-gap organic small molecule semiconductor with a main chain twisted structure is formed by utilizing the difference between a thiophene connection position and an end group electricity pulling unit; the compound has a higher lowest unoccupied molecular orbital (LUMO) energy level, and has a structure shown in the following general formula.

Description

Technical Field

[0001] The present invention belongs to the field of optoelectronic functional materials, and specifically relates to an organic small molecule semiconductor bifunctional material, a preparation method and an application thereof, and such molecules as bifunctional materials in a photoactive layer can be added to the active layer as electron donor materials or electron acceptor materials in corresponding proportions, and their application in organic solar cell (OSC) devices can significantly improve the comprehensive performance of the devices. Background Art

[0002] Organic solar cells (OSCs) are renewable and clean energy with potential application value. Due to their inherent advantages, such as light weight, flexibility, and large-scale production, they have attracted widespread attention from the scientific and industrial communities, and have made great progress in material and device design. Currently, new electron acceptor materials are mainly represented by Y6 and its analogs. With the continuous improvement of device technology, the photoelectric conversion efficiency (PCE) in single-junction cells has reached a commercial level, especially the short-circuit current density (J SC ) has achieved a high level, comparable to perovskite solar cells, but its open circuit voltage (V OC ) is generally not ideal, which also hinders the further improvement of OSC device performance. At the same time, another problem that needs to be solved for high-efficiency OSC devices is the large difference in charge mobility between the conjugated polymer electron donor and the electron acceptor material, which leads to charge aggregation and thus affects the fill factor (FF) of the device. Therefore, increasing V OC and improving charge mobility are necessary ways to enhance the performance of OSC devices.

[0003] The three-dimensional excessive aggregation and high crystallinity of Y6 and its derivatives will produce disproportionate charge mobility in the active layer of organic solar cells, among which the hole mobility (μ h ) is significantly lower than the electron mobility (μ e ). This difference leads to charge accumulation, which has a negative impact on the fill factor (FF). h As a strategy, for example, IDTT-M was introduced into the PM6:Y6 system, thereby increasing μ h to 6.44×10 -4 cm 2 V -1 s -1 , exceeding the 5.23×10 -4 cm 2 V -1 s -1, thereby improving the device's FF to 73.89% and PCE to 16.64%, which are better than the 72.45% and 15.48% of the corresponding binary devices [L. Xiao, X. Wu, G. Ren, M. A. Kolaczkowski, G. Huang, W. Tan, L. Ma, Y. Liu, X. Peng, Y. Min, and Y. Liu: Highly Efficient Ternary Solar Cells with Efficient Resonance Energy Transfer for Simultaneously Enhanced PhotovoltaicParameters, Advanced functional materials, 2021, 31(41), 2105304.] Chen et al. prepared the star-shaped molecule TF1 to inhibit the excessive aggregation of Y6 and enhance the stability of the morphological structure. This method makes μ h Increased from 1.99 to 3.04×10 -4 cm 2 V -1 s -1 And achieved a more balanced μ e / μ h The ratio is 1.36, which is lower than 1.75 of PM6:Y6 system. After optimization, the FF is increased to 75.08% and the PCE is increased to 16.91%. In addition, Chen et al. added a new multifunctional molecule BDTPF4-C6 to the PM6:Y6 binary blend. This method significantly improved the crystallinity of PM6, reduced the π-π stacking distance, and μ h Increased from 1.41 to 2.95×10 -4 cm 2 V -1 s -1 Leading to a more balanced charge transfer, μ e / μ hThe ratio was increased from 1.54 to 1.2. As a result, the device performance was improved overall, with FF reaching 79.16% and PCE reaching 17.93% [X.Liao, M.Liu, H.Pei, P.Zhu, X.Xia, Z.Chen, Y.Zhang, Z.Wu, Y.Cui, G.Xu, M.Gao, L.Ye, R.Ma, T.Liu, X.Lu, H.Zhu, and Y.Chen:'Regulating Crystallinity Mismatch Between Donor and Acceptor to Improve Exciton / Charge Transport in Efficient OrganicSolar Cells, Angewandte Chemie-International Edition, 2024, 63(11), e202318595.].

[0004] With the improvement of μ h In contrast, in the binary device based on the Y system, an appropriate third component is added to inhibit the excessive aggregation of the Y-type receptor and moderately reduce μ e It is another strategy to achieve balanced charge transfer efficiency and can effectively improve the device FF and overall efficiency of the Y6 system. For example, Kan et al. replaced 1-chloronaphthalene with 1-fluoronaphthalene in the PM6:Y6 system, which promoted the mixed phase and improved the morphological properties. This modification resulted in μ h 5.24×10 -4 cm 2 V -1 s -1 , μ e 5.28×10 -4 cm 2 V -1 s -1 , are lower than the device value of chloronaphthalene (μ h and μ e 7.34 and 5.55×10 respectively -4 cm 2 V -1 s -1 ), but μ h / μ eThe ratio is more balanced, which can increase FF from 71.9% to 77.8% and PCE from 15.7% to 17.5% [J.Lv, H.Tang, J.Huang, C.Yan, K.Liu, Q.Yang, D.Hu, R.Singh, J.Lee, S.Lu, G.Li, and Z.Kan: Additive-induced Miscibility Regulation and Hierarchical Morphology Enable 17.5% Binary Organic Solar Cells, Energy & Environmental Science, 2021, 14(5), 3044-3052.].

[0005] The inventors previously studied the use of amorphous small molecule receptor IO-4Cl as the third component in the PM6:Y6 system to prevent excessive aggregation of Y6, balance the charge mobility of PM6:Y6-based devices and increase V OC , achieving a PCE of 17.49% [S.Liu, Z.Xue, Z.Liang, B.Zhao, W.Wang.Z.Cong, H.Wu, G.Lu, J.Zheng, and C.Gao:'High-Performance PM6:Y6-Based Ternary Solar Cells with Enhanced Open Circuit Voltage and Balanced Mobilities via Doping a Wide-Band-Gap Amorphous Acceptor, ACS Applied Materials and Interfaces, 2024, 16 (28), 36705-36714.]. By adding high LUMO energy amorphous small molecule acceptors, another method is provided to improve the photovoltaic performance of PM6:Y6-based devices. In summary, all of these strategies can improve the performance of the device to a certain extent, but generally as a third component (additive) to improve the morphology of the active layer, there are still challenges such as low open circuit voltage and unbalanced mobility. Summary of the invention

[0006] In view of the defects or shortcomings of the prior art, the present invention provides an organic small molecule semiconductor material, which utilizes the steric effect, the push-pull electronic properties of the substituents, etc. to adjust the HOMO and LUMO energy levels, optical band gap and charge transfer efficiency of the material. This type of molecule can be used as a bifunctional material in the photoactive layer of an organic photovoltaic cell alone as an electron donor or electron acceptor, and can be added to the active layer in a corresponding proportion. Its application in organic solar devices can significantly improve the performance of the device.

[0007] In order to achieve the above tasks, the technical solution adopted by the present invention includes:

[0008] An organic small molecule semiconductor dual-functional material, the structure of which is shown in Formula I:

[0009]

[0010] In the formula, R1 is one of an alkyl group having 1 to 20 carbon atoms, a phenyl group substituted by an alkyl group or an alkoxy group, and a thienyl group substituted by an alkyl group or an alkoxy group;

[0011] R2 is a hydrogen atom, an alkyl group or an alkoxy group;

[0012] R3 is a straight or branched chain alkyl group having 1 to 12 carbon atoms;

[0013] X is an O, S or Se atom.

[0014] Optionally, R2 is an alkoxy group having 1 to 20 carbon atoms.

[0015] Optionally, R2 is an alkyl group having 1 to 20 carbon atoms.

[0016] Optionally, the structure of the material is as follows:

[0017]

[0018] Optional, including:

[0019]

[0020] Take 2.96g of the above compound 1 and 2.80g of compound 2, dissolve them in 160ml of toluene, protect with nitrogen, add 240mg of catalyst Pd(PPh3)4, heat to 90°C overnight, remove the solvent after cooling and dissolve with water, extract 3 times with 50ml of ethyl acetate, combine the organic phases, add anhydrous magnesium sulfate and dry for 2 hours, filter to remove the desiccant, and purify the obtained product by column chromatography, select 200-300 mesh column chromatography silica gel, and use ethyl acetate: n-hexane = 1:100 as the eluent to obtain 2.90g of red solid compound 3;

[0021] 120 mg of compound 3 and 85 mg of 1,3-diethyl-2-thiophenethione dihydropyrimidine-4,6 (1-hydrogen, 5-hydrogen) -dione were dissolved in 15 mL of chloroform, 0.4 mL of pyridine was added, and the mixture was heated to 65 ° C and stirred for 6 hours; after cooling, 20 ml of water was added, and the mixture was extracted with chloroform, the organic phase was dried over anhydrous magnesium sulfate and concentrated, poured into methanol for precipitation, and filtered to obtain a solid; the product was further purified by column chromatography, using 200-300 mesh column chromatography silica gel and chloroform as the eluent, and finally 120 mg of a black solid was obtained.

[0022] The application of any organic small molecule semiconductor dual-functional material described in the present invention as an electron donor or electron acceptor in a photoactive layer material of an organic photovoltaic cell.

[0023] Optionally, the active layer of the photoactive layer dual-functional material is a mass ratio system of Z10:Y6=1:1.2, Z10 is a donor, and Y6 is an acceptor;

[0024] When the organic small molecule semiconductor bifunctional material is doped into Y6 as an acceptor, the mass ratio of the organic small molecule semiconductor bifunctional material to the Y6 acceptor is 1:(11-23);

[0025] When the organic small molecule semiconductor bifunctional material is doped into Z10 as a donor, the mass ratio of the organic small molecule semiconductor bifunctional material to the Z10 donor is 1:(9-19).

[0026] Optionally, the active layer of the photoactive layer dual-functional material is a mass ratio system of PM6:BTP-eC9=1:1.2, PM6 is a donor, and BTP-eC9 is an acceptor;

[0027] When the organic small molecule semiconductor bifunctional material is incorporated into BTP-eC9 as an acceptor, the mass ratio of the organic small molecule semiconductor bifunctional material to the BTP-eC9 acceptor is 1:(11-23);

[0028] When the organic small molecule semiconductor bifunctional material is doped into PM6 as a donor, the mass ratio of the organic small molecule semiconductor bifunctional material to the PM6 donor is 1:(9-19).

[0029] Optionally, the active layer of the photoactive layer dual-functional material is a mass ratio system of PM6:L8-BO=1:1.2, PM6 is a donor, and L8-BO is an acceptor;

[0030] When the organic small molecule semiconductor bifunctional material is doped into L8-BO as an acceptor, the mass ratio of the organic small molecule semiconductor bifunctional material to the L8-BO acceptor is 1:(11-23);

[0031] When the organic small molecule semiconductor bifunctional material is doped into PM6 as a donor, the mass ratio of the organic small molecule semiconductor bifunctional material to the PM6 donor is 1:(9-19).

[0032] Beneficial effects of the present invention:

[0033] The organic small molecule semiconductor bifunctional material provided by the present invention introduces an electron-deficient unit into the 4-position of the bridged thiophene ring, introduces a certain distortion into the main chain of the molecule, and effectively adjusts the absorption spectrum and energy level of the material. This small molecule compound has a wide optical band gap, a strong absorption coefficient, a good charge transfer performance, and a higher minimum unoccupied molecular orbital energy level (LUMO). As a bifunctional material for organic solar cells, it can be added to the active layer in a corresponding proportion as an electron donor material or an electron acceptor material, and is blended with polymers such as electron donors Z10 and PM6 and electron acceptors Y6, L8-BO, BTP-eC9 to prepare organic solar devices, and the open circuit voltage and fill factor are improved, and the comprehensive photoelectric conversion efficiency is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0035] Figure 1 The absorption spectra of the solution and film of the compound i-IEDTB according to the embodiment of the present invention;

[0036] Figure 2 HOMO and LUMO energy levels of the compound i-IEDTB of the embodiment of the present invention;

[0037] Figure 3 The current-voltage curve of the Z10:Y6 photovoltaic device with i-IEDTB as the acceptor;

[0038] Figure 4 The current-voltage curve of the Z10:Y6 photovoltaic device with i-IEDTB as the donor;

[0039] Figure 5 The current-voltage curves of PM6:i-IEDTB photovoltaic devices with i-IEDTB as donor or acceptor;

[0040] Figure 6 Current-voltage curves of PM6:L8-BO photovoltaic devices with i-IEDTB as donor or acceptor. DETAILED DESCRIPTION

[0041] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0042] The present invention develops a small molecule bifunctional material with a twisted main chain and a wide band gap, which has a hole mobility superior to that of an electron, and a high LUMO energy level. At the same time, the characteristics of the twisted structure can adjust the crystallinity of the active layer, significantly reduce the excessive aggregation of donors or acceptors, and promote the coordinated distribution of electron and hole mobilities, so that V OC The organic small molecule involved in the present invention is a bifunctional material. In the active layer of an organic solar cell, it can be added to the active layer as an electron acceptor material or an electron donor material in a corresponding proportion. The device performance is better than the corresponding binary device. This bifunctional molecule is universal in Z10:Y6, PM6:BTP-eC9 and PM6:L8-BO systems, and plays a key role in regulating the crystal arrangement and carrier balance in the active layer of the photovoltaic device, thereby improving the overall performance of the organic solar cell.

[0043] The present invention provides an organic small molecule semiconductor dual-functional material, the general structure of which is as follows:

[0044]

[0045] In the formula, R1 is independently an alkyl group having 1 to 20 carbon atoms, a phenyl group substituted by an alkyl group or an alkoxy group, or a thienyl group substituted by an alkyl group or an alkoxy group, R2 is independently a hydrogen atom, an alkyl group, or an alkoxy group, R3 is a straight chain or branched chain alkyl group having 1 to 12 carbon atoms, and X is independently an O, S, or Se atom. As a dual-functional material for a photoactive layer, it is used in the preparation of organic photovoltaic cells to improve device performance.

[0046] For example, R2 is an alkoxy group having 1 to 20 carbon atoms.

[0047] For example, R2 is an alkyl group having 1 to 20 carbon atoms.

[0048] The organic small molecule semiconductor bifunctional material provided by the present invention, as a photoactive layer bifunctional material, can effectively adjust the crystallization properties of the material in the active layer Z10:Y6 system, reduce excessive aggregation of receptors, promote the coordinated distribution of electron and hole mobility, significantly improve the open circuit voltage and fill factor, and comprehensively improve the device performance of organic photovoltaic cells.

[0049] The organic small molecule semiconductor bifunctional material provided by the present invention, as a photoactive layer bifunctional material, can effectively adjust the crystallization properties of the material in the active layer PM6:BTP-eC9 system, reduce excessive aggregation of receptors, promote the coordinated distribution of electron and hole mobility, significantly improve the open circuit voltage and fill factor, and comprehensively improve the device performance of organic photovoltaic cells.

[0050] The organic small molecule semiconductor bifunctional material provided by the present invention, as a photoactive layer bifunctional material, effectively adjusts the crystallization properties of the material in the active layer PM6:L8-BO system, reduces excessive aggregation of receptors, promotes the coordinated distribution of electron and hole mobility, significantly improves the open circuit voltage and fill factor, and comprehensively improves the device performance of organic photovoltaic cells.

[0051] The device structure is ITO / PEDOT:PSS / active layer / PDINO / Al. The wide bandgap electron donor polymer in the active layer material includes DA-type binary or ternary polymer donors based on bisfluorobenzotriazole, benzo[1,2-b:4,5-b']dithiophene, and benzo[1,2-C:4,5-C']dithiophene-4,8-dione, and the structure is as follows:

[0052]

[0053] The electron acceptor materials in the active layer materials include A-DA'DA type Y6, L8-BO, BTP-eC9 and other molecules, and the structure is as follows:

[0054]

[0055] Example 1: Bifunctional organic semiconducting material i-IEDTB and its application in organic solar devices of Z10:Y6 system.

[0056] (1) The synthesis route of compound i-IEDTB is as follows:

[0057]

[0058] Scheme.1 Synthesis route of compound i-IEDTB

[0059] Take 2.96g of the above compound 1 and 2.80g of compound 5-bromo-4-(2-ethylhexyloxy)-thiophene-3-aldehyde (compound 2), place them in a 250ml three-necked flask, dissolve them in 160ml toluene, protect with nitrogen, add 240mg of catalyst Pd(PPh3)4, heat at 90°C overnight, stop heating, cool, spin off the solvent, then add 50ml of water, extract with ethyl acetate (50ml is extracted three times), combine the organic phases, add anhydrous magnesium sulfate and dry for 2 hours, filter to remove the desiccant, and purify the resulting product by column chromatography, select 200-300 mesh column chromatography silica gel, and use ethyl acetate: n-hexane (volume ratio 1:100) as the eluent to obtain 2.90g of red solid compound 3; 1 H NMR (500MHz, CDCl3), δ (ppm): 9.93 (s, 2H), 7.42 (s, 2H), 7.25 (s, 2H), 7.16 (d, 8H), 7.09 (d, 8H), 6.86 (s, 2H),4.05(d,4H),2.57(t,8H),1.76(m,2H),1.60-1.42(m,16H),1.34-1.27(m,32H),0.95-0.86(m,24H). 13 C NMR (125MHz, CDCl3), δ (ppm): 180.27, 164.75, 157.21, 153.90, 146.63, 143.03, 141.95, 141.10, 139.11, 135.25, 128.54, 127.80, 121. 81,119.34,117.78,111.20,74.53,63.15,39.52,35.58,31.73,31.35,30.41,29.15,29.03,23.82,22.99,22.60,14.10,14.06,11.14.

[0060] 120 mg of compound 3 and 1,3-diethyl-2-thiophenethione dihydropyrimidine-4,6 (1-hydrogen, 5-hydrogen) -dione (85 mg) were dissolved in 15 mL of chloroform, 0.4 mL of pyridine was added, heated to 65 ° C and stirred for 6 hours. After cooling, 20 ml of water was added, and the mixture was extracted with chloroform. The organic phase was dried over anhydrous magnesium sulfate and concentrated, poured into methanol for precipitation, and filtered to obtain a solid. The product was further purified by column chromatography, using 200-300 mesh column chromatography silica gel and chloroform as the eluent, and finally 120 mg of black solid was obtained with a yield of 80.8%. 1H NMR(500MHz, CDCl3), δ8.94(s,2H),7.52(s,2H),7.47(s,2H),7.17(d,8H),7.11(d,8H),6.91(s,2H),4.59( m,8H),4.12(m,4H),2.58(t,8H),1.87(m,2H),1.61-1.55(m,16H),1.35-1.30(m,44H),0.99-0.86(m,24H). 13 C NMR (125MHz, CDCl3), δ178.77,169.44,161.43,160.67,158.17,154.48,154.35, 145.23,143.42,142.11,140.77,139.33,135.56,128.63,127.80,123.59,118.1 1,117.46,109.49,105.72,75.20,63.19,43.77,42.93,39.35,35.58,31.72,31.34,30.41,29.11,29.02,23.88,22.97,22.60,14.10,14.05,12.59,12.43,11.07.

[0061] Figure 1 The absorption spectra of the compound i-IEDTB solution and film of the embodiment of the present invention; it has strong absorption in the range of 500-700nm, which can be used to match the photoactive layer with the donor or acceptor, which is beneficial to absorb more sunlight. At the same time, the film absorption is red-shifted relative to the solution absorption, indicating that the material has good accumulation in the film state, which is beneficial to the morphology stability of the active layer.

[0062] Figure 2 The HOMO and LUMO energy levels of the compound i-IEDTB of the embodiment of the present invention are shown in Table 1. The oxidation potential / reduction potential is 0.75V / -1.09V as measured by electrochemical cyclic voltammetry, and the corresponding molecular LUMO / HOMO energy levels are calculated to be -3.62 / -5.46eV. It has a suitable energy level structure and can be used for photoactive layer materials.

[0063] (2) Compound i-IEDTB is used in the Z10:Y6 system to prepare organic photovoltaic devices:

[0064] The device structure adopts ITO / PEDOT:PSS / active layer / PDINO / Al. PEDOT:PSS is spin-coated on ITO glass and then baked at 150℃ for 15min. The donor polymer Z10 and the acceptor material Y6 are dissolved in chloroform according to the corresponding proportions. The concentration of Z10 is controlled to be 7mg / ml. The bifunctional molecule i-IEDTB is added to different proportions of Z10:Y6. With i-IEDTB as the acceptor material and the mass ratio of donor Z10 fixed to 1, Y6:i- The mass ratios of Z10:i-IEDTB were 1.15:0.05 and 1.1:0.10; i-IEDTB was used as the donor material and the mass ratio of acceptor Y6 was fixed at 1.2. The mass ratios of Z10:i-IEDTB were 0.95:0.05 and 0.90:0.10; the mixture was then spin-coated at 3000 rpm with a thickness of 90 nm, the active layer was annealed at 90 °C for 10 min, and then a PDINO layer was spin-coated. Finally, a 100 nm aluminum layer was deposited under vacuum with an effective area of ​​0.039 cm 2 Then the device performance is tested to obtain the current density (J)-voltage (V) curve and EQE, and finally the device PCE is calculated. The device performance under the test conditions of the relevant devices is shown in Table 1. Figure 3 and 4 shown.

[0065] Table 1 i-IEDTB is used for the performance of organic solar devices in the active layer Z10:Y6 system.

[0066]

[0067]

[0068] a) Data are the average and deviation of 10 devices

[0069] Table 1 and Figure 3 It can be seen that when i-IEDTB is used as an acceptor material in a Z10:Y6 photovoltaic device, when the addition ratio Z10:(Y6:i-IEDTB)=1:1.15:0.05, the open circuit voltage V OC Reaching 0.849V, the short-circuit current density J SC Slightly decreased by 26.79 mA cm -2 , the filling factor FF is increased to 78.02%, and the photoelectric conversion efficiency is increased to 17.70%. When the addition ratio Z10:(Y6:i-IEDTB)=1:1.1:0.1, V OC =0.861V, J SC =26.66mA cm -2 , FF=79.91%, the photoelectric conversion efficiency is increased to 17.61%, and the device performance is significantly improved.

[0070] Table 1 and Figure 4 It is shown that when i-IEDTB is used as a donor material in Z10:Y6 photovoltaic devices, when the addition ratio (Z10:i-IEDTB):Y6=0.95:0.05:1.2, V OC =0.846V, J SC =26.43 mA cm -2 , FF = 78.08%, the photoelectric conversion efficiency is increased to 17.47%, when the addition ratio (Z10: i-IEDTB): Y6 = 0.9: 0.1: 1.2, V OC =0.85V, J SC =26.24 mA cm -2 , FF=76.37%, and the photoelectric conversion efficiency is increased to 17.03%. Compared with the Z10:Y6 device, the performance is significantly improved.

[0071] Example 2: Bifunctional organic semiconducting material i-IEDTB and its use in organic solar devices of PM6:BTP-eC9 system.

[0072] The device structure adopts ITO / PEDOT:PSS / active layer / PDINO / Al. PEDOT:PSS is spin-coated on ITO glass and then baked at 150°C for 15 minutes. The donor polymer PM6 and the acceptor material BTP-eC9 are dissolved in chloroform in corresponding proportions, and the PM6 concentration is controlled to be 7 mg / ml. The bifunctional molecule i-IEDTB is added to different proportions of PM6:BTP-eC9. Using i-IEDTB as the acceptor material and fixing the mass ratio of the donor PM6 at 1, the mass ratio of i-IEDTB:BTP-eC9 was selected as 1.15:0.05; using i-IEDTB as the donor material and fixing the mass ratio of the acceptor BTP-eC9 at 1.2, the mass ratio of PM6:i-IEDTB was selected as 0.95:0.05; then the mixture was spin-coated at 3000 rpm with a thickness of 90 nm, the active layer was annealed at 90 °C for 10 min, and then the PDINO layer was spin-coated, and finally a 100 nm aluminum layer was deposited under vacuum with an effective area of ​​0.039 cm 2 Then the device performance is tested to obtain the current density (J)-voltage (V) curve and EQE, and finally the device PCE is calculated. The performance of the test-related devices is shown in Table 2 and Figure 5 shown.

[0073] Table 2 i-IEDTB used for active layer PM6: Performance of organic solar device in BTP-eC9 system

[0074]

[0075]

[0076] a) Data are the average and deviation of 10 devices

[0077] From Table 2 and Figure 5 The results show that when i-IEDTB is used as a donor material in PM6:BTP-eC9 photovoltaic devices, when the addition ratio (PM6:i-IEDTB):BTP-eC9=0.95:0.05:1.2, the open circuit voltage V OC Reaching 0.838V, the short-circuit current density J SC Slightly decreased 27.99 mA cm -2 , the fill factor FF is increased to 75.22%, the photoelectric conversion efficiency is increased to 17.62%, and the overall performance of the device is improved. When i-IEDTB is used as an acceptor material in PM6:BTP-eC9 photovoltaic devices, when the addition ratio PM6:(BTP-eC9:i-IEDTB)=1:1.15:0.05, the open circuit voltage V OC Reaching 0.84V, the short-circuit current density J SC Increased to 28.27 mA cm -2 The fill factor FF is increased to 76.47%, the photoelectric conversion efficiency is increased to 18.14%, and the device performance is comprehensively improved.

[0078] Example 3: Bifunctional organic semiconducting material compound i-IEDTB and its use in organic solar devices of PM6:L8-BO system.

[0079] The device structure adopts ITO / PEDOT:PSS / active layer / PDINO / Al. PEDOT:PSS is spin-coated on ITO glass and then baked at 150℃ for 15min. The donor polymer PM6 and the acceptor material L8-BO are dissolved in chloroform according to the corresponding ratio. The PM6 concentration is controlled to be 7mg / ml. The bifunctional molecule i-IEDTB is added to different ratios of PM6:L8-BO. ​​i-IEDTB is used as the acceptor material. The mass ratio of the donor PM6 is fixed to 1. Under the conditions, the mass ratio of i-IEDTB:L8-BO was selected as 1.15:0.05; i-IEDTB was used as the donor material, and the mass ratio of the acceptor L8-BO was fixed at 1.2, and the mass ratio of PM6:i-IEDTB was selected as 0.95:0.05; then the mixture was spin-coated at 3000 rpm with a thickness of 90 nm, the active layer was annealed at 90 °C for 10 min, and then the PDINO layer was spin-coated, and finally a 100 nm aluminum layer was deposited under vacuum with an effective area of ​​0.039 cm 2Then the device performance is tested to obtain the current density (J)-voltage (V) curve and EQE, and finally the device PCE is calculated. The performance of the test-related devices is shown in Table 3 and Figure 6 shown.

[0080] Table 3 Performance of organic solar devices using i-IEDTB for active layer PM6:L8-BO system

[0081]

[0082]

[0083] a) Data are the average and deviation of 10 devices

[0084] From Table 3 and Figure 6 It can be seen that when i-IEDTB is used as a donor material in PM6:L8-BO photovoltaic devices, when the addition ratio is (PM6:i-IEDTB):L8-BO=0.95:0.05:1.2, the device open circuit voltage V OC Reaching 0.883V, the short-circuit current density J SC Increased to 26.14 mA cm -2 , the fill factor FF is 78.35%, the photoelectric conversion efficiency is increased to 18.06%, and the performance indicators of photovoltaic devices are all improved. i-IEDTB is used as an acceptor material in PM6:L8-BO photovoltaic devices. When the addition ratio PM6:(L8-BO:i-IEDTB)=1:1.15:0.05, the device open circuit voltage V OC Reaching 0.877V, short-circuit current density J SC Increase to 26.20mAcm -2 The filling factor FF is 78.63%, and the photoelectric conversion efficiency is increased to 18.08%. Compared with the PM6:L8-BO binary photovoltaic device, all performance indicators are improved.

[0085] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. An organic small molecule semiconductor dual-functional material, characterized in that: The structure of the material is shown in Formula I: In the formula, R1 is one of an alkyl group having 1 to 20 carbon atoms, a phenyl group substituted by an alkyl group or an alkoxy group, and a thienyl group substituted by an alkyl group or an alkoxy group; R2 is a hydrogen atom, an alkyl group or an alkoxy group; R3 is a straight or branched chain alkyl group having 1 to 12 carbon atoms; X is an O, S or Se atom.

2. The organic small molecule semiconductor dual-functional material according to claim 1, characterized in that: The R2 is an alkoxy group having 1 to 20 carbon atoms.

3. The organic small molecule semiconductor dual-functional material according to claim 1 or 2, characterized in that: The R2 is an alkyl group having 1 to 20 carbon atoms.

4. The organic small molecule semiconductor dual-functional material according to claim 1 or 2, characterized in that: The structure of the material is as follows:

5. The method for preparing the organic small molecule semiconductor dual-functional material according to claim 4, characterized in that: include: Take 2.96g of the above compound 1 and 2.80g of compound 2, dissolve them in 160ml of toluene, protect with nitrogen, add 240mg of catalyst Pd(PPh3)4, heat to 90°C overnight, remove the solvent after cooling and dissolve with water, extract 3 times with 50ml of ethyl acetate, combine the organic phases, add anhydrous magnesium sulfate and dry for 2 hours, filter to remove the desiccant, and purify the obtained product by column chromatography, select 200-300 mesh column chromatography silica gel, and use ethyl acetate: n-hexane = 1:100 as the eluent to obtain 2.90g of red solid compound 3; 120 mg of compound 3 and 85 mg of 1,3-diethyl-2-thiophenethione dihydropyrimidine-4,6 (1-hydrogen, 5-hydrogen) -dione were dissolved in 15 mL of chloroform, 0.4 mL of pyridine was added, and the mixture was heated to 65 ° C and stirred for 6 hours; after cooling, 20 ml of water was added, and the mixture was extracted with chloroform, the organic phase was dried over anhydrous magnesium sulfate and concentrated, poured into methanol for precipitation, and filtered to obtain a solid; the product was further purified by column chromatography, using 200-300 mesh column chromatography silica gel and chloroform as the eluent, and finally 120 mg of a black solid was obtained.

6. Use of the organic small molecule semiconductor bifunctional material according to any one of claims 1 to 4 as an electron donor or electron acceptor in a photoactive layer material of an organic photovoltaic cell.

7. The use according to claim 6, characterized in that: The active layer of the photoactive layer dual-functional material is a mass ratio system of Z10:Y6=1:1.2, Z10 is a donor, and Y6 is an acceptor; When the organic small molecule semiconductor bifunctional material is doped into Y6 as an acceptor, the mass ratio of the organic small molecule semiconductor bifunctional material to the Y6 acceptor is 1:(11-23); When the organic small molecule semiconductor bifunctional material is doped into Z10 as a donor, the mass ratio of the organic small molecule semiconductor bifunctional material to the Z10 donor is 1:(9-19).

8. The use according to claim 6, characterized in that: The active layer of the photoactive layer dual-functional material is a mass ratio system of PM6:BTP-eC9=1:1.2, PM6 is a donor, and BTP-eC9 is an acceptor; When the organic small molecule semiconductor bifunctional material is incorporated into BTP-eC9 as an acceptor, the mass ratio of the organic small molecule semiconductor bifunctional material to the BTP-eC9 acceptor is 1:(11-23); When the organic small molecule semiconductor bifunctional material is doped into PM6 as a donor, the mass ratio of the organic small molecule semiconductor bifunctional material to the PM6 donor is 1:(9-19).

9. The use according to claim 6, characterized in that: The active layer of the photoactive layer dual-functional material is a mass ratio system of PM6:L8-BO=1:1.2, PM6 is a donor, and L8-BO is an acceptor; When the organic small molecule semiconductor bifunctional material is doped into L8-BO as an acceptor, the mass ratio of the organic small molecule semiconductor bifunctional material to the L8-BO acceptor is 1:(11-23); When the organic small molecule semiconductor bifunctional material is doped into PM6 as a donor, the mass ratio of the organic small molecule semiconductor bifunctional material to the PM6 donor is 1:(9-19).

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