A high-efficiency all-polymer organic solar cell structure and its preparation method

Abstract

The present invention relates to a high-efficiency all-polymer organic solar cell structure and a preparation method thereof, comprising a substrate, an anode, a hole transport layer, an active layer, an electron transport layer and a cathode from bottom to top; PM6:PY-IT is added to the active layer. The present invention selects the polymer acceptor BL-102 as the third component material. When the incorporation amount of the third component is 3 wt%, while realizing complementary absorption with the main system to enhance the utilization of sunlight, it also affects the crystallinity of the donors and acceptors in the active layer, inhibits the aggregation of the donors and acceptors, forms a more ordered molecular packing, enhances the solubility of the donors and acceptors, thereby forming a more donor-acceptor interpenetrating nanoscale percolation network, and finally realizes efficient exciton dissociation and carrier transport in the ternary system.

Description

Technical Field

[0001] The present invention relates to a high-efficiency all-polymer organic solar cell structure and a preparation method thereof, belonging to the technical field of the preparation of organic solar cell structures. Background Art

[0002] In recent years, all-polymer solar cells (all-PSCs) have received extensive attention in the scientific research community due to their good film ductility, excellent mechanical flexibility and good morphological stability. Thanks to the "polymerized small molecule acceptor" (PSMA) strategy and chemical structure design methods, polymer acceptor materials have achieved rapid development. Currently, the power conversion efficiency (PCE) of all-PSCs based on novel non-fullerene acceptor materials has reached 15-17%. Nevertheless, due to the difficulty in well-regulating the micro-morphology of polymer films in the active layer, it is more difficult to form a nano-scale percolation network with moderate phase separation and interpenetration of donors and acceptors in all-PSCs compared to organic solar cells based on small molecule acceptors. Therefore, for all-polymer solar cells, morphology regulation is crucial for improving device performance.

[0003] Although the morphology of the active layer can be regulated by changing the solvent, using liquid additives (CN, DIO), heating annealing, and using a bilayer device structure, changing the solvent requires adjusting the concentration of the solute; the additives are difficult to remove during the processing, which will lead to poor device stability; heating annealing requires simultaneous regulation of temperature and time; the manufacturing process of the bilayer device structure is relatively troublesome. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a high-efficiency all-polymer organic solar cell structure; the present invention also provides a method for preparing a high-efficiency all-polymer organic solar cell by optimizing the morphology of the active layer using a ternary strategy;

[0005] Compared with the existing four methods of regulating the morphology of the active layer by changing the solvent, using liquid additives (CN, DIO), heating annealing, and using a bilayer active layer structure, the method of the present invention for introducing a third component into the polymer film to regulate the morphology by a ternary strategy is a simple, widely used and effective way. The third component can not only broaden the absorption spectrum of the main system, but also affect the crystallinity of donors and acceptors, thereby changing the morphology of the active layer. And the morphology of the active layer is crucial for the exciton dissociation and free carrier transport processes. Therefore, the ternary strategy can achieve the improvement of device performance.

[0006] Based on the highly efficient all-PSC of PM6:PY-IT, ternary all-PSCs were prepared by introducing the copolymer polymer acceptor BL-102 based on NDI-IDT. Due to the steric hindrance effect of the chemical structure of BL-102, the self-aggregation of this acceptor is poor. When introduced into the binary system, it can inhibit the self-aggregation behavior of the donor-acceptor, form more donor-acceptor interpenetrating networks, and is beneficial to exciton dissociation. Experiments found that when the introduction amount is 3 wt%, there is a better donor-acceptor interpenetrating network under good phase separation, which can ensure an ideal carrier transport process under efficient exciton dissociation conditions, and finally the efficiency during this period is increased to 15.43%. It illustrates the importance of using the ternary strategy for morphology regulation on the efficiency of solar cells.

[0007] Term Explanation:

[0008] PM6 is a polymer photovoltaic material, mainly used as the donor material for organic solar cells.

[0009] PY-IT is a polymer acceptor material, which is a D-A type copolymer acceptor. It is mainly used as the acceptor material for organic solar cells.

[0010] BL-102 is a polymer acceptor material, which is copolymerized from indole dithiophene (IDT) and naphthalene diimide (NDI) units.

[0011] The technical solution of the present invention is as follows:

[0012] A high-efficiency all-polymer organic solar cell structure includes a substrate, an anode, a hole transport layer, an active layer, an electron transport layer, and a cathode from bottom to top; the main donor and main acceptor in the active layer are PM6 and PY-IT respectively.

[0013] According to the preference of the present invention, the mass ratio of PM6 to PY-IT in PM6:PY-IT is 1:1 to 1:1.2

[0014] Further preferably, the mass ratio of PM6 to PY-IT in PM6:PY-IT is 1:1.

[0015] According to the preference of the present invention, the material of the active layer further includes a third component acceptor, and the mass ratio of PM6:PY-IT to the third component acceptor is 1:1; 0.01 to 1:1:0.1.

[0016] According to the preference of the present invention, the third component acceptor is BL-102.

[0017] Preferably, PM6:PY-IT:BL-102 is 1:1:0.03;

[0018] Preferably, the ratio of PM6:PY-IT:BL-102 is 1:1:0.05;

[0019] Preferably, the ratio of PM6:PY-IT:BL-102 is 1:1:0.1.

[0020] According to a preferred embodiment of the present invention, the substrate is a glass substrate, the anode is ITO, the material of the hole transport layer is PEDOT:PSS; the material of the electron transport layer is PDINN; the cathode is a top metal electrode.

[0021] The preparation method of the above organic solar cell structure includes:

[0022] Spin-coating on the surface of the conductive glass to prepare the hole transport layer;

[0023] Under a nitrogen atmosphere, spin-coat the active layer material on the hole transport layer to prepare the active layer;

[0024] Spin-coating on the surface of the active layer to prepare the electron transport layer;

[0025] Under vacuum conditions, prepare the cathode on the electron transport layer to obtain the product;

[0026] Among them, the active layer material is PM6:PY-IT.

[0027] According to a preferred embodiment of the present invention, under a nitrogen atmosphere, spin-coating the active layer material on the hole transport layer to prepare the active layer includes:

[0028] Under a nitrogen atmosphere, spin-coat the active layer material on the hole transport layer at a rotation speed of 3000 - 4000 rpm for 30 - 40 s, and anneal at 95 - 100 °C for 5 - 10 min.

[0029] Further preferably, under a nitrogen atmosphere, spin-coat the active layer material on the hole transport layer at a rotation speed of 3000 rpm for 30 s, and anneal at 100 °C for 10 min.

[0030] According to a preferred embodiment of the present invention, the conductive glass is ITO conductive glass; before preparing the hole transport layer, the following operations are performed:

[0031] Ultrasonically clean the ITO conductive glass successively with a cleaning agent, deionized water, acetone, absolute ethanol and isopropyl alcohol, dry it with nitrogen, and then treat it with UV for 15 - 25 min.

[0032] Further preferably, treat it with UV for 15 min

[0033] According to a preferred embodiment of the present invention, spin-coating on the surface of the conductive glass to prepare the hole transport layer includes:

[0034] Spin-coat PEDOT:PSS on the surface of the conductive glass and anneal at 130 - 180 °C for 10 - 20 min.

[0035] Further preferably, spin-coat PEDOT:PSS on the surface of the conductive glass and anneal at 150 °C for 15 min.

[0036] Preferably according to the present invention, spin-coat to prepare an electron transport layer on the surface of the active layer, including:

[0037] Spin-coat a 1 - 2 mg / mL PDIN solution onto the active layer at a rotation speed of 2000 - 4000 rpm for 20 - 40 s;

[0038] Further preferably, spin-coat a 1.5 mg / mL PDIN solution onto the active layer at a rotation speed of 3000 rpm for 30 s.

[0039] Preferably according to the present invention, prepare a cathode on the electron transport layer under vacuum conditions, including:

[0040] Under a vacuum condition of 2.5 х 10 -4 -5 х 10 -4 Pa, prepare an 80 - 100 nm Al electrode by thermal evaporation.

[0041] Further preferably, under a vacuum condition of 4 х 10 -4 Pa, prepare a 100 nm Ag electrode by thermal evaporation.

[0042] The beneficial effects of the present invention are:

[0043] The present invention selects the polymer acceptor BL-102 as the third component material. When the doping amount of the third component is 3 wt%, while realizing complementary absorption with the main system to enhance the utilization of sunlight, it also affects the crystallinity of the donors and acceptors in the active layer, inhibits the aggregation of the donors and acceptors, forms a more ordered molecular packing, enhances the solubility of the donors and acceptors, thus forming a more donor-acceptor interpenetrating nanoscale percolation network. Finally, efficient exciton dissociation and carrier transport are achieved in the ternary system, and finally the short-circuit current and fill factor of the device are improved, and the PCE is increased from 14.96% of the binary intrinsic system to 15.43%. Brief Description of the Drawings

[0044] Figure 1 It is a schematic structural diagram of the high-efficiency all-polymer organic solar cell structure of the present invention;

[0045] Figure 2(a) is a schematic diagram of the two-dimensional GIWAXS image of the PM6:PY-IT thin film of the present invention;

[0046] Figure 2(b) is a schematic diagram of the two-dimensional GIWAXS image of the PM6:PY-IT:BL-102 (1:1:0.03) thin film of the present invention;

[0047] Figure 2(c) is a schematic diagram of the two-dimensional GIWAXS image of the PM6:PY-IT:BL-102 (1:1:0.1) thin film of the present invention;

[0048] Figure 2(d) is a schematic diagram of the one-dimensional GIWAXS image of the present invention;

[0049] Figure 3(a) is a schematic diagram of the normalized absorption spectrum of the organic solar cell structure of the present invention;

[0050] Figure 3(b) is a schematic diagram of the J-V curve of the organic solar cell structure of the present invention;

[0051] Figure 4(a) is a schematic diagram of the AFM image of PM6:PY-IT:BL-102 of 1:1:0 of the present invention;

[0052] Figure 4(b) is a schematic diagram of the AFM image of PM6:PY-IT:BL-102 of 1:1:0.03 of the present invention;

[0053] Figure 4(c) is a schematic diagram of the AFM image of PM6:PY-IT:BL-102 of 1:1:0.05 of the present invention;

[0054] Figure 4(d) is a schematic diagram of the AFM image of PM6:PY-IT:BL-102 of 1:1:0.1 of the present invention. Detailed implementation manners

[0055] The present invention will be further limited below in conjunction with the accompanying drawings of the specification and embodiments, but not limited thereto.

[0056] Embodiment 1

[0057] A high-efficiency all-polymer organic solar cell structure, as Figure 1 shown, includes a substrate, an anode, a hole transport layer, an active layer, an electron transport layer, and a cathode from bottom to top; the main donor and the main acceptor in the active layer are PM6 and PY-IT respectively.

[0058] The substrate is a glass substrate, the anode is ITO, the material of the hole transport layer is PEDOT:PSS; the material of the electron transport layer is PDINN; the cathode is a top metal electrode.

[0059] Embodiment 2

[0060] A high-efficiency all-polymer organic solar cell structure according to Embodiment 1, wherein the difference is:

[0061] In PM6:PY-IT, the mass ratio of PM6 to PY-IT is 1:1 to 1:1.2;

[0062] Example 3

[0063] A high-efficiency all-polymer organic solar cell structure according to Example 1, wherein:

[0064] In PM6:PY-IT, the mass ratio of PM6 to PY-IT is 1:1.

[0065] Example 4

[0066] A high-efficiency all-polymer organic solar cell structure according to Example 1, wherein:

[0067] The material of the active layer further includes a third component acceptor, and the mass ratio of PM6:PY-IT to the third component acceptor is 1:1; 0.01 to 1:1:0.1.

[0068] Example 5

[0069] A high-efficiency all-polymer organic solar cell structure according to Example 4, wherein:

[0070] The third component acceptor is BL-102.

[0071] PM6:PY-IT:BL-102 is 1:1:0.03;

[0072] Example 6

[0073] A high-efficiency all-polymer organic solar cell structure according to Example 5, wherein:

[0074] PM6:PY-IT:BL-102 is 1:1:0.05;

[0075] Example 7

[0076] A high-efficiency all-polymer organic solar cell structure according to Example 5, wherein:

[0077] PM6:PY-IT:BL-102 is 1:1:0.1.

[0078] Performance parameters of the organic solar cell: Power conversion efficiency (PCE)

[0079]

[0080] Where J SC is the short-circuit current, V OC is the open-circuit voltage, FF is the fill factor, P inis the incident light intensity (AM 1.5G), and the PCE can be directly measured by a solar cell J-V curve test system (7-SCSpec).

[0081] Figure 2(a) is a schematic diagram of the two-dimensional GIWAXS image of the PM6:PY-IT film; Figure 2(b) is a schematic diagram of the two-dimensional GIWAXS image of the PM6:PY-IT:BL-102 (1:1:0.03) film; Figure 2(c) is a schematic diagram of the two-dimensional GIWAXS image of the PM6:PY-IT:BL-102 (1:1:0.1) film; Figure 2(d) is a schematic diagram of the one-dimensional GIWAXS image; From Figures 2(a) to 2(d) It can be seen that after adding BL-102 to PM6:PY-IT, the molecular packing mode in the film has not changed. The molecular packing modes in the three films are all face-on, which is beneficial to the extraction of carriers. The information obtained from the fitting of Figure 2(d) is shown in Table 1. It can be seen that the addition of BL-102 does not cause a large change in the π-π stacking distance. On the contrary, when the ratio of PM6:PY-IT:BL-102 is 1:1:0.03, the coherent length of the π-π stacking is the largest, indicating that the addition of BL-102 induces the molecules to form a more ordered packing.

[0082] Figure 3(a) is a schematic diagram of the normalized absorption spectrum of the organic solar cell structure; Figure 3(b) is a schematic diagram of the J-V curve of the organic solar cell structure; It can be seen from Figure 3(a) that compared with the binary film, the light absorption in the ternary system has been enhanced, especially at 300-500 nm; The PM6:PY-IT:BL-102 (1:1:0.03) system has the highest power conversion efficiency.

[0083] Figure 4(a) is a schematic diagram of the AFM image of PM6:PY-IT:BL-102 with a ratio of 1:1:0; Figure 4(b) is a schematic diagram of the AFM image of PM6:PY-IT:BL-102 with a ratio of 1:1:0.03; Figure 4(c) is a schematic diagram of the AFM image of PM6:PY-IT:BL-102 with a ratio of 1:1:0.05; Figure 4(d) is a schematic diagram of the AFM image of PM6:PY-IT:BL-102 with a ratio of 1:1:0.1. From Figures 4(a) to 4(d) It can be seen that compared with the binary system, the roughness of the film surface in the ternary system decreases, indicating that after adding BL-102, the crystallinity becomes worse, the donor-acceptor blending behavior is enhanced, and a better donor-acceptor interpenetrating network is formed.

[0084] Table 1

[0085]

[0086] Table 2

[0087]

[0088] In the present invention, the polymer acceptor BL-102 is selected as the third component material. When the doping amount of the third component is 3 wt%, while achieving complementary absorption with the main system to enhance the utilization of sunlight, it also affects the crystallinity of the donor-acceptor in the active layer, inhibits the aggregation of the donor-acceptor, and forms a more ordered molecular packing ( Figures 2(a) to 2(d) and Table 1), enhances the solubility of the donor-acceptor, thereby forming a more donor-acceptor interpenetrating nano-scale percolation network ( Figures 4(a) to 4(d) ), ultimately achieving efficient exciton dissociation and carrier transport in the ternary system. As shown in Table 2, Figure 3(a), and Figure 3(b), the short-circuit current and fill factor of the final device are improved, and the PCE is increased from 14.96% of the binary intrinsic system to 15.43%.

[0089] Example 8

[0090] The preparation method of the organic solar cell structure according to any one of Examples 1-7 includes:

[0091] Spin-coat a hole transport layer on the surface of the conductive glass;

[0092] Under a nitrogen atmosphere, spin-coat the active layer material on the hole transport layer to prepare the active layer;

[0093] Spin-coat an electron transport layer on the surface of the active layer;

[0094] Under vacuum conditions, prepare the cathode on the electron transport layer to obtain the product;

[0095] Among them, the active layer material is PM6:PY-IT.

[0096] Under a nitrogen atmosphere, spin-coat the active layer material on the hole transport layer to prepare the active layer, including: under a nitrogen atmosphere, spin-coat the active layer material on the hole transport layer at a rotation speed of 3000-4000 rpm for 30-40 s, and anneal at 95-100 °C for 5-10 min.

[0097] The conductive glass is ITO conductive glass; before preparing the hole transport layer, perform the following operations:

[0098] Ultrasonically clean the ITO conductive glass successively with a cleaning agent, deionized water, acetone, absolute ethanol, and isopropyl alcohol, dry it with nitrogen, and then treat it with UV for 15-25 min.

[0099] Spin-coat a hole transport layer on the surface of the conductive glass, including:

[0100] Spin-coat PEDOT:PSS on the surface of the conductive glass and anneal at 130-180 °C for 10-20 min.

[0101] Spin-coat the electron transport layer on the surface of the active layer, including:

[0102] Spin-coat a 1 - 2 mg / mL PDIN solution onto the active layer at a rotation speed of 2000 - 4000 rpm for 20 - 40 s;

[0103] Under vacuum conditions, prepare the cathode on the electron transport layer, including:

[0104] Under a vacuum condition of 2.5 х 10 -4 -5 х 10 -4 Pa, prepare an 80 - 100 nm Al electrode by thermal evaporation.

[0105] Example 9

[0106] The preparation method of the organic solar cell structure described in Example 8, the difference is:

[0107] Under a nitrogen atmosphere, spin-coat the active layer material onto the hole transport layer at a rotation speed of 3000 rpm for 30 s, and anneal at 100 °C for 10 min.

[0108] Treat with UV for 15 min

[0109] Spin-coat PEDOT:PSS on the surface of the conductive glass and anneal at 150 °C for 15 min.

[0110] Spin-coat a 1.5 mg / mL PDIN solution onto the active layer at a rotation speed of 3000 rpm for 30 s.

[0111] Under a vacuum condition of 4 х 10 -4 Pa, prepare a 100 nm Ag electrode by thermal evaporation.

Claims

1. A high-efficiency all-polymer organic solar cell structure, characterized in that, It includes a substrate, an anode, a hole transport layer, an active layer, an electron transport layer, and a cathode from bottom to top; The active layer includes a main donor, a main acceptor, and a third component acceptor. The main donor and the main acceptor in the active layer are PM6 and PY-IT respectively, and the third component acceptor is BL-102.

2. The high-efficiency all-polymer organic solar cell structure according to claim 1, characterized in that, In PM6:PY-IT, the mass ratio of PM6 to PY-IT is 1:1 1:1.2 3. The high-efficiency all-polymer organic solar cell structure according to claim 1, characterized in that, In PM6:PY-IT, the mass ratio of PM6 to PY-IT is 1:

1.

4. The high-efficiency all-polymer organic solar cell structure according to claim 1, characterized in that, The mass ratio of PM6:PY-IT to the third component receptor is 1:1:0.01 1:1:0.

1.

5. The high-efficiency all-polymer organic solar cell structure according to claim 1, characterized in that, PM6:PY-IT:BL-102 is 1:1:0.

03.

6. The high-efficiency all-polymer organic solar cell structure according to claim 1, characterized in that, PM6:PY-IT:BL-102 is 1:1:0.

05.

7. The high-efficiency all-polymer organic solar cell structure according to claim 1, characterized in that, PM6:PY-IT:BL-102 is 1:1:0.

1.

8. The high-efficiency all-polymer organic solar cell structure according to claim 1, characterized in that, The substrate is a glass substrate, the anode is ITO, the material of the hole transport layer is PEDOT:PSS; the material of the electron transport layer is PDINN; the cathode is a top metal electrode.

9. A method for preparing the organic solar cell structure according to any one of claims 1-8, characterized in that, It includes: Spin-coat to prepare the hole transport layer on the surface of the conductive glass; Under a nitrogen atmosphere, spin-coat the active layer material on the hole transport layer to prepare the active layer; Spin-coat to prepare the electron transport layer on the surface of the active layer; Under vacuum conditions, prepare the cathode on the electron transport layer to obtain it; Among them, the active layer material is PM6:PY-IT:BL-102.

10. The method for preparing the organic solar cell structure according to claim 9, characterized in that, Under a nitrogen atmosphere, spin-coat the active layer material on the hole transport layer to prepare the active layer, including: Under a nitrogen atmosphere, spin-coat the active layer material on the hole transport layer at a rotation speed of 3000 - 4000 rpm for 30 - 40 s, and anneal at 95 - 100 °C for 5 - 10 min.

11. The method for preparing the organic solar cell structure according to claim 10, characterized in that, Under a nitrogen atmosphere, spin-coat the active layer material on the hole transport layer at a rotation speed of 3000 rpm for 30 s, and anneal at 100 °C for 10 min.

12. The method for preparing the organic solar cell structure according to claim 9, characterized in that, The conductive glass is ITO conductive glass; before preparing the hole transport layer, perform the following operations: Ultrasonically clean the ITO conductive glass successively with a cleaning agent, deionized water, acetone, absolute ethanol, and isopropyl alcohol, dry it with nitrogen, and then treat it with UV for 15 - 25 min.

13. The method for preparing the organic solar cell structure according to claim 12, characterized in that, Treat it with UV for 15 min; Spin-coat to prepare the hole transport layer on the surface of the conductive glass, including: Spin-coat PEDOT:PSS on the surface of the conductive glass and anneal at 130 - 180 °C for 10 - 20 min.

14. The preparation method of the organic solar cell structure according to claim 12, wherein, Spin-coat PEDOT:PSS on the surface of the conductive glass and anneal at 150 °C for 15 min.

15. The preparation method of the organic solar cell structure according to any one of claims 9 - 14, wherein, Spin-coat to prepare the electron transport layer on the surface of the active layer, including: Spin-coat a 1 - 2 mg / mL PDIN solution onto the active layer at a rotation speed of 2000 - 4000 rpm for 20 - 40 s.

16. The preparation method of the organic solar cell structure according to claim 15, wherein, Spin-coat a 1.5 mg / mL PDIN solution onto the active layer at a rotation speed of 3000 rpm for 30 s; Under vacuum conditions, prepare the cathode on the electron transport layer, including: In 2.5х10 -4 -5х10 -4 Under vacuum conditions of 1.3 Pa, 80-100 nm Al electrodes were prepared by thermal evaporation.

17. The preparation method of the organic solar cell structure according to claim 15, wherein, Under a vacuum condition of 4×10 -4 Pa, a 100-nm Ag electrode is prepared by thermal evaporation.

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