A ternary non-fullerene organic solar cell and its preparation method

Abstract

The present invention belongs to the technical field of photovoltaic solar energy, and specifically relates to a ternary non-fullerene organic solar cell and a preparation method thereof. The cell is sequentially arranged from bottom to top as an ITO glass substrate, an anode interfacial layer PEDOT:PSS, an active layer, a cathode interfacial layer PDIN, and a metal cathode layer Al. Among them, the active layer is composed of a polymer donor material (PM6), a fused-ring non-fullerene small molecule acceptor material (Y6), and a linear non-fullerene small molecule acceptor material (BDDTTIC-4FF). The cell adopts a normal structure, and the highest energy conversion efficiency reaches 17.50%, which proves that the construction of the PM6:Y6:BDDTTIC-4F ternary system effectively improves the performance of the device.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic solar energy, and particularly relates to a ternary non-fullerene organic solar cell and a preparation method thereof. Background Art

[0002] With the rapid development of technology and economy, in the face of the continuous reduction of fossil energy and the continuous emergence of environmental pollution problems caused by its large consumption, the development of environmentally friendly renewable energy has become the focus of attention of countries around the world. Non-fullerene organic solar cells are a new type of solar cell developed in recent years. Compared with traditional inorganic solar cells, organic solar cells have the advantages of solution processability, wide material sources, light weight, simple process, large-area preparation, and flexible and semi-transparent preparation, and are a sustainable green renewable energy technology.

[0003] At present, organic solar cells are mainly prepared and studied using a bulk heterojunction structure, and mostly adopt a binary active layer structure, that is, a blend of an organic donor material and another organic acceptor material is used as the active layer material of the battery. However, due to the narrow absorption spectrum of binary organic solar cells, sunlight cannot be fully utilized, which limits the dissociation and transfer of excitons at the interface.

[0004] In order to overcome its inherent defects, broaden the light absorption range of the photoactive layer, obtain more balanced charge transport, and improve the fill factor and energy conversion efficiency of non-fullerene organic solar cells, in recent years, by introducing a third component with complementary absorption and energy level matching into the active layer, a ternary blended organic solar cell is prepared. The addition of a third component small molecule acceptor material with well-matched properties not only broadens the absorption spectrum in the original binary blend film, but also effectively adjusts the voltage gradient of the organic optoelectronic material, improves the surface morphology of the active layer, and thus improves the optoelectronic performance parameters of the organic solar cell. However, there are currently few materials with energy level matching and absorption complementarity between non-fullerene small molecule double acceptor materials and polymer single donor materials, and there is still a lack of understanding of the influence of different active layer material structures on the morphology of the active layer film. Therefore, it is particularly important to develop new non-fullerene small molecule acceptor materials to construct ternary organic active layer materials to obtain high device efficiency. Summary of the Invention

[0005] The present invention aims to provide a ternary non-fullerene organic solar cell with high efficiency and a preparation method thereof.

[0006] In the active layer of a binary bulk heterojunction organic solar cell composed of a polymeric donor material (PM6) (for the preparation method, see: M.J. Zhang, X. Guo, W. Ma, H. Ade and J. H. Hou, Adv. Mater., 2015, 27, 4655 - 4660) and a classical fused-ring non-fullerene small molecule acceptor material (Y6), a linear non-fullerene small molecule acceptor material (BDDTTIC-4F) (for the preparation method, see New J. Chem., 2021, 45, 22093–22100) is introduced, providing a highly efficient ternary blend non-fullerene organic solar cell constructed with one polymeric donor material, one fused-ring non-fullerene small molecule acceptor material and one linear non-fullerene small molecule acceptor material.

[0007] The construction technology of a highly efficient ternary non-fullerene organic solar cell provided by the present invention uses a linear non-fullerene small molecule acceptor material (BDDTTIC-4F) as the third component and introduces it into the active layer of a binary non-fullerene organic solar cell to construct a highly efficient ternary non-fullerene organic solar cell; the introduced linear non-fullerene small molecule acceptor material (BDDTTIC-4F) can not only effectively broaden the spectral absorption of the photoactive layer, but also improve the morphology of the active layer, improve phase separation, reduce the recombination of holes and electrons, and is conducive to promoting the dissociation and transfer of excitons at the interface, thereby improving the short-circuit current, fill factor and energy conversion efficiency of the device.

[0008] The ternary non-fullerene organic solar cell provided by the present invention adopts a bulk heterojunction normal device structure, and the battery is sequentially arranged from bottom to top as an ITO glass substrate, an anode interfacial layer PEDOT:PSS, an active layer, a cathode interfacial layer PDIN, and a metal cathode layer Al.

[0009] The thickness range of the anode interfacial layer is 1 - 45 nm.

[0010] In the photoactive material, it includes a polymeric donor material PM6, a fused-ring small molecule acceptor material Y6 and a linear small molecule acceptor material (BDDTTIC-4F).

[0011] PM6, Y6 and BDDTTIC-4F are proportioned according to the mass ratio of 1.0:(1.0 - x):x, where x is the mass fraction of the acceptor material BDDTTIC-4F, and the mass percentage of x is 5 - 20%.

[0012] The optimal thickness of the ternary photoactive layer is 95 nm.

[0013] The molecular structure of the linear non-fullerene is shown in Formula 1:

[0014]

[0015] The molecular structure of the fused-ring non-fullerene small molecule acceptor material Y6 is shown in Formula 2:

[0016]

[0017] The molecular structure of the polymer donor material PM6 is shown in Formula 3:

[0018]

[0019] The thickness range of the cathode interface layer is 1 - 25 nm.

[0020] The high-efficiency ternary non-fullerene organic solar cell constructed by the present invention has the following advantages:

[0021] 1) The ternary non-fullerene organic solar cell based on the linear non-fullerene small molecule acceptor material (BDDTTIC-4F) has high photoelectric conversion efficiency, simple preparation process, low cost, and is easy to process and form.

[0022] 2) Based on the linear non-fullerene small molecule acceptor material (BDDTTIC-4F) in the ternary non-fullerene organic solar cell, it can not only effectively broaden the spectral absorption of the photoactive layer, but also improve the morphology of the active layer, improve phase separation, reduce the recombination of holes and electrons, and is conducive to promoting the dissociation and transfer of excitons at the interface, thereby increasing the short-circuit current and fill factor of the device and achieving an improvement in the energy conversion efficiency of the battery. Brief Description of the Drawings

[0023] Figure 1 It is the device structure diagram of the high-efficiency ternary non-fullerene organic solar cell of the present invention.

[0024] Figure 2 It is the current density-voltage characteristic curve diagram of the ternary organic solar cell devices with different mass ratios of PM6:Y6:BDDTTIC-4F in Examples 1 - 4 of the present invention.

[0025] Figure 3 It is the external quantum curve diagram of the ternary organic solar cell devices with different mass ratios of PM6:Y6:BDDTTIC-4F in Examples 1 - 4 of the present invention.

[0026] Figure 4 It is the current density-voltage characteristic curve diagram of the devices described in Example 2 and Comparative Example 1 and Comparative Example 2 under AM (intensity of 100 mW / cm 2 ) irradiation.

[0027] Figure 5is the external quantum efficiency corresponding to the devices described in Example 2 and Comparative Example 1 and Comparative Example 2. Detailed implementation mode

[0028] The present invention will be described in detail below with reference to specific embodiments.

[0029] Example 1

[0030] Preparation of a ternary non-fullerene organic solar cell of PM6:Y6:BDDTTIC-4F (mass ratio = 1.0:0.95:0.05).

[0031] The clean ITO anode conductive glass was treated with ultraviolet ozone for 15 min, and a PEDOT:PSS (4500 rpm, 20 s, 30 nm) anode buffer layer was spin-coated on its surface; then a PM6:Y6:BDDTTIC-4F photoactive layer (1750 rpm, 40 s, 95 nm) with a mass ratio of 1.0:0.95:0.05 was spin-coated on the anode buffer layer; then a PDIN methanol solution (2.0 mg / mL) was spin-coated on the active layer (3000 rpm, 20 s) to form an electron transport layer; finally, the cathode Al (90 nm) was evaporated in a vacuum evaporation chamber, and the device area was 0.16 cm 2 . Under standard test conditions (AM1.5, 100 mW / cm 2 ), the V oc = 0.867 V, J sc = 25.82 mA / cm 2 , FF = 75.10%, PCE = 16.83%.

[0032] Example 2

[0033] Preparation of a ternary non-fullerene organic solar cell of PM6:Y6:BDDTTIC-4F (mass ratio = 1.0:0.90:0.10).

[0034] The clean ITO anode conductive glass was treated with ultraviolet ozone for 15 min, and a PEDOT:PSS (4500 rpm, 20 s, 30 nm) anode buffer layer was spin-coated on its surface; then a PM6:Y6:BDDTTIC-4F photoactive layer (1750 rpm, 40 s, 95 nm) with a mass ratio of 1.0:0.90:0.10 was spin-coated on the anode buffer layer; then a PDIN methanol solution (2.0 mg / mL) was spin-coated on the photoactive layer on the active layer (3000 rpm, 20 s) to form an electron transport layer; finally, the cathode Al (90 nm) was evaporated in a vacuum evaporation chamber, and the device area was 0.16 cm 2Under standard test conditions (AM1.5, 100 mW / cm 2 ), the V oc of the device is 0.868 V, J sc is 26.15 mA / cm 2 , FF = 76.17%, and PCE = 17.50%.

[0035] Example 3

[0036] Preparation of PM6:Y6:BDDTTIC-4F (mass ratio = 1.0:0.85:0.15) ternary non-fullerene organic solar cells.

[0037] The clean ITO anode conductive glass was treated with ultraviolet ozone for 15 min, and a PEDOT:PSS (4500 rpm, 20 s, 30 nm) anode buffer layer was spin-coated on its surface; then a PM6:Y6:BDDTTIC-4F photoactive layer (1750 rpm, 40 s, 95 nm) with a mass ratio of 1.0:0.85:0.15 was spin-coated on the anode buffer layer; then a PDIN methanol solution (2.0 mg / mL) was spin-coated on the photoactive layer (3000 rpm, 20 s) to form an electron transport layer; finally, the cathode Al (90 nm) was evaporated in a vacuum evaporation chamber, and the device area was 0.16 cm 2 Under standard test conditions (AM1.5, 100 mW / cm 2 ), the V oc of the device is 0.873 V, J sc is 25.39 mA / cm 2 , FF = 73.29%, and PCE = 16.24%.

[0038] Example 4

[0039] Preparation of PM6:Y6:BDDTTIC-4F (mass ratio = 1.0:0.80:0.20) ternary non-fullerene organic solar cells.

[0040] The clean ITO anode conductive glass was treated with ultraviolet ozone for 15 min, and a PEDOT:PSS (4500 rpm, 20 s, 30 nm) anode buffer layer was spin-coated on its surface; then a PM6:Y6:BDDTTIC-4F photoactive layer (1750 rpm, 40 s, 95 nm) with a mass ratio of 1.0:0.80:0.20 was spin-coated on the anode buffer layer; then a PDIN methanol solution (2.0 mg / mL) was spin-coated on the photoactive layer (3000 rpm, 20 s) to form an electron transport layer; finally, the cathode Al (90 nm) was evaporated in a vacuum evaporation chamber, and the device area was 0.16 cm2 Under standard test conditions (AM1.5, 100 mW / cm 2 ), the V oc of the device was 0.877 V, J sc was 24.79 mA / cm 2 , FF = 71.50%, and PCE = 15.54%.

[0041] Comparative Example 1

[0042] Preparation of a PM6:Y6 (mass ratio = 1.0:1.0) binary non-fullerene organic solar cell.

[0043] The clean ITO anode conductive glass was treated with ultraviolet ozone for 15 min, and a PEDOT:PSS (4500 rpm, 20 s, 30 nm) anode buffer layer was spin-coated on its surface; then a PM6:Y6 photoactive layer (1750 rpm, 40 s, 95 nm) with a mass ratio of 1.0:1.0 was spin-coated on the anode buffer layer; then a PDIN methanol solution (2.0 mg / mL) was spin-coated on the photoactive layer (3000 rpm, 20 s) to form an electron transport layer; finally, a cathode Al (90 nm) was evaporated in a vacuum evaporation chamber, and the device area was 0.16 cm 2 . Under standard test conditions (AM1.5, 100 mW / cm 2 ), the V oc of the device was 0.855 V, J sc was 25.29 mA / cm 2 , FF = 74.39%, and PCE = 16.09%.

[0044] Comparative Example 2

[0045] Preparation of a PM6:BDDTTIC-4F (mass ratio = 1.0:1.0) binary non-fullerene organic solar cell.

[0046] The clean ITO anode conductive glass was treated with ultraviolet ozone for 15 min, and a PEDOT:PSS (4500 rpm, 20 s, 30 nm) anode buffer layer was spin-coated on its surface; then a PM6:BDDTTIC-4F photoactive layer (1750 rpm, 40 s, 95 nm) with a mass ratio of 1.0:1.0 was spin-coated on the anode buffer layer; then a PDIN methanol solution (2.0 mg / mL) was spin-coated on the photoactive layer (3000 rpm, 20 s) to form an electron transport layer; finally, a cathode Al (90 nm) was evaporated in a vacuum evaporation chamber, and the device area was 0.16 cm 2 . Under standard test conditions (AM1.5, 100 mW / cm2 ) to obtain the V of the device oc = 0.929 V, J sc = 3.57 mA / cm 2 , FF = 30.73%, PCE = 1.02%.

[0047] Figure 4 For Comparative Example 1, Comparative Example 2 and the photovoltaic device described in Example 2 under AM1.5 (intensity 100 mA / cm 2 ) illumination condition, the current density-voltage characteristic curve graph shows that: in the binary non-fullerene organic solar cell of PM6:Y6, by introducing the linear small molecule acceptor BDDTTIC-4F, the open circuit voltage, short circuit current and fill factor of the device can be synergistically improved, thereby improving the energy conversion efficiency of the device. That is, when the mass percentage of PM6:Y6:BDDTTIC-4F is 1.0:0.90:0.10, the efficiency of the device is the highest.

[0048] Figure 5 For Comparative Example 1, Comparative Example 2 and the photovoltaic device described in Example 2 under AM1.5 (intensity 100 mA / cm 2 ) illumination condition, the external quantum efficiency curve graph shows that: in the binary non-fullerene organic solar cell of PM6:Y6, by introducing the linear small molecule acceptor BDDTTIC-4F, it is found that the EQE response value of the ternary device is higher than that of the binary device. That is, when the mass percentage of PM6:Y6:BDDTTIC-4F is 1.0:0.90:0.10, the efficiency of the device is the highest.

[0049] Although the present invention has been described in conjunction with the preferred embodiments, the present invention is not limited to the above embodiments. It should be understood that the appended claims define the scope of the present invention. Under the guidance of the inventive concept of the present invention, those skilled in the art should realize that certain changes made to the embodiments of the present invention will be covered by the spirit and scope of the claims of the present invention.

Claims

1. A ternary non-fullerene organic solar cell, which adopts a bulk heterojunction forward structure. Characterized in that, The cell is sequentially arranged from bottom to top as an ITO glass substrate, an anode interfacial layer PEDOT:PSS, an active layer, a cathode interfacial layer PDIN, and a metal cathode layer Al. Among them, the active layer is composed of a polymer donor PM6, a fused-ring non-fullerene small molecule acceptor Y6, and a linear non-fullerene small molecule acceptor BDDTTIC-4F.

2. The ternary non-fullerene organic solar cell according to claim 1, Characterized in that, The thickness of the anode interfacial layer is 1 - 45 nm.

3. The ternary non-fullerene organic solar cell according to claim 1, Characterized in that, The thickness of the active layer is 95 nm.

4. The ternary non-fullerene organic solar cell according to claim 1, Characterized in that, In the active layer, PM6, Y6, and BDDTTIC-4F are proportioned according to a mass ratio of 1.0:(1.0 - x):x, where x is the mass fraction of the acceptor material BDDTTIC-4F, and the mass percentage of x is 5 - 20%.

5. The ternary non-fullerene organic solar cell according to claim 1, Characterized in that, The molecular structure of the linear non-fullerene small molecule acceptor material BDDTTIC-4F is shown in Formula 1:

6. The ternary non-fullerene organic solar cell according to claim 1, Characterized in that, The molecular structure of the fused-ring non-fullerene small molecule acceptor Y6 material is shown in Formula 2:

7. The ternary non-fullerene organic solar cell according to claim 1, Characterized in that, The molecular structure of the polymer donor material PM6 is shown in Formula 3:

8. The ternary non-fullerene organic solar cell according to claim 1, Characterized in that, The thickness of the cathode interfacial layer is 1 - 25 nm.

9. A preparation method of the ternary non-fullerene organic solar cell according to claim 1, Characterized in that, The preparation method is as follows: First, perform ultraviolet ozone treatment on the anode conductive glass, and then sequentially spin-coat to prepare the anode interfacial layer, the photoactive layer, and the cathode interfacial layer on its surface; finally, vacuum deposit the cathode.

Images