Ternary polymer solar cell
11600788 · 2023-03-07
Assignee
Inventors
Cpc classification
H10K85/6572
ELECTRICITY
H10K30/82
ELECTRICITY
H10K85/113
ELECTRICITY
H10K30/30
ELECTRICITY
International classification
Abstract
The present invention discloses a ternary polymer solar cell. A photoactive layer of the ternary polymer solar cell includes two non-fullerene electron acceptors with large planarity. The weight percentage composition of the photoactive layer in the ternary polymer solar cell is: 41.6-50% of polymer electron donor, 0-50% of polymer electron acceptor, and 0-50% of non-fullerene perylene diimide (PDI) electron acceptor. The non-fullerene PDI electron acceptor is added into the photoactive layer to broaden the spectral absorption of the photoactive layer, improve the phase separation of the photoactive layer and inhibit the recombination of bimolecular charges, resulting in more efficient generation and transport of charges, thereby increasing a short-circuit current density of the ternary polymer solar cell device, and finally improving the power conversion efficiency of the ternary polymer solar cell device. Moreover, a new direction is provided for the selection of the all-polymer non-fullerene acceptor.
Claims
1. A polymer solar cell, comprising a substrate layer, a transparent conductive cathode, a cathode buffer layer, a photoactive layer, an anode buffer layer and a metal anode successively from bottom to top, wherein a non-fullerene perylene diimide (PDI) electron acceptor is introduced into the photoactive layer; in the photoactive layer, a ratio of a weight percentage of a polymer electron donor, a polymer electron acceptor and the non-fullerene PDI electron acceptor is 1: (0-1): (0.1-1); the non-fullerene PDI electron acceptor is a compound containing no fullerene group but containing PDI groups; the non-fullerene PDI electron acceptor comprises 2PDINB; an absorbing band of the 2PDINB is between 300 nm and 900 nm; a structural formula of the 2PDINB is: ##STR00004## a preparation method of the 2PDINB comprises: first, making the PDI and concentrated nitric acid react in dichloromethane for 2-4 h to generate PDI with nitro groups, then refluxing the PDI with nitro groups, iron powder and concentrated hydrochloric acid in tetrahydrofuran for 30-60 min to obtain PDI with amino groups, and finally, refluxing the PDI with amino groups, terephthalaldehyde and acetic acid in ethanol for 24-30 h to obtain 2PDINB.
2. The polymer solar cell according to claim 1, wherein the preparation method of the 2PDINB comprises specific steps as follows: 1 dissolving 1 g of PDI into 20 mL of dichloromethane to obtain a reagent A; dissolving 3 mL of fuming concentrated nitric acid into 5 mL of dichloromethane to obtain a reagent B; cooling the reagent Ain an ice bath for 10-20 min, and then dropwise adding the reagent B into the reagent A to obtain a mixed solution; stirring the mixed solution at 0° C. for 2-4 h; pouring the mixed solution into methanol; filtering, washing and drying the solution; purifying by silica column chromatography, spin drying and vacuum drying the solution to obtain dark red PDI with nitro groups; 2 heating, refluxing and stirring 1.21 g of 1.50 mmol PDI with nitro groups, 175 mg of 3.14 mmol iron powder and 6 mL of concentrated hydrochloric acid in 50 mL of anhydrous tetrahydrofuran for 30-60 min; and then cooling, precipitating in deionized water, extracting, drying with anhydrous sodium sulfate, spin drying, then dissolving in chloroform, finally purifying by silica column chromatography, and concentrating by evaporation to obtain the PDI with amino groups; and 3 refluxing 714 mg of 1.00 mmol PDI with amino groups, 281 mg of 2.1 mmol terephthalaldehyde and 5 mL of acetic acid in 40 mL of ethanol for 24-30 h; and cooling, extracting with water and dichloromethane, removing the acetic acid, drying with anhydrous sodium sulfate, spin drying, and finally purifying by silica column chromatography to obtain the 2PDINB.
3. The polymer solar cell according to claim 1, wherein in the photoactive layer, the material of the polymer electron donor is a narrow-band polymer electron donor which comprises any one of polythiophene derivatives, such as P3HT, PTB7-Th and PBDB-T.
4. The polymer solar cell according to claim 1, wherein in the photoactive layer, the material of the polymer electron acceptor is an n-type conjugated polymer electron acceptor containing naphthalimide; and the polymer electron acceptor comprises N2200.
5. The polymer solar cell according to claim 1, wherein the material of the anode buffer layer is an organic compound with hole transport capacity or electron blocking capacity or a metal oxide with hole transport capacity or electron blocking capacity; and a thickness of the anode buffer layer is ranged from 1 nm to 200 nm.
6. The polymer solar cell according to claim 1, wherein the material of the cathode buffer layer is an organic compound with electron transport capacity or hole blocking capacity or a metal oxide with electron transport capacity or hole blocking capacity; the cathode buffer layer comprises one or more of TPBi, BCP, Bphen, Alq.sub.3, AZO, ZnO and TiO.sub.2; and a thickness of the cathode buffer layer is ranged from 1 nm to 200 nm.
7. The polymer solar cell according to claim 1, wherein the material of the substrate layer is glass or a transparent polymer; the material of the transparent polymer is one or more of polyethylene, polymethylmethacrylate, polycarbonate, polyurethane, polyphthalimide, vinyl chloride resin and polyacrylic acid; and the material of the metal anode is any one of gold, silver, platinum, copper and aluminum.
8. The polymer solar cell according to claim 1, wherein the transparent conductive cathode is a conductive material that is transparent or translucent in a visible light zone; and the light transmittance of the transparent conductive cathode is greater than 50%.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1)
(2)
(3)
(4) 1—substrate layer; 2—transparent conductive cathode; 3—cathode buffer layer; 4—photoactive layer; 5—anode buffer layer; and 6—metal anode.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
(5) The present invention discloses a ternary polymer solar cell, which belongs to the technical field of photovoltaics. A photoactive layer of the ternary polymer solar cell includes two non-fullerene electron acceptors with large planarity. The weight percentage composition of the photoactive layer in the ternary polymer solar cell is: 41.6-50% of polymer electron donor, 0-50% of polymer electron acceptor, and 0-50% of non-fullerene perylene diimide (PDI) electron acceptor. The non-fullerene PDI electron acceptor is added into the photoactive layer to broaden the spectral absorption of the photoactive layer, improve the phase separation of the photoactive layer and inhibit the recombination of bimolecular charges, thereby leading to more effective generation and transport of charges, increasing the short-circuit current density of the ternary polymer solar cell device, and finally improving the photoelectric conversion performance of the ternary polymer solar cell device. Moreover, a new direction is provided for the selection of the all-polymer non-fullerene acceptor. The ternary polymer solar cell formed by combining two non-fullerene electron acceptors with large planarity has the advantages of high photoelectric conversion performance, simple preparation technology, short preparation process and low cost.
(6) The present invention is further described below in conjunction with the drawings and embodiments.
EMBODIMENTS
(7) The present invention can be better understood on the basis of the following embodiments. However, those skilled in the art can easily understand that the specific material ratios, technological conditions and results described in the embodiments are only used to illustrate the present invention, and should not and may not limit the present invention described in detail in the claims.
(8) The purpose of the present invention is to provide a ternary polymer solar cell. As shown in
(9) In the photoactive layer, the material of the non-fullerene electron acceptor is 2PDINB. The material of the polymer electron donor is PTB7-Th. The material of the polymer electron acceptor is N2200. The corresponding structure is as shown in
(10) A preparation method of the 2PDINB is as follows: first, the perylene diimide (PDI) and concentrated nitric acid react in dichloromethane for 2-4 h to generate PDI with nitro groups; then the PDI with nitro groups, iron powder and concentrated hydrochloric acid are refluxed in tetrahydrofuran for 30-60 min to obtain PDI with amino groups; and finally, the PDI with amino groups, terephthalaldehyde and acetic acid are refluxed in ethanol for 24-30 h to obtain the 2PDINB.
(11) Specific steps are as follows:
(12) 1) A PDI (1 g, 1.43 mmol) solution dissolved in dichloromethane (20 mL) is cooled in an ice bath for 10-20 min. Then a dichloromethane (5 mL) diluent containing fuming concentrated nitric acid (3 mL) is dropped to obtain a mixed solution. The mixed solution is stirred at 0° C. for 2-4 h. Subsequently, a resulting mixture is poured into methanol, precipitates are collected by vacuum filtering, and the precipitates are washed with water, dried, purified by silica gel column chromatography (petroleum ether/dichloromethane, 1:1 v/v), spin dried, and vacuum dried to obtain dark red PDI with nitro groups. The yield is 98%.
(13) 2) The PDI with nitro groups (1.21 g, 1.50 mmol) (dark red solution), iron powder (175 mg, 3.14 mmol) and concentrated hydrochloric acid (6 mL) are refluxed in anhydrous tetrahydrofuran (50 mL) and stirred for 30-60 min (the color is changed from dark red to dark blue 10 min later). After the reaction is ended, the mixed solution is cooled, precipitated with deionized water (250 mL) and extracted; the collected precipitates are dried with anhydrous sodium sulfate, spin dried, and then dissolved in little chloroform, and finally the precipitates are purified by silica gel column chromatography (chloroform) and concentrated by evaporation to obtain PDI with amino groups. The yield is 70%.
(14) 3) The PDI with amino groups (714 mg, 1.00 mmol), terephthalaldehyde (281 mg, 2.1 mmol) and acetic acid (5 mL) are refluxed in ethanol (40 mL) for 24-30 h. After the reaction is ended, the mixed solution is cooled and extracted with water and dichloromethane; the acetic acid is removed; and then the obtained extract is dried with anhydrous sodium sulfate, spin dried and purified by silica gel column chromatography (ethyl acetate/petroleum ether, 1:10 v/v) to obtain the 2PDINB.
(15) An experimental route is as follows:
(16) ##STR00002## ##STR00003##
(17) The material of the anode buffer layer is molybdenum oxide (MoO.sub.3), and a thickness of the anode buffer layer is 8 nm. The material of the cathode buffer layer is zinc oxide (ZnO), and a thickness of the cathode buffer layer is 35 nm. The material of the substrate layer is a glass substrate. The material of the transparent conductive cathode is indium tin oxide (ITO). The metal anode is silver (Ag).
Embodiment 1
(18) Control Group:
(19) A base plate, which has surface roughness less than 1 nm, composed of a transparent substrate layer and a transparent conductive cathode ITO was washed and then dried by blowing nitrogen. The surface of the transparent conductive cathode ITO was spin coated with ZnO (4500 rpm, 40 s, 25 nm) to prepare a cathode buffer layer, and a formed film was subjected to thermal annealing (200° C., 60 min). The cathode buffer layer was spin coated to prepare a PTB7-Th:N2200 photoactive layer (2000 rpm, 60 s, 95 nm) in a mass ratio of 1:1, and the surface of the photoactive layer was evaporated with MoO.sub.3 (8 nm). An anode buffer layer was evaporated with metal anode Ag (80 nm). Under standard test conditions (AM 1.5, 100 mW/cm.sup.2), it was measured that the open-circuit voltage (V.sub.OC) of the ternary polymer solar cell device was 0.80 V, the short-circuit current (J.sub.SC) was 11.2 mA/cm.sup.2, the fill factor (FF) was 0.45, and the power conversion efficiency (PCE) was 4.01%.
Embodiment 2
(20) A base plate, which has surface roughness less than 1 nm, composed of a transparent substrate layer and a transparent conductive cathode ITO was washed and then dried by blowing nitrogen. The surface of the transparent conductive cathode ITO was spin coated with ZnO (4500 rpm, 40 s, 25 nm) to prepare a cathode buffer layer, and a formed film was subjected to thermal annealing (200° C., 60 min). The cathode buffer layer was spin coated to prepare a PTB7-Th:N2200:2PDINB photoactive layer (2000 rpm, 60 s, 95 nm) in a mass ratio of 1:1:0.1, and the surface of the photoactive layer was evaporated with MoO.sub.3 (8 nm). An anode buffer layer was evaporated with metal anode Ag (80 nm). Under the standard test conditions (AM 1.5, 100 mW/cm.sup.2), it was measured that the open-circuit voltage (V.sub.OC) of the ternary polymer solar cell device was 0.80 V, the short-circuit current (J.sub.SC) was 11.5 mA/cm.sup.2, the fill factor (FF) was 0.45, and the power conversion efficiency (PCE) was 4.07%.
Embodiment 3
(21) A base plate, which has surface roughness less than 1 nm, composed of a transparent substrate layer and a transparent conductive cathode ITO was washed and then dried by blowing nitrogen. The surface of the transparent conductive cathode ITO was spin coated with ZnO (4500 rpm, 40 s, 25 nm) to prepare the cathode buffer layer, and a formed film was subjected to thermal annealing (200° C., 60 min). The cathode buffer layer was spin coated to prepare a PTB7-Th:N2200:2PDINB photoactive layer (2000 rpm, 60 s, 95 nm) in a mass ratio of 1:1:0.2, and the surface of the photoactive layer was evaporated with MoO.sub.3 (8 nm). An anode buffer layer was evaporated with metal anode Ag (80 nm). Under the standard test conditions (AM 1.5, 100 Mw/cm.sup.2), it was measured that the open-circuit voltage (V.sub.OC) of the ternary polymer solar cell device was 0.82V, the short-circuit current (J.sub.SC) was 12.1 mA/cm.sup.2, the fill factor (FF) was 0.45, and the power conversion efficiency (PCE) was 4.52%.
Embodiment 4
(22) A base plate, which has surface roughness less than 1 nm, composed of a transparent substrate layer and a transparent conductive cathode ITO was washed and then dried by blowing nitrogen. The surface of the transparent conductive cathode ITO was spin coated with ZnO (4500 rpm, 40 s, 25 nm) to prepare a cathode buffer layer, and a formed film was subjected to thermal annealing (200° C., 60 min). The cathode buffer layer was spin coated to prepare a PTB7-Th:2PDINB photoactive layer (1000 rpm, 30 s, 85 nm) in a mass ratio of 1:1, and the surface of the photoactive layer was evaporated with MoO.sub.3 (8 nm). An anode buffer layer was evaporated with metal anode Ag (80 nm). Under the standard test conditions (AM 1.5, 100 mW/cm.sup.2), it was measured that the open-circuit voltage (V.sub.OC) of the ternary polymer solar cell device was 0.88V, the short-circuit current (J.sub.SC) was 9.1 mA/cm.sup.2, the fill factor (FF) was 0.46, and the power conversion efficiency (PCE) was 3.71%.
(23)
(24) The preparation method of the ternary polymer solar cell device provided by the present invention is described above in detail. The non-fullerene PDI electron acceptor is added into the binary all-polymer system, so that the stacking of molecules can be effectively inhibited, the spectral absorption can be broadened, and the phase separation can be improved, thereby increasing the short-circuit current of the ternary polymer solar cell device, and increasing the efficiency of the ternary polymer solar cell device.
(25) The above only describes preferred embodiments of the present invention. It should be pointed out that several improvements and modifications may be made by those ordinary skilled in the art without departing from the principle of the present invention. These improvements and modifications shall also be regarded as the protection scope of the present invention.