CN109950402A - Laminated organic thin film solar cell and preparation method thereof - Google Patents

Abstract

The invention discloses a stacked organic thin film solar cell with high filling factor and energy conversion efficiency and a preparation method thereof. The stacked organic thin film solar cell comprises a substrate layer, a transparent conductive cathode layer, a cathode buffer layer, a first photoactive layer, a connection layer, a second photoactive layer, an anode buffer layer and an anode layer, which are arranged in sequence, and the first photoactive layer It is prepared from the first mixed solution, the second photoactive layer is prepared from the second mixed solution, the first mixed solution includes a first donor, a first acceptor, and a first solvent, and the second mixed solution includes a second donor, The second acceptor, the second solvent, the first donor and the second donor are the same donor material, and the first acceptor and the second acceptor are the same acceptor material. The solar cell after the stacking increases the absorption of sunlight, the absorbance is significantly increased, the utilization efficiency of solar energy is improved, and the filling factor and energy conversion efficiency of the solar cell are effectively improved, thereby improving the performance of the cell.

Description

Laminated organic thin film solar cell and preparation method thereof

technical field

The invention relates to the technical field of solar cells, in particular to a laminated organic thin film solar cell and a preparation method thereof.

Background technique

With the increasing depletion of fossil energy, photovoltaic power generation technology, which directly obtains energy from sunlight, is considered to be one of the most basic energy technologies for human beings in the future. Although the solar energy irradiating the earth is very huge, the main difficulty faced by the direct use of solar energy to generate electricity is that its energy density per unit area is too low. Only when we can manufacture large-area, high-efficiency solar cells on a large scale can photovoltaic power generation become the most important energy component in our daily life.

The solar cell power generation is based on the following principle: the P-N junction formed by the semiconductor material generates hole-electron pairs inside after being irradiated by sunlight, and the accumulated electrons (holes) are drawn out through the electrodes to form a current. The spectral range of sunlight is very wide, but any existing semiconductor material can only absorb and utilize photons with energy higher than its energy gap value in sunlight. Photons with lower energy will pass through the battery and be absorbed by the back electrode metal. Converted into heat energy; and the excess energy of high-energy photons beyond the energy gap width will be transferred by the carriers to the battery material itself to heat up. None of the above energy can be converted into effective electrical energy, so the energy conversion efficiency of single-junction solar cells is generally not high.

SUMMARY OF THE INVENTION

A technical problem to be solved by the present invention is how to provide a stacked organic thin film solar cell with high filling factor and energy conversion efficiency and a preparation method thereof.

According to a first aspect of the present invention, the present invention provides a stacked organic thin film solar cell. According to an embodiment of the present invention, the stacked organic thin film solar cell includes a substrate layer, a transparent conductive cathode layer, and a cathode buffer layer arranged in sequence. layer, the first photoactive layer, the connecting layer, the second photoactive layer, the anode buffer layer and the anode layer, the first photoactive layer is made from the first mixed solution, and the second photoactive layer is made from the second mixed solution, The first mixed solution includes a first donor, a first acceptor, and a first solvent, and the second mixed solution includes a second donor, a second acceptor, and a second solvent, and the first donor and the second donor are the same The donor material, the first acceptor and the second acceptor are the same acceptor material.

According to an embodiment of the present invention, the stacked organic thin film solar cell has at least the following beneficial effects:

Compared with the single junction cell, the solar cell after the laminate has an increased absorption of sunlight, the absorbance is obviously increased, and the utilization efficiency of the solar energy is improved. , effectively improving the fill factor and energy conversion efficiency of solar cells, thereby improving the performance of organic solar cells.

In addition, according to the embodiment of the present invention, the stacked organic thin film solar cell may further have the following additional technical features:

In some embodiments of the present invention, the donor material is selected from at least one of PCE-10 and PBDB-T.

In some embodiments of the present invention, the acceptor material is selected from at least one of PC ₇₀ BM, ITTC.

In some embodiments of the present invention, the system composed of the donor material and the acceptor material in the first mixed solution and the second mixed solution is any one of PCE-10: PC ₇₀ BM, PBDB-T: ITTC.

In some embodiments of the present invention, in the first mixed solution, the concentration ratio of the first donor and the first acceptor is 1:(1.2-2); in the second mixed solution, the second donor and the first acceptor have a concentration ratio of 1:(1.2-2). The concentration ratio of the two receptors was 1:(1.2-2). Specifically, the concentration ratio of the first donor and the first acceptor/the concentration ratio of the second donor and the second acceptor may be 1:1.2, 1:1.4, 1:1.5, 1:1.6, 1:1.8, 1:2.

In some embodiments of the present invention, the concentration ratio of the first donor to the first receptor is 8 mg/mL:12 mg/mL, and the concentration ratio of the second donor to the second receptor is 8 mg/mL:12 mg/mL .

In some embodiments of the present invention, the first solvent and the second solvent include chlorobenzene and DIO.

In some embodiments of the present invention, in the first solvent and the second solvent, the volume of DIO is 3% of the volume of chlorobenzene.

In some embodiments of the present invention, the material of the anode buffer layer is selected from at least one of PEDOT: PSS, MoO ₃ , V ₂ O ₅ , and NiO.

In some embodiments of the present invention, the material of the cathode buffer layer is selected from at least one of TiO _x , LiF, and ZnO, and x is selected from any one of 1, 2, 3, and 4.

In some embodiments of the present invention, the material of the connection layer may be at least one of aluminum and silver.

According to a second aspect of the present invention, the present invention provides a method for preparing a stacked organic thin film solar cell. According to an embodiment of the present invention, the method specifically includes the following steps: coating a first mixed layer on the cathode buffer layer. solution, evacuating, evaporating the connection layer and then coating the second mixed solution, evacuating and evaporating the anode buffer layer and the anode layer.

In some embodiments of the present invention, the preparation method specifically comprises the following steps:

(1) drying the conductive substrate after cleaning, and spin-coating the precursor solution of the cathode buffer layer on its surface;

(2) move into a nitrogen-filled glove box, spin-coat the first mixed solution on the cathode buffer layer to obtain the first photoactive layer;

(3) move to the vapor deposition box to vapor-deposit the connection layer on the first photoactive layer;

(4) move into a nitrogen-filled glove box, spin-coat the second mixed solution on the connecting layer to obtain the second photoactive layer;

(5) Move to a vapor deposition box, vapor-deposit an anode buffer layer on the second photoactive layer, and vapor-deposit a metal anode on the anode buffer layer.

Description of drawings

FIG. 1 is a schematic structural diagram of a stacked organic thin film solar cell according to an embodiment of the present invention.

FIG. 2 is a voltage-current density curve of an organic solar cell according to another embodiment of the present invention. The upper part is the voltage-current density curve of Comparative Example 1, and the lower part is the voltage-current density curve of Example 1.

FIG. 3 is a comparison of absorption spectra of organic solar cells of the embodiment shown in FIG. 2 of the present invention. The upper part is the absorption spectrum of Example 1, and the lower part is the absorption spectrum of Comparative Example 1.

Detailed ways

The concept of the present invention and the technical effects produced will be clearly and completely described below with reference to the embodiments, so as to fully understand the purpose, characteristics and effects of the present invention.

Example 1:

FIG. 1 is a schematic structural diagram of a stacked organic thin film solar cell according to an embodiment of the present invention. As shown in Figure 1, the stacked organic thin film solar cell adopts an inverted structure, including a substrate layer 1, a transparent conductive cathode layer 2, a cathode buffer layer 3, a first photoactive layer 4, a connection layer 5, a second Photoactive layer 6 , anode buffer layer 7 and anode layer 8 . The substrate layer 1 is a glass substrate, the transparent conductive cathode layer 2 is an ITO layer, the cathode buffer layer 3 is ZnO, the first photoactive layer 4 includes an electron donor material PCE-10 and an electron acceptor material _PC70BM , and the connection layer 5 is made of Al, the second photoactive layer 6 includes an electron donor material PCE-10 and an electron acceptor material PC ₇₀ BM, the anode buffer layer 7 is MoO ₃ , and the anode layer 8 is a metal anode Al.

The preparation method of the above-mentioned laminated organic thin film solar cell comprises the following steps:

(1) The ITO conductive glass composed of the glass substrate and the ITO layer is cleaned and dried, and 100 mg/mL of zinc acetate solution is spin-coated on the surface of the ITO layer of the transparent conductive cathode layer (the spin-coating speed is 2500 rpm, the time is 30 s, the thickness is about 30 nm), and heat treatment at 200 °C for 1 h to prepare ZnO as a cathode buffer layer.

(2) Move to a nitrogen-filled glove box, spin-coat the first photoactive layer PCE-10: PC ₇₀ BM on the cathode buffer layer (the mass concentration ratio after mixing the two is 8 mg/mL: 12 mg/mL, spin-coating The speed is 1400rmp, the time is 40s, and the thickness is about 100nm) to prepare the first photoactive layer.

(3) Move to an evaporation box and evaporate the connection layer Al (80 nm) on the first photoactive layer.

(4) Move to a nitrogen-filled glove box, spin-coat the second photoactive layer PCE-10: PC ₇₀ BM on the connecting layer (the mass concentration ratio after mixing the two is 8 mg/mL: 12 mg/mL, the spin coating speed 1400 rmp, time 40 s, thickness of about 100 nm) to prepare the second photoactive layer.

(5) Move to an evaporation box to evaporate an anode buffer layer MoO ₃ with a thickness of 10 nm on the second photoactive layer, and evaporate a metal anode Al with a thickness of 80 nm on the anode buffer layer.

The photoactive layer used in the present invention is prepared by mixing donors and receptors of different qualities, and the components contained are non-single components. It is found through experimental research that the use of the photoactive layer material to prepare stacked organic solar cells is beneficial to improve organic solar energy. battery performance. The experiment also found that compared with other solvents, using chlorobenzene alone and using 3% DIO at the same time has a better dissolution effect, and the prepared tandem organic solar cells have better performance.

Example 2:

Performance comparison experiment

The solar cell as Comparative Example 1 was prepared as follows:

(1) The ITO conductive glass composed of the glass substrate and the ITO layer is cleaned and dried, and 100 mg/mL of zinc acetate solution is spin-coated on the surface of the ITO layer of the transparent conductive cathode layer (the spin-coating speed is 2500 rpm, the time is 30 s, the thickness is about 30 nm) to prepare a cathode buffer layer, and heat the formed film (200 °C, 1 h);

(2) Move to a nitrogen-filled glove box, spin-coat the photoactive layer PCE-10: PC ₇₀ BM on the cathode buffer layer (the mass concentration ratio after mixing the two is 8 mg/mL: 12 mg/mL, and the spin coating speed is 1400 rpm , time 40s, thickness 100nm);

(3) Move to the evaporation box, and evaporate the anode buffer layer MoO ₃ on the photoactive layer (the evaporation film thickness rate is 10A/s, 10A=1nm, and the evaporation is 10nm), and the metal anode Al (thickness) is evaporated on the anode buffer layer. 80nm).

The solar cells in Example 1 and Comparative Example 1 were tested under standard test conditions (AM1.5, 100mW/cm ² ), and the test results were as follows:

The solar cell in Example 1: open circuit voltage Voc=0.79V, short circuit current density Jsc=17.49mA/cm ² , fill factor FF=66.93%, energy conversion efficiency PCE=9.25%.

The organic solar cell in Comparative Example 1: open circuit voltage Voc=0.78V, short circuit current density Jsc=16.68mA/cm ² , fill factor FF=63.55%, energy conversion efficiency PCE=8.26%.

It can be seen from the above experimental results that the fill factor of the prepared tandem organic solar cell is improved, and the energy conversion efficiency is also improved. Compared with the solar cell in Comparative Example 1, the energy conversion efficiency of the solar cell provided by the present invention is increased from 8.26% to 9.25%, an increase of 12%.

The voltage-current density curves of the organic solar cells in Example 1 and Comparative Example 1 were measured, and the results are shown in FIG. 2 . FIG. 2 is a voltage-current density curve of an organic solar cell according to another embodiment of the present invention. The upper part is the voltage-current density curve of Comparative Example 1, and the lower part is the voltage-current density curve of Example 1. It can be seen from FIG. 2 that the efficiency of the stacked organic thin film solar cell provided by the present invention is significantly increased.

The absorption spectra of the organic solar cells in Examples 1-2 and Comparative Example 1 were measured, and the results are shown in FIG. 3 . FIG. 3 compares the absorption spectra of the organic solar cells of the embodiment shown in FIG. 2 of the present invention. The upper part is the absorption spectrum of Example 1, and the lower part is the absorption spectrum of Comparative Example 1. It can be seen from FIG. 3 that the absorption rate of sunlight is obviously increased after being prepared into a tandem organic solar cell. This is also the reason for the increased efficiency and fill factor of the resulting solar cells.

Example 3:

A stacked organic thin film solar cell, the difference from Example 1 is that: the first photoactive layer includes an electron donor material PBDB-T and an electron acceptor material ITTC. The mass concentration ratio of PBDB-T and ITTC in the first mixed solution and the second mixed solution was 8 mg/mL:15 mg/mL.

Example 4

A laminated organic thin film solar cell, the difference from Example 1 is that the material of the connection layer is Ag.

Example 5:

A laminated organic thin film solar cell, the difference from Example 1 is that the material of the anode buffer layer is PEDOT:PSS, and the material of the cathode buffer layer is LiF.

Obviously, the above-described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Any changes or substitutions that can be easily conceived by any person skilled in the art within the technical scope disclosed by the present invention shall be included within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (10)

1. a laminated organic thin film solar cell, is characterized in that, comprises the substrate layer, the transparent conductive cathode layer, the cathode buffer layer, the first photoactive layer, the connecting layer, the second photoactive layer, the anode buffer layer and An anode layer, the first photoactive layer is made from a first mixed solution, the second photoactive layer is made from a second mixed solution, and the first mixed solution includes a first donor, a first acceptor, a first solvent, the second mixed solution includes a second donor, a second acceptor, and a second solvent, the first donor and the second donor are the same donor material, the first acceptor The body and the second receptor are the same receptor material. 2 . The stacked organic thin film solar cell according to claim 1 , wherein the donor material is selected from at least one of PCE-10 and PBDB-T. 3 . 3 . The stacked organic thin film solar cell according to claim 1 , wherein the acceptor material is selected from at least one of PC ₇₀ BM and ITTC. 4 . 4. The tandem organic thin film solar cell according to any one of claims 1-3, wherein in the first mixed solution, the concentration ratio of the first donor to the first acceptor is is 1:(1.2-2), and in the second mixed solution, the concentration ratio of the second donor and the second acceptor is 1:(1.2-2). 5 . The stacked organic thin film solar cell according to claim 4 , wherein the concentration ratio of the first donor and the first acceptor is 8 mg/mL:12 mg/mL, and the second donor is 8 mg/mL: 12 mg/mL. 6 . The concentration ratio of the antibody and the second receptor was 8 mg/mL:12 mg/mL. 6 . The stacked organic thin film solar cell according to claim 1 , wherein the first solvent and the second solvent comprise chlorobenzene and DIO. 7 . 7 . The stacked organic thin film solar cell according to claim 6 , wherein, in the first solvent and the second solvent, the volume of the DIO is 3% of the volume of the chlorobenzene. 8 . 8 . The stacked organic thin film solar cell according to claim 1 , wherein the material of the anode buffer layer is selected from at least PEDOT: PSS, MoO ₃ , V ₂ O ₅ , and NiO. 9 . A sort of. 9 . The stacked organic thin film solar cell according to claim 1 , wherein the material of the cathode buffer layer is selected from at least one of TiO _x , LiF, and ZnO, and the x is selected from the group consisting of TiO x , LiF, and ZnO. 10 . Any of 1, 2, 3, and 4. 10. The method for preparing a stacked organic thin film solar cell according to any one of claims 1 to 9, characterized in that: coating the first mixed solution on the cathode buffer layer, evacuating, and evaporating the connection layer after The second mixed solution is applied, and the anode buffer layer and the anode layer are evaporated after being evacuated.