TW201318181A - Solar cell and electrode and manufacturing method thereof - Google Patents

Abstract

A solar cell, an electrode of the solar cell and a method of manufacturing the electrode are provided. The solar cell includes a first electrode, a second electrode and an electrolyte. The first electrode includes CuInS2 quantum dots and CdS. The second electrode includes CuS. The electrolyte is disposed between the first and second electrodes.

Description

Solar cell, electrode and method of manufacturing same

The present invention relates to a solar cell, an electrode of the solar cell, and a method of manufacturing the same, and more particularly to an electrode of a quantum dot sensitized solar cell and a method of manufacturing the same.

With the increasing global warming problem and the high demand for green energy, there is an urgent need for a low-cost and high-efficiency photovoltaic power generation device. In recent decades, dye-sensitized solar cells (DSSCs), which can replace traditional solar cells based on germanium, have attracted great attention in academic research or industrial applications. DSSC is a potential Low-cost photovoltaic power generation device.

DSSC mainly uses organic dye molecules (such as hydrazine) as a light absorbing medium, which has the disadvantages that the dye is easily deteriorated and lacks long-term stability. In recent years, inorganic quantum dots (QD) have been used to replace the emerging technologies in the field of organic dye-based solar cells. Compared with organic dyes, quantum dot-sensitized solar cells have the ability to easily adjust the optical energy gap and reduce the thickness of the device. Higher stability and the potential for higher photoelectric conversion efficiency.

Although quantum dots of many materials or compounds have been proven to be applicable to quantum dot sensitized solar cells, the quantum dot sensitized solar cells of the presently known are relatively low in photoelectric conversion efficiency, so how to configure the optimal quantum dot sensitivity The solar cell structure is an important research and development direction to achieve high conversion efficiency.

One aspect of the invention provides a solar cell comprising a first electrode, a second electrode, and an electrolyte, the first electrode comprising copper indium sulfide quantum dots and cadmium sulfide, the second electrode comprising copper sulfide, and the electrolyte system being disposed on Between the first electrode and the second electrode.

Another aspect of the present invention provides a method of fabricating an electrode for a solar cell, comprising the steps of: providing a layer of a semiconductor material; arranging a quantum dot of a first compound on the layer of semiconductor material; and disposing a second compound in the semiconductor The material layer, wherein the first compound is selected from the group consisting of copper indium sulfide, copper indium selenide, and copper indium telluride, and the second compound is selected from one of the following: cadmium sulfide, cadmium selenide, and antimony. Cadmium.

A further aspect of the present invention provides an electrode for a solar cell comprising a quantum dot of a first compound and a cadmium compound in contact with a quantum dot of the first compound, wherein the first compound is selected from the group consisting of: vulcanization Copper indium, copper indium selenide, and copper indium telluride.

The invention can be further understood by the following drawings and detailed description of specific embodiments:

The technical means of the present invention will be described in detail below, and it is believed that the objects, features, and characteristics of the present invention will become more apparent and understood. Limit it.

Please refer to the first figure, which is a schematic diagram of an embodiment of an electrode of a solar cell of the present invention. The electrode 1 comprises a quantum dot 12 of a first compound and a cadmium compound 14 in contact with the quantum dot 12 of the first compound, such as copper indium sulfide (CuInS ₂ ), copper indium selenide (CuInSe ₂ ) or Copper indium telluride (CuInTe ₂ ).

In the first figure, the electrode 1 may further comprise a semiconductor material layer 10, such as titanium dioxide (TiO ₂ ), and the quantum dots 12 of the first compound and the cadmium compound 14 substantially completely cover the semiconductor The surface 100 of the material layer 10.

In the above embodiment, the cadmium compound 14 may be, for example, cadmium sulfide (CdS), cadmium selenide (CdSe) or cadmium telluride (CdTe). In addition, the electrode 1 may further include a bonding molecule 16 for adsorbing the quantum dots 12 of the first compound to the surface 100 of the semiconductor material layer 10, such as a thiol compound, such as thiol propionate. (3-mercaptopropionic acid, MPA) or 3-mercaptopropyl trimethoxysilane (MPTMS).

In the above embodiment, the electrode 1 may further include a transparent conductive glass as a substrate (not shown), such as an FTO substrate. Furthermore, the electrode 1 serves as the working electrode of the solar cell, and the light absorption range of the working electrode 1 will contain all visible light.

Please refer to the second figure, which is a schematic diagram of an embodiment of a solar cell of the present invention. The solar cell 2 uses the electrode 1 as shown in the first figure as its working electrode. In this embodiment, a composite material of a quantum dot of copper indium sulfide (CuInS ₂ ) and cadmium sulfide (CdS) is mainly used as the working electrode. Sensitized material.

Referring to the second figure, the solar cell 2 includes a first electrode 21, a second electrode 23, and an electrolyte 25 disposed between the first electrode 21 and the second electrode 23. The first electrode 21 includes titanium dioxide 210, The quantum dots 212 of copper indium sulfide and cadmium sulfide 214, and the second electrode 23 contains copper sulfide 230.

In the above embodiment, the first electrode 21 and the second electrode 23 respectively comprise a transparent conductive glass as a substrate, such as an FTO substrate. The first electrode 21 is a working electrode of the solar cell 2, and the second electrode 23 is a counter electrode of the solar cell 2.

In the above embodiment, the titanium dioxide 210 in the first electrode 21 is preferably a nanoporous titanium dioxide film, and in fact, the copper indium sulfide quantum dot 212 and the cadmium sulfide 214 can cover the titanium dioxide 210 almost completely. surface.

In the above embodiment, the electrolyte 25 is preferably a sulfur-containing polysulfide electrolyte, and the electrolyte 25 may be in a liquid state, a colloidal state, or an all-solid state.

In the above embodiment, since the nanoporous titania film 210 has a relatively high specific surface area, the quantum dots 212 capable of providing a large amount of CuInS ₂ (or alternatively CuInSe ₂ or CuInTe ₂ ) are adsorbed on the surface thereof, CdS (or alternatively CdSe or CdTe) 214 is then deposited on the periphery of the CuInS ₂ quantum dot 211 and completely covers the surface of the titanium dioxide 210, i.e., the working electrode 21 of the quantum dot sensitized solar cell 2. Furthermore, the opposite electrode 23 comprising copper sulphide possesses a relatively low charge transfer resistance (transfer electrons to the electrolyte) which is two orders of magnitude lower than the platinum or gold counter electrode conventionally used in dye sensitized solar cells.

The solar cell 2 according to the above embodiment of the present invention has a closed-loop current of 17 mA cm ^-2 , an open-loop voltage of 0.56 V, a fill factor of 0.45, and a photoelectric conversion efficiency of 4.2% under irradiation of a sunlight. The optical energy gap values of both CdS and CuInS ₂ quantum dots are 2.4 eV and 2.1 eV, respectively, and the ultraviolet-visible absorption spectra start positions are 520 nm and 600 nm, respectively, while the CdS and CuInS ₂ proposed by the present invention are respectively. When the quantum dots form a composite structure, the optical response initiation wavelength of the absorption spectrum and external quantum efficiency (IPCE or EQE) will be extended to about 800 due to the red shift due to the relaxation of the quantum confinement effect in the CuInS ₂ quantum dots. Nm, so the absorption range of the working electrode 21 of the solar cell 2 will cover the entire visible light in the sunlight, and the external quantum efficiency is up to nearly 80% (at a wavelength of 510 nm).

Please refer to the third diagram (A), which is a comparison diagram of the ultraviolet-visible absorption spectrum of the composite sensitizing material (CuInS ₂ quantum dot-CdS) and the individual sensitizing material CuInS ₂ quantum dots and CdS. As can be seen from the third graph (A), the absorption spectrum of the composite sensitizing material (CuInS ₂ quantum dot-CdS) can cover the entire visible light range.

Please refer to the third figure (B), which is the external quantum efficiency after assembly of a quantum sensitized solar cell using a composite sensitizing material (CuInS ₂ quantum dot-CdS) and an individual sensitizing material CuInS ₂ quantum dot and CdS ( IPCE) comparison chart. As can be seen from the third graph (B), the composite sensitizing material (CuInS ₂ quantum dot-CdS) has a significant increase in external quantum efficiency compared to the solar cell component composed of individual sensitized materials.

Please refer to the third figure (C), which is a photocurrent-voltage after assembly of a quantum sensitized solar cell using a composite sensitizing material (CuInS ₂ quantum dot-CdS) and an individual sensitizing material CuInS ₂ quantum dot and CdS. Curve ( IV curve). As can be seen from the third graph (C), the composite sensitized material (CuInS ₂ quantum dot-CdS) has a significantly improved photovoltaic characteristic compared to the solar cell component composed of individual sensitized materials.

Please refer to the fourth figure, which is a flow chart of an embodiment of a method for manufacturing an electrode for a solar cell of the present invention. The method 4 comprises the steps of: providing a layer of semiconductor material (step 41); arranging quantum dots of the first compound on the layer of semiconductor material (step 43); and configuring a second compound on the layer of semiconductor material (step 45).

In the above embodiment, the first compound is, for example, selected from the group consisting of copper indium sulfide, copper indium selenide, and copper indium telluride; and the second compound is, for example, selected from one of the following: cadmium sulfide, selenization Cadmium and cadmium telluride.

In the above embodiment, before step 43, a step of synthesizing the quantum dots of the first compound and/or the second compound by chemical liquid phase synthesis may be included.

In the above embodiment, step 43 may comprise the step of adsorbing the quantum dots of the first compound onto the surface of the layer of semiconductor material using a linking molecule such as MPA or MPTMS.

In the above embodiment, step 45 may comprise the step of depositing the second compound on the layer of semiconductor material by continuous ion layer adsorption and reaction.

After completion of step 45, the quantum dots of the first compound and the second compound substantially completely cover the surface of the layer of semiconductor material. Since the composite sensitizing material can cover the surface of the semiconductor film almost completely, the recombination reaction between the electrons and the electrolyte in the semiconductor material layer can be effectively suppressed, thereby effectively improving the electron survival time and the open-loop voltage of the solar cell.

In the above embodiment, the semiconductor material layer is, for example, a nanoporous titanium dioxide film, which can also be synthesized by a liquid phase synthesis method. Therefore, the composite material of the working electrode of the present invention, that is, the quantum dot, the cadmium compound and the semiconductor of the first compound. The material layers can be synthesized by a low-cost liquid phase synthesis method, which greatly reduces the overall production cost of the solar cell.

In addition, in the above embodiment, the solar light absorption range of the photoelectrode can be changed by the size control of the quantum dots of the first compound and the deposition amount of the second compound, and the more the second compound is deposited, the sun The light absorption range will be larger.

In addition to the composite sensitizing material in which CdS and CuInS ₂ quantum dots can be used as electrodes of a preferred solar cell, the present invention further proposes an embodiment in which a CdSe and CuInS ₂ quantum dot are combined as a composite sensitizing material to manufacture an electrode of a solar cell. :

(a) A nanoporous TiO ₂ electrode equipped with a CuInS ₂ quantum dot was immersed in a 0.03 M Cd(NO ₃ ) ₂ solution (methanol, ethanol or water was used as a solvent), and the immersion time was 30 seconds.

(b) Wash the above electrodes with water.

(c) The above electrode was immersed in a 0.03 M NaHSe solution (NaHSe solution was prepared by slowly adding 0.071 g of selenium powder to an aqueous solution containing 0.1 g of NaBH ₄ , methanol or ethanol as a solvent), and soaking for 30 seconds.

(d) Wash the above electrodes with water.

(e) Steps (a)-(d) are the ones in which CdSe is deposited once, and steps (a)-(d) are repeated to increase the amount of CdSe deposited.

According to the above embodiments, the present invention proposes a composite type in which a quantum dot of a specific compound (CuInS ₂ or CuInSe ₂ or CuInTe ₂ ) and another specific compound (CdS or CdSe or CdTe) constitute a working electrode of a quantum dot sensitized solar cell. The sensitizing materials, the solar cells are composed of low cost, covering the entire visible light absorption range and high photocurrent, and have been confirmed to have better photoelectric conversion efficiency than many known quantum dot sensitized solar cells (for example, CdS sensitized solar energy). battery).

Example:

A solar cell comprising a first electrode, a second electrode, and an electrolyte disposed between the first electrode and the second electrode.

2. The solar cell of embodiment 1, the first electrode comprising copper indium sulfide quantum dots and cadmium sulfide.

3. The solar cell of any of the above embodiments, the second electrode comprising copper sulfide.

4. The solar cell of any of the above embodiments, wherein the first electrode is a working electrode and the second electrode is an opposite electrode.

5. The solar cell according to any of the above embodiments, wherein the first electrode further comprises a titanium dioxide layer

6. The solar cell according to any of the above embodiments, wherein the titanium dioxide layer is a nanoporous titanium dioxide film.

7. The solar cell of any of the above embodiments, the copper indium sulfide quantum dots and the cadmium sulfide substantially completely covering the surface of the titanium dioxide layer.

8. The solar cell of any of the above embodiments, the electrolyte comprising sulfur.

9. A method of fabricating an electrode for a solar cell comprising the steps of: providing a layer of semiconductor material; arranging a quantum dot of a first compound on the layer of semiconductor material; and disposing a second compound on the layer of semiconductor material.

10. The method of embodiment 9, wherein the first compound is selected from the group consisting of copper indium sulfide, copper indium selenide, and copper indium telluride.

The method of any one of embodiments 9-10, wherein the second compound is selected from the group consisting of cadmium sulfide, cadmium selenide, and cadmium telluride.

12. The method of any of embodiments 9-11, further comprising the step of synthesizing the quantum dots of the first compound by a chemical liquid phase synthesis.

13. The method of any of embodiments 9-12, further comprising the step of synthesizing the second compound by a chemical liquid phase synthesis.

14. The method of any of embodiments 9-13, further comprising the step of adsorbing the quantum dots of the first compound onto the surface of the layer of semiconductor material using a linker molecule.

15. The method of any of embodiments 9-14, further comprising the step of depositing the second compound onto the layer of semiconductor material by a continuous ion layer adsorption and reaction process.

The method of any of embodiments 9-15, wherein the layer of semiconducting material comprises titanium dioxide.

17. The method of any of embodiments 9-16, wherein the quantum dots of the first compound and the second compound substantially completely cover the surface of the layer of semiconductor material.

18. An electrode for a solar cell comprising a quantum dot of a first compound and a cadmium compound in contact with a quantum dot of the first compound.

19. The electrode of embodiment 18, wherein the first compound is selected from the group consisting of copper indium sulfide, copper indium selenide, and copper indium telluride.

The electrode of any of embodiments 18-19, further comprising a layer of semiconductor material, and the quantum dots of the first compound and the cadmium compound substantially completely cover the surface of the layer of semiconductor material.

21. The electrode of any of embodiments 18-20, which is the working electrode of the solar cell.

The electrode of any one of embodiments 18-21, wherein the cadmium compound is selected from the group consisting of cadmium sulfide, cadmium selenide, and cadmium telluride.

23. The electrode of any of embodiments 18-22, wherein the light absorption range comprises all visible light.

The present invention has been described above in terms of several embodiments or examples, which are not intended to limit the invention, and those skilled in the art can make some modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

1. . . electrode

10. . . Semiconductor material layer

100. . . Surface of the semiconductor material layer

12. . . Quantum dot of the first compound

14. . . Cadmium compound

16. . . Linking molecule

2. . . Solar battery

twenty one. . . First electrode

210. . . Titanium dioxide

212. . . Quantum dots of copper indium sulfide

214. . . Cadmium sulfide

twenty three. . . Second electrode

230. . . Copper sulphide

25. . . Electrolyte

4. . . Electrode manufacturing method

41. . . Step of providing a layer of semiconductor material

43. . . Step of configuring a quantum dot of the first compound on the layer of semiconductor material

45. . . The step of configuring the second compound on the layer of semiconductor material

The first figure is a schematic diagram of an embodiment of an electrode of a solar cell of the present invention;

2 is a schematic view of an embodiment of a solar cell of the present invention;

The third diagram (A) is a comparison diagram of the light absorption range of the electrode of the solar cell of the present invention and the prior art;

The third diagram (B) is a comparison diagram of the photoelectric conversion efficiency of the electrode of the solar cell of the present invention and a conventional technique;

The third diagram (C) is a comparison diagram of the photocurrent-voltage graph of the electrode of the solar cell of the present invention with a conventional technique;

Fig. 4 is a flow chart showing an embodiment of a method of manufacturing an electrode for a solar cell of the present invention.

2. . . Solar battery

twenty one. . . First electrode

210. . . Titanium dioxide

212. . . Quantum dots of copper indium sulfide

214. . . Cadmium sulfide

twenty three. . . Second electrode

230. . . Copper sulphide

25. . . Electrolyte

Claims (10)

A solar cell comprising: a first electrode comprising a copper indium sulfide quantum dot and a cadmium sulfide; a second electrode comprising a copper sulfide; and an electrolyte disposed on the first electrode and the second Between the electrodes. The solar cell of claim 1, wherein the first electrode is a working electrode, the second electrode is an opposite electrode, the first electrode further comprises a titanium dioxide layer, and the titanium dioxide layer is One nanometer porous titanium dioxide film. The solar cell of claim 2, wherein the copper sulfide indium quantum dot and the cadmium sulfide substantially completely cover a surface of the titanium dioxide layer. The solar cell of claim 1, wherein the electrolyte comprises sulfur. A method of manufacturing an electrode for a solar cell, comprising: providing a layer of a semiconductor material; arranging a quantum dot of a first compound on the layer of semiconductor material, wherein the first compound is selected from the group consisting of copper indium sulfide, selenium sulfide Copper indium and copper indium telluride; and a second compound disposed on the layer of semiconductor material, wherein the second compound is selected from the group consisting of cadmium sulfide, cadmium selenide, and cadmium telluride. The method of claim 5, further comprising the steps of: synthesizing the quantum dot of the first compound and the second compound by a chemical liquid phase synthesis method; and using the quantum dot of the first compound by using a linking molecule Adsorbing on a surface of the layer of semiconductor material; and depositing the second compound on the layer of semiconductor material by a continuous ion layer adsorption and reaction method. The method of claim 5, wherein the layer of semiconductor material comprises titanium dioxide, and the quantum dots of the first compound and the second compound substantially completely cover a surface of the layer of semiconductor material. An electrode for a solar cell, comprising: a quantum dot of a first compound, wherein the first compound is selected from the group consisting of copper indium sulfide, copper indium selenide, and copper indium telluride; and a cadmium compound, and the first Quantum point contact of a compound. The electrode of claim 8 further comprising a layer of semiconductor material, and the quantum dots of the first compound and the cadmium compound substantially completely cover a surface of the layer of semiconductor material. An electrode according to claim 9 which is a working electrode of the solar cell, wherein the cadmium compound is selected from one of the following: cadmium sulfide, cadmium selenide and cadmium telluride, and a light absorption range of the working electrode Contains all visible light.