TW201530792A - Solar cell and manufacturing method thereof - Google Patents

Abstract

A solar cell and a manufacturing method thereof are disclosed. The solar cell includes a transparent substrate, a first electrode, a photoelectric converting layer and a second electrode. The transparent substrate has a curved surface. The photoelectric converting layer is adhered to the curved surface of the transparent through an adhesive layer, so that the photoelectric converting layer is curved according to the curved surface. The thickness of the photoelectric converting layer is between 1 micrometer and 50 micrometers. The first electrode is clamped between the adhesive layer and the photoelectric converting layer. The first electrode is electrically connected to the photoelectric converting layer. The second electrode is disposed on the photoelectric converting layer and is at the opposite side to the first electrode. The second electrode is electrically connected to the photoelectric converting layer and the first electrode.

Description

Solar cell and preparation method thereof

The present invention relates to a solar cell and a method of fabricating the same, and more particularly to a thin solar cell having a curved surface and a method of fabricating the same.

Solar energy is the focus of attention from all walks of life because it is easy to obtain, low in pollution, high in safety, and almost inexhaustible. In the research and development of solar cells, how to reduce the production cost of solar cells and improve the performance of solar cells has always been a topic of concern.

In recent years, with the development of related technologies for solar cells, the efficiency and production cost of solar cells have also been greatly improved. However, as the related technologies become more mature, the development of technology has also encountered bottlenecks, and it is difficult to make further breakthroughs in the production cost and performance of solar cells. Therefore, how to further improve the performance of solar cells and reduce the production cost of solar cells has become a topic of great concern.

This proposal is about a solar cell and its preparation method to improve the performance of the solar cell and reduce the production cost of the solar cell.

The solar cell disclosed in one embodiment of the present invention comprises a transparent carrier, a first electrode, a photoelectric conversion layer and a second electrode. The transparent carrier has a curved surface. Photoelectric conversion layer Adhesive layer attached to the curved surface of the transparent carrier. The photoelectric conversion layer is deflected along the curved surface. The thickness of the photoelectric conversion layer is between 1 micrometer and 50 micrometers. The first electrode is sandwiched between the adhesive layer and the photoelectric conversion layer. The first electrode is electrically connected to the photoelectric conversion layer. The second electrode is disposed on a side opposite to the first electrode of the photoelectric conversion layer, and the second electrode is electrically connected to the photoelectric conversion layer and the first electrode.

The method for preparing a solar cell disclosed in an embodiment of the present invention comprises the following steps. A first electrode is formed on a photoelectric conversion layer. An adhesive layer is formed on one side of the photoelectric conversion layer provided with the first electrode. The photoelectric conversion layer is transferred to a curved surface of a transparent carrier through the adhesive layer. A second electrode is formed on the side of the photoelectric conversion layer opposite to the first electrode.

According to the solar cell disclosed in the embodiment of the present invention and the method of manufacturing the same, since the photoelectric conversion layer is attached to the curved surface of the transparent carrier by the transfer method, the photoelectric conversion layer can have a thin thickness. At the same time, through the transfer process, the photoelectric conversion layer can be flexed along the curved surface to have a corresponding curved surface structure. That is to say, the photoelectric conversion layer of the solar cell of the present proposal has both a thin thickness (1 micrometer to 50 micrometers) and a curved surface structure. Since the thickness of the photoelectric conversion layer of the solar cell of the present invention is between 1 micrometer and 50 micrometers, the material required for the photoelectric conversion layer is greatly reduced while maintaining good photoelectric conversion capability, and the solar energy can be effectively reduced. Battery production costs. On the other hand, since the photoelectric conversion layer of the present invention has a curved surface structure, the photoelectric conversion layer can absorb the light directly reflected from the photoelectric conversion layer, and can absorb the light reflected from other regions, thereby achieving the effect of secondary absorption. . Therefore, the photoelectric conversion layer of the present invention can absorb a relatively large amount of light and has a better effective light collecting efficiency.

The above description of the contents of this proposal and the following description of the implementation of the proposal are used to demonstrate and explain the principles of this proposal, and provide a further explanation of the scope of the patent application of this proposal.

9‧‧‧Solar battery array

10, 10x, 10', 10" ‧ ‧ solar cells

11‧‧‧Transparent carrier

110‧‧‧ Surface

12, 12x, 12'‧‧‧ photoelectric conversion layer

121‧‧ ‧ emitter layer

122‧‧‧base layer

123‧‧‧Neutral

13‧‧‧First electrode

14‧‧‧second electrode

15‧‧‧Adhesive layer

16‧‧‧Anti-reflective layer

17‧‧‧Substrate

E‧‧‧ edge

FIG. 1A is a perspective view of a solar cell disclosed in an embodiment of the present invention.

Fig. 1B is a cross-sectional view showing the solar cell of Fig. 1A taken along line A-A.

1C is a top view of a solar cell disclosed in another embodiment of the present proposal.

FIG. 1D is a side view of a solar cell disclosed in another embodiment of the present proposal.

FIG. 1E is a schematic cross-sectional view of a solar cell disclosed in another embodiment of the present proposal.

Fig. 1F is a graph showing the relationship between the thickness of the photoelectric conversion layer and the photoelectric conversion capability.

FIG. 2A is a flow chart of a method for preparing a solar cell according to an embodiment of the present invention.

FIG. 2B is a flow chart of a method for preparing a solar cell according to another embodiment of the present proposal.

3A to 3D are side views corresponding to steps S101 to S104 in Fig. 2A, respectively.

Fig. 4A is a side view corresponding to step S202 in Fig. 2B.

Fig. 4B is a side view of the solar cell fabricated according to the preparation method of Fig. 2B.

4C is a side view of a solar cell fabricated by a method of fabricating a solar cell according to another embodiment of the present proposal.

4D is a side view of a solar cell fabricated by a method of fabricating a solar cell according to another embodiment of the present proposal.

Fig. 5 is a graph showing the relationship between the effective light collection efficiency and the incident angle of the solar cell of the embodiment of the present invention and the solar cell of the comparative example.

6A is a schematic view of a solar cell array composed of solar cells of the embodiment of the present invention.

Fig. 6B is a schematic view showing the collection of light of the solar cell array of Fig. 6A.

The detailed features and advantages of the present proposal are described in detail below in the embodiments. It is sufficient for any skilled person to understand the technical content of this proposal and implement it according to the content, patent application scope and schema disclosed in this specification, and anyone skilled in the art can easily understand the related purposes and advantages of this proposal. . The following examples further illustrate the views of this proposal in detail, but do not limit the scope of this proposal by any point of view.

First, please refer to FIG. 1A and FIG. 1B. FIG. 1A is a perspective view of a solar cell according to an embodiment of the present disclosure, and FIG. 1B is a schematic cross-sectional view of the solar cell of FIG. 1A along a cutting line AA. .

The solar cell 10 includes a transparent carrier 11, a photoelectric conversion layer 12, a first electrode 13, and a second electrode 14. The transparent carrier 11 has a curved surface 110. It should be noted that the curved surface 110 described in this proposal does not include a plane with a curvature of zero.

As shown in FIGS. 1A and 1B, the curvature of the curved surface 110 of the present embodiment remains the same along the direction X, and the bottom edge of the curved surface 110 is maintained at the same horizontal plane in the direction Z. However, the above two structural features are not intended to limit the proposal. Referring to FIG. 1C and FIG. 1D, FIG. 1C is a top view of a solar cell disclosed in another embodiment of the present invention, and FIG. 1D is a side view of a solar cell disclosed in another embodiment of the present proposal. In the embodiment of Fig. 1C, the curvature of the curved surface 110a varies along the direction X. Therefore, in the first C-figure, the opposite end edges E of the curved surface 110a are wavyly changed along the direction X. In the embodiment of Fig. 1D, the bottom edge of the curved surface 110b is located at a different horizontal plane along the direction X. Therefore, in the first DD, the bottom edge of the curved surface 110b is wavyly changed along the direction Z.

In the present embodiment, the curved surface 110 is a convex surface (as shown in FIG. 1B), and the curvature of the curved surface 110 is between 0.005 and 0.01 (cm ^-1 ). Wherein, the curvature refers to the reciprocal of the radius of curvature of the curved surface 110. That is to say, when the curvature of the curved surface 110 is 0.005, the corresponding radius of curvature is 200 cm; when the curvature of the curved surface 110 is 0.01, the corresponding radius of curvature is 100 cm.

The photoelectric conversion layer 12 is attached to the curved surface 110 of the transparent carrier 11 through an adhesive layer 15, and the photoelectric conversion layer 12 is deflected along the curved surface 110. Therefore, the photoelectric conversion layer 12 has a curved surface structure corresponding to the curved surface 110. On the other hand, the thickness of the photoelectric conversion layer 12 is between 1 micrometer and 50 micrometers. Therefore, the photoelectric conversion layer 12 of the present proposal has a relatively thin thickness as compared with a general solar cell.

In more detail, the photoelectric conversion layer 12 includes an emitter layer 121 and a base layer 122. The emitter layer 121 is disposed on the base layer 122, and the emitter layer 121 and the base layer 122 together form a p-n junction structure (PN junction). The emitter layer 121 of the photoelectric conversion layer 12 is disposed on the curved surface 110 of the transparent carrier 11 . The emitter layer 121 and the base layer 122 are, for example, single crystal germanium, polycrystalline germanium or amorphous germanium. However, the crystal form of the germanium in the emitter layer 121 and the base layer 122 is not intended to limit the present proposal.

It should be noted that the adhesive layer 15 of the present proposal is transparent to prevent the adhesive layer from being shielded and to reduce the amount of light entering the photoelectric conversion layer 12.

The first electrode 13 is, for example but not limited to, a metal wire. The first electrode 13 is interposed between the adhesive layer 15 and the photoelectric conversion layer 12 , and the first electrode 13 is electrically connected to the photoelectric conversion layer 12 .

The second electrode 14 is disposed on the side of the photoelectric conversion layer 12 opposite to the first electrode 13 (as shown in FIG. 1B), and thus the first electrode 13 and the second electrode 14 are located on opposite sides of the photoelectric conversion layer 12, respectively. Further, the second electrode 14 is electrically connected to the photoelectric conversion layer 12 and the first electrode 13.

In this embodiment and some other embodiments, the solar cell 10 further includes an anti-reflection layer 16. The anti-reflection layer 16 is disposed on the photoelectric conversion layer 12, and the anti-reflection layer 16 is interposed between the photoelectric conversion layer 12 and the adhesive layer 15. The material composition of the anti-reflective layer 16 may be Indium Tin Oxide (ITO), Aluminium Oxide (AlOx) or Silicon Nitride (SiNx).

Please refer to FIG. 1E. FIG. 1E is a schematic cross-sectional view of a solar cell according to another embodiment of the present disclosure. The present embodiment is similar to the embodiment of FIG. 1B in that the photoelectric conversion layer 12x of the solar cell 10x of the present embodiment further includes a neutral layer 123, and the neutral layer 123 is disposed on the emitter layer 121 and the base. Between layers 122. The emitter layer 121, the base layer 122 and the neutral layer 123 form a p-i-n structure. The neutral layer 123 is, for example, an undoped germanium film layer, but is not limited thereto.

Please refer to FIG. 1F. FIG. 1F is a diagram showing the relationship between the thickness of the photoelectric conversion layer and the photoelectric conversion capability. As shown in FIG. 1F, in the thickness range of 1 micrometer to 50 micrometers (ie, the solar cell 10 of the presently proposed embodiment). The thickness of the photoelectric conversion layer 12), the photoelectric conversion layer 12 still has good photoelectric conversion capability. Generally, the thickness of the photoelectric conversion layer of the solar cell is greater than 160 micrometers. In contrast, the photoelectric conversion layer 12 of the solar cell 10 of the present invention has a thin thickness, and thus, while maintaining good photoelectric conversion capability, the size is greatly reduced. The material to be used for the photoelectric conversion layer 12 can reduce the production cost of the solar cell 10. On the other hand, since the photoelectric conversion layer 12 of the present invention has a curved surface structure, the photoelectric conversion layer 12 can absorb light directly irradiated to the photoelectric conversion layer 12, and each region of the photoelectric conversion layer 12 can also be absorbed from other regions. The light can achieve the effect of secondary absorption. Since a typical solar cell is flat, it cannot absorb light reflected from other areas. In contrast, the photoelectric conversion layer 12 of the present invention can absorb a relatively large amount of light and has a better effective light collecting efficiency.

The following is a description of the preparation method of the solar cell of the present invention. Please refer to FIG. 2A and FIGS. 3A to 3D. FIG. 2A is a flow chart of a method for preparing a solar cell according to an embodiment of the present invention, and FIG. 3A to Fig. 3D is a side view corresponding to steps S101 to S104 in Fig. 2A, respectively.

First, a first electrode 13 is formed on a photoelectric conversion layer 12' (S101), and the first electrode 13 is electrically connected to the photoelectric conversion layer 12'. Wherein, the photoelectric conversion layer 12' is disposed on a substrate 17 on (as shown in Figure 3A). The substrate 17 is, for example, alumina (such as sapphire), yttrium oxide (such as quartz), tantalum carbide, tantalum wafer or oxide crystal, but is not limited thereto.

Next, an adhesive layer 15 (S102) is formed on one side of the photoelectric conversion layer 12' on which one side of the first electrode 13 is provided (that is, opposite to the side of the substrate 17) (as shown in FIG. 3B).

Then, the photoelectric conversion layer 12' is transferred to a curved surface 110 of a transparent carrier 11 through the adhesive layer 15, and the photoelectric conversion layer 12' is separated from the substrate 17 (S103) (as shown in Fig. 3C). Since the photoelectric conversion layer 12' is attached to the curved surface 110 of the transparent carrier 11 by a transfer method, the photoelectric conversion layer 12' is deflected along the curved surface 110, so that the photoelectric conversion layer 12' has a surface corresponding to the curved surface. The curved structure of 110.

In the step (S103) of transmitting the curved structure to form the photoelectric conversion layer, the operating temperature is lower than 300 °C. For example, the transfer can be carried out at room temperature (e.g., 25 ° C). Compared with a general solar cell, the operating temperature required to form the curved surface structure of the photoelectric conversion layer in this embodiment is low.

Finally, a second electrode 14 is formed on the side of the photoelectric conversion layer 12' opposite to the first electrode 13 (S104) (as shown in FIG. 3D). In detail, the second electrode 14 is formed on the photoelectric conversion layer 12' by, for example, electroplating. As shown in FIG. 3D, the first electrode 13 and the second electrode 14 of the prepared solar cell 10' are located on opposite sides of the photoelectric conversion layer 12', respectively.

Please refer to FIG. 2B, FIG. 4A and FIG. 4B. FIG. 2B is a flowchart of a method for preparing a solar cell according to another embodiment of the present disclosure, and FIG. 4A is a side view corresponding to step S202 of FIG. 2B. Fig. 4B is a side view of the solar cell produced according to the preparation method of Fig. 2B.

The embodiment of FIG. 2B is similar to the embodiment of FIG. 2A except that the embodiment of FIG. 2B includes the step of forming an anti-reflective layer 16 on the photoelectric conversion layer 12' before the step of forming the adhesive layer 15. (S202). As shown in FIG. 4A, the anti-reflection layer 16 is interposed on the photoelectric conversion layer 12'. And between the adhesive layers 15. The material composition of the anti-reflection layer 16 is, for example, indium tin oxide or aluminum oxide, but is not limited thereto. The prepared solar cell 10" is as shown in Fig. 4B.

Please refer to FIG. 3A, FIG. 4C and FIG. 4D. FIG. 4C is a side view of a solar cell produced by a method for preparing a solar cell according to another embodiment of the present proposal, and FIG. 4D is a diagram according to the proposal. A side view of a solar cell made by a method of preparing a solar cell disclosed in another embodiment. As shown in FIG. 4C, the photoelectric conversion layer 12 of the solar cell 10 of the present embodiment includes an emitter layer 121 and a base layer 122. The emitter layer 121 is disposed on the base layer 122, and the emitter layer 121 is disposed on the curved surface 110 of the transparent carrier 11 opposite to one side of the base layer 122. In detail, the emitter layer 121 and the base layer 122 are formed on the substrate 17 by chemical vapor deposition (ie, epitaxial) (as shown in FIG. 3A). For example, the SiH ₄ gas may be introduced at an operating temperature of 200 ° C to form the micro-array emitter layer 121 and the base layer 122 on the substrate 17; or by high-temperature epitaxy, for example, at 1000 ° C. At the operating temperature, SiHCl ₃ or SiCl ₄ gas is introduced to form a single crystal germanium emitter layer 121 and a base layer 122 on the substrate 17. As shown in FIG. 4D, in other embodiments of the present proposal, the photoelectric conversion layer 12x of the solar cell 10x further includes a neutral layer 123. The neutral layer 123 is disposed between the emitter layer 121 and the base layer 122. The neutral layer 123 is, for example, an undoped germanium film layer, but is not limited thereto.

In the present proposal, the curved structure of the photoelectric conversion layer is formed by a transfer process. In a general solar cell, the curved surface structure of the photoelectric conversion layer is formed by a high temperature, high pressure die casting process. In contrast, the preparation method of the present proposal requires a lower operating temperature, thereby preventing the components of the solar cell from being damaged due to high temperature and high pressure. On the other hand, in the solar cell made by the die-casting process, internal stress remains in the solar cell, causing paralysis on the structure of the solar cell.

In addition, this proposal is to form a photoelectric conversion layer by an epitaxial method, which has a considerable material loss compared to a process of forming a photoelectric conversion layer by a dicing method. This proposal can avoid such material damage. Lost. On the other hand, the method of forming a photoelectric conversion layer by the epitaxial method does not require a crystal growth process. Since the crystal growth process requires a high temperature operating environment, it requires a considerable amount of energy to be consumed. This proposal can significantly reduce the production cost of solar cells because it does not require a crystal growth process. At the same time, this proposal combines the steps of battery preparation and module packaging, and further simplifies the process of reducing solar cells.

In the following paragraphs, the solar cells of the embodiments of the present proposal and the solar cells of the comparative examples were tested separately. Among them, the solar cells of the embodiments of the present invention have curvatures of 0.005 and 0.01, respectively, and the solar cells of the comparative examples have curvatures of 0.25 and 0, respectively (that is, planar photoelectric conversion layers). Please refer to FIG. 5. FIG. 5 is a diagram showing the relationship between the effective light collection efficiency and the incident angle of the solar cell of the embodiment of the present invention and the solar cell of the comparative example.

In Fig. 5, the curvature of the photoelectric conversion layer of the solar cell of the first embodiment is 0.005, and the curvature of the photoelectric conversion layer of the solar cell of the second embodiment is 0.01, and the curvature of the photoelectric conversion layer of the solar cell of the first comparative example is 0. (i.e., plane), the photoelectric conversion layer of the solar cell of Comparative Example 2 has a curvature of 0.25.

As shown in Fig. 5, the effective light collecting area of the solar cell of the first embodiment is significantly improved as compared with the solar cell of the first comparative example in the range of the incident angle of 30 to about 50 degrees. When the curvature of the photoelectric conversion layer of the solar cell is raised to 0.01 (Embodiment 2), the solar cells of Embodiment 2 have a better effective concentrating area in the range of 0 to about 50 degrees. However, when the curvature of the photoelectric conversion layer of the solar cell was raised to 0.25 (Comparative Example 2), the effective collection area of Comparative Example 2 was inferior to Comparative Example 1 in the range of the incident angle of 0 to 90 degrees. That is to say, the curvature of the photoelectric conversion layer of the solar cell does not exhibit a simple positive correlation with the effective collection area. The photoelectric conversion layer of the solar cell has a curvature in the range of 0.005 to 0.01 to have a better effective light collecting area.

Please refer to FIG. 6A and FIG. 6B. FIG. 6A is a schematic diagram of a solar cell array composed of a solar cell according to an embodiment of the present invention, and FIG. 6B is a schematic diagram of a solar cell array of FIG. 6A. As shown in the figure, the solar cell of the embodiment of the present invention can be formed into a solar cell array 9, and can be used as a large power generation module. In the present embodiment, each solar cell 10 can absorb the light reflected by the other solar cells 10 in addition to the light reflected by the solar cell 10, thereby further increasing the amount of light absorbed and further improving the overall solar cell array 9. Effective collection efficiency.

Although the embodiments of the present disclosure are as described above, they are not intended to limit the proposal, and any person skilled in the art may, without departing from the spirit and scope of the proposal, the shapes, structures, and features described in the scope of application of the proposal. And the spirit of the patent may be subject to change, so the scope of patent protection of this proposal shall be subject to the definition of the scope of the patent application attached to this specification.

10‧‧‧Solar battery

11‧‧‧Transparent carrier

110‧‧‧ Surface

12‧‧‧ photoelectric conversion layer

121‧‧ ‧ emitter layer

122‧‧‧base layer

13‧‧‧First electrode

14‧‧‧second electrode

15‧‧‧Adhesive layer

16‧‧‧Anti-reflective layer

Claims (13)

A solar cell comprising: a transparent carrier having a curved surface; a photoelectric conversion layer attached to the curved surface of the transparent carrier through an adhesive layer, the photoelectric conversion layer being flexed along the curved surface, the photoelectric The thickness of the conversion layer is between 1 micrometer and 50 micrometers; a first electrode is sandwiched between the adhesive layer and the photoelectric conversion layer, the first electrode is electrically connected to the photoelectric conversion layer; and a second The electrode is disposed on the side of the photoelectric conversion layer opposite to the first electrode, and the second electrode is electrically connected to the photoelectric conversion layer and the first electrode. The solar cell of claim 1, wherein the curvature of the curved surface of the transparent carrier is between 0.005 and 0.01 (cm ^-1 ). The solar cell of claim 1, wherein the photoelectric conversion layer comprises an emitter layer and a base layer, the emitter layer is disposed on the base layer, and the emitter layer is opposite to one side of the base layer Attached to the curved surface of the transparent carrier. The solar cell of claim 3, wherein the photoelectric conversion layer further comprises a neutral layer disposed between the emitter layer and the base layer. The solar cell of claim 1, further comprising an anti-reflection layer disposed on the photoelectric conversion layer, the anti-reflection layer being interposed between the photoelectric conversion layer and the adhesive layer. The solar cell of claim 1, wherein the curved surface is a convex surface. The solar cell of claim 6, wherein the transparent carrier has a concave surface opposite to one side of the curved surface. A method for preparing a solar cell, comprising: Forming a first electrode on a photoelectric conversion layer; forming an adhesive layer on one side of the photoelectric conversion layer; and transferring the photoelectric conversion layer to a curved surface of a transparent carrier through the adhesive layer And forming a second electrode on the side opposite to the first electrode of the photoelectric conversion layer. The method for preparing a solar cell according to claim 8, wherein before the one surface of the first electrode is formed on the photoelectric conversion layer, the anti-reflection layer is formed on the photoelectric conversion layer. The layer is sandwiched between the photoelectric conversion layer and the first electrode. The method of producing a solar cell according to claim 8, wherein the step of transferring the photoelectric conversion layer through the adhesive layer to the curved surface of the transparent carrier is performed at an operating temperature of less than 300 °C. The method for preparing a solar cell according to claim 8, wherein the photoelectric conversion layer is disposed on a substrate, the photoelectric conversion layer comprising an emitter layer and a base layer before the photoelectric conversion layer forms the first electrode The emitter layer is disposed on the base layer, and the emitter layer and the base layer are formed on the substrate by chemical vapor deposition. The method of preparing a solar cell according to claim 11, wherein the photoelectric conversion layer further comprises a neutral layer disposed between the emitter layer and the base layer. The method of preparing a solar cell according to claim 11, wherein the photoelectric conversion layer is separated from the substrate after the photoelectric conversion layer is transferred to the curved surface of the transparent carrier through the adhesive layer.