1. Field of the Invention
The present invention relates to a solar cell, and more particularly, to a solar cell including a copper-indium-gallium-diselenide (CIGS) compound and a manufacturing method thereof.
2. Description of the Prior Art
In several well-known solar cells, the solar cell including a CIGS compound is a kind of solar cell having high conversion efficiency and low manufacturing cost, and a product of the CIGS solar cell also has good stability. Therefore, the CIGS solar cell has been one of the well-known solar cells with developing potential.
The aforementioned CIGS solar cell is formed by sequentially forming a molybdenum (Mo) layer, a CIGS compound layer and a transparent conductive layer on a substrate. The CIGS compound layer is used as a light-absorbing layer. When the light emits to the CIGS solar cell, energy of the light can be absorbed by the CIGS compound layer, and the energy of the light can be conversed into electric energy.
However, an energy conversion efficiency of the well-known CIGS solar cell is about 14%, and a difference between the energy conversion efficiency of the well-known CIGS solar cell and an ideal energy conversion efficiency still exists. Therefore, to raise the energy conversion efficiency of the CIGS solar cell and to increase utilization value in industry is an important objective in researching the CIGS solar cell.
It is a primary objective of the present invention to provide a solar cell and a manufacturing method thereof to increase absorbed light and a reacting area, so that a conversion efficiency of light energy being converted into electric energy is raised.
According to the present invention, a solar cell is disclosed. The solar cell includes:
According to the present invention, a manufacturing method of a solar cell is disclosed. The manufacturing method of a solar cell includes:
The present invention transforms the top surface of the substrate into the surface with the waved shape, so that the conductive layer, the CIGS compound layer and the transparent conductive layer formed on the top surface of the substrate in the following steps also have surfaces with the waved shape due to the top surface of the substrate being the surface with the waved shape. Therefore, when the solar cell absorbs the sunlight, the surface with the waved shape can increase the number of the refracting light, and reduces the reflection of the sunlight, so that the absorption rate for the sunlight can be raised. In addition, the reacting area of the CIGS compound layer can be therefore increased, so that the conversion efficiency of the solar cell converting the light energy into electric energy is raised, and the current generated by the solar cell can be increased.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
Please refer to
The substrate can be a board selected from glass and plastic material. A top surface of the substrate has an active surface 101 with a waved shape, and the waved shape can be a plurality of peaks and a plurality of valleys arranged alternately in sequence. In this preferred embodiment, the top surface of the substrate 10 is transformed into the active surface 101 with the waved shape including a plurality of concavities 102. The concavities 102 can be V-shaped, inverted conoid, inverted pyramid-shaped holes.
The conductive layer 11 can be molybdenum (Mo), and is disposed on the active surface 101 of the substrate 10 with the concavities, so that the conductive layer is a film with a waved shape.
The CIGS compound layer 12 is copper-indium-gallium diselenide (CuIn1-xGaxSe2, CIGS), and the CIGS compound layer 12 is disposed on a top surface of the conductive layer 11, so that the CIGS compound layer is a film with a waved shape.
The transparent conductive layer 13 includes indium tin oxide (ITO) or Zinc oxide (ZnO), and the transparent conductive layer 13 is disposed on the CIGS compound layer 12.
In order to describe a manufacturing method of the above-mentioned solar cell, referring to
Next, a surface-roughening method is performed on the top surface of the substrate 10 to form an uneven surface including a plurality of holes, and the surface-roughening method utilizes a destructive forming method, such as a sandblasting method, a laser processing method, an etching method or other forming method being capable of forming the a plurality of holes on the top surface of the substrate 10. As shown in
A shaping method is performed on the uneven surface of the substrate 10 including the holes to form an active surface 101 with a smoothly waved shape, and the waved shape has the peaks and the valleys arranged alternately in sequence. As shown in
As shown in
As shown in
As shown in
The manufacturing method of the solar cell in the present invention further includes a cutting process after forming the transparent conductive layer 13, and the cutting process is performed to generate a cut gap. The cut gap has a pattern and extends from the top surface of the transparent conductive layer 13 to the substrate 10, so that a plurality of solar cell units is formed on a single substrate.
As the above-mentioned description, the present invention transforms the top surface of the substrate into the surface with the waved shape, so that the conductive layer, the CIGS compound layer and the transparent conductive layer formed on the top surface of the substrate in the following steps also have the surface with the waved shape due to the top surface of the substrate being the surface with the waved shape. Therefore, when the solar cell absorbs the sunlight, the surface with the waved shape can increase the number of the refracting light, and reduces the reflection of the sunlight, so that the absorption rate for the sunlight can be raised. By the design of the ripple surface, the reacting area of the CIGS compound layer is increased, so that the conversion efficiency of the solar cell converting the light energy into electric energy is raised, and the current generated by the solar cell can be increased. Therefore, by the design of the present invention, the utilization value of the solar cell in industry can be promoted.
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention.
Number | Date | Country | Kind |
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098115617 | May 2009 | TW | national |