Method For Producing a Solar Cell, in Particular a Silicon Thin-Film Solar Cell

Abstract

A method for producing a solar cell, in particular a silicon thin-film solar cell, wherein a TCO layer (3) is applied to a glass substrate (1) and at least one silicon layer (4, 5) is applied to the TCO layer (3). Before the TCO layer (3) is applied, electron radiation is applied to the glass substrate (1), such that a light-scattering layer (2) of the glass substrate (1) is produced, to which light-scattering layer the TCO layer (3) is applied. Alternatively or additionally, a first silicon layer (4) may be applied to the TCO layer (3), a laser radiation or electron radiation may be applied to the first silicon layer (4), and a second silicon layer (5) may be applied to the irradiated first silicon layer (4).

Description

[0001]This application is a continuation application of U.S. patent application Ser. No. 4 / 902,779, filed on Jan. 4, 2016, which is an application filed under 35 USC §371 of PCT / EP2014 / 065833, filed on Jul. 23, 2014 claiming priority to DE 10 2013 107 910.5, filed on Jul. 24, 2013, each of which is herein incorporated by reference in their entirety.BACKGROUND OF THE INVENTION[0002]The present invention relates to a method for manufacturing a solar cell, in particular a silicon thin-film solar cell.[0003]Silicon thin film solar cells have many applications. Often, these solar cells have a too low efficiency, because only a small fraction of the light is absorbed in the at least one silicon layer. This is partly due to the fact that thick silicon layers are not used or cannot be used in some of the conventional solar cells.[0004]The problem underlying the present invention is to provide a method of the aforementioned type that allows the production of solar cells with higher efficienc...

AI Technical Summary

Benefits of technology

[0005]According to present invention, prior to the application of the TCO layer, the glass substrate is exposed to electron radiation, producing a light-scattering layer of the glass substrate onto which the TCO layer is deposited. The light to be absorbed by the solar cell can be scattered by this light-scattering layer so that a percentage of this light is deflected laterally or propagates at an angle greater than 0° with respect to the normal. This allows this percentage of light to travel through the at least one silicon layer along a longer path, thereby increasing the absorption of the at least one silicon layer.

[0007]The electron radiation may have a line-shaped cross-section and may be moved across the surface of the glass substrate perpendicular to the longitudinal extent of the line. In this way, the surface of the glass substrate can, on the one hand, be relatively quickly exposed to the electron radiation. On the other hand, the local power density is not as high as when a point-shaped intensity distribution moves over the surface of the glass substrate.

[0008]A first silicon layer is deposited on the TCO layer, wherein the first silicon layer is exposed to laser radiation or electron radiation and wherein a second silicon layer is deposited on the irradiated first silicon layer. This silicon layer is relatively stable due to its modular structure. At least the second silicon layer can then have a greater thickness, thereby likewise increasing the absorption of the light.

[0009]The second silicon layer may be thicker than the first silicon layer. The first silicon layer may have a layer thickness of less than 3.0 μm, in particular a layer thickness of less than 2.0 μm, preferably a layer thickness of less than 1.0 μm, for example, a layer thickness between 0.5 μm and 1.0 μm. Furthermore, the second silicon layer may have a layer thickness between 2.0 μm and 20 μm, in particular a layer thickness between 3.5 μm and 15 μm, preferably a layer thickness between 5 μm and 10 μm. With such a configuration, the silicon layers can be securely held on the TCO layer, while nevertheless attaining a high absorption and thus a high efficiency of the solar cell due to the large thickness of the second silicon layer.

[0010]In particular, the TCO layer and / or the at least one silicon layer may be deposited at temperatures below 300° C., preferably at temperatures below 200° C., in particular at temperatures below 100° C., for example at room temperature. On the one hand, the method according to the invention is simplified by this measure because application of heat is not required during the deposition of the TCO layer and / or the at least one silicon layer. On the other hand, the deposition at the aforementioned low temperatures, in particular at room temperature, prevents a temperature-induced impairment or damage to the solar cell to be manufactured.

Problems solved by technology

Often, these solar cells have a too low efficiency, because only a small fraction of the light is absorbed in the at least one silicon layer.

This is partly due to the fact that thick silicon layers are not used or cannot be used in some of the conventional solar cells.

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