Transparent solar cell for electronic device and method for manufacturing the same

Abstract

To provide a solar cell having a high level of transparency while providing high efficiency.SOLUTION: The solar cell comprises: a first electrode (110) made of a transparent electrically conductive material, the first electrode (110) formed on one face of a substrate (100) and comprising an inner face (111) opposite an outer face (112) oriented towards the substrate (100), the inner face (111) comprising a first portion having a roughness greater than the roughness of a second portion; an absorbent layer (130) extending by an outer face (131) over the first portion of the inner face (111) of the first electrode (110); and a second electrode (120) made of an electrically conductive material and extending over an inner face of the absorbent layer (130) opposite the outer face (131) of the absorbent layer (130). The absorbent layer (130) and the second electrode (120) are perforated to delimit a plurality of blind cavities (140), the bottom of each of which is formed by the second portion of the inner face (111) of the first electrode (110).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention is in the field of transparent solar cells for supplying electrical energy to electronic devices.

[0002] More specifically, the invention relates to solar cells intended, in particular in a preferred application, for the field of watchmaking, that is to say for supplying electrical energy to the motor means of a timepiece movement capable of controlling the display means of the timepiece.

[0003] More generally, the solar cells according to the invention are adapted to be integrated into various transparent objects such as windows, portholes or windscreens, or into the screens of portable electronic devices such as electronic tablets, mobile phones and electronic watches. [Background technology]

[0004] In certain fields, particularly in the fields of construction, portable electronic devices and watchmaking devices, a need has arisen for a solar cell that can be hidden from the view of a user to provide a source of electrical energy while still allowing the user to observe through it.

[0005] This type of solar cell consists of an absorber layer, adapted to absorb light and convert it into electrical energy and generally made of a semiconductor material such as silicon, disposed between a first electrode made of a transparent material and a second electrode made of an opaque metallic material, as described in FR 2 681 189. The first electrode extends over a transparent substrate which forms the support for the solar cell.

[0006] The transparent layer and second electrode are perforated down to the transparent substrate to obtain the light transmission necessary to create the transparency of the solar cell.

[0007] In particular, the perforations in the solar cell are sized and distributed to allow a portion of incident light to pass through the absorber layer and the second electrode without being absorbed by the second electrode, to create transparency in the solar cell for a user viewing it with the naked eye.

[0008] Naturally, the larger the surface of the solar cell that is covered by perforations, the more transparent the solar cell will be and the lower its electrical efficiency, and conversely, the smaller the surface, the less transparent the solar cell will be and the higher its electrical efficiency. In fact, semitransparent solar cells allow part of the light to pass through while at the same time converting the other part into electricity by means of the photovoltaic effect.

[0009] The aesthetics of a solar cell, and in particular its transparency, are detrimental to its electrical efficiency, and therefore a compromise must be respected between the level of transparency of the solar cell and its electrical performance.

[0010] To increase the electrical efficiency of the solar cell, the first electrode can be roughened on one of its surfaces, which scatters light and optimizes its absorption by the absorber layer by trapping the incident optical radiation. Such a solution is described in document WO2011 / 083282.

[0011] However, the roughness of the first electrode introduces a scattering coefficient in the solar cell, also known as the "haze factor." This scattering coefficient is the ratio of the scattered light intensity to the total transmitted light intensity. To optimize the electrical efficiency of a solar cell, a scattering coefficient of at least 10% is usually desired.

[0012] This solution is not adapted to transparent solar cells, and indeed such a scattering coefficient is unacceptable for applications specific to transparent solar cells, in particular watchmaking applications, insofar as this scattering coefficient causes a blurring of the solar cell, making it difficult to read the time and to perceive the details of the dial.

[0013] Therefore, there is a need to increase the electrical efficiency of solar cells without compromising transparency. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] FR2681189 [Patent Document 2] WO2011 / 083282 Summary of the Invention [Problem to be solved by the invention]

[0015] The present invention overcomes the aforementioned drawbacks by providing a solar cell that is designed to have a high level of transparency while providing high electrical performance, i.e., high efficiency. [Means for solving the problem]

[0016] To this end, the present invention provides a substrate made of a transparent material intended to be exposed to incident light; a first electrode made of a transparent conductive material and formed on one side of the substrate, the first electrode including an outer surface oriented toward the substrate and an inner surface opposite the outer surface, the inner surface including a first portion having a roughness greater than a roughness of a second portion; an absorber layer having an outer surface extending over a first portion of the inner surface of the first electrode; a second electrode made of a conductive material and extending over an inner surface of the absorbent layer opposite the outer surface of the absorbent layer; The present invention relates to a solar cell for an electronic device, comprising:

[0017] The absorber layer and the second electrode are perforated to define a plurality of blind cavities, the bottom of each of the blind cavities being formed by a second portion of the inner surface of the first electrode.

[0018] These features maximize both the transparency and electrical performance of the solar cell.

[0019] Indeed, the surface finish of the second portion of the inner surface of the first electrode makes it possible to reduce the scattering coefficient, while the fact that no through-openings are formed in the first electrode makes it possible to maintain an optimal electrical performance, in particular facilitating current collection by minimizing series resistance losses, and the scattering power is kept in a place that is useful for the solar cell, namely on the opposite side of the absorber layer.

[0020] Generally speaking, the invention has advantageous applications in all fields where viewing through solar cells is an important criterion, such as in the field of glazing for buildings and transport vehicles, or in the field of electronic devices such as televisions, electronic tablets, mobile phones, etc.

[0021] In particular embodiments, the present invention may further comprise one or more of the following features, taken alone or in any technically possible combination:

[0022] In certain embodiments, the first electrode has a thickness between 0.5 and 5 μm, preferably between 1 and 2 μm.

[0023] In certain embodiments, the second portion of the inner surface of the first electrode has a polished surface finish to transmit optical radiation without scattering it.

[0024] In certain embodiments, the absorbing layer has a thickness between 100 nm and 1 μm, preferably between 300 and 500 nm.

[0025] In certain embodiments, the first and second electrodes are made of a transparent conductive oxide.

[0026] In certain embodiments, the first and second electrodes are made of zinc oxide, tin oxide, or indium tin oxide.

[0027] In certain embodiments, the solar cell includes a transparent protective layer covering the second electrode and filling each cavity.

[0028] In certain embodiments, the material of the protective layer is selected to have a refractive index between 1 and 2, preferably between 1.3 and 1.7.

[0029] In certain embodiments, the protective layer comprises parylene, polyimide, siloxane, nitride, or oxide.

[0030] In certain embodiments, the substrate is formed by a stack of layers including a support layer and an intermediate layer, the intermediate layer being interposed between the support layer and the first electrode and configured to have a refractive index between 1.6 and 1.9.

[0031] According to another object, the invention relates to a timepiece comprising a case with a central part, a crystal and a back defining an internal volume in which the timepiece movement is housed, said timepiece further comprising a solar cell as described above arranged to supply electrical energy to the timepiece movement.

[0032] In certain embodiments, the solar cell is secured to the glass such that the substrate is positioned against the glass with the second electrode facing the interior volume of the case.

[0033] In a particular embodiment, the glass is formed by the substrate and the solar cell is positioned such that the second electrode faces the interior volume.

[0034] In certain embodiments, the substrate forms the dial or is fixed to the dial or to the structure of the timepiece movement, so that the second electrode faces the glass.

[0035] According to another object, the present invention provides a method for producing a method for manufacturing a semiconductor device comprising: - forming a first electrode on a transparent substrate in the form of a conductive transparent layer provided with an inner surface having a roughness such that it can scatter incident optical radiation; forming an absorbing layer on an inner surface of the first electrode, the absorbing layer adapted to absorb incident optical radiation and generate an electric current therefrom; forming a second electrode in the form of a conductive layer on the absorbing layer; structuring the second electrode and the absorber layer to form a plurality of blind cavities extending into the inner surface of the first electrode, said structuring being carried out so as to modify the surface finish of the portion of the inner surface of the first electrode onto which each of the cavities opens in order to reduce its roughness; The present invention relates to a method for manufacturing a solar cell, including:

[0036] In a particular implementation, during the structuring step, the second electrode and the absorber layer are successively perforated by performing first and second successive etching processes, the second etching process being completed by modifying the surface finish of the portions of the inner surface of the first electrode onto which each of the cavities opens.

[0037] In a particular implementation, the second electrode forms an etching mask during the second structuring process.

[0038] In a particular implementation, the first electrode is deposited such that its crystals define a predetermined surface finish on its interior surface.

[0039] In a particular implementation, the method includes depositing a transparent protective layer following the structuring step to cover the second electrode and fill each cavity.

[0040] In a particular implementation, the substrate is formed by stacking layers including a support layer on which an intermediate layer intended to be interposed between the support layer and the first electrode is deposited in a preliminary step.

[0041] Other characteristics and advantages of the invention will become apparent from the following detailed description, given by way of non-limiting example with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0042] [Figure 1] FIG. 1 is a schematic cross-sectional view of a solar cell according to the present invention. [Figure 2] 2A to 2C are schematic cross-sectional views of the solar cell of FIG. 1 at different steps of a manufacturing method according to the invention. [Figure 3] 3A to 3C are schematic cross-sectional views of the solar cell of FIG. 1 at different steps of a manufacturing method according to the invention. [Figure 4] 4A to 4C are schematic cross-sectional views of the solar cell of FIG. 1 at different steps of a manufacturing method according to the invention. [Figure 5] 5A to 5C are schematic cross-sectional views of the solar cell of FIG. 1 at different steps of a manufacturing method according to the invention. DETAILED DESCRIPTION OF THE INVENTION

[0043] Please note that the figures are not necessarily drawn to scale for clarity.

[0044] The present invention will be described in the context of its application to an electronic device formed by a timepiece, for example a wristwatch, but it will be appreciated that the invention is not limited to this application and can be used to advantage in any other application.

[0045] It should also be noted that in this context the term "transparent" refers to the ability of a material to allow all or part of optical radiation to pass through, especially light visible to the naked eye.

[0046] The invention relates to a solar cell (10) adapted to convert light radiation into an electric current for powering, via a power supply circuit, the motor means of a cased timepiece movement, for example, for controlling the display means of a timepiece, the power supply circuit, the motor means and the display means of which will not be described in detail below or shown in the figures, as they are well known to those skilled in the art and do not pertain to the present invention.

[0047] 1, the solar cell 10 includes a substrate 100 made of a transparent material intended to be exposed to light radiation by an outer surface 101. The substrate 100 is formed by a layer or a stack of layers, as will be explained in more detail below in specific examples of implementation of the invention. By way of non-limiting example, the substrate 100 has a thickness between 0.1 and 2 mm, preferably between 0.1 and 0.5 mm.

[0048] In one embodiment, the optical radiation is incident radiation or transmitted radiation, which is symbolized by a thick arrow in Figure 1.

[0049] By way of example, the substrate 100 can be fixed, for example by adhesive bonding or by mechanical or physical fixing means such as ionic or pulsed current bonding, so that its outer surface 101 is placed against the periphery of the watch crystal. The optical radiation received by the outer surface 101 of the substrate 100 is then radiation transmitted through the glass.

[0050] Alternatively, the substrate 100 may constitute the glass of the timepiece, and the optical radiation received by the outer surface 101 of said substrate 100 then becomes incident radiation. In particular in this case, the substrate 100 may include an anti-reflection treatment on its outer surface 101 in order to maximize the amount of optical radiation received through said substrate 100.

[0051] In another application of the invention, the substrate 100 can be fixed, for example by adhesive or mechanical fixing means, so that its outer surface 101 is placed against the dial or against the periphery of the structure of the clock movement of a watch.

[0052] Alternatively, the substrate 100 can form a watch face.

[0053] The substrate 100 may be made of glass, sapphire or a polymer, such as polyethylene naphthalate, also known by the acronym "PEN", or polyethylene terephthalate, also known by the acronym "PET". Other polymers are also possible, such as polycarbonate (PC) or acrylic polymethyl methacrylate (PMMA).

[0054] The solar cell 10 also includes a first electrode 110 formed on all or part of the surface of the inner surface 102 of the substrate 100 opposite the outer surface 101. This first electrode 110 is directly exposed to the optical radiation transmitted through said substrate 100 from the radiation passing through the substrate 100. By way of non-limiting example, the first electrode 110 has a thickness between 0.5 and 5 μm, preferably between 1 and 2 μm.

[0055] The first electrode 110 is made of a transparent conductive material, such as a metal oxide, also known by the acronym "TCO," such as zinc oxide (ZnO), tin oxide (SnO), or indium tin oxide (ITO). It has an outer surface 112 oriented toward the substrate 100 and an inner surface 111 opposite it. The inner surface 111 includes first and second portions with different surface roughnesses. In particular, the first portion of the inner surface 111 has a rougher surface than the second portion, as shown in FIG. 1. Advantageously, due to the roughness of the first portion, the first electrode 110 scatters incident optical radiation.

[0056] More precisely, the roughness of the first portion of the inner surface 111 is due primarily to the crystallographic arrangement of the material of the first electrode 110, and the deposition method and parameters of the first electrode 110 are selected to control said arrangement. In other words, the first electrode 110 is deposited such that its crystallography defines a predetermined surface finish of its inner surface 111.

[0057] The second portion advantageously has a polished surface so as to transmit the optical radiation without scattering it and to reduce the scattering coefficient of the solar cell 10. This feature advantageously serves to increase the transparency of the solar cell 10, thus allowing a user to see clearly through the solar cell 10.

[0058] The solar cell 10 includes an absorber layer 130 disposed between the first electrode 110 and the second electrode 120. As can be seen in Figure 1, the absorber layer 130 has an outer surface 131 that extends beyond only a first portion of the inner surface 111 of the first electrode 110 and has a thickness, for example, between 100 nm and 1 µm, preferably between 300 and 500 nm.

[0059] The absorption layer 130 is made of a semiconductor material, such as silicon, e.g., amorphous silicon, and is adapted to absorb optical radiation and generate a current therefrom at terminals connected to the first and second electrodes 110 and 120.

[0060] Advantageously, as shown in FIG. 1, the absorbing layer 130 matches any point on the surface of the first portion of the inner surface 111 of the first electrode 110, so that the outer surface 131 of the absorbing layer 130 has a shape complementary to the shape of said first portion, and therefore also has the same roughness.

[0061] The second electrode 120 is made of a conductive material and extends over an inner surface 132 of the absorbent layer 130 opposite an outer surface 131 of the absorbent layer 130 .

[0062] Advantageously, the second electrode 120 can be made of TCO, which allows the absorbing layer 130 to absorb part of the radiation transmitted through the substrate 100 and part of the radiation reflected by any element placed in the vicinity of the solar cell 10 on the opposite side of said substrate 100, i.e. on the side of the second electrode 120. This feature therefore maximizes the amount of radiation absorbed by the absorbing layer 130, thus increasing its electrical performance.

[0063] In another alternative embodiment of the present invention, the second electrode 120 is made of a metallic material such as silver or aluminum.

[0064] 1 and 5, the absorber layer 130 and the second electrode 120 are perforated to define a plurality of blind cavities 140, the bottom of each of which is formed by the second portion of the inner surface 111 of the first electrode 110. In other words, the solar cell 10 includes cavities 140 that pass through the second electrode 120 and the absorber layer 130 and extend to the inner surface 111 of the first electrode 110.

[0065] Due to these features, transmitted light radiation can pass through the solar cell 10 and the solar cell 10 can have a very good level of transparency depending on the surface finish of the second portion of the inner surface 111 of the first electrode 110, as well as the distribution pattern of the cavities 140 and their dimensions.

[0066] Advantageously, the cavity 140 may have a circular or hexagonal cross section, the latter shape having the advantage that electrical losses are minimized.

[0067] The cross section of the cavity 140 may alternatively have any kind of regular or irregular, geometrically simple or multiple shape that results in a paving opening in the inner surface 111 of the first electrode 110. By way of example, the cavity 140 may be in the shape of a filiform such as a groove, or a polygon such as a triangle, square, letter, logo, etc.

[0068] 1, the solar cell 10 may advantageously comprise, in addition to the first and second electrodes 110 and 120, a protective layer 150 made of a transparent material that encapsulates the absorber layer 130, i.e., fills each cavity 140. This protective layer 150 is therefore deposited on the side of the solar cell 10 opposite the substrate 100, and protects the solar cell 10 from external attack or contamination.

[0069] Such a protective layer 150 can be made of parylene, polyimide, siloxane, a nitride, such as silicon nitride, or an oxide, such as silicon oxide.

[0070] This layer may have a thickness that provides an advantageous optical function. In particular, the material of the protective layer 150 may be selected to have a refractive index between the refractive index of the surrounding air, which is approximately 1, and the refractive index of the first electrode 110, which is approximately 2, so as to minimize light reflection and further increase the transparency of the solar cell 10 in the cavity 140. In particular, the protective layer 150 is configured so that its refractive index is between 1.3 and 1.7.

[0071] In an implementation of the invention not shown in the figures, the substrate 100 is formed by a stack of layers including a support layer and an intermediate layer, the intermediate layer being interposed between the support layer and the first electrode 110 and configured to have a refractive index so as to minimize optical reflection and thus promote transparency of the solar cell 10. In particular, the intermediate layer extends over a thickness of, for example, between 60 and 100 nm and has a refractive index between 1.6 and 1.9. This intermediate layer can be made of a suitable transparent material.

[0072] The support layer can be made of any transparent material, such as those materials described above for substrate 100 .

[0073] The present invention also relates to a method for manufacturing a solar cell 10, preferably the solar cell 10 described above.

[0074] The manufacturing method comprises the following successive steps, shown in chronological order in FIGS. 2 to 5 and 1, respectively:

[0075] Advantageously, the method includes a step of forming a first electrode 110 on a substrate 100, so that said first electrode 110 has a roughness over its entire inner surface 111 that allows it to scatter incident optical radiation.

[0076] This step is followed by forming an absorbent layer 130 on the inner surface 111 of the first electrode 110 and then forming a second electrode 120 on the absorbent layer 130 .

[0077] Next, a structuring step is performed via the second electrode 120 and the absorber layer 130 to form a plurality of blind cavities 140 on the inner surface 111 of the first electrode 110, in particular on the second portion of said inner surface 111. The structuring step is performed to modify the surface finish of the second portion of the inner surface 111 of the first electrode 110 in order to reduce its roughness.

[0078] The areas to be perforated during the structuring step are determined by masking, for example by photolithography, the areas of the second electrode 120 and the absorber layer 130 that are to be preserved.

[0079] During the structuring step, the second electrode 120 and the absorber layer 130 may be successively perforated by carrying out successive etching processes. In particular, a first etching process may consist of forming a plurality of cavities 140 through the second electrode 120 and extending down to the absorber layer 130, and a second etching process may be carried out so as to extend the cavities 140 through the absorber layer 130 down to the first electrode 110. This second etching process may advantageously be completed by modifying the surface finish of a second portion of the inner surface 111 of the first electrode 110.

[0080] Given the materials constituting the second electrode 120 and the absorber layer 130, respectively, the first etching process can be performed using a wet chemical etching method, and the second etching process can be performed using a dry etching method such as a plasma chemical etching method or an ion etching method.

[0081] Advantageously, the second electrode 120 can be used as an etching mask during the second structuring process and thus protect a first part of the inner surface 111 of the first electrode 110, on which it is deposited.

[0082] Because the surface finish modification of the second portion of the inner surface 111 of the first electrode 110 is performed during the second etching process, the cost and manufacturing time of the solar cell 10 is significantly reduced.

[0083] Furthermore, the fact that the first electrode 110 is not perforated means that its electrical resistance does not increase, meaning that the electrical performance of the solar cell 10 is maintained.

[0084] An optional step of depositing a transparent protective layer 150 can be performed following the structuring step, so as to cover the second electrode 120 and fill each cavity 140 .

[0085] In particular, this step can be performed by spin coating, for example, if the material of the protective layer 150 is polyimide. Alternatively, this step can be performed by chemical vapor deposition if the material of the protective layer 150 is parylene, or by plasma-enhanced chemical vapor deposition if the material selected to form the protective layer 150 is an oxide or nitride. Also, if the protective layer 150 is made of a nitride, it is possible to deposit the protective layer 150 by physical vapor deposition, evaporation, or sputtering.

[0086] The substrate 100 can be formed by a stack of layers including, in a preliminary step, a support layer onto which an intermediate layer is deposited, and on which the first electrode 110 is deposited. Advantageously, the intermediate layer has a refractive index between 1.6 and 1.9 to reduce the reflection of incident optical radiation.

[0087] The formation of the first electrode 110 can be achieved by performing a chemical vapor deposition process, the formation of the absorbing layer 130 can be achieved by performing a plasma-assisted chemical vapor deposition process, and the formation of the second electrode 120 can be achieved by performing a physical vapor deposition process.

[0088] Of course, these deposition methods are given as a guide, as the first and second electrodes 110 and 120 and the absorbing layer 130 can be deposited by any suitable deposition method depending on the respective materials.

[0089] More generally, it should be noted that the implementation and manufacturing methods discussed above are described as non-limiting examples, and that other variations are therefore possible.

[0090] In particular, the first and second electrodes 110 and 120, as well as the absorbing layer 130 and the protective layer 150, can be formed by a single layer or a stack of layers. [Explanation of symbols]

[0091] 10. Solar Cells 100 boards 101 Exterior 102 Inside 110 first electrode 111 Inside 112 Exterior 120 Second electrode 130 Absorbing layer 131 External surface 132 Inside 140 Blind Cavity 150 protective layer

Claims

1. a substrate (100) made of a transparent material intended to be exposed to incident light; a first electrode (110) made of a transparent conductive material and formed on one side of the substrate (100), the first electrode (110) including an inner surface (111) opposite an outer surface (112) oriented toward the substrate (100), the inner surface (111) including a second portion and a first portion having a roughness greater than the roughness of the second portion; an absorbing layer (130) having an outer surface (131) extending over the first portion of the inner surface (111) of the first electrode (110); a second electrode (120) made of a conductive material and extending onto an inner surface (132) of the absorber layer (130) opposite the outer surface (131) of the absorber layer (130); the absorber layer (130) and the second electrode (120) are perforated to define the opening hole shapes of a plurality of blind cavities (140), and the shape of the bottom of each of the blind cavities is formed by the second portion of the inner surface (111) of the first electrode (110); The second portion of the inner surface (111) of the first electrode (110) has a thickness smaller than that of the first portion of the first electrode (110). A solar cell (10) for an electronic device, characterized in that:

2. The solar cell (10) of claim 1, wherein the first electrode (110) has a thickness between 0.5 and 5 μm, or between 1 and 2 μm.

3. 2. The solar cell (10) of claim 1, wherein the second portion of the inner surface (111) of the first electrode (110) has a polished surface finish to transmit optical radiation without scattering it.

4. The solar cell (10) of claim 1, wherein the absorber layer (130) has a thickness between 100 nm and 1 μm, or between 300 and 500 nm.

5. 10. The solar cell (10) of claim 1, wherein the first and second electrodes (110, 120) are made of a transparent conductive oxide.

6. 6. The solar cell (10) of claim 5, wherein the first and second electrodes (110, 120) are made of zinc oxide, tin oxide, or indium tin oxide.

7. 10. The solar cell (10) of claim 1, including a transparent protective layer (150) covering the second electrode (120) and filling each cavity (140).

8. 8. The solar cell (10) of claim 7, wherein the material of the protective layer (150) is selected to have a refractive index between 1 and 2, or between 1.3 and 1.

7.

9. The solar cell (10) according to claim 7 or 8, wherein the protective layer (150) is made of parylene, polyimide, siloxane, nitride or oxide.

10. 2. The solar cell (10) of claim 1, wherein the substrate (100) is formed by stacking layers including a support layer and an intermediate layer, the intermediate layer being interposed between the support layer and the first electrode (110) and configured to have a refractive index between 1.6 and 1.

9.

11. A timepiece comprising a case with a center, a crystal, and a back defining an internal volume in which a clock movement is housed, characterized in that the timepiece further comprises a solar cell (10) according to claim 1 arranged to supply electrical energy to the clock movement.

12. 12. The timepiece according to claim 11, wherein the solar cell (10) is fixed to the glass such that the substrate (100) is positioned in contact with the glass with the second electrode (120) facing the internal volume of the case.

13. 12. The timepiece of claim 11, wherein the glass is formed by the substrate (100), and the solar cell (10) is arranged so that the second electrode (120) faces the internal volume.

14. 12. The timepiece according to claim 11, wherein the substrate (100) forms a dial or is fixed to the dial or to the structure of a timepiece movement, so that the second electrode (120) faces the crystal.

15. forming on a transparent substrate (100) a first electrode (110) in the form of a conductive transparent layer provided with an inner surface (111) having a first portion with a roughness such that it is able to scatter incident optical radiation; forming an absorbing layer (130) on the inner surface (111) of the first electrode (110), the absorbing layer (130) adapted to absorb incident optical radiation and generate an electric current therefrom; forming a second electrode (120) in the form of a conductive layer on said absorbing layer (130); structuring the second electrode (120) and the absorber layer (130) by forming a plurality of blind cavities (140) through the second electrode (120) and the absorber layer (130) to define opening shapes of a plurality of blind cavities (140) extending to the inner surface (111) of the first electrode (110), the cavities (140) opening onto the first electrode (110) and performed to provide a surface finish of the second portion of the inner surface (111) of the first electrode (110) such that the roughness of the second portion of the inner surface (111) is reduced below the roughness of the first portion; Including, A method for manufacturing a solar cell (10), characterized in that the second portion of the inner surface (111) of the first electrode (110) has a thickness of the first electrode (110) that is thinner than the first portion.

16. 16. A method for manufacturing a solar cell (10) according to claim 15, wherein during the structuring step, the second electrode (120) and the absorber layer (130) are successively perforated by carrying out first and second successive etching processes, the second successive etching process being completed by surface finishing of the second portion of the inner surface (111) of the first electrode (110), onto which each of the cavities (140) opens.

17. 17. The method for manufacturing a solar cell (10) according to claim 16, wherein the second electrode (120) is formed as an etch mask during the second sequential etching process.

18. 16. The method of claim 15, wherein the first electrode is deposited such that a crystalline arrangement of the first electrode defines a surface of the first portion of the inner surface.

19. 16. The method for manufacturing a solar cell (10) according to claim 15, further comprising, following the structuring step, depositing a transparent protective layer (150) so as to cover the second electrode (120) and fill each cavity (140).

20. 16. A method for producing a solar cell (10) according to claim 15, wherein the substrate (100) is formed by stacking layers including a support layer on which, in a preliminary step, an intermediate layer intended to be interposed between the support layer and the first electrode (110) has been deposited.

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