Transparent solar cell for electronic devices and method for manufacturing said solar cell

Abstract

The invention relates to a solar cell (10) for an electronic device, comprising a substrate (100) made of a transparent material intended to be exposed to incident light radiation, a first electrode (110) made of a transparent conductive material formed on one side of the substrate (100) and comprising an inner side (111) opposite an outer side (112) facing the substrate (100), the first electrode (110) has an inner face (111) having a roughness over its entire surface such that it is suitable for scattering incident light radiation, an absorption layer (130) extending via an outer face (131) onto the inner face (111) of the first electrode (110), and a second electrode (120) made of an electrically conductive material and extending onto its inner face (132) opposite the outer face (131) of the absorption layer (130), wherein the absorber layer (130) and the second electrode (120) are perforated to define a plurality of blind cavities (140), the bottom of each blind cavity being formed by the inner face (111) of the first electrode (110), the solar cell further comprising a transparent protective layer (150) covering the second electrode (120) and filling each cavity (140) and having a refractive index of 1.3-1.8.

Description

[0001] Technical Field of the Invention

[0002] The present invention relates to the field of transparent solar cells for powering electronic devices.

[0003] More specifically, the invention relates to a solar cell which, in a preferred application, is especially intended for use in the watchmaking field, namely for powering a drive of a timepiece movement capable of controlling a display of the timepiece.

[0004] More generally, the solar cell of the invention is suitable for integration into various transparent objects, such as windows, portholes or windshields, or into screens of portable electronic devices, such as electronic tablets, mobile phones and electronic watches. Technical Background

[0005] In certain fields, particularly in the fields of architecture, portable electronics or watchmaking, a need has arisen for solar cells that can be hidden from the user's view to provide power while allowing the user to see through.

[0006] This type of solar cell is composed of an absorbing layer suitable for absorbing light and converting it into electrical energy, generally made of a semiconductor material such as silicon and arranged between a first electrode made of a transparent material and a second electrode made of an opaque metallic material, as described in patent document FR 2 681 189. The first electrode extends on a transparent substrate forming the support of the solar cell.

[0007] The transparent layer and the second electrode are perforated to the transparent substrate to obtain the light transmittance required to produce the transparency of the solar cell.

[0008] In particular, the perforations in the solar cell are sized and distributed in a manner to allow some incident light to pass through the absorber layer and the second electrode without being absorbed thereby, to create transparency in the solar cell to a user viewing it with the naked eye.

[0009] It is obvious that the larger the surface area of ​​the solar cell covered by the perforations, the greater the transparency of the solar cell and the lower its electrical efficiency. Conversely, the smaller the surface area, the lower the transparency of the solar cell and the higher its electrical efficiency. This is because semi-transparent solar cells allow part of the light to pass through, while converting the rest into electrical energy using the photovoltaic effect.

[0010] Therefore, the requirements regarding the aesthetic appearance of the solar cell, in particular its transparency, are detrimental to its electrical efficiency, and a compromise must therefore be found between the transparency level of the solar cell and its electrical performance.

[0011] In order to improve the electrical efficiency of the solar cell, the first electrode may have on one of its sides a roughness that allows it to scatter light and thus optimize the absorption of incident light radiation by the absorbing layer by capturing it. This solution is described in patent document WO 2011 / 083282.

[0012] However, the roughness of the first electrode produces a certain haze factor. The haze factor is the ratio of the intensity of scattered light to the intensity of the total transmitted light. A haze factor of at least 10% is usually sought to optimize the electrical performance of the solar cell.

[0013] This solution is not suitable for transparent solar cells because the haze factor is unacceptable for certain applications of transparent solar cells, especially watchmaking applications, as it would cause blurring of the solar cell and hinder the reading of time and the perception of details on the dial.

[0014] Therefore, there is a need to improve the electrical efficiency of solar cells without compromising their transparency. SUMMARY OF THE INVENTION

[0016] The present invention overcomes the above disadvantages by providing a solar cell which is intended to have a high level of transparency while providing high electrical performance, ie high efficiency.

[0017] To this end, the invention relates to a solar cell for an electronic device, comprising a substrate made of a transparent material intended to be exposed to incident light radiation and a first electrode made of a transparent conductive material, the latter being formed on one face of the substrate and comprising an inner face opposite to the outer face facing the substrate. Over its entire surface, the inner face has a roughness such that it is suitable for scattering the incident light radiation, for example a roughness represented by its root mean square Rq of 5-70 nm or even 20-70 nm. The solar cell further comprises an absorbing layer extending via the outer face onto the inner face of the first electrode and a second electrode made of a conductive material and extending onto its inner face opposite to the outer face of the absorbing layer, wherein the absorbing layer and the second electrode are perforated to define a plurality of blind cavities, the bottom of each of these blind cavities being formed by the inner face of the first electrode. The solar cell further comprises a transparent protective layer covering the second electrode and filling the cavities and having a refractive index of 1.3-1.8.

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

[0019] Since the refractive index of the first electrode and the refractive index of the protective layer are very close, their interface has a low refractive power, which makes it possible to reduce the haze factor and thus maximize the transparency of the cell.

[0020] In addition, maintaining the surface condition of the first electrode advantageously allows optimization of the battery manufacturing process. Specifically, this feature eliminates the need for a step of patterning the first electrode. In addition, the fact that no through openings are generated in the first electrode means that optimal electrical performance can be maintained, especially promoting current collection by minimizing series resistance losses.

[0021] Finally, thanks to the invention the scattering power is retained where it is useful in the solar cell, namely towards the absorber layer.

[0022] Generally speaking, the invention has advantageous applications in all fields in which viewing through solar cells is an important criterion, such as in the field of architectural or traffic glazing, or in the field of electronic devices, such as televisions, electronic tablets or mobile phones.

[0023] In certain embodiments, the invention may further comprise one or more of the following features, which have to be considered individually or in any technically possible combination.

[0024] In certain embodiments, the protective layer has a refractive index of 1.4-1.6, such as a refractive index of 1.5.

[0025] In a specific embodiment, the protective layer is formed of a two-layer stack comprising a first layer deposited against the first and second electrodes and a second layer deposited against the first layer, wherein the first layer has a refractive index of 1.5-1.8 and the second layer has a refractive index of 1.3-1.5.

[0026] In certain embodiments, the first layer has a refractive index of 1.6 or 1.7.

[0027] In a particular embodiment, the second layer has a refractive index of 1.4.

[0028] In certain embodiments, the protective layer is made of parylene, polyimide, siloxane, nitride, or silicon oxide.

[0029] In a particular embodiment, the substrate is formed by a layer stack comprising a support layer and an intermediate layer, wherein the intermediate layer is interposed between the support layer and the first electrode and is configured with a refractive index of 1.6 to 1.9.

[0030] Another subject of the invention relates to a timepiece comprising a case including a middle portion defining an interior space in which a timepiece movement is housed, a crystal and a back. The timepiece further comprises a solar cell as described above for powering the timepiece movement.

[0031] In a particular embodiment, the solar cell is fixed to the watch mirror so that the substrate is attached thereto, wherein the second electrode faces the interior space of the watch case.

[0032] In a particular embodiment, the mirror is formed by the substrate and the solar cell is arranged so that the second electrode faces the interior space.

[0033] In a particular embodiment, the substrate forms the dial so that it faces the crystal.

[0034] Another subject of the present invention relates to a method for producing a solar cell, the method comprising the following steps:

[0035] - forming a first electrode in the form of a transparent conductive layer on a transparent substrate, the first electrode being provided with an inner face having a roughness allowing it to scatter incident optical radiation;

[0036] - forming an absorption layer on the inner face of the first electrode, which is suitable for absorbing incident light radiation and generating electric current therefrom;

[0037] - forming a second electrode in the form of a conductive layer on the absorption layer;

[0038] - patterning the second electrode and the absorption layer to form a plurality of blind cavities extending to the inner face of the first electrode,

[0039] The patterning step is performed without modifying the surface condition of the inner surface;

[0040] - Deposition of a transparent protective layer with a refractive index of 1.3-1.8 or even 1.4-1.6 to cover the second electrode and the bottom of each cavity.

[0041] In a specific implementation, the second electrode and the absorption layer are sequentially perforated during the patterning step by performing first and second consecutive etching operations.

[0042] In certain implementations, the second electrode forms an etch mask during the second patterning operation.

[0043] In a particular implementation, the step of depositing a protective layer comprises an operation consisting of depositing a first layer having a refractive index of 1.5-1.8, followed by an operation consisting of depositing a second layer having a refractive index of 1.3-1.5.

[0044] In a particular implementation, the substrate is formed in a preliminary step from a layer stack comprising a support layer on which the intermediate layer intended to be interposed between said support layer and the first electrode is deposited. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Other features and advantages of the present invention will become apparent from the following detailed description given by way of example and not limiting in any way, with reference to the accompanying drawings, in which:

[0047] - Figure 1 A cross-sectional view schematically showing a solar cell of the present invention;

[0048] - Figure 2-5Summary display Figure 1 A cross-sectional view of a solar cell during different steps of the manufacturing method of the present invention;

[0049] - Figure 6 A cross-sectional view schematically shows a solar cell according to another embodiment of the present invention.

[0050] It should be noted that for the sake of clarity, the drawings are not necessarily drawn to scale. DETAILED DESCRIPTION OF THE INVENTION

[0052] The following description of the invention is made with respect to its application to an electronic device formed by a timepiece, such as a watch. However, it is obvious that the invention is not limited to this application and that it can be advantageously used in any other application.

[0053] It should also be noted that the term "transparent" is used herein to refer to the ability of a material to allow all or part of the light, particularly light visible to the naked eye, to pass through.

[0054] The present invention relates to a solar cell 10 suitable for converting light radiation into electric current, for example to power a drive device of a timepiece movement housed in a watch case, via a power supply circuit, in order to control a display device of the timepiece. This power supply circuit, this drive device and this display device of the timepiece are well known to those skilled in the art and are not related to the present invention per se; therefore, they are not described in detail below and are not shown in the drawings.

[0055] like Figure 1 As shown, the solar cell 10 comprises a substrate 100 made of a transparent material intended to be exposed to incident light radiation via an outer face 101. The substrate 100 is formed of a layer or a layer stack as described in more detail below in a specific exemplary embodiment of the invention. As a non-limiting example, the substrate 100 has a thickness of 0.1-2 mm, preferably 0.1-0.5 mm.

[0056] In alternative embodiments, the optical radiation is incident or transmitted radiation. Figure 1 In , incident or transmitted radiation is represented by thick arrows.

[0057] By way of example, the substrate 100 can be fixed so that its outer face 101 is arranged on its periphery against the mirror, for example by bonding or by mechanical or physical fixing means, such as ionic bonding or galvanic bonding. Thus, the optical radiation to which the outer face 101 of the substrate 100 is exposed is the radiation transmitted by the mirror.

[0058] Alternatively, the substrate 100 may constitute a watch crystal. The optical radiation to which the outer face 101 of the substrate 100 is exposed is therefore incident radiation. In particular in this case the substrate 100 may include an anti-reflection treatment on its outer face 101 in order to maximize the amount of optical radiation received by said substrate 100.

[0059] In another application of the present invention, the substrate 100 forms a dial so that it is arranged facing a crystal.

[0060] The substrate 100 is made, for example, 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 such as polycarbonate (PC) or polymethyl methacrylate (PMMA) are also possible.

[0061] The solar cell 10 further includes a first electrode 110 formed on all or part of the surface of the inner face 102 of the substrate 100 opposite to the outer face 101. The first electrode 110 is directly exposed to light radiation transmitted through the substrate 100 from the radiation passing through the substrate 100. As a non-limiting example, the first electrode 110 has a thickness of 0.5-5 μm, preferably 1-2 μm.

[0062] The first electrode 110 is made of a transparent conductive material, for example a metal oxide also known by the acronym “TCO”, such as zinc oxide (ZnO), tin oxide (SnO 2 ) or indium tin oxide (ITO) and comprises an inner face 111 opposite to an outer face 112 facing the substrate 100. The inner face 111 has a surface condition that allows incident light radiation to be scattered.

[0063] More specifically, the inner face 111 has a roughness over its entire surface due to the arrangement of the crystals of the material of the first electrode 110; the method of depositing the first electrode 110 and its parameters are selected to control said arrangement. In other words, the first electrode 110 is deposited in such a way that its crystals define a predetermined surface condition of its inner face 111, thereby allowing incident light radiation to be scattered. In particular, the inner face 111 is configured to have a roughness represented by its root mean square Rq of 5-70 nm or even 20-70 nm.

[0064] The solar cell 10 includes an absorption layer 130 disposed between a first electrode 110 and a second electrode 120. Figure 1 It can be seen that the absorption layer 130 extends only over a portion of the inner face 111 of the first electrode 110 via the outer face 131 and has a thickness of, for example, 100 nm-1 μm, preferably 300-500 nm.

[0065] The absorption layer 130 is made of a semiconductor material, such as silicon, for example amorphous silicon, and is suitable for absorbing light radiation and generating an electric current therefrom toward terminals connected to the first and second electrodes 110 and 120 .

[0066] Advantageously and as Figure 1As shown schematically, the absorber layer 130 conforms to any point on the surface of the inner face 111 of the first electrode 110 so that they have complementary shapes and therefore the same roughness.

[0067] The second electrode 120 is made of a conductive material and extends on an inner face 132 of the absorption layer 130 opposite to its outer face 131 .

[0068] Advantageously, the second electrode 120 may be made of a TCO, which allows the absorber layer 130 to absorb some of the radiation transmitted through the substrate 100 and some of the radiation reflected by any element arranged near the solar cell 10 (opposite to the substrate 100, i.e., on the side of the second electrode 120). This feature thus maximizes the amount of radiation absorbed by the absorber layer 130 and thus improves its electrical performance.

[0069] In another alternative embodiment of the present invention, the second electrode 120 is made of a metallic material, such as silver or aluminum.

[0070] Depend on Figure 1 and 5 It can be seen that the absorption layer 130 and the second electrode 120 are perforated to define a plurality of blind cavities 140, each of which has a bottom formed by the inner face 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 absorption layer 130 and extend to the inner face 111 of the first electrode 110.

[0071] Due to these features, the transmitted light radiation can pass through the solar cell 10 and the latter can have a very good transparency level, depending on the distribution pattern of the cavities 140 and their dimensions.

[0072] Advantageously, the cavity 140 may have a circular or hexagonal cross section. The latter shape has the advantage of minimizing electrical losses.

[0073] The cross section of the cavity 140 may alternatively have all kinds of regular or irregular, geometrically single or multiple shapes, providing a paved opening on the inner face 111 of the first electrode 110. By way of example, the cavity 140 may be linear, such as a groove, or polygonal, such as a triangle, a square, or in the form of a letter or logo, etc.

[0074] like Figure 1 As shown, the solar cell 10 advantageously comprises a protective layer 150 made of a transparent material, which encapsulates the first and second electrodes 110 and 120 and the absorber layer 130; i.e. it fills the cavities 140. This protective layer 150 is thus deposited on the side of the solar cell 10 opposite to the substrate 100 and protects the solar cell 10 from any external attack or contamination.

[0075] The protection layer 150 may be made of polyparaxylene, polyimide, siloxane, nitride, such as silicon nitride, or oxide, such as silicon oxide.

[0076] This layer has advantageous optical functions. The material of the protective layer 150 is particularly selected so that it has a refractive index between the refractive index of the ambient air (approximately equal to 1) and the refractive index of the first electrode 110 (approximately equal to 2). This is to minimize the haze factor at the interface between the inner face 111 of the first electrode 110 and the protective layer 150 and to minimize the reflectivity at the interface between the air and the protective layer 150. The protective layer 150 is particularly configured so that its refractive index is 1.3-1.8 or even 1.4-1.6, preferably equal to 1.5.

[0077] This feature improves the transparency of the solar cell 10 at the cavity 140. This is because, since the refractive indices of the inner face 111 of the first electrode 110 and the protective layer 150 are close to each other, very little light radiation is scattered by the inner face 111 of the first electrode 110. In addition, since the refractive index of the protective layer 150 is also close to the refractive index of air, very little light radiation is reflected by the solar cell 10. The interface between the inner face 110 of the first electrode 110 and the protective layer 150 in particular transmits a very large proportion, for example more than 98%, of the light radiation.

[0078] For example, if the inner surface 111 of the first electrode 110 has a roughness Rq equal to 60nm and the protective layer 150 has a refractive index of 1.5, the haze factor of the first electrode 110 is 4-5%, and if the inner surface 111 has an interface with the air, the haze factor thereof is 35%. In addition, if the protective layer 150 has a refractive index of 1.7, the haze factor of the first electrode 110 is 1%.

[0079] Thanks to the present invention, the solar cell 10 thus has a high level of transparency, which allows the user to see through clearly. This transparency is achieved by maintaining the surface condition of the inner face 111 of the first electrode 110 and thus avoiding the need for any patterning operation at the bottom of the cavity 140. For reference, this patterning operation will make it possible to eliminate a portion of the first electrode 110 or smooth its surface condition.

[0080] exist Figure 6 In the illustrated example embodiment of the present invention, the protective layer 150 is formed of a two-layer stack including a first layer 151 deposited against the first and second electrodes 110 and 120 and a second layer 152 deposited against the first layer 151 .

[0081] The first layer 151 advantageously has a refractive index of 1.5-1.8, preferably a refractive index of 1.6 or 1.7. The second layer 152 has a refractive index of 1.3-1.5, preferably a refractive index of 1.4. Thus, the difference between the refractive indexes of the first electrode 110 and the first layer 151 is minimized, as is the difference between the latter and the second layer 152 and the second layer 152 and the air. Minimizing the difference between the two continuous media makes it possible to significantly improve the transparency of the solar cell 10 as described above.

[0082] In an exemplary embodiment of the present invention not shown in the drawings, the substrate 100 is formed by a layer stack including a carrier layer and an intermediate layer, wherein the intermediate layer is interposed between the carrier layer and the first electrode 110 and is configured to have a refractive index that minimizes optical reflection and thus improves the transparency of the solar cell 10. The intermediate layer extends in a thickness of 60-100 nm and has a refractive index of 1.6-1.9, for example. The intermediate layer can be made of any suitable transparent material.

[0083] The carrier layer may be made of any transparent material, for example the materials mentioned above for the substrate 100 .

[0084] The invention further relates to a method for producing a solar cell 10, preferably a solar cell 10 as described above.

[0085] The manufacturing method includes the following steps which are shown in chronological order: Figure 2-5 and Figure 1 The following consecutive steps in .

[0086] The method advantageously comprises a step of forming the first electrode 110 on the substrate 100 so that it has, over its entire inner face 111 , a roughness such as to scatter incident light radiation, for example a roughness Rq of 5-70 nm or even 20-70 nm.

[0087] This step is followed by a step of forming an absorption layer 130 on the inner face 111 of the first electrode 110 , and then a step of forming a second electrode 120 on the absorption layer 130 .

[0088] A patterning step is then performed to form a plurality of blind cavities 140 passing through the second electrode 120 and the absorption layer 130 to the inner surface 111 of the first electrode 110 .

[0089] The areas to be perforated during the patterning step are determined by masking the areas to be retained of the second electrode 120 and the absorption layer 130, for example by photolithography.

[0090] During the patterning step, the second electrode 120 and the absorption layer 130 may be perforated sequentially by performing consecutive etching operations. The first etching operation may include forming a plurality of cavities 140 through the second electrode 120 and extending to the absorption layer 130, and the second etching operation may be performed to extend the cavities 140 through the absorption layer 130 to the first electrode 110.

[0091] Considering the materials constituting the second electrode 120 and the absorption layer 130 , respectively, the first etching operation may be performed using a wet chemical etching method and the second etching operation may be performed using a dry etching method such as a plasma chemical etching method or an ion etching method.

[0092] Advantageously, the second electrode 120 may be used as an etch mask during the second patterning operation, thereby protecting the portion of the absorber layer 130 deposited thereon.

[0093] The fact that the first electrode 110 is not perforated means that its resistance is not increased, thus maintaining the electrical performance of the solar cell 10. This also reduces the time required to carry out the method and the energy consumed thereby.

[0094] The patterning step is then followed by a step of depositing a transparent protective layer 150 to cover the second electrode 120 and the bottom of each cavity 140 .

[0095] This step can be carried out in particular by spin coating, for example if the material of the protective layer 150 is made of polyimide. This step can alternatively be carried out by a chemical vapor deposition method, if the material of the protective layer 150 is made of parylene, or by a plasma enhanced chemical vapor deposition method, if the material chosen to form the protective layer 150 is an oxide or a nitride. The protective layer 150 can also be deposited using a physical vapor deposition method, by evaporation or by cathode sputtering, for example in the case where the protective layer 150 is made of nitride.

[0096] Alternatively, the protective layer 150 may be formed of a transparent self-adhesive film bonded to the first and second electrodes 110 and 120 during the deposition step.

[0097] The substrate 100 may be formed in a preliminary step from a layer stack comprising a support layer on which an intermediate layer is deposited, wherein the first electrode 110 is deposited on the intermediate layer.

[0098] The first electrode 110 may be formed by performing a chemical vapor deposition method, the absorption layer 130 may be formed by performing a plasma enhanced chemical vapor deposition method, and the second electrode 120 may be formed by performing a physical vapor deposition method.

[0099] It will be apparent that these deposition methods are given as an indication, since the first and second electrodes 110 and 120 and the absorption layer 130 may be deposited by any deposition method suitable for their respective materials.

[0100] More generally, it should be noted that the implementations and embodiments considered above have been described by way of non-limiting examples and that other alternatives are therefore possible.

[0101] The first and second electrodes 110 and 120 as well as the absorption layer 130 and the protection layer 150 may be formed of a single layer or a layer stack, in particular.

Claims

1. A solar cell (10) for electronic devices, characterized in that It comprises a substrate (100) made of a transparent material intended to be exposed to incident light radiation, a first electrode (110) made of a transparent conductive material formed on one side of the substrate (100) and comprising an inner face (111) opposite to an outer face (112) facing the substrate (100), the inner face (111) having a roughness over its entire surface so as to make it suitable for scattering the incident light radiation, an absorption layer (130) extending onto the inner face (111) of the first electrode (110) via an outer face (131), and a conductive layer (131) formed on the inner face (111) of the first electrode (110). A second electrode (120) is made of a material and extends to the inner surface (132) of the absorption layer (130) opposite to the outer surface (131) of the absorption layer (130), wherein the absorption layer (130) and the second electrode (120) are perforated to define a plurality of blind cavities (140), the bottom of each of the blind cavities is formed by the inner surface (111) of the first electrode (110), and the solar cell further includes a transparent protective layer (150) covering the second electrode (120) and filling each cavity (140) and having a refractive index of 1.3-1.

8.

2. The solar cell (10) according to claim 1, wherein the protective layer (150) has a refractive index of 1.

5.

3. A solar cell (10) according to claim 1 or 2, wherein the protective layer (150) is formed by a two-layer stack comprising a first layer (151) deposited against the first and second electrodes (110, 120) and a second layer (152) deposited against the first layer (151), wherein the first layer (151) has a refractive index of 1.5-1.8 and the second layer (152) has a refractive index of 1.3-1.

5.

4. The solar cell (10) according to claim 3, wherein the first layer (151) has a refractive index of 1.6 or 1.

7.

5. The solar cell (10) according to claim 3 or 4, wherein the second layer (152) has a refractive index of 1.

4.

6. The solar cell (10) according to any one of claims 1 to 5, wherein the protective layer (150) is made of polyparaxylene, polyimide, siloxane, nitride or oxide.

7. The solar cell (10) according to any one of claims 1 to 6, wherein the substrate (100) is formed by a layer stack comprising a carrier layer and an intermediate layer, wherein the intermediate layer is interposed between the carrier layer and the first electrode (110) and is configured with a refractive index of 1.6 to 1.

9.

8. A timepiece comprising a case including a middle portion defining an interior space for accommodating a timepiece movement therein, a mirror and a back portion, the timepiece being characterized in that it further comprises a solar cell (10) according to any one of claims 1 to 7 for powering the timepiece movement.

9. A timepiece according to claim 8, wherein the solar cell (10) is fixed to the watch crystal so that the substrate (100) is arranged to be attached thereto, wherein the protective layer (150) faces the inner space of the watch case.

10. The timepiece according to claim 8, wherein the watch crystal is formed by a substrate (100), wherein the solar cell (10) is arranged with the protective layer (150) facing the inner space.

11. The timepiece according to claim 8, wherein the substrate (100) constitutes the dial so that it faces the crystal.

12. A method for manufacturing a solar cell (10), characterized in that It includes the following steps: - forming a first electrode (110) in the form of a transparent conductive layer on a transparent substrate (100), said first electrode being provided with an inner face having a roughness allowing it to scatter incident light radiation; - forming an absorption layer (130) on the inner face (111) of the first electrode (110) which is suitable for absorbing incident light radiation and generating electric current therefrom; - forming a second electrode (120) in the form of a conductive layer on the absorption layer (130); - patterning the second electrode (120) and the absorption layer (130) to form a plurality of blind cavities (140) extending to the inner surface (111) of the first electrode (110), wherein the patterning step is performed without modifying the surface condition of the inner surface (111); - Depositing a transparent protective layer (150) with a refractive index of 1.3-1.8 to cover the second electrode (120) and the bottom of each cavity (140).

13. The method of manufacturing a solar cell (10) according to claim 12, wherein the second electrode (120) and the absorber layer (130) are perforated sequentially during the patterning step by performing first and second consecutive etching operations.

14. Method for manufacturing a solar cell (10) according to claim 12, wherein the second electrode (120) constitutes an etching mask during the second patterning operation.

15. A method for manufacturing a solar cell (10) according to any one of claims 12 to 14, wherein the step of depositing a protective layer (150) comprises an operation consisting of depositing a first layer (151) having a refractive index of 1.5 to 1.8, followed by an operation consisting of depositing a second layer (152) having a refractive index of 1.3 to 1.

5.

16. Method for manufacturing a solar cell (10) according to any one of claims 12 to 15, wherein the substrate (100) is formed in a preliminary step from a layer stack comprising a carrier layer, on which an intermediate layer intended to be interposed between the carrier layer and the first electrode (110) is deposited.

Images