DE102017209226B4 - Method for producing a photovoltaic element - Google Patents

Abstract

The invention relates to a method for producing a photovoltaic element (2), in particular an organic photovoltaic element (2). In the method, a lower electrode (6) is formed in a first step. Thereafter, in a second step, an active layer (8) is applied to the lower electrode (6). Thereafter, in a third step, the lower electrode (6) is patterned, forming a number of separation points (20) which divide the lower electrode (6) into a plurality of lower sub-electrodes (6a, 6b). In addition, in the third step, the active layer (8) is patterned such that a number of contact points (22) are formed, at which the lower electrode (6) is exposed. Thereafter, in a fourth step, an upper electrode (14) is applied to the active layer (8). At a respective contact point (22), the upper electrode (14) is contacted with the lower electrode (6). Furthermore, a corresponding photovoltaic element (2) is specified.

Description

The invention relates to a method for producing a photovoltaic element.

A photovoltaic element serves to generate energy by converting light. For this purpose, the photovoltaic element has two electrodes, namely a lower electrode and an upper electrode, between which an active layer is arranged. The active layer is also referred to as a functional layer. In the active layer, light is absorbed, whereupon charges are released. These are removed via the electrodes. In particular, in the case of an organic photovoltaic element, the active layer is often a stack of several, in particular two individual layers of different active materials. The individual layers are produced in particular in successive process steps, i. applied.

The usually small thicknesses of the layers of a photovoltaic element already lead to significant losses due to a corresponding electrical resistance during charge transport of the generated charges. In addition, often at least one of the electrodes is formed as a transparent electrode and then typically has a material-related poor conductivity, thus also leads to significant losses in charge transport. This also limits the usable area accordingly, i. the fill factor of the photovoltaic element is reduced.

In order to keep the path during the charge transport as low as possible, the photovoltaic element usually has a plurality of cells and a number of plated-through holes in order to interconnect the cells. This makes it possible to reduce the losses in charge transport, in particular by the charges are transported by means of the upper electrode, which is usually made of a particularly highly conductive material. The photovoltaic element then has a total voltage which results from the number of cells and their interconnection with one another by means of the plated-through holes and which is proportional to the total number of interconnected cells.

The production takes place, for example, in such a way that first the lower electrode is produced by a conductive material being applied flatly to a support and structured in a first structuring step in order to form a plurality of partial electrodes for a plurality of cells. Subsequently, the active layer is formed by one or more active materials are applied flat on the lower electrode and also structured in a second structuring step. In structuring the active layer, a number of recesses are created therein, each of which selectively exposes a number of subregions of the lower electrode. Finally, another conductive material is applied and patterned onto the active layer to form the upper electrode. In this case, a number of plated-through holes are formed, which conductively connect the upper and lower electrodes to one another. The plated-through holes then consist of the material of the upper electrode which, when applied to the structured, active layer, penetrates into the recesses in the active layer and connects to the lower electrode in the exposed partial regions.

Various production methods for photovoltaic elements are described, for example, in US 4,243,432 . US 4,873,201 A and US 2004/0219710 A1 ,

Against this background, it is an object of the invention to provide an improved method for producing a photovoltaic element and a corresponding photovoltaic element. The production should be as inexpensive as possible and allow the most flexible production.

The object is achieved by a method with the features of claim 1. Advantageous embodiments, developments and variants are the subject of the dependent claims. The statements in connection with the method also apply mutatis mutandis to a corresponding photovoltaic element and vice versa.

The method is used to produce a photovoltaic element, in particular an organic photovoltaic element. A photovoltaic element is briefly referred to as a PV element. An organic photovoltaic element is also referred to as an OPV element for short. An organic photovoltaic element is characterized by an active layer of one or more organic materials. An organic photovoltaic element is particularly flexible, i. bendable. An organic photovoltaic element can be produced in a simple manner in a printing process, preferably in a web-fed printing process, also referred to as a roll-to-roll process. The method is thus preferably a printing method, in particular a web-fed printing method.

In a first step, a lower electrode is formed. The lower electrode is made of a conductive material. The lower electrode is in particular made of a transparent material, preferably indium tin oxide, and thus as a transparent electrode. The lower electrode preferably has a thickness in the range between 10 nm and 500 nm. The lower electrode is made consistently, ie unstructured. A division into a number of sub-electrodes, which are electrically separated from each other, does not occur in the first step. The lower electrode is formed in particular on a carrier, also referred to as a carrier layer. The carrier is suitably made of a transparent plastic. The carrier serves in particular as a robust base in the production of the photovoltaic element and preferably has a thickness in the range of 10 .mu.m to 500 .mu.m. The lower electrode is in particular flat, ie continuously applied to the carrier, in particular sputtered.

The first step is followed by a second step in which an active layer is applied to the lower electrode. The active layer is made of a number of individual layers, each consisting of an active material. In particular, the active layer consists of a mixture of two different active materials. The active materials are preferably organic semiconductor materials such that the photovoltaic element is then an organic photovoltaic element. The individual layers, and thus the active layer as a whole, are applied with an applicator, preferably by means of a slot-die coating process, i. the applicator is preferably a slot die coating machine.

The second step is followed by a third step, in which the lower electrode is patterned. The lower electrode is thereby in particular from above, i. structured through the already applied active layer. In this case, a number of separation points is formed, which divide the lower electrode into a plurality of lower sub-electrodes. For this purpose, the material of the lower electrode is removed in regions, so that a recess in the lower electrode is formed at a respective separation point. The structuring of the lower electrode after the application of the active layer is also referred to as the first structuring step, P1 * for short. In contrast, structuring of the electrode prior to application of the active layer is briefly referred to as P1, as mentioned above.

In the third step, furthermore, the active layer is structured in such a way that a number of contact points are formed, at which the lower electrode is exposed. The lower electrode is thus partially exposed. The contact points are not the separation points. In other words, the active layer is broken at a number of pads without breaking the lower electrode. All individual layers of the active layer are broken through. The lower electrode, on the other hand, remains intact at the contact points, to be contacted later with the upper electrode. Thus, in particular, a blind hole is formed, i. a hole which passes completely through the active layer but at most partially, preferably not at all, penetrates into the lower electrode. The structuring of the active layer, wherein the active layer is completely broken, is also referred to as the second structuring step, P2 for short.

In addition, in the third step, the active layer is only partially broken, in particular at partial interruption points, i. in particular, that at least one of the individual layers is broken, but another of the individual layers is not, i. remains intact. Such structuring of the active layer, wherein the active layer is only partially broken, is also referred to as the third structuring step, P3 for short.

The third step is followed by a fourth step, in which an upper electrode is applied to the active layer. The upper electrode is made of a conductive material, preferably of silver. The upper electrode is preferably formed as a grid electrode. The upper electrode is formed in particular structured, i. with several upper part electrodes.

A respective contact point is expediently arranged between a separation point and a partial interruption point. In each case a separation point, a contact point and in particular also a partial interruption point together form a through-connection. A respective separation point divides the lower electrode into two lower sub-electrodes, i. at the point of separation the lower electrode is broken, whereas the upper electrode is continuous, i. is consistent. A respective part interruption point divides the upper electrode into two upper part electrodes, i. at the part interruption point, the upper electrode is broken, whereas the lower electrode is interrupted continuously, i. is consistent. A respective contact point divides the active layer into two active portions and connects the upper electrode to the lower electrode. In other words, at a respective pad, the upper electrode is and is contacted with the lower electrode, i. conductively connected. A respective active subregion forms a cell of the photovoltaic element with the underlying lower subelectrode and with the upper subelectrode located above it.

In particular, several cells are formed in the method. The cells are connected to each other through the vias, i. interconnected, preferably in series. In this case, a respective through-contact makes contact with a lower partial electrode of one of the cells with an upper partial electrode of another of the cells.

A core idea of the invention is in particular that the lower electrode is not structured as described above before the application of the active layer, but only after. A significant advantage of this sequence of steps is, in particular, that prior to the application of the active layer no design decision with respect to the final design of the photovoltaic element, ie in particular with regard to the cell layout and the cell size, must be made. Such a determination can now be made even after the application of the active layer, whereby the production of the photovoltaic element is designed much more flexible. An assembly of carrier, lower electrode and active layer is preferably provided as a semi-finished product for any desired configurations. The application of the active layer is thus procedurally decoupled from the design decision. When structuring the lower electrode before applying the active layer, however, the latter step must be waited until it is clear which design the photovoltaic element should have. The application of the active layer can take place afterwards. The production time from the existence of a specific design decision, ie from the receipt of a specific order is thus drastically shortened in the present method, since the step of applying the active layer at this time has already been completed and no longer arises.

The application of the active layer also requires regular operation of a corresponding order system whose operation causes corresponding costs. Since the application of the active layer no longer belongs to the production process of a concrete design, but to the manufacturing process of the semi-finished, which is suitable for a variety of designs, now even very small production quantities are economical, since not the order system for each individual production order commissioned must be, but only the semifinished product is developed accordingly. Starting from the semifinished product, it is advantageously possible to produce a photovoltaic element of any desired design. Since the operation of the application system is now advantageous regardless of the design decision of a specific production order, the application system can be operated particularly economically and with uniform output and regardless of the order situation.

The subsequent structuring of the lower electrode is also advantageous for the application of the active layer. In a prior structuring of the lower electrode residues of the removed material may remain behind and form impositions, tips, scales or other irregularities, which complicate a subsequent material application. Such irregularities must then be removed in a complex cleaning step. In this case, the lower electrode is e.g. smoothed, resulting in further defects, e.g. Can result in scratches, which lead to a corresponding committee. Furthermore, even due to the desired structuring of the lower electrode, irregularities may possibly arise, which may disadvantageously lead to dewetting or an uneven thickness of the active layer. All of these problems are overcome by applying the active layer before structuring the lower electrode, because then the active layer is deposited on an unstructured, i. in particular flat substrate, namely on the unstructured lower electrode. An additional cleaning step is not necessary, which is why such is preferably also omitted. This also considerably shortens the production time.

The lower electrode is preferably structured in the third step by means of laser radiation, in particular by means of a laser ablation process. The lower electrode is cut as it were. In this way, several cells of the photovoltaic element are formed.

In principle, it is possible in the third step to structure the lower electrode without affecting the overlying active layer, i. without also structuring the active layer. In particular, in the case of structuring by means of laser radiation, the parameters of the laser radiation, in particular its dimension or its wavelength, are chosen such that the laser radiation penetrates through the active layer into the lower electrode and is absorbed predominantly by the material of the lower electrode, whereas the active Layer remains intact. However, this is particularly problematic for thin layers such as organic photovoltaic cells. By "thin" is generally understood a thickness of at most 1 μm, in particular of at most 500 nm. The lower electrode and the active layer have in common, in particular a thickness of only up to 500 nm, which is many times less than usual lengths of about 10 microns of a focus region of the laser radiation. The lower electrode can thus hardly be patterned without influencing the active layer. Also, due to the small thickness of the lower electrode and the active layer, the ablated material of the lower electrode does not have enough space to spread, as a result, possibly resulting in the blowing of the active layer.

In the present case, however, it was recognized that a simultaneous structuring of the active layer at the separation points initially has no disadvantages, so that in a preferred embodiment in the Structuring the lower electrode at the same time also the active layer is structured at the separation points. In other words, structuring of the active layer also takes place in the first structuring step, which, however, does not correspond to structuring in the second structuring step. Accordingly, the active layer is patterned in the same way as the lower electrode, ie a number of recesses are produced in the active layer, wherein the recesses of the active layer overlap in principle with the recesses of the lower electrode, ie the recesses of the active layer are also arranged at the separation points. Thus, at the point of separation, a continuous hole is formed, ie a hole which extends both completely through the active layer and completely through the lower electrode. In the simultaneous structuring of the lower electrode and the active layer, the requirements for the parameters of the laser radiation are particularly low, ie freely selectable in larger areas than in a targeted structuring of only the lower electrode. In particular, structuring takes place with similar parameters as in a conventional cutting method. However, it is essential that the carrier remains undamaged. For this purpose, the carrier expediently consists of a material which is transparent to the laser radiation.

A further advantage of the method is, in particular, that all structuring can be carried out together in a single method step. Therefore, in an advantageous embodiment, the lower electrode and the active layer are structured in the third step by means of the same laser radiation, so that in the third step by means of the laser radiation both the separation points, and the contact points and in particular the partial interruption points are formed. This is based in particular on the knowledge that the same laser can be used for all structurings, and therefore the same laser, and therefore the same laser radiation, is expediently also used for the first, the second and possibly also the third structuring step. In particular, a change in wavelength is not necessary, i. All structuring is done with laser radiation of the same wavelength. However, under certain circumstances, a respective adjustment of the intensity of the laser radiation, i. the energy or dimensions of the laser beam or both. In the third step, all structuring, i. all structuring steps, in particular by means of a single laser processing step executed.

In the fourth step is particularly problematic that when applying the material for the upper electrode with high probability a part of just that material can penetrate at the separation point in the hole there. This would lead to unwanted contacting of the lower electrode at the point of separation, i. to a short circuit. To prevent this, a barrier material is applied to the separation points before the fourth step, which prevents contacting of the upper electrode with the lower electrode at the separation points. This is understood to mean, in particular, that the separation point does not necessarily have to be formed when the barrier material is applied, i. E. the barrier material is either applied to an already formed separation point or before forming the separation point at a location at which subsequently the separation point is formed. The barrier material serves as a blockage and blocks, closes or blocks access to the lower electrode, i. the hole at the separation point. From the barrier material, a closure, e.g. a lid or plug is formed, which sits on the hole or is seated in this or both. In the fourth step, the upper electrode is then also formed over the separation point and thus over the barrier material, which may then be in contact with the upper electrode. Particularly preferably, the hole at the separation point is completely filled with barrier material.

In particular, the barrier material becomes non-planar, i. not applied consistently, but expediently only at the separation points.

The barrier material is applied in front of the upper electrode, namely in the third step. In a first variant, in the third step, first the lower electrode is patterned, i. formed the separation point, and then applied the barrier material. In a second variant, which is used in the present case, the barrier material is first applied in the third step and then the lower electrode is patterned. In a third variant, the first and second variants are combined such that some of the separation sites are formed before the barrier material is applied and the remaining separation sites after the barrier material has been applied. However, the first and the second variant advantageously allow shorter production times, since the application of the barrier material in this case does not have to be applied in two stages, but is applied in one go.

In the described first variant, structuring in the third step may possibly raise material, which then typically accumulates crater-shaped on top of the active layer and around the hole, forming an increase, ie an irregularity. Preferably, therefore, with the barrier material, a head part is formed, which is arranged on the active layer, in particular for subsequent inclusion of thrown material from the lower electrode or from the active layer or both. Accordingly, in particular, a closure is formed, with a lid which sits on top of the active layer and closes the hole. The head part of barrier material then advantageously ensures that the material thrown up is hidden under or in the barrier material, so that advantageously results in a more homogeneous surface.

In the described second variant, the lower electrode is structured through the barrier material. For this purpose, the barrier material is transparent to the laser radiation used. Apart from the second variant, a transparent barrier material is also generally advantageous for the method. By "transparent" is generally understood that the respective material has an absorbance of less than 30% or a transparency of at least 70% for the respective laser radiation. The barrier material advantageously absorbs any material thrown up, i. Any material thrown up during structuring is retained by the barrier material and, as it were, remains stuck in it. This ensures that when applying the upper electrode then there is still a homogeneous and defined surface. As has already been explained above, there is the problem, especially in the case of thin layers, that during the structuring of the lower electrode there is the danger that an overlying thin layer will be blown away as it were. This is prevented by the additional barrier material, i. the active layer in combination with the barrier material is then no longer a thin layer at the point of separation. In other words, the active layer and the barrier material together expediently have a thickness which is greater than 1 μm, in particular greater than 500 nm.

A further advantage of the barrier material is, in particular, that in all of the variants described above, a purification step, i. a removal of thrown up material, can be dispensed with and is preferably also dispensed with. Any material thrown up in patterning the lower electrode is advantageously hidden by the barrier material or trapped by the barrier material, or both.

The barrier material is preferably an insulating material, more preferably a dielectric material, i. a dielectric. With such a material, it is ensured that no conductive connection is made between the upper electrode and the lower electrode at the separation point even if the barrier material is arranged to come in contact with the lower electrode.

The barrier material is preferably applied with a thickness in the range from 0.5 μm to 150 μm, particularly preferably with a thickness in the range from 10 μm to 18 μm. The thickness of the barrier material is measured starting from an upper side of the active layer. In other words, the thickness of the barrier material corresponds to the portion which is arranged above the active layer, whereas parts of the barrier material which are arranged in the hole are not counted. This ensures that the barrier material is applied sufficiently thick to develop the effects described above.

A respective separation point has, in particular, a width in the range between 5 μm and 300 μm. In particular, a respective contact point has a width in the range between 20 μm and 800 μm. A respective partial interruption point has, in particular, a width in the range between 5 μm and 300 μm. A respective plated through hole has a width, which results as the sum of the three widths mentioned above, optionally plus a distance between separation point, contact point and partial interruption point. In particular, a plated through hole has a width in the range between 30 μm and 1400 μm.

A photovoltaic element according to the invention is produced by the method described above. The photovoltaic element is in particular an organic photovoltaic element. The photovoltaic element has a lower electrode, an upper electrode, and an active layer disposed between the lower and upper electrodes. The photovoltaic element further has a number of separation points, which divide the lower electrode into a plurality of lower sub-electrodes, and a number of contact points, at which the lower electrode is in each case contacted with the upper electrode. At the separation points, the lower electrode is not contacted with the upper electrode.

A photovoltaic element produced by the above method is characterized in particular by the fact that material impurities which are produced during production are not removed, but remain in the finished photovoltaic element. In other words, the lower electrode is made of a material which is partially removed during the formation of the separation points and in particular deposits around a respective separation point in a crater-like manner, thereby forming a suspension. The posing is located above the lower electrode and in particular on the lower electrode.

Alternatively or additionally, a photovoltaic element produced according to the above method is characterized in particular in that not only the lower electrode is broken at the separation points, ie it is severed, but also the active layer. In the training of a respective Separation point is generated in the lower electrode a recess and in the overlying active layer is also a recess produced simultaneously, wherein the finished photovoltaic element at a respective separation point, the recess of the lower electrode and the recess of the active layer are superimposed and aligned in particular. In other words, at the separation points, a continuous hole is formed, which breaks through the active layer and the lower electrode.

In a particularly preferred embodiment, the hole is covered by an insulating barrier material, which is arranged between the active layer and the upper electrode. In this case, the blocking material forms in particular a closure for the hole, which ensures that in the finished photovoltaic element the lower electrode and the upper electrode are not contacted with one another at the separation point.

• 1 ausschnittsweise ein Photovoltaikelement in einer Schnittansicht,
• 2a bis 2f jeweils einen Schritt eines Verfahrens zur Herstellung eines Photovoltaikelements,
• 3a bis 3e jeweils einen Schritt eines Verfahrens zur Herstellung eines Photovoltaikelements, und
• 4a bis 4e jeweils einen Schritt einer erfindungsgemäßen Variante des Verfahrens aus den 3a bis 3e.

Embodiments of the invention will be explained in more detail with reference to a drawing. In each case schematically show:

• 1 partial view of a photovoltaic element in a sectional view,
• 2a to 2f one step each of a method for producing a photovoltaic element,
• 3a to 3e each a step of a method for producing a photovoltaic element, and
• 4a to 4e in each case one step of a variant of the method according to the invention from the 3a to 3e ,

In 1 is fragmentary and in a sectional view an organic photovoltaic element 2 shown. This has a carrier 4 on which a lower electrode 6 is arranged. On this is an active layer 8th arranged, which in the present case of two individual layers 10 . 12 consists. The individual layers 10 . 12 consist of different organic semiconductor materials. Above the active layer 8th is an upper electrode 14 arranged. The active layer 8th is used to generate charge by absorbing light. At the electrodes 6 . 14 the generated charges are dissipated.

The photovoltaic element 2 has several cells 16a . 16b on, which by means of vias 18 interconnected with each other. In 1 are in particular two cells 16a . 16b recognizable, which by means of a via 18 are connected in series. For this purpose, the via 18 a separation point 20 on which the lower electrode 6 in two lower sub-electrodes 6a . 6b Splits. Next has the via 18 a contact point 22 on which the active layer 8th from a hole 24 is completely broken. Through the hole 24 penetrates the upper electrode 14 through the active layer 8th through to the lower electrode 6 so that the two electrodes 6 . 14 at the contact point 22 contacted each other. The upper electrode 14 is also divided into a plurality of sub-electrodes, namely present in two upper sub-electrodes 14a . 14b , For this purpose, the via 18 a partial interruption point 26 on, which in this case also the upper single layer 12 breaks through. About the via 18 , more precisely about their contact point 22 , is the upper part electrode 14a one cell 16a with the lower part electrode 6b the other cell 16b connected.

At the separation point 20 is not just the bottom electrode 6 broken, but also the active layer 8th , In the formation of the separation point 20 is in the lower electrode 6 creates a recess and in the overlying active layer 8th At the same time, a recess is also produced, so that in the finished photovoltaic element 2 at the separation point 20 the recess of the lower electrode 6 and the recess of the active layer 8th over each other and the hole 24 form. This hole 24 is in 1 from an insulating barrier material 28 obscured, which between the active layer 8th and the upper electrode 14 is arranged. The barrier material 28 This forms a closure for the hole 24 , which ensures that the lower electrode 6 and the upper electrode 14 at the separation point 20 not contacted with each other.

In the 1 shown through hole 18 has a width B which is the sum of the widths of the separation point 20 , the contact point 22 and the part interruption point 26 and additional distance between separation point 18 and contact point 20 results. In the present case, the width is B between 30μm and 1400μm.

Based on 2a-2f . 3a-3e . 4a-4e will be explained below how the photovoltaic element described above is produced.

Basically, a photovoltaic element 2 on the in the 2a-2f shown manner are produced. It is first as in 2a shown the lower electrode 6 made by placing a conductive material flat on a support 4 applied and as in 2 B is shown structured in a first structuring step to a plurality of lower sub-electrodes 6a . 6b for multiple cells 16a . 16b to build. This creates uprisings 30 which are removed in an additional cleaning step, as in 2c shown. 2d now shows how then the active layer 8th is formed by the lower electrode 6 one or more active areas Materials are applied. The active layer 8th will be like in 2e shown also structured in a second structuring step. When structuring the active layer 8th In this case, a number of recesses are generated, each of which selectively has a number of partial areas of the lower electrode 6 expose, but not with the already generated recesses of the lower electrode 6 overlap, but rather offset from it are arranged. Finally, on the active layer 8th another conductive material applied flat and structured to the upper electrode 14 train as in 2f shown. There will also be a number of vias 18 formed, which the upper electrode 14 and the lower electrode 6 interconnect with each other.

In contrast, in the process of 3a-3e . 4a-4e the lower electrode 6 before applying the active layer 8th is structured, but only afterwards. Therefore, before applying the active layer needs 8th no design decision regarding the final design of the photovoltaic element 2 to be met. An arrangement of carriers 4 , lower electrode 6 and active layer 8th rather, it is kept ready as a semi-finished product for any desired configurations. Applying the active layer 8th is thus decoupled procedurally from the design decision. As in 2 B remain shown in a prior structuring of the lower electrode 6 Remains of the removed material back and form impositions 30 which must be removed a cleaning step. How out 2c Moreover, it becomes clear that the lower electrode is structurally intended 6 even irregularities, which when applying the active layer 8th in 2d may lead to dewetting or uneven thickness. In the procedures of 3a-3e . 4a-4e becomes the active layer 8th already before the structuring of the lower electrode 6 applied and thus applied to an unstructured substrate, namely on the unstructured lower electrode 6 , An additional cleaning step does not take place.

3a shows a step in which the lower electrode 6 is trained. This is made of a conductive and transparent material and has a thickness D1 in the range between 10nm and 500nm. The lower electrode 6 is made consistently, ie unstructured. A subdivision into a number of lower sub-electrodes 6a . 6b does not take place in the first step. The lower electrode 6 gets on a carrier 4 formed, which in the present case consists of a transparent plastic and serves as a robust base during production. The carrier 4 has a thickness D2 in the range of 10μm to 500μm.

3b shows a second step in which the active layer 8th on the lower electrode 6 is applied. The active layer 8th in the present case consists of two individual layers 10 . 12 made, each consisting of an active material. The active layer 8th here has a thickness D3 in the range between 10nm and 500nm.

3c shows a third step in which the lower electrode 6 is structured, in this case by means of laser radiation L from above, ie through the already applied active layer 8th therethrough. There will be a number of separation points 20 formed, which the lower electrode 6 into several lower partial electrodes 6a . 6b divide. The structuring of the lower electrode 6 after applying the active layer 8th is also called the first structuring step, in short P1 *, whereas a structuring of the lower electrode 6 before applying the active layer 8th as in 2 B abbreviated as P1.

In the third step of the 3c will continue to be the active layer 8th structured such that a number of contact points 22 is formed, to which the lower electrode 6 is exposed. In doing so, all individual layers are created 10 . 12 the active layer 8th broken through, the lower electrode 6 however, remains intact to later with the upper electrode 14 to be contacted. Thus, in particular, a blind hole is formed. This structuring of the active layer 8th for the formation of the contact points 22 is also referred to as a second structuring step, P2 for short.

In the third step according to 3c becomes the active layer 8th in the present case additionally at partial interruption points 26 only partially broken by only the single layer 10 is broken, with the single layer 12 remains intact. Such structuring of the active layer 8th for the training of the Teilunterbrechungsstelle 26 is also called the third structuring step, in short P3 designated.

The contact point 22 is like in 3c shown between the separation point 20 and the part interruption point 26 arranged. The separation point 20 , the contact point 22 and the partial interruption point 26 together form a via 18 , The process involves multiple cells 16a . 16b formed, which through the feedthrough 18 be connected to each other. During this process, the via contacts 18 the lower part electrode 6b the cell 16b with an upper part electrode 14a the cell 16a ,

The structuring of the lower electrode 6 and the active layer 8th in the third embodiment, in the embodiment shown by means of a laser ablation method using laser radiation L , In the present case, the three structuring steps are also carried out P1 * P2 and P3 together in a single structuring step and by means of the same laser radiation L , In doing so, both the separation points 20 , as well as the contact points 22 , as well as the partial interruption points 26 educated.

In 3d is shown, we in the third step at the separation points 20 a barrier material 28 is applied to subsequently contacting the upper electrode 14 with the lower electrode 6 at just this separation point 20 to prevent. The barrier material 28 serves as a blockage and blocks, closes or blocks access to the lower electrode 6 ie the hole 24 , In 3d becomes the barrier material 28 not applied flat, but only at the separation point 20 , In 3d is also the hole 24 complete with barrier material 28 filled. It is essential that the barrier material 28 in front of the upper electrode 14 is applied. As in 3c is shown, the structuring in the third step, material is thrown, which is cratered on top of the active layer 8th and around the hole 24 accumulates around and a posing 30 forms. With the barrier material 28 is now in 3d a headboard 32 formed on the active layer 8th is arranged for subsequent inclusion of the posing 30 , The headboard 32 sits on top of the active layer 8th open and close the hole 24 ,

The barrier material 28 In the present case, this is a dielectric material, ie a dielectric. This ensures that at the separation point 20 no conductive connection between the upper electrode 14 and the lower electrode 6 will be produced. The barrier material 28 comes with a thickness D4 in the range of 0.5μm to 150μm, the thickness D4 starting from the active layer 8th measured upwards.

3e Figure 4 shows a fourth step in which the active layer 8th the upper electrode 14 is applied, which consists of a conductive material and in the present case is formed as a grid electrode. The upper electrode 14 comes with a thickness D5 in the range of 1 .mu.m to 50 .mu.m. The upper electrode 14 is also formed structured, ie with several upper sub-electrodes 14a . 14b , The upper electrode 14 will also be above the separation point 20 trained and thus on the barrier material 28 , which then in contact with the upper electrode 14 stands. At the separation point 20 prevents the barrier material 28 a contact of the upper electrode 14 with the lower electrode 6 , In contrast, at the contact point 22 the upper electrode 14 with the lower electrode 6 contacted, ie conductively connected.

In the 4a-4e is a variant of the process of 3a-3e shown. The essential difference here is that in the third step, the application of the barrier material 28 before structuring the lower electrode 6 he follows. Otherwise, the above statements apply accordingly. In particular, the comments apply to 3a also for 4a , the comments too 3b also apply to 4b and the comments too 3e also apply to 4e ,

In the variant of 4a-4e becomes the bottom electrode 6 as in 4d shown by the barrier material 28 structured through. This is the barrier material 28 transparent for the laser radiation used L , The previously applied barrier material 28 absorbs any material thrown up, ensuring that when applying the top electrode 14 as in 4e shown then still a homogeneous and defined surface is present. The schematic representation in 4d Although shows that in the present embodiment, a white space 34 between the carrier 4 and the barrier material 28 remains, however, it is in the production of regular material shifts, so any voids 34 be closed and the result is no white space 34 remains.

LIST OF REFERENCE NUMBERS

2

photovoltaic element

4

carrier

6

lower electrode

6a, 6b

lower part electrode

8th

active layer

10, 12

monolayers

14

upper electrode

14a, 14b

upper part electrode

16a, 16b

cell

18

via

20

separation point

22

contact point

24

hole

26

Part breakpoint

28

barrier material

30

beautiful

32

headboard

34

whitespace

B

width

D1

Thickness (the lower electrode)

D2

Thickness (of the wearer)

D3

Thickness (of the active layer)

D4

Thickness (of the barrier material)

D5

Thickness (of the upper electrode)

L

laser radiation

Claims (6)

Method for producing a photovoltaic element (2), wherein in a first step, a lower electrode (6) is formed, the first step is followed by a second step in which an active layer (8) is applied to the lower electrode (6), the second step is followed by a third step in which the lower electrode (6) is patterned, wherein a number of separation points (20) are formed which subdivide the lower electrode (6) into a plurality of lower sub-electrodes (6a, 6b), in the third step, the active layer (8) is structured such that a number of contact points (22) are formed, at which the lower electrode (6) is exposed, the third step is followed by a fourth step in which an upper electrode (14) is applied to the active layer (8), - At a respective contact point (22), the upper electrode (14) is contacted with the lower electrode (6), - Before the fourth step at the separation points (20) a barrier material (28) is applied, which prevents contacting of the upper electrode (14) with the lower electrode (6) at the separation points (20), in the third step, first the barrier material (28) is applied and then the lower electrode (6) is structured, - The lower electrode (6) in the third step by means of laser radiation (L) is structured and that the barrier material (28) is transparent to the laser radiation (L). Method according to Claim 1 , characterized in that the barrier material (28) is an insulating material. Method according to Claim 2 , characterized in that the barrier material (28) is a dielectric material. Method according to one of Claims 1 to 3 , characterized in that the barrier material (28) with a thickness (D3) in the range of 0.5 .mu.m to 150 .mu.m is applied. Method according to one of Claims 1 to 4 , characterized in that the lower electrode (6) and the active layer (8) in the third step by means of the same laser radiation (L) are structured so that in the third step by means of the laser radiation (L) both the separation points (20), as well the contact points (22) are formed. Method according to one of the preceding claims, characterized in that in the structuring of the lower electrode (6) at the same time the active layer (8) at the separation points (20) is structured.

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