Thin film device with additional conductive lines and method for producing it

Abstract

Object of the invention is to provide a new thin film device comprising at least one thin film cell, wherein the thin film cell comprises a first electrode, a photoactive layer and a second electrode, wherein the photoactive layer is arranged between the first and the second electrode, wherein at least one additional conductive line is arranged within an active area of the thin film cell and included in the photoactive layer and electrically interconnected with the first electrode and electrically insulated from the second electrode. Furthermore, the invention provides a method of forming a thin film device comprising at least one thin film cell, wherein the thin film cell comprises a first electrode, a photoactive layer and a second electrode and the photoactive layer is arranged between the first and the second electrode.

Claims

1. A thin film device comprising at least one thin film cell, wherein the thin film cell comprises a first electrode, a photoactive layer and a second electrode, wherein the photoactive layer is arranged between the first and the second electrode, characterized in that at least one additional conductive line is arranged within an active area of the thin film cell and included in the photoactive layer and electrically interconnected with the first electrode and electrically insulated from the second electrode.

2. The thin film device according to claim 1, wherein the first electrode is made of a transparent conductive material.

3. The thin film device according to claim 1 or 2, wherein the at least one additional conductive line has a width of 10 m to 10 cm.

4. The thin film device according to any of claims 1 to 3, wherein the at least one additional conductive line has a height within the photoactive layer of 1 to 99% of the height of the photoactive layer, preferably 70-80%.

5. The thin film device according to any of claims 1 to 4, wherein the at least one additional conductive line is embedded in a groove, which is formed within the active area within the photoactive layer and which adjoins the first electrode.

6. The thin film device according to claim 5, wherein the groove is at least partially filled with a conductive material forming the conductive line.

7. The thin film device according to claim 6, wherein the groove is filled with conductive material having a height within the photoactive layer of 1 to 99% of the height of the photoactive layer and is additionally filled with an insulating material until 100% of the height within the photoactive layer.

8. The thin film device according to claim 7, wherein the insulating material is arranged between the conductive material and the second electrode and wherein the conductive material adjoins the first electrode.

9. The thin film device according to any of claims 1 to 8, wherein the thin film device comprises a plurality of thin film cells connected in series, wherein the first electrode of a first cell is electrically interconnected to the second electrode of a second cell by a contact line and wherein at least one conductive line is electrically interconnected to the contact line.

10. A method of forming a thin film device comprising at least one thin film cell, wherein the thin film cell comprises a first electrode, a photoactive layer and a second electrode, wherein the photoactive layer is arranged between the first and the second electrode, comprising the following steps: a forming a first electrode, b forming a second electrode, c forming a photoactive layer between the first and the second electrode, and d forming a conductive line within the at least one photoactive layer, wherein the conductive line is electrically interconnected with the first electrode and electrically insulated from the second electrode.

11. The method according to claim 10, wherein step d comprises the following steps: x forming a groove within the photoactive layer and xx at least partially filling the groove with a conductive material such that the conductive material is electrically interconnected with the first electrode.

12. The method according to claim 10 or 11, wherein the groove is only partially filled with a conductive material in step xx and step d further comprises the following step: xxx filling the groove with an insulating material to electrically insulate the conductive material from the second electrode.

13. The method according to claim 11 or 12, wherein the thin film device comprises a first and a second thin film cell and wherein the first electrode, the photoactive layer and the second electrode of the first and the second thin film cells are each formed as a continuous layer, the method comprising the following additional steps: i. scribing a first line through at least the layer of the first electrode for separation of the first electrodes of the first and second thin film cell, ii. scribing a second line parallel to the first line through the photoactive layer to generate a contact line for series interconnection of the first electrode of the first cell with the second electrode of the second cell, iii. scribing a third line parallel to the first and the second lines through at least the layer of the second electrode for separation of the second electrodes of the first and the second thin film cell, iv. filling the first line with an insulating material, and v. filling the second line with a conductive material to form the contact line for electrically interconnection the first electrode of the first cell to the second electrode of the second cell, wherein the additional step i follows step xx, the additional step ii follows step c or step x and additional step iii follows step b.

14. The method according to claim 13, wherein the additional step iv is carried out in one process step together with step xxx.

15. The method according to any of claim 13 or 14, wherein the additional step v is carried out in one process step together with step b.

Description

FIGURES

[0078] FIG. 1 schematically shows an exemplary thin film cell with neighboring thin film cells in cross section.

[0079] FIG. 2A schematically shows an exemplary thin film device in top view according to the present invention.

[0080] FIG. 2B schematically shows a detailed section of the additional conductive lines of FIG. 2A.

[0081] FIG. 2C schematically shows different possible arrangements of the additional conductive lines within the thin film cell.

[0082] FIG. 3 schematically shows an embodiment of the method according to the present invention, wherein additional steps S70, S80, S90, S100 and S110 are included in the manufacturing process to produce the thin film device in a superstrate configuration with additional conductive lines according to the present invention.

EXEMPLARY EMBODIMENTS

[0083] The thin film device and the method to manufacture the thin film device according to the invention is explained in the following exemplary embodiment, wherein the figures are not intended to imply a restriction to the shown embodiments.

[0084] FIG. 1 shows in cross section a thin film cell 100 completely and two neighboring thin film cells 100a, 100b partially. The thin film cell comprises a first electrode 101, at least one photoactive layer 102 and a second electrode 103. Three scribed lines 105, 106, 107 for physically separating and electrically connecting a plurality of thin film cells 100, 100a, 100b to a thin film module are visible, defining an active area 108 and a dead area or scribing region 109 of the thin film cell 100. Also visible is a groove 104 within the photoactive layer, which is filled with a conductive material to form an additional conductive line 104a within the active area of the thin film cell 100. The conductive line 104a forms a direct contact with the first electrode 101. In addition, the groove is filled with an insulating material 104b to electrically insulate the conductive line from the second electrode 103. A first scribed line 105 separates the first electrode 101 into individual thin film cells 100, 100a, 100b and is filled with an insulating material 105a. A second scribed line 106 through the at least one photoactive layer is generated and filled with a conductive material 106a to form a contact line 106b. The contact line 106b connect the thin film cell 100a with the thin film cell 100 in series, that means the second electrode 103 of the thin film cell 100a is electrically connected to the first electrode 101 of the thin film cell 100. A third scribed line 107 separates the second electrode 103 into individual thin film cells 100, 100a, 100b. The third scribed line 107 may penetrate the second electrode 103 and the photoactive layer 102 thereby reaching the first electrode 101 as shown in FIG. 1 or may penetrate only the second electrode 103.

[0085] FIGS. 2A to 2C show top views on exemplary thin film devices. FIG. 2A shows an exemplary thin film module 200 in top view comprising a plurality of individual thin film cells 203 divided by several sets 201 of three scribed lines and with additional conductive lines 202, 202a. A first additional conductive line 202 is arranged parallel to the set 201 of three scribed lines within each thin film cell 203. A second additional conductive line 202a is arranged perpendicular to the set 201 of three scribed lines.

[0086] FIG. 2B shows a detailed marked section of FIG. 2A wherein one set 201 of three scribed lines is split up into a first scribed line 201a, a second scribed line 201b and a third scribed line 201c. The second additional conductive line 202a, which is perpendicular to the three scribed lines201a-201c is interrupted by the first scribed line 201a such, that no electrical contact between the additional conductive lines 202, 202a of one thin film cell 203 and neighboring thin film cells is formed. In the result, additional conductive lines 200 and 202a contribute to the charge collection and transfer only in that thin film cell 203 in which they are arranged. The conductive line 202a makes electrical contact with 201b.

[0087] FIG. 2C shows different exemplary arrangements of the additional conductive lines 202, 202a within the thin film cell 203. The lower part of FIG. 2C shows an arrangement, wherein the first additional conductive line 202 forms a zig-zag-pattern within the thin film cell 203. The middle part of FIG. 2C shows an arrangement, wherein the first additional conductive line 202 within the thin film cell 203 comprises a line parallel to the set 201 of three scribed lines and several shorter lines, which cross the parallel line. The upper part of FIG. 2C shows an arrangement, wherein the first additional conductive line 202 comprises a curved line and a crossing additional short line, which is perpendicular to the set 201 of three scribed lines.

[0088] Apart from the description, the additional conductive lines can have many different design patterns and lengths in a thin film module. Moreover, the arrangement and number of the additional conductive lines within the active area of a single thin film solar cell can be choosen according to simulation results in order to achieve higher yields. Increasing the number of additional conductive lines will increase the thin film module efficiency via increase in filling factor of the thin film solar cell.

[0089] FIG. 3 shows an embodiment of the method to manufacture the thin film device according to the present invention, wherein the thin film device is produced in the superstrate configuration. The method comprises the following steps: S10 forming a first electrode on a suitable substrate, S20 forming a photoactive layer on the first electrode, S30 forming a groove within the photoactive layer within the active area of the thin film cell, S40 partially filling the groove with a conductive material to form an additional conductive line, S50 filling the remaining groove with an insulating material and S60 forming a second electrode on the photoactive layer and the insulating material within the groove. The method may further comprise additional steps S70 to S110. S70 is scribing a second line to generate a contact line for series connection of the individual thin film cells to a thin film module and may be carried out either between S20 and S30 or between S30 and S40 such, that forming the groove and the second scribed line can be carried out in one manufacturing step with the same scribing tool. S80 is scribing a first line to separate the first electrodes into individual thin film cells and follows S 40. It automatically causes the interruption of any additional conductive line crossing the dead area of the thin film cell. S90 is filling the first scribed line with an insulating material and is carried out in one manufacturing step together with S50 by the same printing tool. S100 is filling the second scribed line with a conductive material and is performed automatically by S60, if the second electrode is formed by a large-area deposition process. In this case, both steps are carried out by one manufacturing step and the conductive material within the second line, i.e. the contact line, and the material of the second electrode are the same. S110 is scribing of the third line to separate the second electrode into individual thin film cells and is carried out after S60.

[0090] For realization of the invention it is advantageous to combine the described embodiments and features of the claims as described above. However, the embodiments of the invention described in the foregoing description are examples given by way of illustration and the invention is nowise limited thereto. Any modification, variation and equivalent arrangement as well as combinations of embodiments should be considered as being included within the scope of the invention.

CITED LITERATURE

[0091] [1] Guilln C. et al TCO/metal/TCO structures for energy and flexible electronics, Thin Solid Films 520 (2011) 1-17

REFERENCE SIGNS

[0092] 100 thinfilmcell [0093] 100a neighboring thin film cell [0094] 100b neighboringthinfilmcell [0095] 101 firstelectrode [0096] 102 at least one photoactive layer [0097] 103 secondelectrode [0098] 104 groove within the at least one photoactive layer [0099] 104a additional conductive line [0100] 104b insulating material for filling the groove [0101] 105 first scribed line [0102] 105a insulating material for filling the first scribed line [0103] 106 second scribed line [0104] 106a conductive material for filling the second scribed line [0105] 106b contact line for series connection of neighboring thin film cells [0106] 107 third scribed line [0107] 108 active area of the thin film cell [0108] 109 dead area/scribing region of the thin film cell [0109] 200 thinfilmmodule [0110] 201 set of three scribed lines [0111] 201a first scribed line [0112] 201b second scribed line [0113] 201c third scribed line [0114] 202 first additional conductive line [0115] 202a second additional conductive line [0116] 203 thin film cell of a certain width