Abstract:
A photovoltaic device includes a substrate and has a transparent conductive oxide layer, a conductive back layer, and at least one intermediate semiconductor layer formed thereon. An isolation scribe divides and electrically isolates the oxide layer, the back layer and the semiconductor layer to define two photovoltaic cells. A conductor extends across the isolation scribe and connects the back layer of one photovoltaic cell to the oxide layer of the other photovoltaic cell.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of priority of U.S. Provisional Patent Application Ser. No. 61/953,279 filed on Mar. 14, 2014 hereby incorporated herein by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention relates in general to a photovoltaic device (or photovoltaic device). Thin film photovoltaic devices are formed by the deposition of multiple semiconductor or organic thin films on rigid or flexible substrates or superstrates. Electrical contact to the solar cell material on the substrate side is provided by an electrically conductive substrate material or an additional electrically conductive layer between the solar cell material and the substrate such as a transparent conductive layer. 
         [0003]    Photovoltaic devices typically comprise subdevices connected in parallel. Each subdevice comprises multiple photovoltaic cells, typically connected in series. The photovoltaic devices are typically split into subdevices and cells by a plurality of scribe lines often referred to as a P1 scribe, a P2 scribe, and a P3 scribe. The P1 scribe provides electrical isolation between the cells by isolating a front contact layer (often referred to as a TCO layer), the P2 scribe immediately adjacent the P1 scribe provides interconnection of the cells and involves removal of all layers of the device down to the front contact layer to facilitate electrical connection with the front contact layer via a conductive coating, and the P3 scribe adjacent to the P2 scribe and is another isolation scribe that ablates through and isolates the metal back contact layer of each cell. Areas of the subdevices may be less efficient or may not be electrically conductive at all due to the scribes and the areas of the device lost due to scribing. Areas of the cells located between P1 and P3 are not functional, i.e., non-electrically conductive, thus lowering an electrical output of each cell of the device. The non-electrically conductive area(s) are typically the width of the P1 scribe plus the space between the P1 and P2 scribes plus the width of the P2 scribe plus the spacing between the P2 and P3 scribes plus the width of the P3 scribe (i.e., P1 width+P2/P3 spacing+P2 width+P2/P3 spacing+P3 width), as best shown in  FIG. 12 . Thus, it would be desirable to minimize non-electrically conductive areas photovoltaic devices and, in general, to develop a more efficient photovoltaic device. 
       SUMMARY OF THE INVENTION 
       [0004]    Concordant and congruous with the present invention, a more efficient photovoltaic device has surprisingly been discovered. 
         [0005]    In one embodiment of the invention, a photovoltaic device comprises a substrate having a transparent conductive oxide layer, a conductive back contact layer, and a semiconductor layer formed thereon; an isolation scribe formed through the transparent conductive oxide layer, the conductive back contact layer, and the semiconductor layer to define a first photovoltaic cell and a second photovoltaic cell, the isolation scribe electrically isolating the first photovoltaic cell from the second photovoltaic cell; and an interconnection scribe formed through the back contact layer and the semiconductor layer of the second photovoltaic cell, the interconnection scribe spaced laterally apart from the isolation scribe and facilitating a series connection between the first photovoltaic cell and the second photovoltaic cell. 
         [0006]    In another embodiment of the invention, a method for manufacturing a photovoltaic device comprises forming a plurality of isolation scribes in a photovoltaic device through a transparent conductive oxide layer, a semiconductor layer, and a back contact layer of disposed upon a substrate to define an array of photovoltaic cells on the photovoltaic device; forming interconnection scribes through the semiconductor layer and the back contact layer of each of the photovoltaic cells to expose a portion of the transparent conductive oxide layer; and depositing a dielectric material into the plurality of isolation scribes, wherein at least a portion of the dielectric material is disposed on at least a portion of the back contact layer of one of the photovoltaic cells, a portion of the back contact layer of a another of the photovoltaic cells adjacent to the one of the photovoltaic cells, and at least a portion of the interconnection scribe of the one of the photovoltaic cells. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a perspective view of a photovoltaic device. 
           [0008]      FIG. 2  is a schematic, side view taken along the cut line  2 - 2  of  FIG. 1 , showing a photovoltaic cell according to an embodiment of the invention. 
           [0009]      FIG. 2   a  is a schematic, side view of a photovoltaic cell according to another embodiment of the invention. 
           [0010]      FIG. 3  is a schematic, side view taken along the cut line  3 - 3  of  FIG. 1 , showing a photovoltaic cell including a bus bar. 
           [0011]      FIG. 4  is a schematic, side view taken along the cut line  4 - 4  of  FIG. 1 , showing a photovoltaic cell including a second bus bar. 
           [0012]      FIG. 5  is a flow chart of one method to manufacture the photovoltaic device shown in  FIG. 1 . 
           [0013]      FIG. 6   a  is a perspective view of a portion of the photovoltaic device before any scribes have been cut. 
           [0014]      FIG. 6   b  is a schematic, side view of the photovoltaic device shown in  FIG. 6   a.    
           [0015]      FIG. 7   a  is a perspective view of a portion of the photovoltaic device shown in  FIG. 6   a  after isolation scribes have been cut. 
           [0016]      FIG. 7   b  is a schematic, side view of the photovoltaic device shown in  FIG. 7   a.    
           [0017]      FIG. 8   a  is a perspective view of a portion of the photovoltaic device shown in  FIG. 7   a  after interconnection scribes have been cut in the photovoltaic device. 
           [0018]      FIG. 8   b  is a schematic, side view of the photovoltaic device shown in  FIG. 8   a.    
           [0019]      FIG. 9   a  is a perspective view of a portion of the photovoltaic device shown in  FIG. 8   a  after a dielectric material has been added to cover portions of the photovoltaic device. 
           [0020]      FIG. 9   b  is a schematic, side view of the photovoltaic device shown in  FIG. 9   a.    
           [0021]      FIG. 10   a  is a perspective view of a portion of the photovoltaic device shown in  FIG. 9   a  after portions of the dielectric material have been removed. 
           [0022]      FIG. 10   b  is a schematic, side view of the photovoltaic device shown in  FIG. 10   a.    
           [0023]      FIG. 11   a  is a perspective view of a portion of the photovoltaic device shown in  FIG. 10   a  after a metallic interconnection material has been added to portions of the photovoltaic device. 
           [0024]      FIG. 11   b  is a schematic, side view of the photovoltaic device shown in  FIG. 11   a.    
           [0025]      FIG. 12  is a schematic, side view of a photovoltaic device as known in the art. 
           [0026]      FIG. 13  is a flow chart of another method to manufacture a photovoltaic device (shown in  FIGS. 14   a  and  14   b ) according to another embodiment of the invention. 
           [0027]      FIG. 14   a  is a schematic, side view of the photovoltaic device manufactured by the method of  FIG. 13  during an ablation step. 
           [0028]      FIG. 14   b  is a schematic, side view of the photovoltaic device of  FIG. 14   a  after the ablation step and during a curing step. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0029]    Referring now to the drawings, there is illustrated in  FIG. 1  a perspective view of a photovoltaic device, indicated generally at  10 . The photovoltaic device  10  includes a plurality of photovoltaic cells,  12   a ,  12   b ,  12   c , etc. The illustrated photovoltaic cells  12   a ,  12   b ,  12   c , etc. are not shown to scale, and are provided for purposes of explanation of the features of the photovoltaic device  10 . The photovoltaic device  10  may have a different number of photovoltaic cells from that illustrated. Each photovoltaic cell is electrically connected to at least one adjacent photovoltaic cell, as will be described below. Furthermore as will be described herein, each cell of the device  10  will include one or more layers of material. Each layer can cover all or a portion of the device  10  and/or all or a portion of a layer or a substrate underlying the layer. For example, a “layer” can include any amount of any material that contacts all or a portion of a surface. Furthermore, layers herein may be described generally by a numeral (e.g.,  18 ) or individually for a particular cell by a numeral and a character (e.g.,  18   c ). It is understood that disclosure with respect to a particular layer for a particular cell may apply in similar fashion to layers of other cells or of the layer generally, except where noted otherwise. 
         [0030]    Referring to  FIG. 2 , a side view of a portion of the photovoltaic device  10 , taken along the cut line  2 - 2  of  FIG. 1  is shown. The photovoltaic device  10  includes a transparent substrate  14 . The transparent substrate  14  is formed of a material that provides rigid support, light transmission, chemical stability and typically includes one of a float glass, soda lime glass, polymer, or other suitable material. The photovoltaic device  10  includes a transparent conductive oxide (TCO) layer  16 . The transparent conductive oxide layer  16  is formed of a material that provides low resistance electrical conduction, chemical and dimensional stability and typically includes one of a tin oxide, zinc oxide, cadmium stannate, combinations or doped variations thereof, or any other suitable material. The photovoltaic device  10  includes a semiconductor layer  18 . The semiconductor layer  18  is formed of a photoactive material or combination of materials. Typically, the semiconductor layer includes one or more n-type or p-type semiconductors to form a p-n junction. In one embodiment, the semiconductor layer  18  is a semiconductor bi-layer including an n-type cadmium sulfide and a p-type cadmium telluride, however other compounds and materials may be used, including silicon based semiconductors, copper indium gallium selenide, and other suitable materials. The photovoltaic device  10  includes a back contact layer  20 . The back contact layer  20  is an electrically conductive material, typically selected from among silver, nickel, copper, aluminum, titanium, palladium, chromium, molybdenum, gold, and combinations thereof. 
         [0031]    As previously described in reference to  FIG. 1 , the photovoltaic device  10  is divided into a plurality of photovoltaic cells  12   a ,  12   b ,  12   c , etc. Adjacent photovoltaic cells are separated by isolation scribes  22   a ,  22   b ,  22   c , etc., which electrically isolate each photovoltaic cell from the one or more adjacent photovoltaic cells. For example, in reference to  FIG. 2 , the photovoltaic cell  12   c  is isolated from the photovoltaic cell  12   b  by the isolation scribe  22   b , and is isolated from the photovoltaic cell  12   d  by the isolation scribe  22   c . The isolation scribes  22   a ,  22   b ,  22   c , etc. divide the several layers of the photovoltaic device into separate cells, and so the photovoltaic cell  12   c  includes a cell transparent conductive oxide layer  16   c , a cell semiconductor layer  18   c , and a cell back contact layer  20   c . These layers are isolated from the similar layers of adjacent photovoltaic cells  12   b  and  12   d  by the isolations scribes  22   b  and  22   c.    
         [0032]    The photovoltaic cell  12   c  includes an interconnection scribe  24   c  spaced laterally apart from the isolation scribe  22   c . Instead of the interconnection scribe  24   c  being located at an end or an edge of a cell  12   c  adjacent the isolation scribe  22   c , the interconnection scribe  24   c  is located at or near a center of the cell  12   c . The interconnection scribe  24   c  provides an opening through at least a portion of the back contact layer  20  and the semiconductor layer  18  and provides access to the TCO layer  16   c . A dielectric material  26   c  is disposed within the isolation scribe  22   b . The dielectric material  26   c  may be a UV curable polymer, for example, or any suitable electrically insulating material as desired. The dielectric material  26   c  also covers a portion of the back contact layer  20   b  of the photovoltaic cell  12   b , a portion of the back contact layer  20   c  of the photovoltaic cell  12   c , and a portion of the interconnection scribe  24   c  of the photovoltaic cell  12   c . Similar to the device  10  shown in  FIG. 2   a , the isolation scribe  22   c  and the interconnection scribe  24   c  are spaced apart such that the only non-electrically conductive area corresponding to the non-electrically conductive area  31  of  FIG. 2   a  is a width of the isolation scribe  22   c  (the P1 scribe) plus the width of the interconnection scribe  24   c  (the P2 scribe) (or P1 width+P2 width), thereby resulting in a device  10  having a larger active area able to generate additional electricity as compared to prior art devices. By forming the interconnection scribe  24   c  spaced apart from the isolation scribe  22   c , resistance loses of current traveling through the TCO layer  16   c  is minimized. If resistances in the TCO layer  16   c  are minimized, TCO layers  16   c  may be formed from materials with higher resistances but with an increase in transmission (e.g., higher Isc). 
         [0033]    The photovoltaic device  10  includes a metallic interconnection material  28   c  that is disposed in electrical contact with a portion of the transparent conductive oxide material  16   c  of the photovoltaic cell  12   c , and in electrical contact with a portion of the back contact layer  20   b  of the adjacent photovoltaic cell  12   b . The metallic interconnection material  28  may include titanium, aluminum, nickel, chromium, tantalum, copper, tungsten, titanium nitride, tantalum nitride, tungsten nitride and various compounds and combinations thereof. One example embodiment of photovoltaic cell  12  may include a back contact layer  20  comprising a compound of molybdenum, nickel, aluminum and a metallic interconnection layer  28  comprising a compound of titanium and aluminum. Alternatively, a second exemplary embodiment may include a back contact layer  20  comprising a compound of molybdenum, nickel, aluminum, and chromium, and a metallic interconnection layer  28  comprising a compound of tungsten and copper. This forms a series connection between the photovoltaic cell  12   c  and the adjacent photovoltaic cell  12   b . As shown in  FIG. 8   a , the interconnection scribe  24   c  is a series of discrete scribes that are separated by non-scribed space  30   c . Therefore, the back contact layer  20   c  of the photovoltaic cell  12   c  extends from a first side of the interconnection scribe  24   c  to a second side of the interconnection scribe  24   c  and provides a conductive pathway across the full width of the photovoltaic cell  12   c . Referring back to  FIG. 2 , an electrical current flow path is shown by the dashed line  32 . 
         [0034]    Although photovoltaic cell  12   c  and its connection to adjacent photovoltaic cell  12   b  has been described in detail, it should be appreciated that all the photovoltaic cells in the photovoltaic device  10  may be similarly connected to the adjacent photovoltaic cells. The other photovoltaic cells will not be described in detail, with the exception of a photovoltaic cell  12   h  and a photovoltaic cell  12   i.    
         [0035]    Referring to  FIG. 3 , side, schematic view of the photovoltaic cell  12   h  is shown. The photovoltaic cell  12   h  includes many features similar to the previously described photovoltaic cell  12   c , and similar features are identified with similar numbers with the suffix letter “h.” The photovoltaic cell  12   h  includes a bus bar  34  that is in electrical contact with a front contact layer  16   h . The configuration of the photovoltaic cell  12   h  is such that the space below the bus bar  34  is photovoltaicly active, and is not dead space. The bus bar  34 , along with other bus bars in the device, provide electrically accessible features within the photovoltaic device to engage with other integration components (not shown), including conductive tapes and foils which may pass through an edge encapsulant, back cover glass or other device enclosure to facilitate the interconnection of multiple devices, the connection of the device to an electrical load, grid, array, or otherwise. 
         [0036]    Referring to  FIG. 4 , a side, schematic view of the photovoltaic cell  12   j  is shown. The photovoltaic cell  12   j  includes many features similar to the previously described photovoltaic cell  12   c , and similar features are identified with similar numbers with the suffix letter “j.” The photovoltaic cell  12   j  includes a bus bar  36  that is in electrical contact with a back contact layer  20   j . The configuration of the photovoltaic cell  12   j  is such that the space below the bus bar  36  is photovoltaicly active, and is not dead space. The bus bar  36  creates an electrical circuit with the bus bar  34  in the photovoltaic cell  12   h.    
         [0037]    It should be appreciated that the photovoltaic device may include the bus bar  34  at one end, and the bus bar  36  at the opposite end, placing all the photovoltaic cells in the photovoltaic device in series. Alternatively, the photovoltaic device may include to matching bus bars similar to one of bus bar  34  and bus bar  36  at each end of the photovoltaic device, and a single bus bar similar to the other of bus bar  36  and bus bar  34  in the center of the photovoltaic device. In that case, the photovoltaic device would include two subdevices, and the center bus bar would be connected to two series of photovoltaic cells, extending to each edge of the photovoltaic device. It should be appreciated that the center bus bar would include a mirror image, taken through the center line of the bus bar, of the configuration shown in one of  FIG. 3  and  FIG. 4 . Additionally, it should be appreciated that the photovoltaic device may be divided into more than two subdevices, if desired, with the appropriate number and placement of bus bars. 
         [0038]    Referring now to  FIG. 5 , a flow chart of a method for manufacturing the photovoltaic device  10  is shown generally at  38 . The steps of the method shown in  FIG. 5  are best understood in further reference to  FIGS. 6   a  and  6   b  through  11   a  and  11   b.    
         [0039]    Step  40  is the application of the transparent conductive oxide layer  16  to the transparent substrate  14 . Processes to apply the transparent conductive oxide layer  16  to the transparent substrate  14  are known in the art, and will not be detailed here. The transparent conductive oxide layer  16  is applied across the full surface of the transparent substrate  14 . Step  42  is the application of the semiconductor layer  18 . Processes to apply the semiconductor layer  18  are known in the art, and will not be detailed here. The semiconductor layer  18  is applied across the full surface of the transparent conductive oxide layer  16 . Step  44  is the application of the back contact layer  20 . Processes to apply the back contact layer  20  are known in the art, and will not be detailed here. The back contact layer  20  is applied across the full surface of the semiconductor layer  18 . The back contact layer  20  may be sealed with, for example, chromium. At this point, the photovoltaic device  10  is in the condition shown in  FIGS. 6   a  and  6   b . It should be appreciated that the back contact layer  20 , by covering the full surface of the semiconductor layer  18 , provides protection against undesirable oxidation, contamination or deterioration of the semiconductor layer  18 . As a result, the photovoltaic device may be brought through step  44 , and then moved to a different facility where additional steps may be performed, without degradation of the materials of photovoltaic device. 
         [0040]    At step  46  the isolation scribes  22   a ,  22   b ,  22   c , etc. are cut into the photovoltaic device  10 . The disposition of the photovoltaic device  10  after step  46  is shown in  FIGS. 7   a  and  7   b . The isolation scribes  22   a ,  22   b ,  22   c , etc. are cut using a laser that ablates the transparent conductive oxide layer  16 , the semiconductor layer  18 , and the back contact layer  20  without affecting and/or altering the transparent substrate  14 . 
         [0041]    At step  48  interconnection scribes  24   a ,  24   b ,  24   c , etc. are cut into the photovoltaic device  10 . The disposition of the photovoltaic device  10  after step  48  is shown in  FIGS. 8   a  and  8   b . The interconnection scribes  24   a ,  24   b ,  24   c , etc. are cut using a laser that ablates the semiconductor layer  18  and the back contact layer  20  without affecting and/or altering the transparent substrate  14  and the transparent conductive oxide layer  16 . The interconnection scribes  24   a ,  24   b ,  24   c , etc. may comprise a series of discontinuous ablations of material between two isolation scribes (as shown in  FIG. 8   a ), for example isolation scribes  22   a  and  22   b , or alternatively, between an isolation scribe and an end edge of the photovoltaic device, for example isolation scribe  22   a . The discontinuous ablations of the interconnection scribes  24   a ,  24   b ,  24   c , etc. may result in a series of substantially circular dots or short rectilinear scribes (not shown) or the discontinuous ablation may result in a dashed line scribe, as best shown in  FIG. 8   a . Alternatively, the interconnection scribes  24   a ,  24   b ,  24   c , etc. may comprise a continuous ablation of material resulting in an elongate trough. 
         [0042]    Regardless of the shape and/or length of the interconnection scribes  24   a ,  24   b ,  24   c , etc. and as best shown in  FIG. 2 , the photovoltaic device  10  does not include a so-called P3 scribe as is known in the art. Instead, the device  10  includes the isolation scribe  22  (a P1 scribe) and the interconnection scribe  24  (a P2 scribe) spaced apart from another isolation scribe(s)  22  (another P1 scribe). The P3 scribe is replaced by an additional metallic interconnection material  28  discussed hereinafter in more detail. By eliminating a P3 scribe as known in the art, the isolation scribe  22  (the P1 scribe) and the interconnection scribe  24  (the P2 scribe) may be performed by the same laser-providing device, thereby minimizing a cost of equipment for producing the device  10  and the space required to manufacture the device  10 . Furthermore, by eliminating the P3 scribe known in the art, scribe tolerances of the isolation scribe  22  (the P1 scribe) and the interconnection scribe  24  (the P2 scribe) may be relaxed. That is, because there is no second isolation scribe (the P3 scribe) spacing considerations or constraints between the isolation scribe  22  (the P1 scribe) and the P3 isolation scribe are eliminated and the accuracy of the interconnection scribe  24  (the P2 scribe) may be relaxed from, for example, by about +/−20 μm to about +/−100 μm, thereby allowing for less stringent process controls. 
         [0043]    Another embodiment of photovoltaic device  10  of the invention is shown in  FIG. 2   a . The embodiment of  FIG. 2   a  is substantially similar to the embodiment of  FIG. 2  except that the metallic interconnection material  28  includes an etch  29  that is an isolation etch that, unlike the P3 scribe, only removes a portion of the metallic interconnection material  28  and does not etch or ablate the back contact layer  20 . The etch  29  may be formed by a wet or dry etch as known in the art, or a laser may be used to ablate the material  28  to form the etch  29 , as desired. The etch  29  is formed in the metallic interconnection material  28  thus negating the need for a P3 scribe, thereby militating against the unintentional removal or affecting of the back contact layer  20 . 
         [0044]    In one embodiment of the invention, at step  50  dielectric material  26   a ,  26   b ,  26   c , etc. is deposited on the photovoltaic device  10 . The disposition of the photovoltaic device  10  after step  50  is shown in  FIGS. 9   a  and  9   b . The dielectric material  26   a ,  26   b ,  26   c , etc. is applied using an inkjet printing process, though any other desired process suitable to apply the dielectric material  26   a ,  26   b ,  26   c , etc. may be used, such as a roll coating process, spraying application, and the like. 
         [0045]    According to an embodiment of the invention, the step  50  involves selectively depositing the dielectric material  26   a ,  26   b ,  26   c , etc. whereby the dielectric material  26   a ,  26   b ,  26   c , etc. includes at least two portions. The first portion of the dielectric material  26   a ,  26   b ,  26   c , etc. has a thickness, and the first portion is deposited on at least a portion of the device  10  where the dielectric material  26   a ,  26   b ,  26   c , etc. will not be ablated. The second portion of the dielectric material  26   a ,  26   b ,  26   c , etc. has a thickness less than that of the first portion. The second portion of the dielectric material  26   a ,  26   b ,  26   c , etc. is deposited on a portion of the device  10  that is to be ablated. The second portion of the dielectric material  26   a ,  26   b ,  26   c , etc. that is to be ablated may be deposited in the interconnection scribe  24 , for example, though the second portion may be deposited on other areas of the device  10  to be ablated, as desired. 
         [0046]    The process of selectively depositing the dielectric material  26   a ,  26   b ,  26   c , etc. having the first portion and the second portion is conducted using a single-pass inkjet printing process (or other single-pass deposition process) such that the first portion of the dielectric material  26   a ,  26   b ,  26   c , etc. is deposited to provide insulation between metal layers of the device  10 , such as between the back contact layer  20  and the metallic interconnection material  28 , for example, and the second portion of the dielectric material  26   a ,  26   b ,  26   c , etc. is deposited over areas to be ablated. Because the second portion has a thickness less than the thickness of the first portion, the second portion of the dielectric material  26   a ,  26   b ,  26   c , etc. is more easily ablated and removed, thereby minimizing waste and facilitating thorough and efficient ablation thereof. The single-pass process of depositing the dielectric material  26   a ,  26   b ,  26   c , etc. may be performed using an inkjet process with printhead control by reducing a voltage of center aligned piezoelectric (PZ) jets of the inkjet printer. Alternatively, the portions of the dielectric material  26   a ,  26   b ,  26   c , etc. thicknesses may be controlled by altering: the voltage charge (e.g., altering the waveform associated with each jet) to increase or decrease a volume of material discharged thereby; the number of attenuated jets; and a time between the deposition of the first portion and a curing step and the deposition of the second portion and a curing step (e.g., allowing more time between deposition and cure facilitates the spreading of the material over a larger area). 
         [0047]    In yet another embodiment of the invention, the step  50  involves selectively depositing the dielectric material  26   a ,  26   b ,  26   c , etc. to form gaps (also known as vias)  33  (as shown in  FIGS. 10   a  and  10   b ) in the dielectric material  26   a ,  26   b ,  26   c , etc. The gaps  33  may be metallized in a step  54  (as described below in more detail) to form contacts between conductive surfaces of the device  10 . The size and shape of the gaps  33  may be controlled by altering one or more of the following: PZ inkjet deposition conditions, such as a temperature of the dielectric material ink (i.e., higher temperature inks will have a different viscosity and surface tension compared to inks having a lower temperature); a temperature of the substrate  14 ; by controlling surface conditions of the substrate  14  and a contact wetting angle by treatment of the surface of the substrate  14  such as mild acid etch, oxidizing chemical treatments, plasma or corona ionization of the surface (e.g., a TCO layer), or interfacial chemical adsorption; and a length of time between deposition of the dielectric material  26   a ,  26   b ,  26   c , etc. and a curing thereof (as noted herein). 
         [0048]    Using an inkjet printing process, the gaps  33  are formed by providing an image programmed into the inkjet printer to be converted to an appropriate inkjet waveform to enable ink droplet size control and to position the match of the image. The images may result in a substantially identical printed ink or the image biasing may be used to obtain a printed ink having a different but desired shape. Furthermore, the substrate  14  may be modified so that a surface thereof is unfavorable for ink wetting. For example, a two-printhead printer system may be used where a first printhead applies an inverse pattern to a desired pattern resulting in the gaps  33 , the inverse pattern applied with a material that causes the ink to dewet. The second printhead then deposits either a blanket coating of material or a selective coating of material, and the dewetting material is then removed using a selective chemical etch, heating, or a plasma treatment. 
         [0049]    The gaps  33  formed by the process according to this embodiment of the invention would be similar to those shown in  FIGS. 10   a  and  10   b . According to this embodiment of the invention, the following step  52  is not required to be performed to ablate the dielectric material  26   a ,  26   b ,  26   c , etc. in contact with the transparent conductive oxide layer  16  within the interconnection scribe  24   a ,  24   b ,  24   c , etc. Because the step  52  is not required to be performed, contact between the laser for the ablation of the step  52  and the TCO layer  16  is eliminated, thereby mitigating against unintentional removal of or undesirable effects on the TCO layer  16 . 
         [0050]    In yet another embodiment of the invention where the dielectric material  26   a ,  26   b ,  26   c , etc. is a curable material, such as a UV curable polymer, the step  50  involves application of the curable material and a two-step curing procedure. The curable material has a viscosity low enough that the curable material may flow upon application to smooth out striations from the depositing step. In this embodiment, the step  50  includes a step of partially curing the dielectric material  26   a ,  26   b ,  26   c , etc. to allow the curable material to retain a desired shape, such as a shape formed by a laser-patterning step or ablation step without fully curing the curable material. The material removal of step  52  (described in further detail below) is then performed on the curable material forming the dielectric material  26   a ,  26   b ,  26   c , etc. to remove at least a portion thereof and to give the dielectric material  26   a ,  26   b ,  26   c , etc. a desired shape. The dielectric material  26   a ,  26   b ,  26   c , etc. is then fully cured, thereby resulting in the dielectric material  26   a ,  26   b ,  26   c , etc. retaining the desired shape formed by the removal step  52 . By providing a flowable and formable curable material as the dielectric material  26   a ,  26   b ,  26   c , etc. that is cured in multiple steps and has a desired shape, the cross-sectional profile of the dielectric material  26   a ,  26   b ,  26   c , etc. is compatible with a deposition of a metallic material as described in the step  54 , thereby minimizing undesirable effects of laser ablation such as shunting, or undesirably high resistances. 
         [0051]    At step  52  at least a portion of the dielectric material  26   a ,  26   b ,  26   c , etc. in contact with the transparent conductive oxide layer  16  within the interconnection scribe  24   a ,  24   b ,  24   c , etc. is removed to form the gaps  33 . The disposition of the photovoltaic device  10  after step  52  is shown in  FIGS. 10   a  and  10   b . The dielectric material  26   a ,  26   b ,  26   c , etc. is removed using a laser that ablates the dielectric material  26   a ,  26   b ,  26   c , etc. without affecting and/or altering the transparent substrate  14  and/or the transparent conductive oxide layer  16 . As noted above, step  52  is not performed in the embodiment of the invention where the dielectric material  26   a ,  26   b ,  26   c , etc. is deposited and the depositing process forms the gaps  33 . 
         [0052]    At step  54 , metallic interconnection material  28   a ,  28   b ,  28   c , etc. is applied to the photovoltaic device. The disposition of the photovoltaic device  10  after step  54  is shown in  FIGS. 11   a  and  11   b . The metallic interconnection material  28   a ,  28   b ,  28   c , etc. is applied using an inkjet printing process, though any other desired process suitable to apply the material may be used. The metallic interconnection material  28   a ,  28   b ,  28   e , etc., may be deposited over the entirety of the photovoltaic device&#39;s exposed surface, or alternatively may be selectively deposited within certain regions and not others. For example, as shown in  FIGS. 11   a  and  11   b , the metallic interconnection material  28   a ,  28   b ,  28   c , etc. may be selectively deposited to overlap slightly onto the back contact layer  20   a ,  20   b ,  20   c , etc. of the photovoltaic cell adjacent to photovoltaic cell  12   c  and continuously over dielectric material  26   c  to the interconnection scribe  24   c.    
         [0053]    At optional step  56 , an edge  58   a ,  58   b ,  58   c , etc. is created on the metallic interconnection material  28   a ,  28   b ,  28   c , etc. The disposition of the photovoltaic device  10  after step  56  is shown in  FIGS. 11   a  and  11   b . In the situation where the metallic interconnection material  28   a ,  28   b ,  28   c , etc. is deposited over the entirety of the photovoltaic device&#39;s exposed surface, the edge  58   a ,  58   b ,  58   c , etc. is created to prevent electrical connect between, for example, metallic interconnection material  28   c  and back contact layer  20   c , since such contact would create a short circuit that would allow current flow to bypass photovoltaic cell  12   c . The edge  58   a ,  58   b ,  58   c , etc. may be created by acid etch, mechanical removal (abrasion), laser ablating, or any other desired method. 
         [0054]    The described method for manufacturing  38  may be performed on an automated assembly line using known techniques. The isolation scribes and interconnection scribes may be cut or ablated using lasers. Multiple laser sources may be used in the method of manufacturing  38 . Alternatively, light from a single laser source may be manipulated using known optics techniques in order to cut various scribes, either simultaneously or sequentially. 
         [0055]    Referring now to  FIG. 13 , a flow chart of a method for manufacturing a photovoltaic device  110  according to another embodiment of the invention is shown generally at  138 . The steps of the method shown in  FIG. 13  are best understood in further reference to  FIGS. 6   a - 11   b  and  14   a  and  14   b.    
         [0056]    Step  140  is the application of a transparent conductive oxide (TCO) layer  116  to the transparent substrate  114 . Processes to apply the transparent conductive oxide layer  116  to the transparent substrate  114  are known in the art, and will not be detailed here. The transparent conductive oxide layer  116  is applied across the full surface of the transparent substrate  114 . Step  142  is the application of a semiconductor layer  118 . Processes to apply the semiconductor layer  118  are known in the art, and will not be detailed here. The semiconductor layer  118  is applied across the full surface of the transparent conductive oxide layer  116 . Step  144  is the application of a back contact layer  120 . Processes to apply the back contact layer  120  are known in the art, and will not be detailed here. The back contact layer  120  is applied across the full surface of the semiconductor layer  118 . The back contact layer  120  may be sealed with, for example, chromium. At this point, the photovoltaic device  110  is in the condition similar to that shown in  FIGS. 6   a  and  6   b . It should be appreciated that the back contact layer  120 , by covering the full surface of the semiconductor layer  118 , provides protection against undesirable oxidation, contamination or deterioration of the semiconductor layer  118 . As a result, the photovoltaic device may be brought through step  144 , and then moved to a different facility where additional steps may be performed, without degradation of the materials of photovoltaic device. 
         [0057]    At step  146  isolation scribes (not shown) are cut into the photovoltaic device  110 . The disposition of the photovoltaic device  110  after step  146  is similar to that shown in  FIGS. 7   a  and  7   b . The isolation scribes are cut using a laser that ablates the transparent conductive oxide layer  116 , the semiconductor layer  118 , and the back contact layer  120  without affecting the transparent substrate  114 . 
         [0058]    Step  148  is the application of a dielectric material  126  to the back contact layer  120 . The dielectric material  126  may be applied across the full surface of the back contact layer  120  or only a portion thereof, as desired. In each case, the dielectric material  126  substantially fills the isolation scribes formed in the step  146 . The dielectric material  126  is a curable material, such as a UV curable polymer, for example. The dielectric material  126  may be applied is applied using an inkjet printing process, though any other desired process suitable to apply the dielectric material  126  may be used, such as a roll coating process, spraying application, and the like. During the step  148 , the dielectric material  126  is applied in an uncured and flowable state. 
         [0059]    At step  150  at least one interconnection scribe  124  is cut into the photovoltaic device  110 , as shown in  FIG. 14   a . The step  148  is performed by introducing a laser  160  to the substrate  114  of the device  110 . The laser  160  may be applied directly to the device  110  or indirectly via a mirror  162 . The laser passes through the transparent substrate  114  and the transparent TCO layer  116  and ablates the semiconductor layer  118  and the back contact layer  120  without affecting the transparent substrate  114  and the transparent conductive oxide layer  116  to form the interconnection scribe  124 , as shown in  FIG. 14   b . The interconnection scribes  124  may comprise a series of discontinuous ablations of material between isolation scribes (similar to that shown in  FIG. 8   a ), or alternatively, between an isolation scribe and an end edge of the photovoltaic device  110 . The discontinuous ablations of the interconnection scribe  124  may result in a series of substantially circular dots or short rectilinear scribes (not shown) or the discontinuous ablation may result in a dashed line scribe, similar to that shown in  FIG. 8   a . Alternatively, the interconnection scribe  124  may comprise one continuous ablation of material to form a trough. 
         [0060]    During the step  152 , a curing means  164  is directed on the device  110  at the location of the laser ablation. It is understood that the curing means  164  may be directed on the device  110  at the location of the laser ablation during the step  150 , as desired. The curing means  164  may be heat or UV light  166  or any means selected to cure the curable material of the dielectric material  126 . As the laser  160  ablates one or more layers of material underneath the dielectric material  126 , forces exerted by the plum of ablated material from the semiconductor layer  118  and/or the back contact layer  120  are forced through the uncured dielectric material  126 , thereby opening a hole in the dielectric material  126 . The surface tension in the uncured dielectric material  126  causes the uncured dielectric material  126  to flow into the hole ablated through the semiconductor layer  118  and the back contact layer  120 . Being directed at the hole created by the laser  160 , the curing means  164  causes the dielectric material  126  that has flowed therein to cure, thereby militating against the dielectric material  126  completely covering the TCO layer  116  exposed by the step  150 , as shown in  FIG. 14   b . In this way, the step  150  the hole remains and a self-aligned gap (or via)  133  is formed that provides selective electrical communication with the TCO layer  116  while electrically insulating the sidewalls of the interconnection scribe  124  to militate against shunting. It is understood that changing any or all of the following may affect the sidewall profile of the dielectric material  126  and/or the width of the gap  133 : the angle of the curing means  164 ; the intensity of the curing means  164 ; and a time delay between the laser ablation and the curing steps. 
         [0061]    At step  154 , a metallic interconnection material (not shown) is applied to the photovoltaic device  110 . The disposition of the photovoltaic device  110  after step  152  is similar to that of the photovoltaic device  10  shown in  FIGS. 11   a  and  11   b . The metallic interconnection material is applied using an inkjet printing process, though any other desired process suitable to apply the material may be used. The metallic interconnection material may be deposited over the entirety of the exposed surface of the photovoltaic device  110 , or alternatively may be selectively deposited within certain regions and not others. For example, similar to that shown in  FIGS. 11   a  and  11   b , the metallic interconnection material may be selectively deposited to overlap slightly onto the back contact layer  120  of a photovoltaic cell adjacent to another photovoltaic cell and continuously over the dielectric material  126  to the interconnection scribe  124 . 
         [0062]    The described method for manufacturing  138  may be performed on an automated assembly line using known techniques. The isolation scribes and interconnection scribes may be cut or ablated using lasers. Multiple laser sources may be used in the method of manufacturing  138 . Alternatively, light from a single laser source may be manipulated using known optics techniques in order to cut various scribes, either simultaneously or sequentially. 
         [0063]    From the foregoing description, one ordinarily skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications to the invention to adapt it to various usages and conditions.