Patent Publication Number: US-2020295204-A1

Title: Article with Transparent Conductive Oxide Coating

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. application Ser. No. 14/963,778, filed Dec. 9, 2015, which claims priority to Provisional Application No. 62/131,938, filed Mar. 12, 2015, both of which are incorporated herein by reference in their entirety. 
    
    
     NOTICE OF GOVERNMENT SUPPORT 
     This invention was made with Government support under Contract No. DE-EE0004736 awarded by the Department of Energy. The United States government may have certain rights in this invention. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to electronic devices, for example solar cells, and to methods of making the same. 
     2. Technical Considerations 
     A solar cell or photovoltaic (PV) cell is an electronic device that directly converts sunlight into electricity. Light shining on the solar cell produces both a current and a voltage to generate electric power. In a solar cell, photons from sunlight are adsorbed by a semiconducting material. Electrons are knocked loose from their atoms, causing an electric potential difference. Current flows through the semiconductor material to cancel the potential difference. Due to the special composition of solar cells, the electrons are only allowed to move in a single direction. 
     A typical solar cell includes a glass substrate (cover plate) over which is provided a barrier layer, a transparent conductive oxide contact layer, and a semiconductor layer. A rear metallic layer acts as a reflector and back contact. Light scattering or “haze” is used to trap light in the active region of the cell. The more light that is trapped in the cell, the higher the efficiency that can be obtained. However, the haze cannot be so great as to adversely impact upon the transmittance of light through the conductive oxide layer. 
     It is also desirable that the conductive oxide layer is highly transparent to permit the maximum amount of solar radiation to pass to the semiconductor layer. As a general rule, the more photons that arrive at the semiconductor material, the higher the efficiency of the cell. Further, the conductive oxide layer should be highly conductive to facilitate the transfer of electrons in the cell. 
     Articles such as Organic Light Emitting Diodes (OLED) and Light Emitting Diodes (LED) also utilize conductive oxide layers and would benefit from enhanced haze and/or high transparency. 
     It would be desirable to provide a conductive oxide layer having enhanced conductivity and/or light transmission and/or light scattering. It would be desirable to provide a method of modifying a conductive oxide layer to affect (e.g., increase or decrease) one or more of these factors. It would be desirable to provide a conductive oxide layer useful in solar cells, OLEDs, LEDs, as well as other electronic devices. It would be desirable to provide a coater useful for manufacturing solar cells, OLEDs, LEDs, as well as other electronic devices. It would be desirable to provide a method of coating a glass substrate on one or both major surfaces to provide a coated substrate useful in solar cells, OLEDs, LEDs, as well as other electronic devices. It would be desirable to provide an article and/or method to accomplish one or more of the above results. 
     SUMMARY OF THE INVENTION 
     A solar cell comprises a first substrate having a first surface and a second surface. An underlayer is located over the second surface. A first conductive layer is located over the underlayer. An overlayer is located over the first conductive layer. A semiconductor layer is located over the conductive oxide layer. A second conductive layer is located over the semiconductor layer. The first conductive layer comprises a conductive oxide and at least one dopant selected from the group consisting of tungsten, molybdenum, niobium, and/or fluorine. For example, the first conductive layer can comprise tin oxide doped with tungsten. 
     A transparent conductive oxide layer for a solar cell comprises a metal oxide doped with tungsten. For example, tin oxide doped with tungsten. 
     A vapor deposition coater comprises a plenum assembly comprising an inlet plenum and an exhaust plenum; and a nozzle block comprising a discharge face. A discharge channel is in flow communication with the inlet plenum. An exhaust conduit is in flow communication with the exhaust plenum. The discharge channel is angled with respect to the discharge face of the coating block. 
     A method of forming a coating on a glass substrate in a glass manufacturing system comprises: providing a first coating precursor material to a first inlet plenum of a vapor deposition coater having a discharge face, wherein the first inlet plenum is in flow communication with a first discharge channel, and wherein the first discharge channel defines a first discharge path; and providing a second coating precursor material to a second inlet plenum of the vapor deposition coater, wherein the second inlet plenum is in flow communication with a second discharge channel, and wherein the second discharge channel defines a second discharge path. The first discharge path intersects the second discharge path at a position selected from (a) above a surface of a glass ribbon or (b) at a surface of a glass ribbon or (c) below a surface of a glass ribbon. 
     A drawdown assembly comprises a receiver and a nanoparticle deposition device, such as a flame spray device, located adjacent a first side and/or a second side of a glass ribbon path. 
     A method of forming a coated glass article in a drawdown process comprises: locating at least one second coater adjacent a second side of a glass ribbon path; optionally, locating at least one first coater adjacent a first side of the glass ribbon path; and using the second coater and optional first coater to apply a coating on a second side of a glass ribbon and, optionally, on the first side of the glass ribbon. 
     A double sided coated article formed by a drawdown process comprises a glass substrate having a first surface and an opposed second surface. A first coating is formed over the first surface by a first chemical vapor deposition coater adjacent the first surface. A second coating is formed over the second surface by a second chemical vapor deposition coater adjacent the second surface. An internal light extraction region is formed on and/or in the second surface of the glass substrate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A complete understanding of the invention will be obtained from the following description when taken in connection with the accompanying drawing figures. 
         FIG. 1  is a side, sectional view of an article in the form of a solar cell incorporating features of the invention; 
         FIG. 2  is a side, sectional view of a chemical vapor deposition (CVD) coater incorporating features of the invention; 
         FIG. 3  is a side, sectional view of a nozzle block of a modified CVD coater having a modified discharge channel arrangement; and 
         FIG. 4  is an end, sectional view of a glass drawdown process incorporating features of the invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Spatial or directional terms used herein, such as “left”, “right”, “inner”, “outer”, and the like, relate to the invention as it is shown in the drawing figures. It is to be understood that the invention can assume various alternative orientations and, accordingly, such terms are not to be considered as limiting. 
     All numbers used in the specification and claims are to be understood as being modified in all instances by the term “about”. All ranges disclosed herein are to be understood to encompass the beginning and ending range values and any and all subranges subsumed therein. The ranges set forth herein represent the average values over the specified range. 
     When referring to a layer of a coating, the term “over” means “farther from the substrate”. For example, a second layer located “over” a first layer means that the second layer is located farther from the substrate than the first layer. The second layer can be in direct contact with the first layer or one or more other layers can be located between the second layer and the first layer. 
     The terms “polymer” or “polymeric” include oligomers, homopolymers, copolymers, and terpolymers. 
     All documents referred to herein are to be considered to be “incorporated by reference” in their entirety. 
     Any reference to amounts, unless otherwise specified, is “by weight percent”. 
     The term “film” means a region having a desired or selected composition. A “layer” comprises one or more “films”. A “coating” is comprised of one or more “layers”. The term “organic material” includes polymers as well as small molecule organic materials that can be used to fabricate organic opto-electronic devices. 
     The term “visible light” means electromagnetic radiation having a wavelength in the range of 380 nm to 780 nm. The term “infrared radiation” means electromagnetic radiation having a wavelength in the range of greater than 780 nm to 100,000 nm. The term “ultraviolet radiation” means electromagnetic energy having a wavelength in the range of 100 nm to less than 380 nm. 
     The terms “metal” and “metal oxide” include silicon and silica, respectively, as well as traditionally recognized metals and metal oxides, even though silicon may not be conventionally considered a metal. The term “curable” means a composition capable of polymerizing or crosslinking. By “cured” is meant that the material is at least partly polymerized or cross-linked, preferably fully polymerized or cross-linked. By “at least” is meant “greater than or equal to”. By “not more than” is meant “less than or equal to”. The terms “upstream” and “downstream” refer to the direction of travel of the glass ribbon. 
     Haze and transmittance values herein are those determined using a Haze-Gard Plus hazemeter (commercially available from BYK-Gardner USA) or a Perkin Elmer Lamda 9 Spectrophotometer. Sheet resistance values were determined using a four-point probe (e.g., Nagy Instruments SD-600 measurement device). Surface roughness values were determined using an Instrument Dimension 3100 Atomic Force Microscope. 
     The discussion of the invention may describe certain features as being “particularly” or “preferably” within certain limitations (e.g., “preferably”, “more preferably”, or “even more preferably”, within certain limitations). It is to be understood that the invention is not limited to these particular or preferred limitations but encompasses the entire scope of the disclosure. 
     The invention comprises, consists of, or consists essentially of, the following aspects of the invention, in any combination. Various aspects of the invention are illustrated in separate drawing figures herein. However, it is to be understood that this is simply for ease of illustration and discussion. In the practice of the invention, one or more aspects of the invention shown in one drawing figure can be combined with one or more aspects of the invention shown in one or more of the other drawing figures. 
     The invention will be described with respect to a solar cell. However, it is to be understood that the invention could be practiced with other devices, for example, photovoltaic cells, organic light-emitting diodes, light emitting diodes, visual displays, and/or electronic switches. 
     An exemplary article, in the form of a solar cell  10 , incorporating features of the invention is shown in  FIG. 1 . The solar cell  10  includes a first (outer) substrate  12  having a first (outer) major surface  14  and a second (inner) major surface  16 . By “outer” is meant the surface facing the incident radiation, e.g., sunlight. An underlayer  18  is located over the second surface  16 . A first conductive layer  20  is located over the underlayer  18 . An overlayer  22  is located over the first conductive layer  20 . A semiconductor layer  24  is located over the overlayer  22 . A second conductive layer  26  is located over the semiconductor layer  24 . An optional second (inner) substrate  28  can be located over the second conductive layer  26 . For example, the second substrate  28  can be connected to the second conductive layer  26  by a polymeric interlayer  30 . An optional functional layer  32  can be located over the first surface  14  of the substrate  12 . An optional internal light extraction region or layer  34  can be located in and/or on the substrate  12 . 
     The first substrate  12  preferably has a high visible light transmission. By “high visible light transmission” is meant a visible light transmission at a reference wavelength of 550 nanometers (nm) and a reference thickness of 2 mm of at least 85%, such as at least 87%. For example, such as at least 90%. For example, such as at least 91%. For example, such as at least 92%. For example, such as at least 93%. 
     The first substrate  12  can be a low iron glass. By “low iron” is meant having a total iron content of less than 400 parts per million (ppm), such as less than 350 ppm. For example, the total iron content can be less than 300 ppm. For example, the total iron content can be less than 200 ppm. 
     Examples of suitable materials for the first substrate  12  include soda-lime silicate glass, for example, float glass. 
     Examples of glass that can be used for the invention include Starphire®, Solarphire®, Solarphire® PV, and CLEAR™ glass, all commercially available from PPG Industries, Inc. of Pittsburgh, Pa. 
     The first substrate  12  can be of any desired thickness. For example, the first substrate  12  can have a thickness in the range of 0.5 mm to 10 mm, such as 1 mm to 10 mm, such as 1 mm to 4 mm. For example, the first substrate  12  can have a thickness in the range of 2 mm to 3.2 mm. 
     The underlayer  18  can be a single layer, a homogeneous layer, a gradient layer, or can include a plurality of layers. By “homogeneous layer” is meant a layer in which the materials are randomly distributed throughout the coating. By “gradient layer” is meant a layer having two or more components, with the concentration of the components varying (e.g., continually changing or step change) as the distance from the substrate  12  changes. 
     The underlayer  18  can be or can include an optional bottom optical layer  36 . The bottom optical layer  36  can include one or more metal oxide layers. Examples of suitable oxide materials include oxides of silicon, titanium, aluminum, zirconium, phosphorus, hafnium, niobium, zinc, bismuth, lead, indium, tin, and/or alloys and/or mixtures thereof. For example, the bottom optical layer  36  can include an oxide of zinc, silicon, tin, aluminum, and/or titanium. For example, the bottom optical layer  36  can include an oxide of zinc and/or tin. 
     A zinc target to sputter a zinc oxide film may include one or more other materials to improve the sputtering characteristics of the zinc target. For example, the zinc target can include up to 10 wt. %, such as up to 5 wt. %, of such a material. The resultant zinc oxide layer would include a small percentage of an oxide of the added material, e.g., up to 10 wt. % of the material oxide, e.g., up to 5 wt. % of the material oxide. A layer deposited from a zinc target having up to 10 wt. % of an additional material to enhance the sputtering characteristics of the zinc target is referred to herein as “a zinc oxide layer” even though a small amount of the added material (or an oxide of the added material) may be present. An example of such a material is tin. 
     The bottom optical layer  36  can include or can be a zinc stannate layer. By “zinc stannate” is meant a composition of the formula: Zn X Sn 1-X O 2-X  (Formula 1) where “x” varies in the range of greater than 0 to less than 1. For instance, “x” can be greater than 0 and can be any fraction or decimal between greater than 0 to less than 1. A zinc stannate layer has one or more of the forms of Formula 1 in a predominant amount. A zinc stannate layer in which x=⅔ is conventionally referred to as “Zn 2 SnO 4 ”. 
     The underlayer  18  can be or can include an optional sodium ion barrier layer  38 . Examples of suitable materials for the sodium ion barrier layer  38  include metal oxide and metal alloy oxide materials. For example, oxides of silicon, titanium, aluminum, zirconium, phosphorus, hafnium, niobium, zinc, bismuth, lead, indium, tin, and alloys and mixtures thereof. For example, the sodium ion barrier layer  38  can comprise silicon oxide. For example, the sodium ion barrier layer  38  can comprise a mixture of at least silica and titania. For example, the sodium ion barrier layer  38  can comprise a mixture of silica, titania, and phosphorous oxide. 
     In  FIG. 1 , the sodium ion barrier layer  38  is illustrated over the bottom optical layer  36 . However, alternatively, the sodium ion barrier layer  38  could be positioned between the first substrate  12  and the bottom optical layer  36 . 
     The underlayer  18  can comprise both the optional bottom optical layer  36  and the optional sodium ion barrier layer  38 . Alternatively, only one of the bottom optical layer  36  or the sodium ion barrier layer  38  may be present. 
     The underlayer  18  can have a thickness in the range of 10 nm to 500 nm, such as 20 nm to 400 nm. For example, such as 20 nm to 300 nm. 
     The first conductive layer  20  can be a single layer or can have multiple layers or regions. The first conductive layer  20  comprises at least one conductive oxide layer. For example, the first conductive layer  20  can comprise a doped oxide layer. For example, the first conductive layer  20  can include one or more metal oxide materials. For example, the first conductive layer  20  can include one or more oxides of one or more of Zn, Fe, Mn, Al, Ce, Sn, Sb, Hf, Zr, Ni, Zn, Bi, Ti, Co, Cr, Si, In, or an alloy of two or more of these materials, such as zinc stannate. For example, the first conductive layer  20  can comprise tin oxide. 
     The first conductive layer  20  can include one or more dopant materials, such as but not limited to, F, In, Al, P, Cu, Mo, Ta, Ti, Ni, Nb, W, Ga, Mg, and/or Sb. For example, the dopant can be W, Mo, Nb, and/or F. For example, the dopant can be W or F. For example, the dopant can be W. 
     For example, the first conductive layer  20  can comprise W and an oxide material. For example, the first conductive layer can comprise tin oxide doped with tungsten. 
     The dopant can be present in an amount less than 10 wt. %, such as less than 5 wt. %, such as less than 4 wt. %, such as less than 2 wt. %. For example, such as less than 1 wt. %. For example, less than 0.5 wt. %. For example, less than 0.1 wt. %. 
     The first conductive layer  20  can be a multilayer comprising a first layer or region and a second layer or region located over the first layer. For example, the first layer or region can be tungsten doped tin oxide. For example, the second layer or region can be fluorine doped tin oxide. 
     The first conductive layer  20  can have a thickness in the range of 150 nm to 700 nm, such as 200 nm to 600 nm, such as 200 nm to 500 nm. For example, the first conductive layer  20  can have a thickness in the range of 200 nm to 450 nm. 
     The first conductive layer  20  can have a sheet resistance in the range of 8 ohms per square (Ω/□) to 25Ω/□, such 10Ω/□ to 20Ω/□. For example, such as 10Ω/□ to 17Ω/□. 
     The first conductive layer  20  can have a surface roughness (RMS) in the range of 5 nm to 60 nm, such as 5 nm to 40 nm, such as 5 nm to 30 nm, such as 10 nm to 30 nm, such as 10 nm to 20 nm. For example, such as 10 nm to 15 nm. For example, such as 11 nm to 15 nm. 
     The overlayer  22  can be a homogeneous layer, a gradient layer, and/or can include a plurality of layers or films. 
     The overlayer  22  can be or can include an optional buffer layer  42 . The buffer layer  42  can improve the amount of electromagnetic energy to the semiconductor layer  24 . 
     The buffer layer  42  can include one or more oxide materials. Examples of materials suitable for the buffer layer  42  include oxides of silicon, titanium, aluminum, zirconium, phosphorus, hafnium, magnesium, niobium, zinc, bismuth, gallium, lead, indium, and/or tin, and/or alloys and/or mixtures thereof. For example, the buffer layer  42  can comprise an oxide of zinc, indium, gallium, and/or tin. For example, the buffer layer  42  can comprise tin oxide. 
     The buffer layer  42  can include one or more other materials doped with or alloyed with the oxide materials. Examples of the other materials include zinc, magnesium, and/or tin. 
     For example, the buffer layer  42  can comprise zinc stannate. For example, the buffer layer  42  can comprise tin oxide doped with zinc and/or magnesium. For example, the buffer layer  42  can comprise tin oxide doped with zinc. 
     The overlayer  22  can be or can include an optional insulating layer  44 . Suitable materials for the insulating layer  44  include cadmium sulfide and/or a cadmium sulfate. An insulating layer  44  is particularly useful for a cadmium telluride solar cell. 
     The overlayer  22  can comprise both the optional buffer layer  42  and the optional insulating layer  44 . Alternatively, only one of the optional buffer layer  42  and the optional insulating layer  44  may be present. 
     The overlayer  22  can have thickness in the range of 20 nm to 500 nm, such as 20 nm to 400 nm, such as 20 nm to 300 nm. For example, the overlayer  22  can have thickness in the range of 20 nm to 200 nm. 
     The semiconductor layer  24  can comprise any conventional solar cell semiconductor material. Examples of semiconductor material include monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, and/or copper indium celenide/sulfide. 
     The semiconductor layer  24  can have a thickness in the range of 200 nm to 1,000 nm, such as 200 nm to 800 nm, such as 300 nm to 500 nm. For example, such as 300 nm to 400 nm. For example, such as 350 nm. 
     The second conductive layer  26  is preferably a metal layer. Examples of suitable materials for the second conductive layer  26  include silver, barium, calcium, and magnesium. The second conductive layer  26  can be a relatively thick layer. For example, the second conductive layer  26  can be opaque to light having a wavelength of 550 nm. By “opaque” is meant having a transmittance at a wavelength of 550 nm of less than 10%, such as less than 5%, such as less than 3%. For example, such as less than 1%. For example, 0%. 
     The optional second substrate  28  can be of any material described above for the first substrate  12 . The first substrate  12  and second substrate  28  can be of the same or different materials and can be of the same or different thicknesses. For example, the second substrate  28  can comprise float glass. 
     The interlayer  30  can be an elastomeric polymer. Examples include ethylene vinyl acetate (EVA) and polyvinyl butyral (PVB). 
     The optional functional layer  32  can be a homogeneous layer, a gradient layer, and/or can include a plurality of layers or films. 
     The optional functional layer  32  can be or can include an optional antireflective layer  33 . For example, the antireflective layer  33  can be a single layer or can comprise multiple films of antireflective materials and/or dielectric materials. Examples include metal oxides, oxides of metal alloys, nitrides, oxynitrides, or mixtures thereof. Examples of suitable metal oxides for the antireflective layer  33  include oxides of titanium, hafnium, zirconium, niobium, zinc, bismuth, lead, indium, tin, and/or mixtures thereof. These metal oxides can have small amounts of other materials, such as manganese in bismuth oxide, tin in indium oxide, etc. Additionally, oxides of metal alloys or metal mixtures can be used, such as oxides containing zinc and tin (e.g., zinc stannate), oxides of indium-tin alloys, silicon nitrides, silicon aluminum nitrides, or aluminum nitrides. Further, doped metal oxides, such as antimony or indium doped tin oxides or nickel or boron doped silicon oxides, can be used. 
     The antireflective layer  33  can have a thickness in the range of 5 nm to 600 nm, such as 10 nm to 500 nm, such as 20 nm to 400 nm, such as 25 nm to 300 nm, such as 25 nm to 200 nm, such as 25 nm to 100 nm. For example, such as 25 nm to 50 nm. For example, such as 30 nm to 40 nm. 
     The optional functional layer  32  can be or can include an optional external extraction layer  35 . The external extraction layer  35  can be formed by a coating, such as a metal oxide coating, having a roughened exterior surface. Examples of oxides useful for the external extraction layer  35  include silica, alumina, zinc oxide, titania, zirconia, tin oxide, and/or mixtures thereof. 
     The external extraction layer  35  can have an average surface roughness (Ra) in the range of 5 nm to 500 nm, such as 5 nm to 500 nm, such as 50 nm to 500 nm. For example, such as 50 nm to 200 nm. For example, such as 100 nm to 200 nm. 
     The external extraction layer  35  can have a root mean square roughness (Rq) in the range of 100 nm to 250 nm. For example, such as 150 nm to 200 nm. 
     The external extraction layer  35  can have a thickness in the range of 10 nm to 500 nm, such as 50 nm to 500 nm. For example, such as 100 nm to 500 nm. The external extraction layer  35  can be a single layer or optionally a multilayer coating. 
     The optional functional layer  32  can comprise both the antireflective layer  33  and the external extraction layer  35 . Alternatively, the optional functional layer  32  can comprise only one of the antireflective layer  33  and the external extraction layer  35 . Alternatively, the functional layer  32  may not be present. 
     One or more of the layers described above can be formed by any conventional coating methods. Examples include spray pyrolysis; vapor deposition, such as chemical vapor deposition (CVD), packed-bed vaporization, flat-bed vaporization, and falling film vaporization; and/or magnetron sputtered vacuum deposition (MSVD). The layers can all be formed by the same method or different layers can be formed by different methods. For example, one or more of the layers can be formed by a CVD method while one or more other layers can be formed by MSVD or spray pyrolysis, for example. 
     For example, one or more of the layers or regions can be formed in a float glass process. In another example, one or more of the layers or regions can be formed in a drawdown process. 
     In a float glass process, glass batch materials are melted in a furnace and poured onto the top of a pool of molten metal in a float bath. The glass melt spreads across the surface of the molten metal to form a glass ribbon. The glass ribbon exits the float bath and can be conveyed to a lehr for controlled cooling. One or more coaters, such as chemical vapor deposition (CVD) coaters or flame spray devices, can be located in the float bath. 
     A CVD coater  46  particularly well suited for applying volatile precursors is shown in  FIG. 2 . The coater  46  includes a plenum assembly  48  and a nozzle block  50 . The nozzle block  50  has a discharge face  51  directed toward the substrate to be coated, e.g., a glass ribbon  96 . The illustrated exemplary plenum assembly  48  has a first inlet plenum  52 , a second inlet plenum  54 , and a third inlet plenum  56 . The plenum assembly  48  has a first exhaust plenum  58  and a second exhaust plenum  60 . The exemplary nozzle block  50  is connected to the plenum assembly  48 , such as by bolts. 
     The first inlet plenum  52  is in flow communication with a first discharge channel  62  having a first discharge outlet (slot)  64 . The second inlet plenum  54  is in flow communication with a second discharge channel  66  having a second discharge outlet (slot)  68 . The third inlet plenum  56  is in flow communication with a third discharge channel  70  having a third discharge outlet (slot)  72 . Inlet mixing chambers  74  can be located in the discharge channels. 
     A first exhaust conduit  76  extends from the discharge face  51  to the first exhaust plenum  58 . A second exhaust conduit  78  extends from the discharge face  51  to the second exhaust plenum  60 . Exhaust chambers  80  can be located in the exhaust conduits  76 ,  78 . 
     In the illustrated example, the second discharge channel  66  is perpendicular to the discharge face  51  (i.e. a centerline axis of the second discharge channel  66  is perpendicular to the plane of the discharge face  51 ). However, the first discharge channel  62  and third discharge channel  70  are angled with respect to the discharge face  51 . The centerline axes of the first discharge channel  62  and the third discharge channel  70  intersect at a position below the discharge face  51 . Thus, the precursor vapors from the discharge outlets  64 ,  68 ,  72  are not mixed until after discharge from the nozzle block  50 . This is particularly useful for volatile precursors where premixing of the precursors would cause premature reaction. 
     The angle of one or more of the discharge channels  62 ,  66 ,  70  with respect to the discharge face  51  can be changed so that the centerline axes of two or more of the discharge channels  62 ,  66 ,  70  intersect at a desired location (e.g., distance from the discharge face  51  and/or location with respect to an underlying substrate). For example, different nozzle blocks  50  having different discharge channel angles can be provided. A nozzle block  50  having the desired discharge channel angles can be selected and bolted onto the plenum assembly  48 . Alternatively, the nozzle block  50  can be formed by separate sections. The first exhaust conduit  76  can be in one section, the second exhaust conduit  78  can be in another section, and the discharge channels  62 ,  66 ,  70  can be in a third section. The different sections can be individually connectable with the plenum assembly  48 . In this aspect, only the section of the nozzle block  50  with the discharge channels  62 ,  66 ,  70  would need to be replaced with a section having a desired discharge channel angle. Alternatively, the first discharge channel  62 , second discharge channel  66 , and third discharge channel  70  can be located in separate sections of the nozzle block  50  and movably connected, for example slidably connected, to the plenum assembly  48 . For example, with reference to  FIG. 2 , if the first discharge channel  62  is located in one slidable section and the third discharge channel  70  is located in a separate slidable section, sliding the slidable section containing the first discharge channel and/or the other slidable section containing the third discharge channel  70  to the left or the right with reference to  FIG. 2  would change the point of intersection of the centerlines of the discharge channels. For example, sliding the section containing the first discharge channel  62  to the left and sliding the section containing the third discharge channel  70  to the right in  FIG. 2  would increase the distance of the point of intersection with respect to the discharge face  51 . 
     The angles of the discharge channels  62  and/or  70  can be varied such that the centerline axes intersect above the surface of the substrate, e.g., glass ribbon  96 , or at the surface of the substrate, or below the surface of the substrate. If the calculated intersection is below the surface of the substrate, the vapors from the second discharge channel  66  perpendicular to the discharge face  51  form a monolayer on the glass ribbon and the material from the first discharge channel  62  and third discharge channel  70  react with it. In  FIG. 2 , the centerline axes of the discharge channels would intersect above the glass ribbon  96 . 
     A central portion of a modified nozzle block  50  of a modified coater  47  is shown in  FIG. 3 . In this modification, the first discharge outlet  64  and third discharge outlet  72  are in flow communication with the second discharge channel  66  above the discharge face  51 . Thus, the vapors from the three discharge channels mix before they are discharged from the second discharge outlet  68 . 
     A coater  46 ,  47  having multiple discharge slots is particularly useful for applying one or more of the layers described above. 
     One or more of the above-described layers can be made by selective deposition of multiple precursor materials. For example, the first conductive layer  20  can be formed using two or more different precursor materials. Tin oxide coatings made with monobutyltin trichloride (MBTC) typically provide coatings with lower haze than other tin precursors, such as tin tetrachloride (TTC). However, the deposition efficiency for TTC is better than MBTC. Also, TTC tends to produce a coating with a lower sheet resistance than a coating made from MBTC. Therefore, the first conductive layer  20  can initially be formed using MBTC (for haze) and then the precursor material switched to TTC to form the remainder of the first conductive layer  20 . The overall efficiency is increased and the resultant coating has the haze benefits of MBTC and the sheet resistance benefits of TTC. 
     For another example, the first conductive layer  20  can be formed using MBTC and dibutyltin diacetate (DBTA). Tin coatings formed with MBTC typically have a higher surface roughness than tin coatings formed with DBTA. However, DBTA has a slower deposition rate. If MBTC is mixed with DBTA, the resultant coating is smother than with MBTC alone and the deposition rate is not as low as with DBTA alone. 
     The first conductive layer  20  can be formed having multiple layers and or regions. For example, a first region of the first conductive layer  20  can be formed using a tin precursor and a tungsten precursor to provide a tungsten doped tin oxide coating. For example, the tin precursor can be MBTC or TTC. The tungsten precursor can be tungsten tetrachloride. For example, a second region of the first conductive layer  20  can then be deposited using a tin precursor and a fluorine precursor to provide a fluorine doped tin oxide region. 
     The buffer layer  42  can be made using a tin precursor and a precursor for zinc or magnesium. For example, the tin precursor can be MBTC or TTC. The zinc precursor can be diethylzinc (DEZ), dimethyl zinc (DMZ), zincacetyl acetate, or alkzinc alkoxide. The magnesium precursor can be bis(cyclopentadienyl)magnesium. For example, the buffer layer  42  can be made using magnesium chloride mixed with MBTC. 
     The invention is not limited to the float glass process. One or more of the layers can be formed using a glass drawdown manufacturing process. In a drawdown process, molten glass is located in a receiver. The molten glass flows out of the receiver and forms a glass ribbon, which moves downwardly under the influence of gravity. Examples of drawdown processes include a slot drawdown process and a fusion drawdown process. In a slot drawdown process, the receiver is an elongated trough having an open discharge slot in the bottom of the trough. Molten glass flows through the discharge slot to form the glass ribbon. In a fusion drawdown process, the receiver is a trough with an open top. Molten glass flows out of the top of the trough, down the opposed outer sides of the trough, and forms a glass ribbon under the trough.  FIG. 4 . illustrates a drawdown assembly  81  configured as a fusion drawdown assembly. However, the drawdown assembly  81  could also be illustrated as a slot drawdown assembly. 
     In the exemplary fusion drawdown process illustrated in  FIG. 4 , molten glass  82  is located in a receiver  83  in the form of a forming trough  86  having a channel  84  and opposed sides  88 ,  90 . The molten glass  82  overflows the channel  84  and forms two glass films  92 ,  94  that flow downwardly along the outer surfaces of the sides  88 ,  90 , respectively, and join together under the trough  86  to form a glass ribbon  96 . The glass ribbon  96  moves downwardly under the force of gravity. The vertical plane along which the glass ribbon  96  moves defines the glass ribbon path  98  for the drawdown process. The glass ribbon path  98  has a first side  106  and a second side  108 , defining a first side  114  and a second side  116  of the glass ribbon  96 , respectively. As discussed above, in a slot drawdown process, the receiver  83  would be in the form of an elongated trough having a slot in the bottom of the trough through which the glass ribbon  96  emerges. 
     One or more coaters are located adjacent the glass ribbon  96  (i.e. adjacent the glass ribbon path  98 ). The coaters can be, for example, CVD coaters and/or spray coaters and/or flame spray coaters and/or vapor coaters. In the illustrated example, at least one coater  100  is located adjacent the second side  116  of the glass ribbon. Optionally, at least one other coater  102  can be located adjacent the first side  114  of the glass ribbon  96 . Thus, one or more of any of the above-described layers can be formed on one or both surfaces of the glass ribbon  96 . For example, the coaters  100 ,  102  can be conventional CVD coaters. For example, one or more of the coaters  100 ,  102  can be the coater  46  or the coater  47  described above. 
     As shown in  FIG. 1 , the substrate  12  can include an optional internal light extraction region  34 . The internal light extraction region  34  can be formed by nanoparticles  40  incorporated on the second surface  16  of the substrate  12  and/or embedded in or incorporated into a region of the glass adjacent the second surface  16 . Examples of suitable nanoparticles  40  include, but are not limited to, oxide nanoparticles. For example but not limited to alumina, titania, cerium oxide, zinc oxide, tin oxide, silica, and zirconia. Other examples include metallic nanoparticles. For example but not limited to iron, steel, copper, silver, gold, and titanium. Further examples include alloy nanoparticles containing alloys of two or more materials. Additional examples include sulfide-containing nanoparticles and nitride-containing nanoparticles. These nanoparticles can be incorporated into the substrate  12  (e.g., glass ribbon  96 ) at a depth in the range of 0 microns to 50 microns, such as 0 microns to 10 microns, such as 0 micron to 5 microns. For example, such as 0 microns to 3 microns. 
     The nanoparticles can be incorporated onto and/or into the substrate  12  by propelling the nanoparticles from a coater toward the substrate  12 . For example, in a float glass process, a flame spray device (or combustion deposition device) can be mounted in the float chamber upstream of the CVD coater in the float process described above. A suitable flame spray device is commercially available from Beneq-Oy Vantaa, Finland. Another suitable flame spray device is described in WO 01/28941. In the flame spray device, coating materials are atomized, combusted, and then sprayed directly onto the hot glass ribbon. The particles are formed on and/or diffused into the surface of the ribbon or penetrate the surface and are incorporated into the upper portion of the glass ribbon. These particles, such as metal oxide nanoparticles, are present on the surface of the glass or are diffused into the glass and react with the glass matrix. This process can be practiced at any suitable place in the float chamber but is believed to be more practical at locations where the temperature of the glass ribbon is in the range of 400° C. to 1,000° C., such as 500° C. to 900° C., such as 500° C. to 800° C., such as 600° C. to 800° C. For example, such as 700° C. to 800° C. After deposition of the nanoparticles on and/or in the surface, the glass ribbon can move under the CVD coater for the application of one or more coating layers described above. 
     In the drawdown process illustrated in  FIG. 4 , one or more flame spray devices  104  can be located adjacent the glass ribbon path  98 . For example, the flame spray device(s)  104  can be located upstream of (i.e., above) one or both of the coaters  100 ,  102 . The nanoparticles  40  can be deposited onto and/or into one or both sides  114 ,  116  of the glass ribbon  96 . Subsequently, one or more of the coating layers described above can be applied over one or both sides  114 ,  116  of the glass ribbon  96  by the coaters  100 ,  102 . For example, the flame spray device  104  can deposit nanoparticles  40  onto and/or into the second side  116  of the glass ribbon  96  (e.g., corresponding to the second surface  16  of the substrate  12 ). Subsequently, one or more coaters  100  can apply one or more of the underlayer  18 , and/or first conductive layer  20 , and/or overlayer  22 , and/or semiconductor layer  24 , and/or second conductive layer  26  over the second side  116  of the glass ribbon  96 . One or more second coaters  102  can apply the optional functional layer  32  over the first side  114  of the glass ribbon  96 . 
     The nanoparticles can be produced by any conventional method. In one specific example, a liquid precursor can be heated in a vaporizer to form a vapor. The vapor can be directed to a reaction zone to form the desired nanoparticles. Examples of liquid reactant vaporizers are disclosed in U.S. Pat. Nos. 4,924,936, 5,356,451 and 7,730,747. For example, a metal chloride, such as titanium tetrachloride, can be heated in a vaporizer to form a precursor vapor. The vapor can be directed to an applicator or a collector. For example, the vaporizer can be connected to a flame spray device. The titanium tetrachloride vapor can be hydrolyzed or oxidized to form titanium dioxide nanoparticles. Other precursors, such as organometallic compounds, can be used. Titanium isopropoxide is an example of another material that can be vaporized to form titanium dioxide nanoparticles. The precursor stream may be composed of one, two or more liquid reactant materials of different compositions so as to form nanoparticles having a pure composition, a composition with mixed phases and/or compositions, or homogeneous alloys of a single or multiple phases. As will be appreciated by one skilled in the art, the liquid reactant materials can be supplied in various ratios to form nanoparticles of a desired composition. Further, one or more precursors may be supplied from a gaseous source to form nanoparticles of a desired composition. Examples of this include supplying hydrogen sulfide as a sulfur containing precursor to form a sulfide containing nanoparticle, or supplying ammonia (NH3) to form a nitride containing nanoparticle. 
     The invention can be described further in the following numbered clauses: 
     Clause 1: An article, for example a solar cell  10 , comprising: a first substrate  12  having a first surface  14  and a second surface  16 ; an underlayer  18  located over the second surface  16 ; a first conductive layer  20  over the underlayer  18 ; an overlayer  22  over the first conductive layer  20 ; a semiconductor layer  24  over the first conductive layer  20 ; and a second conductive layer  26  over the semiconductor layer  24 . The first conductive layer  20  comprises a conductive oxide and at least one dopant selected from the group consisting of tungsten, molybdenum, niobium, and/or fluorine. 
     Clause 2: The article of clause 1, wherein the first substrate  12  comprises low iron glass. 
     Clause 3: The article of clauses 1 or 2, wherein the underlayer  18  comprises a sodium ion barrier layer  38  comprising silicon oxide. 
     Clause 4: The article of any of clauses 1 to 3, wherein the underlayer  18  comprises a bottom optical layer  36  comprising an oxide of tin, zinc, silicon, aluminum, titanium, and/or mixtures thereof. 
     Clause 5: The article of any of clauses 1 to 4, wherein the underlayer  18  comprises a sodium barrier layer  38  comprising silicon oxide and a bottom optical layer  36  comprising oxides of tin and zinc. 
     Clause 6: The article of any of clauses 1 to 5, wherein the first conductive layer  20  comprises tin oxide and tungsten. 
     Clause 7: The article of any of clauses 1 to 6, wherein the first conductive layer  20  comprises a first layer comprising tin oxide and tungsten, and a second layer comprising tin oxide and fluorine. 
     Clause 8: The article of any of clauses 1 to 7, wherein the overlayer  22  comprises a buffer layer  42  comprising tin oxide and at least one of zinc, indium, gallium, magnesium, and nitrogen. 
     Clause 9: The article of any of clauses 1 to 8, wherein the overlayer  22  comprises a buffer layer  42  comprising tin oxide and zinc. 
     Clause 10: The article of any of clauses 1 to 9, wherein the overlayer  22  comprises an insulating layer  44  comprising cadmium sulfide and/or cadmium sulfate. 
     Clause 11: The article of any of clauses 1 to 10, wherein the overlayer  22  comprises a buffer layer  42  comprising tin oxide and zinc and/or magnesium, and an insulating layer  44  comprising cadmium sulfide and/or cadmium sulfate. 
     Clause 12: The article of any of clauses 1 to 11, wherein the semiconductor layer  24  comprises cadmium telluride. 
     Clause 13: The article of any of clauses 1 to 12, wherein the second conductive layer  26  comprises a metallic layer. 
     Clause 14: The article of any of clauses 1 to 13, wherein the second conductive layer  26  comprises silver. 
     Clause 15: The article of any of clauses 1 to 14, including a second substrate  28  over the second conductive layer  26 , wherein the second substrate  28  comprises glass. 
     Clause 16: The article of any of clauses 1 to 15, including an internal light extraction region  34  in and/or on the second surface  16  of the first substrate  12 . The internal light extraction region  34  can comprise nanoparticles. 
     Clause 17: The article of any of clauses 1 to 16, including a functional layer  32  over the first surface  14  of the first substrate  12 , wherein the functional layer  32  is selected from the group consisting of an antireflective layer  33  and an external light extraction layer  35 . 
     Clause 18: The article of clause 17, wherein the antireflective layer  33  comprises an oxide of a material selected from the group consisting of titanium, zirconium, zinc, tin, and mixtures thereof. 
     Clause 19: The article of clauses 17 or 18, wherein the external light extraction layer  35  is selected from the group consisting of silica, alumina, zinc oxide, titania, zirconia, tin oxide, and mixtures thereof. 
     Clause 20: The article of any of clauses 1 to 19, wherein the first conductive layer  20  comprises a first region deposited from a first precursor material and a second region deposited from a second precursor material. 
     Clause 21: The article of clause 20, wherein the first precursor material comprises MBTC and the second precursor material is selected from the group consisting of TTC and DBTA. 
     Clause 22: A transparent conductive oxide layer  20  for an article, for example a solar cell  10 , comprising a tin oxide and tungsten, preferably tungsten doped tin oxide. 
     Clause 23: A vapor deposition coater  46 ,  47  comprising: a plenum assembly  48  comprising at least one inlet plenum  52 ,  54 ,  56  and at least one exhaust plenum  58 ,  60 ; and a nozzle block  50  comprising a discharge face  51 , at least one discharge channel  62 ,  66 ,  70  in flow communication with the at least one inlet plenum  52 ,  54 ,  56 , and at least one exhaust conduit  76  in flow communication with the at least one exhaust plenum  58 ,  60 . The at least one discharge channel  62 ,  66 ,  70  is angled with respect to the discharge face  51  of the nozzle block  50 . 
     Clause 24: The vapor deposition coater  46 ,  47  of clause 23, wherein the at least one exhaust conduit  76  is angled with respect to the discharge face  51 . 
     Clause 25: The vapor deposition coater  46 ,  47  of clauses 23 or 24, including a first inlet plenum  52  in flow communication with a first discharge channel  62 , a second inlet plenum  54  in flow communication with a second discharge channel  66 , and a third inlet plenum  56  in flow communication with a third discharge channel  70 , wherein at least one of the discharge channels  62 ,  66 ,  70  is angled with respect to the discharge face  51  and at least one of the discharge channels  62 ,  66 ,  70  is perpendicular to the discharge face  51 . 
     Clause 26: The vapor deposition coater  46 ,  47  of any of clauses 23 to 25, including a first exhaust plenum  58  in flow communication with a first exhaust conduit  76  and a second exhaust plenum  60  in flow communication with a second exhaust conduit  78 , wherein the first exhaust conduit  76  and the second exhaust conduit  78  are angled with respect to the discharge face  51 . 
     Clause 27: The vapor deposition coater  46 ,  47  of any of clauses 23 to 26, including at least one mixing chamber  74  located in the discharge channels  62 ,  66   70  between the inlet plenums  52 ,  54 ,  56  and the discharge face  51 . 
     Clause 28: The vapor deposition coater  46 ,  47  of any of clauses 23 to 27, including at least one exhaust chamber  80  located in the exhaust conduits  76 ,  78  between the exhaust plenum  58 ,  60  and the discharge face  52 . 
     Clause 29: The vapor deposition coater  46 ,  47  of clause 25, wherein the first discharge channel  62  has a first discharge outlet  64 , the second discharge channel  66  has a second discharge outlet  68 , and the third discharge channel  70  has a third discharge outlet  72 , wherein the first discharge outlet  64 , the second discharge outlet  68 , and the third discharge outlet  72  are located on the discharge face  51 . 
     Clause 30: The vapor deposition coater  46 ,  47  of clause 25, wherein the first discharge channel  62  has a first discharge outlet  64 , the second discharge channel  66  has a second discharge outlet  68 , and the third discharge channel  70  has a third discharge outlet  72 , wherein the second discharge outlet  68  is located on the discharge face  51 , and wherein the first discharge outlet  64  and the third discharge outlet  72  are in flow communication with the second discharge channel  66  at a distance from the discharge face  51 , for example, above the discharge face  51 . 
     Clause 31: The vapor deposition coater  46 ,  47  of any of clauses 23 to 30, wherein the angle of at least one discharge channel  62 ,  66 ,  70  is adjustable with respect to the discharge face  51 . 
     Clause 32: A method of forming a coating on a glass substrate, such as a glass ribbon  96 , in a glass manufacturing process, comprising: providing a first coating precursor material to a first inlet plenum  52  of a vapor deposition coater  46 ,  47  having a discharge face  51 , wherein the first inlet plenum  52  is in flow communication with a first discharge channel  62 , and wherein the first discharge channel  62  defines a first discharge path; and providing a second coating precursor material to a second inlet plenum  54  of the vapor deposition coater  46 ,  47 , wherein the second inlet plenum  54  is in flow communication with a second discharge channel  70 , and wherein the second discharge channel  70  defines a second discharge path; wherein the first discharge path intersects the second discharge path at a position selected from (a) above a surface of a glass ribbon  96  or (b) at a surface of a glass ribbon  96  or (c) below a surface of a glass ribbon  96 . 
     Clause 33: A drawdown assembly  81 , comprising: a receiver  83 ; and at least one vapor coater  100 ,  102  located adjacent a first side  106  and/or a second side  108  of a glass ribbon path  98 . For example, the receiver can comprise a forming trough  86  or an elongated trough having a discharge slot. 
     Clause 34: The drawdown assembly  81  of clause 33, including at least one flame spray device  104  located adjacent the first side  106  and/or second side  108  of the glass ribbon path  98 . 
     Clause 35: The drawdown assembly  81  of clauses 33 or 34, including a vapor coater  100  located on the second side  108 , another vapor coater  102  located on the first side  106 , and a flame spray device  104  located upstream of the vapor coater  100  on the first side  106 . 
     Clause 36: A method of forming a coated glass article in a drawdown process, comprising: locating at least one coater  100 ,  104  adjacent a second side  108  of a glass ribbon path  98 ; locating at least one other coater  102  adjacent a first side  106  of the glass ribbon path  98 ; and using the coaters  100 ,  102 ,  104  to apply at least one coating on at least one of the opposed sides of a glass ribbon  96 . 
     Clause 37: The method of clause 36, wherein the at least one coater  100 ,  104  comprises a chemical vapor deposition coater  100 . 
     Clause 38: The method of clauses 36 or 37, wherein the at least one other coater  102  comprises a chemical vapor deposition coater. 
     Clause 39: The method of any of clauses 36 to 38, further including at least one flame spray coater  104  located on the second side  108 , and, optionally, at least one flame spray coater  104  located on the first side  106 . 
     Clause 40: The method of any of clauses 36 to 39, wherein the at least one coater  100 ,  102 ,  104  comprises a flame spray device  104  located upstream of a chemical vapor deposition coater  100 . 
     Clause 41: A double sided coated article  110  formed by a drawdown process, comprising: a glass substrate  12  having a first surface  14  and an opposed second surface  16 ; a second coating  120  formed over the second surface  16  by a first chemical vapor deposition coater  100  adjacent the first surface  114 ; and a first coating  118  formed over the first surface  114  by another chemical vapor deposition coater  102  adjacent the first surface  114 . 
     Clause 42: A buffer layer  42  for a solar cell  10 , comprising: tin oxide and at least one of zinc, indium, gallium, and magnesium. 
     Clause 43: The buffer layer  42  of clause 42, wherein the buffer layer  42  comprises tin oxide and zinc. 
     Clause 44: The buffer layer  42  of clause 42, wherein the buffer layer  42  comprises tin oxide and magnesium. 
     Clause 45: An article, for example a solar cell  10 , comprising: a first substrate  12  having a first surface  14  and a second surface  16 : an underlayer  18  located over the second surface  16 ; a first conductive layer  20  over the underlayer  18 ; an overlayer  22  over the first conductive layer  20 ; a semiconductor layer  24  over the first conductive layer  20 ; and a second conductive layer  26  over the semiconductor layer  24 . The overlayer  18  comprises a buffer layer  42  comprising tin oxide and at least one of zinc, indium, gallium, and magnesium. 
     Clause 46: The solar cell  10  of clause 45, wherein the buffer layer comprises tin oxide and zinc. 
     Clause 47: The article of clause 45, wherein the buffer layer  42  comprises tin oxide and magnesium. 
     Clause 48: The article of any of clauses 45 to 47, including a functional layer  32  over the first surface  14  of the substrate  12 , wherein the functional layer  32  is selected from the group consisting of an antireflective layer  33  and an external light extraction layer  35 . 
     Clause 49: The article of any of clauses 45 to 48, wherein at least one layer over the first surface  14  and at least one layer over the second surface  16  are formed in a glass drawdown process having at least one coater  100 ,  102 ,  104  located on opposed sides of a glass ribbon path  98 . 
     Clause 50: The article of any of clauses 45 to 49, wherein the first conductive layer  20  comprises a conductive oxide and at least one dopant selected from the group consisting of tungsten, molybdenum, niobium, and/or fluorine. 
     Clause 51: The article of any of clauses 45 to 50, wherein the first substrate  12  comprises low iron glass. 
     Clause 52: The article of any of clauses 45 to 51, wherein the underlayer  18  comprises a sodium ion barrier layer  38  comprising silicon oxide. 
     Clause 53: The article of any of clauses 45 to 52, wherein the underlayer  18  comprises a bottom optical layer  36  comprising an oxide of tin, zinc, silicon, aluminum, titanium, and/or mixtures thereof. 
     Clause 54: The article of any of clauses 45 to 53, wherein the underlayer  18  comprises a sodium barrier layer  38  comprising silicon oxide and a bottom optical layer  36  comprising oxides of tin and zinc. 
     Clause 55: The article of any of clauses 45 to 54, wherein the first conductive layer  20  comprises tin oxide and tungsten. 
     Clause 56: The article of any of clauses 45 to 55, wherein the first conductive layer  20  comprises a first layer comprising tin oxide and tungsten, and a second layer comprising tin oxide and fluorine. 
     Clause 57: The article of any of clauses 45 to 56, wherein the overlayer  22  comprises an insulating layer  44  comprising cadmium sulfide and/or cadmium sulfate. 
     Clause 58: The article of any of clauses 45 to 57, wherein the overlayer  22  comprises a buffer layer  42  comprising tin oxide and zinc and/or magnesium, and an insulating layer  44  comprising cadmium sulfide and/or cadmium sulfate. 
     Clause 59: The article of any of clauses 45 to 58, wherein the semiconductor layer  24  comprises cadmium telluride. 
     Clause 60: The article of any of clauses 45 to 59, wherein the second conductive layer  26  comprises a metallic layer. 
     Clause 61: The article of any of clauses 45 to 60, wherein the second conductive layer  26  comprises silver. 
     Clause 62: The article of any of clauses 45 to 61, including a second substrate  28  over the second conductive layer  26 , wherein the second substrate  28  comprises glass. 
     Clause 63: The article of any of clauses 45 to 62, including an internal light extraction region  34  in and/or on the second surface  16  of the substrate  12 , wherein the internal light extraction region  34  comprises nanoparticles  40 . 
     Clause 64: The article of any of clauses 45 to 63, including a functional layer  32  over the first surface  14  of the substrate  12 , wherein the functional layer  32  is selected from the group consisting of an antireflective layer  33  and an external light extraction layer  35 . 
     Clause 65: The article of clause 64, wherein the antireflective layer  33  comprises an oxide of a material selected from the group consisting of titanium, zirconium, zinc, tin, and mixtures thereof. 
     Clause 66: The article of clauses 64 or 65, wherein the external light extraction layer  35  is selected from the group consisting of silica, alumina, zinc oxide, titania, zirconia, tin oxide, and mixtures thereof. 
     Clause 67: The article of any of clauses 45 to 66, wherein the first conductive layer  20  comprises a first region deposited from a first precursor material and a second region deposited from a second precursor material. 
     Clause 68: The article of clause 67, wherein the first precursor material comprises MBTC and the second precursor material is selected from the group consisting of TTC and DBTA. 
     Clause 69: A transparent conductive oxide layer  20  for an electronic device, comprising: a tin oxide layer doped with a material selected from the group consisting of tungsten, molybdenum, and niobium. 
     Clause 70: The transparent conductive oxide layer  20  of clause 69, wherein the transparent conductive oxide layer  20  comprises tin oxide and tungsten. 
     Clause 71: The transparent conductive oxide layer  20  of clauses 69 or 70, wherein the electronic device is selected from the group consisting of a solar cell, a photovoltaic cell, an organic light emitting diode, and a light emitting diode. 
     Clause 72: A coated article  110 , comprising: a first substrate  12  having a first surface  14  and a second surface  16 ; a first coating  118  over the first surface  14 ; and a second coating  120  over the second surface  16 . The second coating  120  comprises a first conductive layer  20  comprising tin oxide doped with a material selected from the group consisting of tungsten, molybdenum, and niobium. 
     Clause 73: The coated article  110  of clause 72, wherein the first conductive layer  20  comprises tin oxide doped with tungsten. 
     Clause 74: The coated article  110  of clauses 72 or 73, wherein at least one layer over the first surface  14  and at least one layer over the second surface  16  are formed in a glass drawdown process having at least one coater  100 ,  102 ,  104  on opposed sides of a glass ribbon path  98 . 
     Clause 75: The coated article  110  of any of clauses 72 to 74, wherein the coated article  110  is selected from the group consisting of a solar cell, a photovoltaic cell, an organic light emitting diode, and a light emitting diode. 
     Clause 76: The coated article  110  of any of clauses 72 to 75, wherein the second coating  120  comprises: an underlayer  18  located over the second surface  116 ; the first conductive layer  20  over the underlayer  18 ; an overlayer  22  over the first conductive layer  20 ; a semiconductor layer  24  over the first conductive layer  20 ; and a second conductive layer  26  over the semiconductor layer  24 . 
     Clause 77: The coated article  110  of clause 76, wherein the first substrate  12  comprises low iron glass. 
     Clause 78: The coated article  110  of clauses 76 or 77, wherein the underlayer  18  comprises a sodium ion barrier layer  38  comprising silicon oxide. 
     Clause 79: The coated article  110  of any of clauses 76 to 78, wherein the underlayer  18  comprises a bottom optical layer  36  comprising an oxide of tin, zinc, silicon, aluminum, titanium, and/or mixtures thereof. 
     Clause 80: The coated article  110  of any of clauses 76 to 79, wherein the underlayer  18  comprises a sodium barrier layer  38  comprising silicon oxide and a bottom optical layer  36  comprising oxides of tin and zinc. 
     Clause 81: The coated article  110  of any of clauses 76 to 80, wherein the first conductive layer  20  comprises tin oxide and tungsten. 
     Clause 82: The coated article  110  of any of clauses 76 to 81, wherein the first conductive layer  20  comprises a first layer comprising tin oxide and tungsten, and a second layer comprising tin oxide and fluorine. 
     Clause 83: The coated article  110  of any of clauses 76 to 82, wherein the overlayer  22  comprises a buffer layer  42  comprising tin oxide and at least one of zinc, indium, gallium, magnesium, and nitrogen. 
     Clause 84: The coated article  110  of any of clauses 76 to 83, wherein the overlayer  22  comprises a buffer layer  42  comprising tin oxide and zinc. 
     Clause 85: The coated article  110  of any of clauses 76 to 84, wherein the overlayer  22  comprises an insulating layer  44  comprising cadmium sulfide and/or cadmium sulfate. 
     Clause 86: The coated article  110  of any of clauses 76 to 85, wherein the overlayer  22  comprises a buffer layer  42  comprising tin oxide and zinc and/or magnesium, and an insulating layer  44  comprising cadmium sulfide and/or cadmium sulfate. 
     Clause 87: The coated article  110  of any of clauses 76 to 86, wherein the semiconductor layer  24  comprises cadmium telluride. 
     Clause 88: The coated article  110  of any of clauses 76 to 87, wherein the second conductive layer  26  comprises a metallic layer. 
     Clause 89: The coated article  110  of any of clauses 76 to 88, wherein the second conductive layer  26  comprises silver. 
     Clause 90: The coated article  110  of any of clauses 76 to 89, including a second substrate  28  over the second conductive layer  26 , wherein the second substrate  28  comprises glass. 
     Clause 91: The coated article  110  of any of clauses 76 to 90, including an internal light extraction region  34  in and/or on the second surface  16  of the substrate  12 , wherein the internal light extraction region  34  comprises nanoparticles  40 . 
     Clause 92: The coated article  110  of any of clauses 76 to 91, including a functional layer  32  over the first surface  14  of the substrate  12 , wherein the functional layer  32  is selected from the group consisting of an antireflective layer  33  and an external light extraction layer  35 . 
     Clause 93: The coated article  110  of clause 92, wherein the antireflective layer  33  comprises an oxide of a material selected from the group consisting of titanium, zirconium, zinc, tin, and mixtures thereof. 
     Clause 94: The coated article  110  of clauses 92 or 93, wherein the external light extraction layer  35  is selected from the group consisting of silica, alumina, zinc oxide, titania, zirconia, tin oxide, and mixtures thereof. 
     Clause 95: The coated article  110  of any of clauses 76 to 94, wherein the first conductive layer  20  comprises a first region deposited from a first precursor material and a second region deposited from a second precursor material. 
     Clause 96: The coated article  110  of clause 95, wherein the first precursor material comprises MBTC and the second precursor material is selected from the group consisting of TTC and DBTA. 
     Clause 97: A method of making a making an article  110 , such as a solar cell  10 , in a glass drawdown process, comprising: locating at least one coater  100 ,  104  adjacent a second side  108  of a glass ribbon path  98 ; optionally, locating at least one other coater  102 ,  104  adjacent a first side  106  of the glass ribbon path  98 ; and applying a second coating over a second surface  116  of a glass ribbon  96 , wherein the second coating comprises at least one of (i) a buffer layer  42  comprising tin oxide and at least one material selected from the group consisting of zinc, indium, gallium, and magnesium, and (ii) a transparent conductive oxide layer  20  comprising tin oxide doped with a material selected from the group consisting of tungsten, molybdenum, and niobium. 
     Clause 98: The method of clause 97, wherein the buffer layer  42  comprises tin oxide and zinc. 
     Clause 99: The method of clause 97, wherein the buffer layer  42  comprises tin oxide and magnesium. 
     Clause 100: The method of any of clauses 97 to 99, wherein the transparent conductive oxide layer  20  comprises tin oxide doped with tungsten. 
     Clause 101: A vapor deposition coater  46 ,  47 , comprising: a nozzle block  50  comprising a discharge face  51 , at least one discharge channel  62 ,  66 ,  70  in flow communication with at least one inlet plenum  52 ,  54 ,  56 . An angle of the at least one discharge channel  62 ,  66 ,  70  is adjustable with respect to the discharge face  51 . 
     Clause 102: The vapor deposition coater  46 ,  47  of clause 101, including a first discharge channel  62 , a second discharge channel  66 , and a third discharge channel  70 , wherein at least one of the discharge channels  62 ,  66 ,  70  is angled with respect to the discharge face  51  and at least one of the discharge channels  62 ,  66 ,  70  is perpendicular to the discharge face  51 . 
     Clause 103: The vapor deposition coater  46 ,  47  of clauses 101 or 102, wherein the first discharge channel  62  has a first discharge outlet  64 , the second discharge channel  66  has a second discharge outlet  68 , and the third discharge channel  70  has a third discharge outlet  72 , wherein the first discharge outlet  64 , the second discharge outlet  66 , and the third discharge outlet  72  are located on the discharge face  51 . 
     Clause 104: The vapor deposition coater  46 ,  47  of clauses 101 or 102, wherein the first discharge channel  62  has a first discharge outlet  64 , the second discharge channel  66  has a second discharge outlet  68 , and the third discharge channel  70  has a third discharge outlet  72 , wherein the second discharge outlet  68  is located on the discharge face  51 , and wherein the first discharge outlet  64  and the third discharge outlet  72  are in flow communication with the second discharge channel  66  above the discharge face  51 . 
     Clause 105: A method of forming a coating layer on a glass substrate in a glass manufacturing process, comprising: providing a first coating precursor material for a selected coating layer composition to at least one multislot coater  46 ,  47  to form a first coating region of the selected coating layer; and providing a second coating precursor material for the selected coating layer composition to at least one multislot coater  46 ,  47  to form a second coating region of the selected coating layer over the first region. The first coating precursor material is different than the second precursor coating material. 
     Clause 106: The method of clause 105, wherein the glass manufacturing process is a float glass process and the at least one multislot coater  46 ,  47  is located in a float bath. 
     Clause 107: The method of clause 105, wherein the glass manufacturing process is a glass drawdown process and the at least one multislot coater  46 ,  47  is located adjacent a glass ribbon path  98 . 
     Clause 108: The method of clause 107, wherein the glass manufacturing process is a glass drawdown process having a glass ribbon path  98  comprising a first side  106  and a second side  108 , wherein at least one multislot coater  100  is located adjacent the first side  106  of the glass ribbon path  98 , and wherein at least one other multislot coater  102  is located adjacent the second side  108  of the glass ribbon path  98 . 
     Clause 109: The method of clause 107, wherein the glass manufacturing process is a glass drawdown process having a glass ribbon path  98  comprising a first side  106  and a second side  108 , wherein at least one multislot coater  100  is located adjacent the second side  108  of the glass ribbon path  98 , and wherein at least one other multislot coater  102  is located adjacent the first side  106  of the glass ribbon path  98 . 
     Clause 110: A method of forming a coating on a glass substrate in a glass manufacturing process, comprising: providing a first coating precursor material to a first discharge channel  62 ,  66 ,  70  having a first discharge path; and providing a second coating precursor material to a second discharge channel  62 ,  66 ,  70  having a second discharge path. The first discharge path intersects the second discharge path at a position selected from (a) above a surface of a glass ribbon  96  or (b) at a surface of a glass ribbon  96  or (c) below a surface of a glass ribbon  96 . 
     It will be readily appreciated by those skilled in the art that modifications may be made to the invention without departing from the concepts disclosed in the foregoing description. Accordingly, the particular embodiments described in detail herein are illustrative only and are not limiting to the scope of the invention, which is to be given the full breadth of the appended claims and any and all equivalents thereof.