WO2008063305A2 - Front electrode for use in photovoltaic device and method of making same - Google Patents
Front electrode for use in photovoltaic device and method of making same Download PDFInfo
- Publication number
- WO2008063305A2 WO2008063305A2 PCT/US2007/021693 US2007021693W WO2008063305A2 WO 2008063305 A2 WO2008063305 A2 WO 2008063305A2 US 2007021693 W US2007021693 W US 2007021693W WO 2008063305 A2 WO2008063305 A2 WO 2008063305A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- layer
- photovoltaic device
- oxide
- tco
- film
- Prior art date
Links
- 238000004519 manufacturing process Methods 0.000 title description 7
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims abstract description 88
- 239000011787 zinc oxide Substances 0.000 claims abstract description 44
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 claims abstract description 33
- 229910001887 tin oxide Inorganic materials 0.000 claims abstract description 33
- 229910052709 silver Inorganic materials 0.000 claims abstract description 26
- 239000004332 silver Substances 0.000 claims abstract description 26
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052737 gold Inorganic materials 0.000 claims abstract description 8
- 239000010931 gold Substances 0.000 claims abstract description 8
- 239000000758 substrate Substances 0.000 claims description 71
- 239000004065 semiconductor Substances 0.000 claims description 67
- 239000011521 glass Substances 0.000 claims description 47
- 229910021417 amorphous silicon Inorganic materials 0.000 claims description 19
- 229910044991 metal oxide Inorganic materials 0.000 claims description 17
- 150000004706 metal oxides Chemical class 0.000 claims description 17
- JYMITAMFTJDTAE-UHFFFAOYSA-N aluminum zinc oxygen(2-) Chemical compound [O-2].[Al+3].[Zn+2] JYMITAMFTJDTAE-UHFFFAOYSA-N 0.000 claims description 16
- 230000005540 biological transmission Effects 0.000 claims description 15
- AMGQUBHHOARCQH-UHFFFAOYSA-N indium;oxotin Chemical compound [In].[Sn]=O AMGQUBHHOARCQH-UHFFFAOYSA-N 0.000 claims description 12
- 229910004613 CdTe Inorganic materials 0.000 claims description 11
- YVTHLONGBIQYBO-UHFFFAOYSA-N zinc indium(3+) oxygen(2-) Chemical compound [O--].[Zn++].[In+3] YVTHLONGBIQYBO-UHFFFAOYSA-N 0.000 claims description 11
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 7
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 7
- 239000010936 titanium Substances 0.000 claims description 7
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 6
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 6
- 229910052710 silicon Inorganic materials 0.000 claims description 6
- 239000010703 silicon Substances 0.000 claims description 6
- 229910052719 titanium Inorganic materials 0.000 claims description 6
- 229910052782 aluminium Inorganic materials 0.000 claims description 5
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 5
- 229910052814 silicon oxide Inorganic materials 0.000 claims description 4
- 230000003647 oxidation Effects 0.000 claims description 3
- 238000007254 oxidation reaction Methods 0.000 claims description 3
- 229910052758 niobium Inorganic materials 0.000 claims description 2
- 239000010955 niobium Substances 0.000 claims description 2
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims description 2
- 239000000463 material Substances 0.000 abstract description 28
- 238000000576 coating method Methods 0.000 abstract description 15
- 239000011248 coating agent Substances 0.000 abstract description 13
- 229910052751 metal Inorganic materials 0.000 abstract description 5
- 239000002184 metal Substances 0.000 abstract description 5
- -1 ITO Chemical compound 0.000 abstract description 4
- 239000010410 layer Substances 0.000 description 208
- 239000010408 film Substances 0.000 description 40
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 18
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 11
- 230000005855 radiation Effects 0.000 description 11
- 238000000034 method Methods 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 9
- 239000010409 thin film Substances 0.000 description 8
- 238000000411 transmission spectrum Methods 0.000 description 7
- 239000000853 adhesive Substances 0.000 description 6
- 230000001070 adhesive effect Effects 0.000 description 6
- XXLJGBGJDROPKW-UHFFFAOYSA-N antimony;oxotin Chemical compound [Sb].[Sn]=O XXLJGBGJDROPKW-UHFFFAOYSA-N 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 230000003667 anti-reflective effect Effects 0.000 description 5
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 239000011651 chromium Substances 0.000 description 4
- BFMKFCLXZSUVPI-UHFFFAOYSA-N ethyl but-3-enoate Chemical compound CCOC(=O)CC=C BFMKFCLXZSUVPI-UHFFFAOYSA-N 0.000 description 4
- KYKLWYKWCAYAJY-UHFFFAOYSA-N oxotin;zinc Chemical compound [Zn].[Sn]=O KYKLWYKWCAYAJY-UHFFFAOYSA-N 0.000 description 4
- 229920003023 plastic Polymers 0.000 description 4
- 239000004033 plastic Substances 0.000 description 4
- 229910052708 sodium Inorganic materials 0.000 description 4
- 239000011734 sodium Substances 0.000 description 4
- 239000008393 encapsulating agent Substances 0.000 description 3
- 238000004544 sputter deposition Methods 0.000 description 3
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 3
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 description 2
- LEVVHYCKPQWKOP-UHFFFAOYSA-N [Si].[Ge] Chemical compound [Si].[Ge] LEVVHYCKPQWKOP-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 229910052787 antimony Inorganic materials 0.000 description 2
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 239000003989 dielectric material Substances 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 229910052738 indium Inorganic materials 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 229910021424 microcrystalline silicon Inorganic materials 0.000 description 2
- 150000004767 nitrides Chemical class 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000002356 single layer Substances 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 229910052718 tin Inorganic materials 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 229920006355 Tefzel Polymers 0.000 description 1
- 229910003087 TiOx Inorganic materials 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- JCXGWMGPZLAOME-UHFFFAOYSA-N bismuth atom Chemical compound [Bi] JCXGWMGPZLAOME-UHFFFAOYSA-N 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000002019 doping agent Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- QHSJIZLJUFMIFP-UHFFFAOYSA-N ethene;1,1,2,2-tetrafluoroethene Chemical compound C=C.FC(F)=C(F)F QHSJIZLJUFMIFP-UHFFFAOYSA-N 0.000 description 1
- 239000005329 float glass Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229910000484 niobium oxide Inorganic materials 0.000 description 1
- URLJKFSTXLNXLG-UHFFFAOYSA-N niobium(5+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Nb+5].[Nb+5] URLJKFSTXLNXLG-UHFFFAOYSA-N 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 1
- 229920005591 polysilicon Polymers 0.000 description 1
- 229920002620 polyvinyl fluoride Polymers 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000000197 pyrolysis Methods 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 150000003376 silicon Chemical class 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- HLLICFJUWSZHRJ-UHFFFAOYSA-N tioxidazole Chemical compound CCCOC1=CC=C2N=C(NC(=O)OC)SC2=C1 HLLICFJUWSZHRJ-UHFFFAOYSA-N 0.000 description 1
- 239000012780 transparent material Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/02—Details
- H01L31/0224—Electrodes
- H01L31/022466—Electrodes made of transparent conductive layers, e.g. TCO, ITO layers
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C17/00—Surface treatment of glass, not in the form of fibres or filaments, by coating
- C03C17/34—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions
- C03C17/36—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions at least one coating being a metal
- C03C17/3602—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions at least one coating being a metal the metal being present as a layer
- C03C17/3644—Surface treatment of glass, not in the form of fibres or filaments, by coating with at least two coatings having different compositions at least one coating being a metal the metal being present as a layer the metal being silver
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/02—Details
- H01L31/0216—Coatings
- H01L31/02161—Coatings for devices characterised by at least one potential jump barrier or surface barrier
- H01L31/02167—Coatings for devices characterised by at least one potential jump barrier or surface barrier for solar cells
- H01L31/02168—Coatings for devices characterised by at least one potential jump barrier or surface barrier for solar cells the coatings being antireflective or having enhancing optical properties for the solar cells
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/02—Details
- H01L31/0224—Electrodes
- H01L31/022408—Electrodes for devices characterised by at least one potential jump barrier or surface barrier
- H01L31/022425—Electrodes for devices characterised by at least one potential jump barrier or surface barrier for solar cells
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/02—Details
- H01L31/0224—Electrodes
- H01L31/022466—Electrodes made of transparent conductive layers, e.g. TCO, ITO layers
- H01L31/022483—Electrodes made of transparent conductive layers, e.g. TCO, ITO layers composed of zinc oxide [ZnO]
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C2217/00—Coatings on glass
- C03C2217/90—Other aspects of coatings
- C03C2217/94—Transparent conductive oxide layers [TCO] being part of a multilayer coating
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
Definitions
- This invention relates to a photovoltaic device including an electrode such as a front electrode/contact.
- the front electrode of the photovoltaic device includes a multi-layer coating having at least one infrared (IR) reflecting and conductive substantially metallic layer of or including silver, gold, or the like, and possibly at least one transparent conductive oxide (TCO) layer (e.g., of or including a material such as tin oxide, zinc oxide, or the like).
- IR infrared
- TCO transparent conductive oxide
- the multilayer front electrode coating is designed to realize one or more of the following advantageous features: (a) reduced sheet resistance and thus increased conductivity and improved overall photovoltaic module output power; (b) increased reflection of infrared (IR) radiation thereby reducing the operating temperature of the photovoltaic module so as to increase module output power; (c) reduced reflection and/or increased transmission of light in the region of from about 450-700 ran, and/or 450-600 nm, which leads to increased photovoltaic module output power; (d) reduced total thickness of the front electrode coating which can reduce fabrication costs and/or time; and/or (e) improved or enlarged process window in forming the TCO layer(s) because of the reduced impact of the TCO 's conductivity on the overall electric properties of the module given the presence of the highly conductive substantially metallic IR reflecting layer(s).
- Amorphous silicon photovoltaic devices include a front electrode or contact.
- the transparent front electrode is made of a pyrolytic transparent conductive oxide (TCO) such as zinc oxide or tin oxide formed on a substrate such as a glass substrate.
- TCO pyrolytic transparent conductive oxide
- the transparent front electrode is formed of a single layer using a method of chemical pyrolysis where precursors are sprayed onto the glass substrate at approximately 400 to 600 degrees C.
- Typical pyrolitic fluorine-doped tin oxide TCOs as front electrodes may be about 400 nm thick, which provides for a sheet resistance (R s ) of about 15 ohms/square.
- R s sheet resistance
- a front electrode having a low sheet resistance and good ohm-contact to the cell top layer, and allowing maximum solar energy in certain desirable ranges into the absorbing semiconductor film, are desired.
- photovoltaic devices e.g., solar cells
- TCO front electrodes suffer from the following problems.
- a pyrolitic fluorine-doped tin oxide TCO about 400 nm thick as the entire front electrode has a sheet resistance (R 5 ) of about 15 ohms/square which is rather high for the entire front electrode.
- R 5 sheet resistance
- a lower sheet resistance (and thus better conductivity) would be desired for the front electrode of a photovoltaic device.
- a lower sheet resistance may be achieved by increasing the thickness of such a TCO, but this will cause transmission of light through the TCO to drop thereby reducing output power of the photovoltaic device.
- conventional TCO front electrodes such as pyrolytic tin oxide allow a significant amount of infrared (IR) radiation to pass therethrough thereby allowing it to reach the semiconductor or absorbing layer(s) of the photovoltaic device.
- IR radiation causes heat which increases the operating temperature of the photovoltaic device thereby decreasing the output power thereof.
- conventional TCO front electrodes such as pyrolytic tin oxide tend to reflect a significant amount of light in the region of from about 450-700 nm so that less than about 80% of useful solar energy reaches the semiconductor absorbing layer; this significant reflection of visible light is a waste of energy and leads to reduced photovoltaic module output power.
- the TCO coated glass at the front of the photovoltaic device typically allows less than 80% of the useful solar energy impinging upon the device to reach the semiconductor film which converts the light into electric energy.
- the process window for forming a zinc oxide or tin oxide TCO for a front electrode is both small and important. In this respect, even small changes in the process window can adversely affect conductivity of the TCO. When the TCO is the sole conductive layer of the front electrode, such adverse affects can be highly ' detrimental.
- the front electrode of a photovoltaic device is comprised of a multilayer coating including at least one conductive substantially metallic IR reflecting layer (e.g., based on silver, gold, or the like), and optionally at least one transparent conductive oxide (TCO) layer (e.g., of or including a material such as tin oxide, zinc oxide, or the like).
- the multilayer front electrode coating may include a plurality of TCO layers and/or a plurality of conductive substantially metallic IR reflecting layers arranged in an alternating manner in order to provide for reduced visible light reflections, increased conductivity, increased IR reflection capability, and so forth.
- a multilayer front electrode coating may be designed to realize one or more of the following advantageous features: (a) reduced sheet resistance (R s ) and thus increased conductivity and improved overall photovoltaic module output power; (b) increased reflection of infrared (IR) radiation thereby reducing the operating temperature of the photovoltaic module so as to increase module output power; (c) reduced reflection and increased transmission of light in the region(s) of from about 450-700 nm and/or 450-600 nm which leads to increased photovoltaic module output power; (d) reduced total thickness of the front electrode coating which can reduce fabrication costs and/or time; and/or (e) an improved or enlarged process window in forming the TCO layer(s) because of the reduced impact of the TCO's conductivity on the overall electric properties of the module given the presence of the highly conductive substantially metallic layer(s).
- R s reduced sheet resistance
- IR infrared
- a photovoltaic device comprising: a front glass substrate; a semiconductor film; a substantially transparent front electrode located between at least the front glass substrate and the semiconductor film; wherein the substantially transparent front electrode comprises, moving away from the front glass substrate toward the semiconductor film, at least a first substantially transparent layer that may or may not be conductive, a substantially metallic infrared (IR) reflecting layer comprising silver and/or gold, and a first transparent conductive oxide (TCO) film located between at least the IR reflecting layer and the semiconductor film.
- IR infrared
- TCO transparent conductive oxide
- an electrode adapted for use in an electronic device such as a photovoltaic device including a semiconductor film comprising: an electrically conductive and substantially transparent multilayer electrode supported by a glass substrate; wherein the substantially transparent multilayer electrode comprises, moving away from the glass substrate, at least a first substantially transparent conductive substantially metallic infrared (IR) reflecting layer comprising silver and/or gold, and a first transparent conductive oxide (TCO) film.
- IR infrared
- TCO transparent conductive oxide
- a photovoltaic device comprising: a glass substrate; a semiconductor film; a substantially transparent electrode located between at least the substrate and the semiconductor film; and wherein the substantially transparent electrode comprises, moving away from the glass substrate toward the semiconductor film, at least a first substantially transparent conductive substantially metallic layer comprising silver, and a first transparent conductive oxide (TCO) film located between at least the layer comprising silver and the semiconductor film.
- TCO transparent conductive oxide
- FIGURE 1 is a cross sectional view of an example photovoltaic device according to an example embodiment of this invention.
- FIGURE 2 is a refractive index (n) versus wavelength (nm) graph illustrating refractive indices (n) of glass, a TCO film, silver thin film, and hydrogenated silicon (in amorphous, micro- or poly-crystalline phase).
- FIGURE 3 is a percent transmission (T%) versus wavelength (nm) graph illustrating transmission spectra into a hydrogenated Si thin film of a photovoltaic device comparing examples of this invention versus a comparative example (TCO reference); this shows that the examples of this invention (Examples 1 , 2 and 3) have increased transmission in the approximately 450-700 nm wavelength range and thus increased photovoltaic module output power, compared to the comparative example (TCO reference).
- FIGURE 4 is a percent reflection (R %) versus wavelength (nm) graph illustrating reflection spectra from a hydrogenated Si thin film of a photovoltaic device comparing the examples of this invention (Examples 1 , 2 and 3 referred to in Fig. 3) versus a comparative example (TCO reference referred to in Fig. 3); this shows that the example embodiment of this invention have increased reflection in the IR range, thereby reducing the operating temperature of the photovoltaic module so as to increase module output power, compared to the comparative example. Because the same Examples 1 -3 and comparative example (TCO reference) are being referred to in Figs. 3 and 4, the same curve identifiers used in Fig. 3 are also used in Fig. 4.
- FIGURE 5 is a cross sectional view of the photovoltaic device according to Example 1 of this invention.
- FIGURE 6 is a cross sectional view of the photovoltaic device according to Example 2 of this invention.
- FIGURE 7 is a cross sectional view of the photovoltaic device according to Example 3 of this invention.
- FIGURE 8 is a cross sectional view of the photovoltaic device according to another example embodiment of this invention.
- FIGURE 9 is a cross sectional view of the photovoltaic device according to another example embodiment of this invention.
- FIGURE 10 is a cross sectional view of the photovoltaic device according to another example embodiment of this invention.
- Photovoltaic devices such as solar cells convert solar radiation into usable electrical energy.
- the energy conversion occurs typically as the result of the photovoltaic effect.
- Solar radiation e.g., sunlight
- impinging on a photovoltaic device and absorbed by an active region of semiconductor material e.g., a semiconductor film including one or more semiconductor layers such as a-Si layers, the semiconductor sometimes being called an absorbing layer or film
- an active region of semiconductor material e.g., a semiconductor film including one or more semiconductor layers such as a-Si layers, the semiconductor sometimes being called an absorbing layer or film
- the electrons and holes may be separated by an electric field of a junction in the photovoltaic device. The separation of the electrons and holes by the junction results in the generation of an electric current and voltage.
- the electrons flow toward the region of the semiconductor material having n-type conductivity, and holes flow toward the region of the semiconductor having p-type conductivity.
- Current can flow through an external circuit connecting the n-type region to the p-type region as light continues to generate electron-hole pairs in the photovoltaic device.
- single junction amorphous silicon (a-
- Si photovoltaic devices include three semiconductor layers. .In particular, a p-layer, an n-layer and an i-layer which is intrinsic.
- the amorphous silicon film (which may include one or more layers such as p, n and i type layers) may be of hydrogenated amorphous silicon in certain instances, but may also be of or include hydrogenated amorphous silicon carbon or hydrogenated amorphous silicon germanium, or the like, in certain example embodiments of this invention.
- a photon of light when a photon of light is absorbed in the i-layer it gives rise to a unit of electrical current (an electron-hole pair).
- the p and n-layers which contain charged dopant ions, set up an electric field across the i-layer which draws the electric charge out of the i-layer and sends it to an optional external circuit where it can provide power for electrical components.
- this invention is not so limited and may be used in conjunction with other types of photovoltaic devices in certain instances including but not limited to devices including other types of semiconductor material, single or tandem thin-film solar cells, CdS and/or CdTe (including CdS/CdTe) photovoltaic devices, polysilicon and/or microcrystalline Si photovoltaic devices, and the like.
- Fig. 1 is a cross sectional view of a photovoltaic device according to an example embodiment of this invention.
- the photovoltaic device includes transparent front glass substrate 1 (other suitable material may also be used for the substrate instead of glass in certain instances), optional dielectric layer(s) 2, multilayer front electrode 3, active semiconductor film 5 of or including one or more semiconductor layers (such as pin, pn, pinpin tandem layer stacks, or the like), back electrode/contact 7 which may be of a TCO or a metal, an optional encapsulant 9 or adhesive of a material such as ethyl vinyl acetate (EVA) or the like, and an optional superstrate 1 1 of a material such as glass.
- transparent front glass substrate 1 other suitable material may also be used for the substrate instead of glass in certain instances
- optional dielectric layer(s) 2 multilayer front electrode 3
- active semiconductor film 5 of or including one or more semiconductor layers (such as pin, pn, pinpin tandem layer stacks, or the like)
- back electrode/contact 7 which may be
- Front glass substrate 1 and/or rear superstrate (substrate) 1 1 may be made of soda-lime-silica based glass in certain example embodiments of this invention; and it may have low iron content and/or an antireflection coating thereon to optimize transmission in certain example instances. While substrates 1, 1 1 may be of glass in certain example embodiments of this invention, other materials such as quartz, plastics or the like may instead be used for substrate(s) 1 and/or 1 1. Moreover, superstrate 1 1 is optional in certain instances. Glass 1 and/or 1 1 may or may not be thermally tempered and/or patterned in certain example embodiments of this invention. Additionally, it will be appreciated that the word "on" as used herein covers both a layer being directly on and indirectly on something, with other layers possibly being located therebetween.
- Dielectric layer(s) 2 may be of any substantially transparent material such as a metal oxide and/or nitride which has a refractive index of from about 1.5 to 2.5, more preferably from about 1.6 to 2.5, more preferably from about 1.6 to 2.2, more preferably from about 1.6 to 2.0, and most preferably from about 1.6 to 1.8. However, in certain situations, the dielectric layer 2 may have a refractive index (n) of from about 2.3 to 2.5.
- Example materials for dielectric layer 2 include silicon oxide, silicon nitride, silicon oxynitride, zinc oxide, tin oxide, titanium oxide (e.g., TiO 2 ), aluminum oxynitride, aluminum oxide, or mixtures thereof.
- Dielectric layer(s) 2 functions as a barrier layer in certain example embodiments of this invention, to reduce materials such as sodium from migrating outwardly from the glass substrate 1 and reaching the IR reflecting layer(s) and/or semiconductor.
- dielectric layer 2 is material having a refractive index (n) in the range discussed above, in order to reduce visible light reflection and thus increase transmission of visible light (e.g., light from about 450-700 nm and/or 450-600 nm) through the coating and into the semiconductor 5 which leads to increased photovoltaic module output power.
- layer 3a may be a dielectric layer instead of a TCO in certain example instances and serve as a seed layer for the layer 3b.
- This multilayer film 3 makes up the front electrode in certain example embodiments of this invention.
- Front electrode 3 may be continuous across all or a substantial portion of glass substrate 1, or alternatively may be patterned into a desired design (e.g., stripes), in different example embodiments of this invention.
- Each of layers/films 1-3 is substantially transparent in certain example embodiments of this invention.
- 3b and 3d may be of or based on any suitable IR reflecting material such as silver, gold, or the like. These materials reflect significant amounts of IR radiation, thereby reducing the amount of IR which reaches the semiconductor film 5. Since IR increases the temperature of the device, the reduction of the amount of IR radiation reaching the semiconductor film 5 is advantageous in that it reduces the operating temperature of the photovoltaic module so as to increase module output power. Moreover, the highly conductive nature of these substantially metallic layers 3b and/or 3d permits the conductivity of the overall electrode 3 to be increased.
- the multilayer electrode 3 has a sheet resistance of less than or equal to about 12 ohms/square, more preferably less than or equal to about 9 ohms/square, and even more preferably less than or equal to about 6 ohms/square.
- the increased conductivity increases the overall photovoltaic module output power, by reducing resistive losses in the lateral direction in which current flows to be collected at the edge of cell segments.
- first and second conductive substantially metallic IR reflecting layers 3b and 3d are thin enough so as to be substantially transparent to visible light.
- first and/or second conductive substantially metallic IR reflecting layers 3b and/or 3d are each from about 3 to 12 nm thick, more preferably from about 5 to 10 nm thick, and most preferably from about 5 to 8 nm thick. In embodiments where one of the layers 3b or 3d is not used, then the remaining conductive substantially metallic IR reflecting layer may be from about 3 to 18 nm thick, more preferably from about 5 to 12 nm thick, and most preferably from about 6 to 1 1 nm thick in certain example embodiments of this invention.
- These thicknesses are desirable in that they permit the layers 3b and/or 3d to reflect significant amounts of IR radiation, while at the same time being substantially transparent to visible radiation which is permitted to reach the semiconductor 5 to be transformed by the photovoltaic device into electrical energy.
- the highly conductive materials are desirable in that they permit the layers 3b and/or 3d to reflect significant amounts of IR radiation, while at the same time being substantially transparent to visible radiation which is permitted to reach the semiconductor 5 to be transformed by the photovoltaic device into electrical energy.
- IR reflecting layers 3b and 3d attribute to the overall conductivity of the electrode 3 much more than the TCO layers; this allows for expansion of the process window(s) of the TCO layer(s) which has a limited window area to achieve both high conductivity and transparency.
- First, second, and third TCO layers 3a, 3c and 3e, respectively, may be of any suitable TCO material including but not limited to conducive forms of zinc oxide, zinc aluminum oxide, tin oxide, indium-tin-oxide, indium zinc oxide (which may or may not be doped with silver), or the like. These layers are typically substoichiometric so as to render them conductive as is known in the art. For example, these layers are made of material(s) which gives them a resistance of no more than about 10 ohm-cm (more preferably no more than about 1 ohm-cm, and most preferably no more than about 20 mohm-cm).
- TCO layers 3c and/or 3e are thicker than layer 3a (e.g., at least about 5 nm, more preferably at least about 10, and most preferably at least about 20 or 30 nm thicker).
- TCO layer 3a is from about 3 to 80 nm thick, more preferably from about 5-30 nm thick, with an example thickness being about 10 nm.
- Optional layer 3a is provided mainly as a seeding layer for layer 3b and/or for antireflection purposes, and its conductivity is not as important as that of layers 3b-3e (thus, layer 3a may be a dielectric instead of a TCO in certain example embodiments).
- TCO layer 3c is from about 20 to 150 nm thick, more preferably from about 40 to 120 nm thick, with an example thickness being about 74-75 nm.
- TCO layer 3e is from about 20 to 180 nm thick, more preferably from about 40 to 130 nm thick, with an example thickness being about 94 or 1 15 nm.
- part of layer 3e e.g., from about 1 -25 nm or 5-25 nm thick portion, at the interface between layers 3e and 5 may be replaced with a low conductivity high refractive index (n) film 3f such as titanium oxide to enhance transmission of light as well as to reduce back diffusion of generated electrical carriers; in this way performance may be further improved.
- n refractive index
- the photovoltaic device may be made by providing glass substrate 1 , and then depositing (e.g., via sputtering or any other suitable technique) multilayer electrode 3 on the substrate 1. Thereafter the structure including substrate 1 and front electrode 3 is coupled with the rest of the device in order to form the photovoltaic device shown in Fig. 1.
- the semiconductor layer 5 may then be formed over the front electrode on substrate 1.
- the back contact 7 and semiconductor 5 may be fabricated/formed on substrate 11 (e.g., of glass or other suitable material) first; then the electrode 3 and dielectric 2 may be formed on semiconductor 5 and encapsulated by the substrate 1 via an adhesive such as EVA.
- the alternating nature of the TCO layers 3a, 3c and/or 3e, and the conductive substantially metallic IR reflecting layers 3b and/or 3d, is also advantageous in that it also one, two, three, four or all of the following advantages to be realized: (a) reduced sheet resistance (R s ) of the overall electrode 3 and thus increased conductivity and improved overall photovoltaic module output power; (b) increased reflection of infrared (IR) radiation by the electrode 3 thereby reducing the operating temperature of the semiconductor 5 portion of the photovoltaic module so as to increase module output power; (c) reduced reflection and increased transmission of light in the visible region of from about 450-700 nm (and/or 450-600 nm) by the front electrode 3 which leads to increased photovoltaic module output power; (d) reduced total thickness of the front electrode coating 3 which can reduce fabrication costs and/or time; and/or (e) an improved or enlarged process window in forming the TCO layer(s) because of the reduced impact of the TCO's conductivity
- the active semiconductor region or film 5 may include one or more layers, and may be of any suitable material.
- the active semiconductor film 5 of one type of single junction amorphous silicon (a-Si) photovoltaic device includes three semiconductor layers, namely a p-layer, an n-layer and an i-layer.
- the p-type a-Si layer of the semiconductor film 5 may be the uppermost portion of the semiconductor film 5 in certain example embodiments of this invention; and the i- layer is typically located between the p and n-type layers.
- amorphous silicon based layers of film 5 may be of hydrogenated amorphous silicon in certain instances, but may also be of or include hydrogenated amorphous silicon carbon or hydrogenated amorphous silicon germanium, hydrogenated microcrystalline silicon, or other suitable material(s) in certain example embodiments of this invention. It is possible for the active region 5 to be of a double-junction or triple-junction type in alternative embodiments of this invention. CdTe may also be used for semiconductor film 5 in alternative embodiments of this invention.
- Back contact, reflector and/or electrode 7 may be of any suitable electrically conductive material.
- the back contact or electrode 7 may be of a TCO and/or a metal in certain instances.
- Example TCO materials for use as back contact or electrode 7 include indium zinc oxide, indium-tin- oxide (ITO), tin oxide, and/or zinc oxide which may be doped with aluminum (which may or may not be doped with silver).
- the TCO of the back contact 7 may be of the single layer type or a multi-layer type in different instances.
- the back contact 7 may include both a TCO portion and a metal portion in certain instances.
- the TCO portion of the back contact 7 may include a layer of a material such as indium zinc oxide (which may or may not be doped with silver), indium-tin-oxide (ITO), tin oxide, and/or zinc oxide closest to the active region 5, and the back contact may include another conductive and possibly reflective layer of a material such as silver, molybdenum, platinum, steel, iron, niobium, titanium, chromium, bismuth, antimony, or aluminum further from the active region 5 and closer to the superstrate 1 1.
- the metal portion may be closer to superstrate 1 1 compared to the TCO portion of the back contact 7.
- the photovoltaic module may be encapsulated or partially covered with an encapsulating material such as encapsulant 9 in certain example embodiments.
- An example encapsulant or adhesive for layer 9 is EVA or PVB.
- other materials such as Tedlar type plastic, Nuvasil type plastic, Tefzel type plastic or the like may instead be used for layer 9 in different instances.
- a multilayer front electrode 3 Utilizing the highly conductive substantially metallic IR reflecting layers 3b and 3d, and TCO layers 3a, 3c and 3d, to form a multilayer front electrode 3, permits the thin film photovoltaic device performance to be improved by reduced sheet resistance (increased conductivity) and tailored reflection and transmission spectra which best fit photovoltaic device response.
- Refractive indices of glass 1 , hydrogenated a-Si as an example semiconductor 5, Ag as an example for layers 3b and 3d, and an example TCO are shown in Fig. 2. Based on these refractive indices (n), predicted transmission spectra impinging into the semiconductor 5 from the incident surface of substrate 1 are shown in Fig. 3. In particular, Fig.
- FIG. 3 is a percent transmission (T%) versus wavelength (nm) graph illustrating transmission spectra into a hydrogenated Si thin film 5 of a photovoltaic device comparing Examples 1-3 of this invention (see Examples 1 -3 in Figs. 5-7) versus a comparative example (TCO reference).
- the TCO reference was made up of 3 mm thick glass substrate 1 and from the glass outwardly 30 nm of tin oxide, 20 nm of silicon oxide and 350 nm of TCO.
- Fig. 3 thus shows that the examples of this invention (Examples 1 -3 shown in Figs. 5-7) has increased transmission in the approximately 450-600 and 450-700 nm wavelength ranges and thus increased photovoltaic module output power, compared to the comparative example (TCO reference).
- Example 1 shown in Fig. 5 and charted in Figs. 3-4 was made up of 3 mm thick glass substrate 1, 16nm thick TiO 2 dielectric layer 2, 10 nm thick zinc oxide TCO doped with Al 3a, 8 nm thick Ag IR reflecting layer 3b, and 1 15 nm thick zinc oxide TCO doped with Al 3e. Layers 3c, 3d and 3f were not present in Example 1.
- 3-4 was made up of 3 mm thick glass substrate 1, 16nm thick Ti ⁇ 2 dielectric layer 2, 10 nm thick zinc oxide TCO doped with Al 3a, 8 nm thick Ag IR reflecting layer 3b, 100 nm thick zinc oxide TCO doped with Al 3e, and 20 nm thick titanium suboxide layer 3f.
- 3-4 was made up of 3 mm thick glass substrate 1 , 45 nm thick dielectric layer 2, 10 nm thick zinc oxide TCO doped with Al 3a, 5 nm thick Ag IR reflecting layer 3b, 75 nm thick zinc oxide TCO doped with Al 3c, 7 nm thick Ag IR reflecting layer 3d, 95 nm thick zinc oxide TCO doped with Al 3e, and 20 nm thick titanium suboxide layer 3f.
- These single and double-silver layered coatings of Examples 1 -3 had a sheet resistance less than 10 ohms/square and 6 ohms/square, respectively, and total thicknesses much less than the 400 nm thickness of the prior art.
- Examples 1 -3 had tailored transmission spectra, as shown in Fig.
- AMI .5 having more than 80% transmission into the semiconductor 5 in part or all of the wavelength range of from about 450-600 nm and/or 450-700 nm, where AMI .5 has the strongest intensity and photovoltaic devices may possibly have the highest or substantially the highest quantum efficiency.
- Fig. 4 is a percent reflection (R %) versus wavelength
- the front glass substrate 1 and front electrode 3 taken together have a reflectance of at least about 45% (more preferably at least about 55%) in a substantial part or majority of a near to short IR wavelength range of from about 1000-2500 nm and/or 1000 to 2300 nm. In certain example embodiments, it refelects at least 50% of solar energy in the range of from 1000-2500 nm and/or 1200-2300 nm. In certain example embodiments, the front glass substrate and front electrode 3 taken together have an IR reflectance of at least about 45% and/or 55% in a ' substantial part or a majority of a near IR wavelength range of from about 1000-2500 nm, possibly from 1200-2300 nm. In certain example embodiments, it may block at least 50% of solar energy in the range of 1000-2500 nm.
- the electrode 3 is used as a front electrode in a photovoltaic device in certain embodiments of this invention described and illustrated herein, it is also possible to use the electrode 3 as another electrode in the context of a photovoltaic device or otherwise.
- Fig. 8 is a cross sectional view of a photovoltaic device according to another example embodiment of this invention.
- An optional anti reflective (AR) layer Ia may be provided on the light incident side of the front glass substrate 1 in any embodiment of this invention, as indicated for example by AR layer(s) I a shown in Fig. 8 (e.g., see also Figs. 9-10).
- AR layer(s) I a shown in Fig. 8 e.g., see also Figs. 9-10.
- dielectric layer(s) 2 e.g., of or including one or more of silicon oxide, silicon oxynitride, silicon nitride, titanium oxide, niobium oxide, and/or the like
- seed layer 4b e.g., of or including zinc oxide, zinc aluminum oxide, tin oxide, tin antimony oxide, indium zinc oxide, or the like
- silver based IR reflecting layer 4c optional overcoat or contact layer 4d (e.g., of or including an oxide of Ni and/or Cr, zinc oxide, zinc aluminum oxide, or the like) which may be a TCO
- TCO 4e e.g., of or including zinc oxide, zinc aluminum oxide, tin oxide, tin antimony oxide, zinc tin oxide, indium tin oxide, indium zinc oxide, or the like
- optional buffer layer 4 e.g., of or including one or more of silicon oxide, silicon oxynitride, silicon nitride, titanium oxide, niobium oxide, and/
- layer 4b may be the same as layer 3a described above
- layer 4c may be the same as layer 3b or 3d described above this applies to Figs. 8-10
- layer 4e may be the same as layer 3e described above (this also applies to Figs. 8-10)
- layer 4f may be the same as layer 3f described above (this also applies to Figs. 8-10) (see descriptions above as to other embodiments in this respect).
- layers 1 , 5, 7, 9 and 1 1 are also discussed above in connection with other embodiments.
- an example of the Fig. 8 embodiment is as follows (note that certain optional layers shown in Fig. 8 are not used in this example).
- glass substrate 1 e.g., about 3.2 mm thick
- dielectric layer 2 e.g., silicon oxynitride about 20 nm thick possibly followed by dielectric TiOx about 20 nm thick
- Ag seed layer 4b e.g., dielectric or TCO zinc oxide or zinc aluminum oxide about 10 nm thick
- IR reflecting layer 4c e.g., dielectric or TCO zinc oxide or zinc aluminum oxide about 10 nm thick
- IR reflecting layer 4c e.g., IR reflecting layer 4c (silver about 5-8 nm thick)
- TCO 4e e.g., conductive zinc oxide, tin oxide, zinc aluminum oxide, ITO from about 50-250 nm thick, more preferably from about 100-150 nm thick
- possibly conductive buffer layer 4f TCO zinc oxide, tin oxide, zinc aluminum oxide, I
- the buffer layer 4f (or 3f) is designed to have a refractive index (n) of from about 2.1 to 2.4, more preferably from about 2.15 to 2.35, for substantial index matching to the semiconductor 5 (e.g., CdS or the like) in order to improve efficiency of the device.
- n refractive index
- the photovoltaic device of Fig. 8 may have a sheet resistance of no greater than about 18 ohms/square, more preferably no grater than about 15 ohms/square, even more preferably no greater than about 13 ohms/square in certain example embodiments of this invention.
- the Fig. 8 embodiment may have tailored transmission spectra having more than 80% transmission into the semiconductor 5 in part or all of the wavelength range of from about 450-600 nm and/or 450-700 nm, where AMI .5 may have the strongest intensity and in certain example instances the cell may have the highest or substantially the highest quantum efficiency.
- Fig. 9 is a cross sectional view of a photovoltaic device according to yet another example embodiment of this invention.
- the photovoltaic device of the Fig. 9 embodiment includes optional antireflective (AR) layer Ia on the light incident side of the front glass substrate 1 , first dielectric layer 2a, second dielectric layer 2b, third dielectric layer 2c which may optionally function as a seed layer (e.g., of or including zinc oxide, zinc aluminum oxide, tin oxide, tin antimony oxide, indium zinc oxide, or the like) for the silver based layer 4c, conductive silver based IR reflecting layer 4c, optional overcoat or contact layer 4d (e.g., of or including an oxide of Ni and/or Cr, zinc oxide, zinc aluminum oxide, or the like) which may be a TCO or dielectric, TCO 4e (e.g., including one or more layers, such as of or including zinc oxide, zinc aluminum oxide, tin oxide, tin antimony oxide, zinc tin oxide, indium
- Semiconductor film 5 may include a single pin or pn semiconductor structure, or a tandem semiconductor structure in different embodiments of this invention.
- Semiconductor 5 may be of or include silicon in certain example instances.
- semiconductor film 5 may include a first layer of or including CdS (e.g., window layer) adjacent or closest to layer(s) 4e and/or 4f and a second semiconductor layer of or including CdTe (e.g., main absorber) adjacent or closest to the back electrode or contact 7.
- CdS e.g., window layer
- CdTe e.g., main absorber
- first dielectric layer 2a has a relatively low refractive index (n) (e.g., n of from about 1.7 to 2.2, more preferably from about 1.8 to 2.2, still more preferably from about 1.95 to 2.1, and most preferably from about 2.0 to 2.08)
- second dielectric layer 2b has a relatively high (compared to layer 2a) refractive index (n) (e.g., n of from about 2.2 to 2.6, more preferably from about 2.3 to 2.5, and most preferably from about 2.35 to 2.45)
- third dielectric layer 2c has a relatively low (compared to layer 2b) refractive index (n) (e.g., n of from about 1.8 to 2.2, more preferably from about 1.95 to 2.1 , and most preferably from about 2.0 to 2.05).
- the first low index dielectric layer 2a may be of or include silicon nitride, silicon oxynitride, or any other suitable material
- the second high index dielectric layer 2b may be of or include an oxide of titanium (e.g., TiO 2 or the like)
- the third dielectric layer 2c may be of or include zinc oxide or any other suitable material.
- layers 2a-2c combine to form a good index matching stack which also functions as a buffer against sodium migration from the glass 1.
- the first dielectric layer 2a is from about 5-30 nm thick, more preferably from about 10-20 nm thick
- the second dielectric layer 2b is from about 5-30 nm thick, more preferably from about 10-20 nm thick
- the third layer 2c is of a lesser thickness and is from about 3-20 nm thick, more preferably from about 5-15 nm thick, and most preferably from about 6-14 nm thick. While layers 2a, 2b and 2c are dielectrics in certain embodiments of this invention, one, two or all three of these layers may be dielectric or TCO in certain other example embodiments of this invention.
- Layers 2b and 2c are metal oxides in certain example embodiments of this invention, whereas layer 2a is a metal oxide and/or nitride, or silicon nitride in certain example instances. Layers 2a-2c may be deposited by sputtering or any other suitable technique.
- the TCO layer(s) 4e may be of or include any suitable TCO including but not limited to zinc oxide, zinc aluminum oxide, tin oxide and/or the like. TCO layer or file 4e may include multiple layers in certain example instances.
- the TCO 4 includes a first layer of a first TCO metal oxide (e.g., zinc oxide) adjacent Ag 4c, Ag overcoat 4d and a second layer of a second TCO metal oxide (e.g., tin oxide) adjacent and contacting layer 4f and/or 5.
- a first TCO metal oxide e.g., zinc oxide
- a second TCO metal oxide e.g., tin oxide
- an example of the Fig. 9 embodiment is as follows.
- glass substrate 1 e.g., float glass about 3.2 mm thick, and a refractive index n of about 1.52
- first dielectric layer 2a e.g., silicon nitride about 15 nm thick, having a refractive index n of about 2.07
- second dielectric layer 2b e.g., oxide of Ti, such as TiO 2 or other suitable stoichiometry, about 16 nm thick, having a refractive index n of about 2.45
- third dielectric layer 2c e.g., zinc oxide, possibly doped with Al, about 9 nm thick, having a refractive index n of about 2.03
- IR reflecting layer 4c silver about 5-8 nm thick, e.g., 6 nm
- silver overcoat 4d OfNiCrO x about 1-3 nm thick which may or may not be
- the photovoltaic device of Fig. 9 may have a sheet resistance of no greater than about 18 ohms/square, more preferably no grater than about 15 ohms/square, even more preferably no greater than about 13 ohms/square in certain example embodiments of this invention.
- the Fig. 9 (and/or Fig. 10) embodiment may have tailored transmission spectra having more than 80% transmission into the semiconductor 5 in part or all of the wavelength range of from about 450-600 nm and/or 450-700 nm, where AMI .5 may have the strongest intensity.
- Fig. 10 is a cross sectional view of a photovoltaic device according to still another example embodiment of this invention.
- the Fig. 10 embodiment is the same as the Fig. 9 embodiment discussed above, except for the TCO film 4e.
- the TCO film 4e includes a first layer 4e' of or including a first TCO metal oxide (e.g., zinc oxide, which may or may not be doped with Al or the like) adjacent and contacting layer 4d and a second layer 4e" of a second TCO metal oxide (e.g., tin oxide) adjacent and contacting layer 4f and/or 5 (e.g., layer 4f may be omitted, as in previous embodiments).
- a first TCO metal oxide e.g., zinc oxide, which may or may not be doped with Al or the like
- a second layer 4e" of a second TCO metal oxide e.g., tin oxide
- layer 4f may be omitted, as in previous embodiments.
- Layer 4e' is also substantially thicker than layer 4e" in certain example embodiments.
- the first TCO layer 4e' has a resistivity which is less than that of the second TCO layer 4e".
- the first TCO layer 4e' may be of zinc oxide, Al- doped zinc oxide, or ITO about 70-150 run thick (e.g., about 1 10 nm) having a resistivity of no greater than about 1 ohm. cm
- the second TCO layer 4e" may be of tin oxide about 10-50 nm thick (e.g., about 30 nm) having a resistivity of from about 10-100 ohm. cm, possibly from about 2-100 ohm. cm.
- the first TCO layer 4e' is thicker and more conductive than the second TCO layer 4e" in certain example embodiments, which is advantageous as layer 4e' is closer to the conductive Ag based layer 4c thereby leading to improved efficiency of the photovoltaic device. Moreover, this design is advantageous in that CdS of the film 5 adheres or sticks well to tin oxide which may be used in or for layer 4e". TCO layers 4e' and/or 4e" may be deposited by sputtering or any other suitable technique.
- the first TCO layer 4e' may be of or include ITO (indium tin oxide) instead of zinc oxide.
- ITO indium tin oxide
- the ITO of layer 4e' may be about 90% In, 10% Sn, or alternatively about 50% In, 50% Sn.
- the use of at least these three dielectrics 2a-2c is advantageous in that it permits reflections to be reduced thereby resulting in a more efficient photovoltaic device.
- the overcoat layer 4d e.g., of or including an oxide of Ni and/or Cr
- the overcoat layer 4d to be oxidation graded, continuously or discontinuously, in certain example embodiments of this invention.
- layer 4d may be designed so as to be more metallic (less oxided) at a location therein closer to Ag based layer 4d than at a location therein further from the Ag based layer 4d; this has been found to be advantageous for thermal stability reasons in that the coating does not degrade as much during subsequently high temperature processing which may be associated with the photovoltaic device manufacturing process or otherwise.
- a thickness of from about 120-160 nm, more preferably from about 130-150 nm (e.g., 140 nm), for the TCO film 4e is advantageous in that the Jsc peaks in this range.
- the Jsc decreases by as much as about 6.5% until it bottoms out at about a TCO thickness of about 60 nm.
- Below 60 nm it increases again until at a TCO film 4e thickness of about 15-35 nm (more preferably 20-30 nm) it is attractive, but such thin coatings may not be desirable in certain example non-limiting situations.
- the thickness of TCO film 4e may be provided in the range of from about 15-35 nm, or in the range of from about 120-160 nm or 130-150 nm.
Landscapes
- Engineering & Computer Science (AREA)
- Computer Hardware Design (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Physics & Mathematics (AREA)
- Power Engineering (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Photovoltaic Devices (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP07839454A EP2132781A2 (en) | 2006-11-02 | 2007-10-11 | Front electrode for use in photovoltaic device and method of making same |
BRPI0718304-6A BRPI0718304A2 (en) | 2006-11-02 | 2007-10-11 | FRONT ELECTRODE FOR USE IN PHOTOVOLTAIC DEVICE AND MANUFACTURING METHOD OF THE SAME. |
CA002667941A CA2667941A1 (en) | 2006-11-02 | 2007-10-11 | Front electrode for use in photovoltaic device and method of making same |
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/591,668 US20080105298A1 (en) | 2006-11-02 | 2006-11-02 | Front electrode for use in photovoltaic device and method of making same |
US11/591,668 | 2006-11-02 | ||
US11/790,812 US20080105293A1 (en) | 2006-11-02 | 2007-04-27 | Front electrode for use in photovoltaic device and method of making same |
US11/790,812 | 2007-04-27 | ||
US11/898,641 US20080105302A1 (en) | 2006-11-02 | 2007-09-13 | Front electrode for use in photovoltaic device and method of making same |
US11/898,641 | 2007-09-13 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2008063305A2 true WO2008063305A2 (en) | 2008-05-29 |
WO2008063305A3 WO2008063305A3 (en) | 2010-01-21 |
Family
ID=39430245
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2007/021693 WO2008063305A2 (en) | 2006-11-02 | 2007-10-11 | Front electrode for use in photovoltaic device and method of making same |
Country Status (1)
Country | Link |
---|---|
WO (1) | WO2008063305A2 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2009064331A2 (en) * | 2007-11-13 | 2009-05-22 | Guardian Industries Corp. | Front electrode for use in photovoltaic device and method of making same |
WO2009134302A1 (en) * | 2008-04-29 | 2009-11-05 | Guardian Industries Corp. | Transparent front electrode for use in photovoltaic device and method of making same |
WO2009099509A3 (en) * | 2008-02-01 | 2009-11-26 | Guardian Industries Corp. | Transparent front electrode for use in photovoltaic device and method of making same |
CN109841743A (en) * | 2013-03-12 | 2019-06-04 | Vitro可变资本股份有限公司 | Transparent conductive oxide coating for Organic Light Emitting Diode and solar device |
CN116435395A (en) * | 2023-06-13 | 2023-07-14 | 金阳(泉州)新能源科技有限公司 | Color-adjustable flexible photovoltaic module, preparation method, solar cell and application |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8334452B2 (en) | 2007-01-08 | 2012-12-18 | Guardian Industries Corp. | Zinc oxide based front electrode doped with yttrium for use in photovoltaic device or the like |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6123824A (en) | 1996-12-13 | 2000-09-26 | Canon Kabushiki Kaisha | Process for producing photo-electricity generating device |
US6288325B1 (en) | 1998-07-14 | 2001-09-11 | Bp Corporation North America Inc. | Producing thin film photovoltaic modules with high integrity interconnects and dual layer contacts |
US6613603B1 (en) | 1997-07-25 | 2003-09-02 | Canon Kabushiki Kaisha | Photovoltaic device, process for production thereof, and zinc oxide thin film |
US6784361B2 (en) | 2000-09-20 | 2004-08-31 | Bp Corporation North America Inc. | Amorphous silicon photovoltaic devices |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4663495A (en) * | 1985-06-04 | 1987-05-05 | Atlantic Richfield Company | Transparent photovoltaic module |
DE3704880A1 (en) * | 1986-07-11 | 1988-01-21 | Nukem Gmbh | TRANSPARENT, CONDUCTIVE LAYER SYSTEM |
US4940495A (en) * | 1988-12-07 | 1990-07-10 | Minnesota Mining And Manufacturing Company | Photovoltaic device having light transmitting electrically conductive stacked films |
DE19958878B4 (en) * | 1999-12-07 | 2012-01-19 | Saint-Gobain Glass Deutschland Gmbh | Thin film solar cell |
US6576349B2 (en) * | 2000-07-10 | 2003-06-10 | Guardian Industries Corp. | Heat treatable low-E coated articles and methods of making same |
JP2002260448A (en) * | 2000-11-21 | 2002-09-13 | Nippon Sheet Glass Co Ltd | Conductive film, method of making the same, substrate and photoelectric conversion device equipped with the same |
-
2007
- 2007-10-11 WO PCT/US2007/021693 patent/WO2008063305A2/en active Application Filing
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6123824A (en) | 1996-12-13 | 2000-09-26 | Canon Kabushiki Kaisha | Process for producing photo-electricity generating device |
US6613603B1 (en) | 1997-07-25 | 2003-09-02 | Canon Kabushiki Kaisha | Photovoltaic device, process for production thereof, and zinc oxide thin film |
US6288325B1 (en) | 1998-07-14 | 2001-09-11 | Bp Corporation North America Inc. | Producing thin film photovoltaic modules with high integrity interconnects and dual layer contacts |
US6784361B2 (en) | 2000-09-20 | 2004-08-31 | Bp Corporation North America Inc. | Amorphous silicon photovoltaic devices |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2009064331A2 (en) * | 2007-11-13 | 2009-05-22 | Guardian Industries Corp. | Front electrode for use in photovoltaic device and method of making same |
WO2009064331A3 (en) * | 2007-11-13 | 2010-06-24 | Guardian Industries Corp. | Front electrode for use in photovoltaic device and method of making same |
WO2009099509A3 (en) * | 2008-02-01 | 2009-11-26 | Guardian Industries Corp. | Transparent front electrode for use in photovoltaic device and method of making same |
WO2009134302A1 (en) * | 2008-04-29 | 2009-11-05 | Guardian Industries Corp. | Transparent front electrode for use in photovoltaic device and method of making same |
CN109841743A (en) * | 2013-03-12 | 2019-06-04 | Vitro可变资本股份有限公司 | Transparent conductive oxide coating for Organic Light Emitting Diode and solar device |
CN109841743B (en) * | 2013-03-12 | 2022-12-27 | 维特罗平板玻璃有限责任公司 | Transparent conductive oxide coatings for organic light emitting diodes and solar devices |
CN116435395A (en) * | 2023-06-13 | 2023-07-14 | 金阳(泉州)新能源科技有限公司 | Color-adjustable flexible photovoltaic module, preparation method, solar cell and application |
CN116435395B (en) * | 2023-06-13 | 2023-09-12 | 金阳(泉州)新能源科技有限公司 | Color-adjustable flexible photovoltaic module, preparation method, solar cell and application |
Also Published As
Publication number | Publication date |
---|---|
WO2008063305A3 (en) | 2010-01-21 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7964788B2 (en) | Front electrode for use in photovoltaic device and method of making same | |
US8203073B2 (en) | Front electrode for use in photovoltaic device and method of making same | |
US8076571B2 (en) | Front electrode for use in photovoltaic device and method of making same | |
US20080105302A1 (en) | Front electrode for use in photovoltaic device and method of making same | |
US20080302414A1 (en) | Front electrode for use in photovoltaic device and method of making same | |
US8012317B2 (en) | Front electrode including transparent conductive coating on patterned glass substrate for use in photovoltaic device and method of making same | |
US7888594B2 (en) | Photovoltaic device including front electrode having titanium oxide inclusive layer with high refractive index | |
US20080105298A1 (en) | Front electrode for use in photovoltaic device and method of making same | |
US8022291B2 (en) | Method of making front electrode of photovoltaic device having etched surface and corresponding photovoltaic device | |
US20080178932A1 (en) | Front electrode including transparent conductive coating on patterned glass substrate for use in photovoltaic device and method of making same | |
US20080223436A1 (en) | Back reflector for use in photovoltaic device | |
EP2153470A2 (en) | Textured rear electrode structure for use in photovoltaic device such as cigs/cis solar cell | |
WO2008063305A2 (en) | Front electrode for use in photovoltaic device and method of making same | |
US20110180130A1 (en) | Highly-conductive and textured front transparent electrode for a-si thin-film solar cells, and/or method of making the same |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
WWE | Wipo information: entry into national phase |
Ref document number: 2667941 Country of ref document: CA |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2917/DELNP/2009 Country of ref document: IN |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2007839454 Country of ref document: EP |
|
ENP | Entry into the national phase |
Ref document number: 2009120693 Country of ref document: RU Kind code of ref document: A |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 07839454 Country of ref document: EP Kind code of ref document: A2 |
|
ENP | Entry into the national phase |
Ref document number: PI0718304 Country of ref document: BR Kind code of ref document: A2 Effective date: 20090430 |