U.S. patent application number 12/793469 was filed with the patent office on 2010-12-09 for metal barrier-doped metal contact layer.
This patent application is currently assigned to First Solar, Inc.. Invention is credited to Anke Abken, Benyamin Buller, Long Cheng, Akhlesh Gupta.
Application Number | 20100307568 12/793469 |
Document ID | / |
Family ID | 43299862 |
Filed Date | 2010-12-09 |
United States Patent
Application |
20100307568 |
Kind Code |
A1 |
Cheng; Long ; et
al. |
December 9, 2010 |
METAL BARRIER-DOPED METAL CONTACT LAYER
Abstract
A photovoltaic device can include an intrinsic metal layer
adjacent to a semiconductor absorber layer; and a doped metal
contact layer adjacent to the intrinsic metal layer, where the
doped metal contact layer includes a metal base material and a
dopant.
Inventors: |
Cheng; Long; (Perrysburg,
OH) ; Gupta; Akhlesh; (Sylvania, OH) ; Abken;
Anke; (Whitehouse, OH) ; Buller; Benyamin;
(Sylvania, OH) |
Correspondence
Address: |
STEPTOE & JOHNSON LLP
1330 CONNECTICUT AVENUE, N.W.
WASHINGTON
DC
20036
US
|
Assignee: |
First Solar, Inc.
Perrysburg
OH
|
Family ID: |
43299862 |
Appl. No.: |
12/793469 |
Filed: |
June 3, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61184212 |
Jun 4, 2009 |
|
|
|
Current U.S.
Class: |
136/251 ;
136/252; 136/265; 257/E31.124; 438/98 |
Current CPC
Class: |
H01L 31/1884 20130101;
H01L 31/18 20130101; Y02P 70/50 20151101; Y02P 70/521 20151101;
H01L 31/022425 20130101; H01L 31/022466 20130101; H01L 31/0296
20130101; Y02E 10/543 20130101; H01L 31/073 20130101 |
Class at
Publication: |
136/251 ;
136/252; 136/265; 438/98; 257/E31.124 |
International
Class: |
H01L 31/0203 20060101
H01L031/0203; H01L 31/0256 20060101 H01L031/0256; H01L 31/18
20060101 H01L031/18 |
Claims
1. A photovoltaic device, comprising: an intrinsic metal layer
adjacent to a semiconductor absorber layer; and a doped metal
contact layer adjacent to the intrinsic metal layer, the doped
metal contact layer comprising a metal base material and a
dopant.
2. The photovoltaic device of claim 1, wherein the intrinsic metal
layer is selected from the group consisting of molybdenum,
aluminum, chromium, iron, nickel, titanium, vanadium, manganese,
cobalt, zinc, ruthenium, tungsten, silver, gold, and platinum.
3. The photovoltaic device of claim 1, wherein the intrinsic metal
layer comprises a nitride.
4. The photovoltaic device of claim 1, wherein the intrinsic metal
layer comprises a molybdenum nitride.
5. The photovoltaic device of claim 1, wherein the metal base
material is selected from the group consisting of molybdenum,
aluminum, chromium, iron, nickel, titanium, vanadium, manganese,
cobalt, zinc, ruthenium, tungsten, silver, gold, and platinum.
6. The photovoltaic device of claim 1, wherein the dopant is
selected from the group consisting of copper, antimony, potassium,
sodium, cesium, silver, gold, phosphorous, arsenic, and
bismuth.
7. The photovoltaic device of claim 1, wherein the doped metal
contact layer comprises a copper concentration of about 0.1% to
about 10%.
8. The photovoltaic device of claim 1, further comprising a
semiconductor window layer, wherein the semiconductor absorber
layer is positioned adjacent to the semiconductor window layer, the
semiconductor window layer and the semiconductor absorber layer are
at least a part of a semiconductor bi-layer, and the semiconductor
window layer comprises a cadmium sulfide layer.
9. A method for manufacturing a photovoltaic device, the method
comprising: depositing an intrinsic metal layer on a semiconductor
absorber layer; and depositing a doped metal contact layer on the
intrinsic metal layer, the doped metal contact layer comprising a
metal base material and a dopant.
10. The method of claim 9, wherein depositing an intrinsic metal
layer comprises sputtering a molybdenum nitride.
11. The method of claim 9, wherein depositing an intrinsic metal
layer comprises depositing one selected from the group consisting
of a molybdenum, aluminum, chromium, iron, nickel, titanium,
vanadium, manganese, cobalt, zinc, ruthenium, tungsten, silver,
gold, and platinum.
12. The method of claim 9, further comprising doping a metal base
material to form a doped metal contact layer.
13. The method of claim 9, further comprising: doping a metal base
material with a dopant, wherein the metal base material is selected
from the group consisting of molybdenum, aluminum, chromium, iron,
nickel, titanium, vanadium, manganese, cobalt, zinc, ruthenium,
tungsten, silver, gold, and platinum, and wherein the dopant is
selected from the group consisting of copper, antimony, potassium,
sodium, cesium, silver, gold, phosphorous, arsenic, and
bismuth.
14. The method of claim 9, further comprising doping a metal base
material with about 0.1% to about 10% copper.
15. The method of claim 9, wherein depositing a doped metal contact
layer comprises sputtering a copper-doped molybdenum.
16. The method of claim 9, wherein depositing a doped metal contact
layer comprises sputtering a metal base material that comprises the
same metal as the intrinsic metal layer.
17. A photovoltaic module comprising: a plurality of photovoltaic
cells adjacent to a substrate; and a back cover adjacent to the
plurality of photovoltaic cells, the plurality of photovoltaic
cells comprising: an intrinsic metal layer adjacent to a
semiconductor absorber layer; and a doped metal contact layer
adjacent to the intrinsic metal layer, the doped metal contact
layer comprising a metal base material and a dopant.
18. The photovoltaic module of claim 17, further comprising: a
first strip of tape having a length distributed along a contact
region of each photovoltaic cell, the first strip of tape
comprising a front surface and a back surface, each surface
containing an adhesive; a first lead foil distributed along the
length of the first strip of tape; a second strip of tape, having a
length shorter than that of the first strip of tape, distributed
along the length and between the ends of the first strip of tape,
wherein the second strip of tape comprises a front and back
surface, each containing an adhesive; a second lead foil, having a
length shorter than that of the second strip of tape, distributed
along the length of the second strip of tape; and a plurality of
parallel bus bars, positioned adjacent and perpendicular to the
first and second strips of tape, wherein each one of the plurality
of parallel bus bars contacts one of the first or second lead
foils.
19. The photovoltaic module of claim 18, further comprising first
and second submodules, wherein the first submodule comprises two or
more cells of the plurality of photovoltaic cells connected in
series, and the second submodule comprises another two or more
cells of the plurality of photovoltaic cells connected in series,
wherein the first and second submodules are connected in parallel
through a shared cell.
20. A method for generating electricity, the method comprising:
illuminating a photovoltaic cell with a beam of light to generate a
photocurrent; and collecting the generated photocurrent, wherein
the photovoltaic cell comprises: an intrinsic metal layer adjacent
to a semiconductor absorber layer; and a doped metal contact layer
adjacent to the intrinsic metal layer, the doped metal contact
layer comprising a metal base material and a dopant.
Description
CLAIM FOR PRIORITY
[0001] This application claims priority under 35 U.S.C.
.sctn.119(e) to U.S. Provisional Patent Application Ser. No.
61/184,221 filed on Jun. 4, 2009, which is hereby incorporated by
reference.
TECHNICAL FIELD
[0002] The present invention relates to photovoltaic devices and
methods of production.
BACKGROUND
[0003] Photovoltaic devices can include semiconductor material
deposited over a substrate, for example, with a first layer serving
as a window layer and a second layer serving as an absorber layer.
The semiconductor window layer can allow the penetration of solar
radiation to the absorber layer, such as a cadmium telluride layer,
which converts solar energy to electricity. Photovoltaic devices
can also contain one or more transparent conductive oxide layers,
which are also often conductors of electrical charge.
DESCRIPTION OF DRAWINGS
[0004] FIG. 1 is a schematic of a photovoltaic device having
multiple layers.
[0005] FIG. 2 is a schematic of a photovoltaic device having
multiple layers.
DETAILED DESCRIPTION
[0006] Photovoltaic devices can include multiple layers created on
a substrate (or superstrate). For example, a photovoltaic device
can include a barrier layer, a transparent conductive oxide (TCO)
layer, a buffer layer, and a semiconductor layer formed in a stack
on a substrate. Each layer may in turn include more than one layer
or film. For example, the semiconductor layer can include a first
film including a semiconductor window layer, such as a cadmium
sulfide layer, formed on the buffer layer and a second film
including a semiconductor absorber layer, such as a cadmium
telluride layer formed on the semiconductor window layer.
Additionally, each layer can cover all or a portion of the device
and/or all or a portion of the layer or substrate underlying the
layer. For example, a "layer" can include any amount of any
material that contacts all or a portion of a surface.
[0007] Photovoltaic devices can include optically transparent
substrates, such as glass. Because glass is not conductive, a
transparent conductive oxide (TCO) layer can be deposited between
the substrate and the semiconductor bi-layer to serve as a front
contact. A metal layer can be deposited onto the p-type absorber
layer to serve as a back contact. The front and back contacts can
serve as electrodes for the device. A variety of materials are
available for the metal layer, including, but not limited to
molybdenum, aluminum, chromium, iron, nickel, titanium, vanadium,
manganese, cobalt, zinc, ruthenium, tungsten, silver, gold, and
platinum. Molybdenum functions particularly well as a back contact
metal due to its relative stability at processing temperatures and
low contact resistance. Copper has also proven effective for
preserving fill factor. The inventions disclosed herein relate to
the composition and deposition of back contacts for photovoltaic
devices.
[0008] In one aspect, a photovoltaic device can include an
intrinsic metal layer adjacent to a semiconductor absorber layer.
The photovoltaic device can include a doped metal contact layer
adjacent to the intrinsic metal layer. The doped metal contact
layer can include a metal base material and a dopant.
[0009] The intrinsic metal layer can include a molybdenum,
aluminum, chromium, iron, nickel, titanium, vanadium, manganese,
cobalt, zinc, ruthenium, tungsten, silver, gold, or platinum, or
combinations thereof. The intrinsic metal layer can include a
molybdenum. The intrinsic metal layer can include a nitrogen. The
intrinsic metal layer can include a molybdenum nitride. The
intrinsic metal layer can include a chromium. The metal base
material can include a molybdenum, aluminum, chromium, iron,
nickel, titanium, vanadium, manganese, cobalt, zinc, ruthenium,
tungsten, silver, gold, or platinum, or combinations thereof. The
metal base material can include a molybdenum. The dopant can
include a copper, antimony, potassium, sodium, cesium, silver,
gold, phosphorous, arsenic, and bismuth. The dopant can include a
copper. The dopant can include a sodium. The doped metal contact
layer can include a copper concentration of about 0.1% to about
10%. The photovoltaic device can include a semiconductor window
layer, where the semiconductor absorber layer is positioned
adjacent to the semiconductor window layer, and where the
semiconductor window layer and the semiconductor absorber layer are
at least a part of a semiconductor bi-layer. The semiconductor
window layer can include a cadmium sulfide layer. The photovoltaic
device can include a transparent conductive oxide stack, where the
semiconductor bi-layer is positioned adjacent to the transparent
conductive oxide stack. The photovoltaic device can include a first
substrate, where the transparent conductive oxide stack is
positioned adjacent to the first substrate. The first substrate can
include a glass. The glass can include a soda-lime glass. The
transparent conductive oxide stack can include a buffer layer
positioned adjacent to a transparent conductive oxide layer, and
where the transparent conductive oxide layer is positioned adjacent
to one or more barrier layers. The transparent conductive oxide
layer can include a cadmium stannate. The buffer layer can include
a zinc tin oxide, tin oxide, zinc oxide, or zinc magnesium oxide,
or combinations thereof. Each of the one or more barrier layers can
include a silicon nitride, aluminum-doped silicon nitride, silicon
oxide, aluminum-doped silicon oxide, boron-doped silicon nitride,
phosphorous-doped silicon nitride, silicon oxide-nitride, or tin
oxide, or combinations thereof. The photovoltaic device can include
a back support adjacent to the doped metal contact layer.
[0010] In one aspect, a method for manufacturing a photovoltaic
device can include depositing an intrinsic metal layer on a
semiconductor absorber layer. The method can include depositing a
doped metal contact layer on the intrinsic metal layer. The doped
metal contact layer can include a metal base material and a
dopant.
[0011] Depositing an intrinsic metal layer can include sputtering a
molybdenum. Depositing an intrinsic metal layer can include
sputtering a chromium. Depositing an intrinsic metal layer can
include sputtering a molybdenum nitride. Depositing an intrinsic
metal layer can include depositing a molybdenum, aluminum,
chromium, iron, nickel, titanium, vanadium, manganese, cobalt,
zinc, ruthenium, tungsten, silver, gold, or platinum, or
combinations thereof. The method can include doping a metal base
material to form a doped metal contact layer. The method can
include doping a metal base material with a dopant, where the metal
base material can include a molybdenum, aluminum, chromium, iron,
nickel, titanium, vanadium, manganese, cobalt, zinc, ruthenium,
tungsten, silver, gold, or platinum, or any combination thereof,
and where the dopant can include a copper, antimony, potassium,
sodium, cesium, silver, gold, phosphorous, arsenic, or bismuth, or
any combination thereof. The method can include doping a metal base
material with about 0.1% to about 10% copper. Depositing a doped
metal contact layer can include sputtering a copper-doped
molybdenum. Depositing a doped metal contact layer can include
sputtering a metal base material that includes the same metal as
the intrinsic metal layer. The method can include depositing the
semiconductor absorber layer adjacent to a semiconductor window
layer, where the semiconductor absorber layer includes a cadmium
telluride layer, and where the semiconductor window layer includes
a cadmium sulfide layer. The method can include depositing the
semiconductor window layer adjacent to a transparent conductive
oxide stack, where the transparent conductive oxide stack can
include a buffer layer adjacent to a transparent conductive oxide
layer, where the transparent conductive oxide layer is positioned
adjacent to one or more barrier layers. The method can include
depositing the transparent conductive oxide stack adjacent to a
first substrate. The first substrate can include a glass. The glass
can include a soda-lime glass. Each of the one or more barrier
layers can include a silicon nitride, aluminum-doped silicon
nitride, silicon oxide, aluminum-doped silicon oxide, boron-doped
silicon nitride, phosphorous-doped silicon nitride, silicon
oxide-nitride, or tin oxide, or combinations thereof. The
transparent conductive oxide layer can include a cadmium stannate.
The buffer layer can include a zinc tin oxide, tin oxide, zinc
oxide, or zinc magnesium oxide, or combinations thereof. The method
can include annealing the transparent conductive oxide stack. The
method can include depositing a back support adjacent to the doped
metal contact layer.
[0012] In one aspect, a photovoltaic module may include a plurality
of photovoltaic cells adjacent to a substrate. The photovoltaic
module may include a back cover adjacent to the plurality of
photovoltaic cells. The plurality of photovoltaic cells may include
a second metal layer adjacent to a first layer. The first layer may
be positioned adjacent to a substrate. The second metal layer may
include a dopant. The plurality of photovoltaic cells may include
an intrinsic metal layer adjacent to a semiconductor absorber
layer. The plurality of photovoltaic cells may include a doped
metal contact layer adjacent to the intrinsic metal layer. The
doped metal contact layer may include a metal base material and a
dopant.
[0013] The photovoltaic module may include a first strip of tape
having a length distributed along a contact region of each
photovoltaic cell. The first strip of tape may include a front
surface and a back surface. Each surface may contain an adhesive.
The photovoltaic module may include a first lead foil distributed
along the length of the first strip of tape. The photovoltaic
module may include a second strip of tape, having a length shorter
than that of the first strip of tape, distributed along the length
and between the ends of the first strip of tape. The second strip
of tape may include a front and back surface. Each surface may
contain an adhesive. The photovoltaic module may include a second
lead foil, having a length shorter than that of the second strip of
tape, distributed along the length of the second strip of tape. The
photovoltaic module may include a plurality of parallel bus bars,
positioned adjacent and perpendicular to the first and second
strips of tape. Each one of the plurality of parallel bus bars may
contact one of the first or second lead foils. The photovoltaic
module may include first and second submodules. The first submodule
may include two or more cells of the plurality of photovoltaic
cells connected in series. The second submodule may include another
two or more cells of the plurality of photovoltaic cells connected
in series. The first and second submodules may be connected in
parallel through a shared cell.
[0014] In one aspect, a method for generating electricity may
include illuminating a photovoltaic cell with a beam of light to
generate a photocurrent. The method may include collecting the
generated photocurrent. The photovoltaic cell may include a second
metal layer adjacent to a first layer. The first layer may be
positioned adjacent to a substrate. The second metal layer may
include a dopant. The photovoltaic cell may include an intrinsic
metal layer adjacent to a semiconductor absorber layer. The
photovoltaic cell may include a doped metal contact layer adjacent
to the intrinsic metal layer. The doped metal contact layer may
include a metal base material and a dopant.
[0015] Referring to FIG. 1 by way of example, photovoltaic device
10 can be formed by depositing transparent conductive oxide layer
110 onto substrate 100 to serve as a front contact for photovoltaic
device 10. Transparent conductive oxide layer 110 can include any
suitable contact material, including a cadmium stannate, and can be
deposited using any suitable technique, including sputtering.
Semiconductor window layer 120 can be deposited on transparent
conductive oxide layer 110. Semiconductor window layer 120 can
include any suitable n-type semiconductor material, including
cadmium sulfide. Semiconductor window layer 120 can be deposited
using any suitable technique, including vapor transport.
Semiconductor absorber layer 130 can be deposited onto
semiconductor window layer 120. Semiconductor absorber layer 130
can include any suitable p-type semiconductor material, including
cadmium telluride. Semiconductor absorber layer 130 can be
deposited using any suitable deposition technique, including vapor
transport. An intrinsic metal layer 140 can be deposited onto
semiconductor absorber layer 130. Intrinsic metal layer 140 can
include any intrinsic semiconductor material, including but not
limited to molybdenum, aluminum, chromium, iron, nickel, titanium,
vanadium, manganese, cobalt, zinc, ruthenium, tungsten, silver,
gold, or platinum. Intrinsic metal layer 140 can also include a
nitrogen. For example, intrinsic metal layer 140 can include a
molybdenum nitride. Intrinsic metal layer 140 can be deposited
using any suitable deposition technique, including sputtering, such
as RF sputtering. Doped metal layer 150 can be deposited onto
intrinsic metal layer 140 to serve as a back contact for
photovoltaic device 10. Intrinsic metal layer 140 and/or doped
metal layer 150 can also be of a suitable thickness, for example
greater than about 10 A, greater than about 20 A, greater than
about 50 A, greater than about 100 A, greater than about 250 A,
greater than about 500 A, less than about 2000 A, less than about
1500 A, less than about 1000 A, or less than about 750 A. Doped
metal layer 150 may include a metal base material and a dopant
material. The metal base material can include any suitable metal or
alloy, including molybdenum, aluminum, chromium, iron, nickel,
titanium, vanadium, manganese, cobalt, zinc, ruthenium, tungsten,
silver, gold, or platinum. The dopant material can include any
suitable dopant, including copper, antimony, potassium, sodium,
cesium, silver, gold, phosphorous, arsenic, or bismuth. For
example, doped metal layer 150 can include a molybdenum, doped with
about 0.1% to about 10% copper. Intrinsic metal layer 140 and/or
doped metal layer 150 can be substantially pure, containing a
single metal or a binary alloy, mixture, or solid solution thereof.
Photovoltaic device 10 can undergo heat treatment, during which the
dopant material from doped metal layer 150 can diffuse into
intrinsic metal layer 140. For example, copper from a copper-doped
molybdenum can diffuse into a molybdenum nitride layer to create a
concentration gradient.
[0016] Referring to FIG. 2, photovoltaic device 10 can further
include a barrier layer 200 deposited between substrate 100 and
transparent conductive oxide 110. Barrier layer 200 can preserve
and/or enhance device performance by prohibiting diffusion of
sodium (or other chemicals) from substrate 100. Barrier layer 200
can include any suitable barrier material, including silicon
nitride, aluminum-doped silicon nitride, silicon oxide,
aluminum-doped silicon oxide, boron-doped silicon nitride,
phosphorous-doped silicon nitride, silicon oxide-nitride, or tin
oxide, or any combinations thereof. Barrier layer 200 can include
multiple barrier layers. In continuing reference to FIG. 2,
photovoltaic device can also include a buffer layer 210 to enable
smooth and continuous deposition of the subsequent semiconductor
window layer 120. Buffer layer 120 can include any suitable buffer
material, including zinc tin oxide, tin oxide, zinc oxide, or zinc
magnesium oxide. A back support 230 can be deposited onto doped
contact layer 150, and can include any suitable material, for
example, a soda-lime glass.
[0017] A variety of deposition techniques are available for
depositing the layers discussed above, including for example, low
pressure chemical vapor deposition, atmospheric pressure chemical
vapor deposition, plasma-enhanced chemical vapor deposition,
thermal chemical vapor deposition, DC or AC sputtering, spin-on
deposition, and spray-pyrolysis. A sputtering target can be
manufactured by ingot metallurgy. A sputtering target can be
manufactured from cadmium, tin, silicon, or alumium, or
combinations or alloys thereof suitable to make the layer. For
example, the target can be Si.sub.85Al.sub.15 The cadmium and tin
can be present in the same target in stoichiometrically proper
amounts. A sputtering target can be manufactured as a single piece
in any suitable shape. A sputtering target can be a tube. A
sputtering target can be manufactured by casting a metallic
material into any suitable shape, such as a tube.
[0018] A sputtering target can be manufactured from more than one
piece. A sputtering target can be manufactured from more than one
piece of metal, for example, a piece of cadmium and a piece of tin.
The cadmium and tin can be manufactured in any suitable shape, such
as sleeves, and can be joined or connected in any suitable manner
or configuration. For example, a piece of cadmium and a piece of
tin can be welded together to form the sputtering target. One
sleeve can be positioned within another sleeve.
[0019] A sputtering target can be manufactured by powder
metallurgy. A sputtering target can be formed by consolidating
metallic powder (e.g., cadmium or tin powder) to form the target.
The metallic powder can be consolidated in any suitable process
(e.g., pressing such as isostatic pressing) and in any suitable
shape. The consolidating can occur at any suitable temperature. A
sputtering target can be formed from metallic powder including more
than one metal powder (e.g., cadmium and tin). More than one
metallic powder can be present in stoichiometrically proper
amounts.
[0020] A sputter target can be manufactured by positioning wire
including target material adjacent to a base. For example wire
including target material can be wrapped around a base tube. The
wire can include multiple metals (e.g., cadmium and tin) present in
stoichiometrically proper amounts. The base tube can be formed from
a material that will not be sputtered. The wire can be pressed
(e.g., by isostatic pressing).
[0021] A sputter target can be manufactured by spraying a target
material onto a base. Metallic target material can be sprayed by
any suitable spraying process, including thermal spraying and
plasma spraying. The metallic target material can include multiple
metals (e.g., cadmium and tin), present in stoichiometrically
proper amounts. The base onto which the metallic target material is
sprayed can be a tube.
[0022] Photovoltaic devices/cells fabricated using the methods
discussed herein may be incorporated into one or more photovoltaic
modules, each of which may include one or more submodules. Such
modules may by incorporated into various systems for generating
electricity. For example, a photovoltaic module may include one or
more submodules consisting of multiple photovoltaic cells connected
in series. One or more submodules may be connected in parallel via
a shared cell to form a photovoltaic module.
[0023] A bus bar assembly may be attached to a contact surface of a
photovoltaic module to enable connection to additional electrical
components (e.g., one or more additional modules). For example, a
first strip of double-sided tape may be distributed along a length
of the module, and a first lead foil may be applied adjacent
thereto. A second strip of double-sided tape (smaller than the
first strip) may be applied adjacent to the first lead foil. A
second lead foil may be applied adjacent to the second strip of
double-sided tape. The tape and lead foils may be positioned such
that at least one portion of the first lead foil is exposed, and at
least one portion of the second lead foil is exposed. Following
application of the tape and lead foils, a plurality of bus bars may
be positioned along the contact region of the module. The bus bars
may be positioned parallel from one another, at any suitable
distance apart. For example, the plurality of bus bars may include
at least one bus bar positioned on a portion of the first lead
foil, and at least one bus bar positioned on a portion of the
second lead foil. The bus bar, along with the portion of lead foil
on which it has been applied, may define a positive or negative
region. A roller may be used to create a loop in a section of the
first or second lead foil. The loop may be threaded through the
hole of a subsequently deposited back glass. The photovoltaic
module may be connected to other electronic components, including,
for example, one or more additional photovoltaic modules. For
example, the photovoltaic module may be electrically connected to
one or more additional photovoltaic modules to form a photovoltaic
array.
[0024] The photovoltaic cells/modules/arrays may be included in a
system for generating electricity. For example, a photovoltaic cell
may be illuminated with a beam of light to generate a photocurrent.
The photocurrent may be collected and converted from direct current
(DC) to alternating current (AC) and distributed to a power grid.
Light of any suitable wavelength may be directed at the cell to
produce the photocurrent, including, for example, more than 400 nm,
or less than 700 nm (e.g., ultraviolet light). Photocurrent
generated from one photovoltaic cell may be combined with
photocurrent generated from other photovoltaic cells. For example,
the photovoltaic cells may be part of one or more photovoltaic
modules in a photovoltaic array, from which the aggregate current
may be harnessed and distributed.
[0025] The embodiments described above are offered by way of
illustration and example. It should be understood that the examples
provided above may be altered in certain respects and still remain
within the scope of the claims. It should be appreciated that,
while the invention has been described with reference to the above
preferred embodiments, other embodiments are within the scope of
the claims.
* * * * *