Sanyo AMORTON User Manual
Amorphous Silicon Solar Cells / Amorphous Photosensors
2007-11
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The development of the solar cell is progressing with rapid speed.
As a new energy tool which can effectively harness the amazing power of sunlight,
solar cells have the potential to replace fossil fuels as our main means of power generation.
Solar energy is both a clean and inexhaustible resource,
and it can be used to produce electricity wherever and whenever sunlight is available.
Of these technologies, amorphous silicon solar cells have many strengths
that surpass those of the earlier crystalline silicon solar cells.
In addition, they require little energy to manufacture and use less raw materials,
and thus are truly environmentally friendly devices.
This technology also allows larger area cells to be manufactured
and can take advantage of the flexibility of thin film materials,
and they have already been used in a wide range of applications.
SANYO was one of the first companies to focus on amorphous silicon solar cells, and
developed and is now mass producing the Amorton integrated type
amorphous silicon solar cells that feature a new device structure.
Amorphous Crystal
Amorphous Silicon Solar Cells
The Concept Behind Solar Cell Power Generation
Solar cell power is generated using the photovoltaic effect of
semiconductors. When a semiconductor is exposed to a light source
of suitable intensity, a large number of pairs of an electron and a
positive hole are generated as a result of the reciprocal action
between photons and silicon atoms.
At a p/n junction between two different semiconductor materials, the
electrons are diffused in the n-type material and the positive holes
are scattered in the p-type material. They are then collected at both
electrodes respectively, resulting in a voltage difference between the
electrodes.
When an external load is connected, electricity flows through the
load. In this way, an a-Si solar cell converts light energy into
electricity and supplies power to external loads.
Solar cells are classified according to the material employed, i.e., crystal silicon, amorphous silicon,
and compound semiconductor solar cells. "Amorphous" refers to objects having no definite shape and
is defined as non-crystal material.
Unlike crystal silicon, in which atomic arrangements are regular, amorphous silicon features
irregular atomic arrangements as shown in the figures below.
As a result, the reciprocal action between photons and silicon atoms occurs more frequently in
amorphous silicon than in crystal silicon, allowing much more light to be absorbed. Thus, an ultrathin amorphous silicon film of less than 1μm can be produced and used for power generation. Also, by
utilizing metal or plastics for the substrate, flexible solar cells can be produced.
Amorton is an integrated amorphous silicon solar cell which has been developed by SANYO.
Amorton uses silane (SiH
4) as its source gas and is fabricated using a plasma CVD method.
Three amorphous silicon layers ⎯ p-layer, i-layer, and n-layer ⎯ are formed consecutively on a glass
substrate. This p-i-n junction corresponds to the p/n
junction of a crystal silicon solar cell. In the process of
this junction formation, a number of cells are connected
in series on a substrate at one time. This allows any
desired voltage to be obtained for a variety of
equipment operation.
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Transparent
electrode
p
i
n
Metal
electrode
Light
Electron
Positive hole
Electric current
Load
Application Examples
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Features of Amorton
The figure shows the relationship
between illumination level and
output. There is an enormous
difference between the
illumination levels indoors and
outdoors. SANYO provides two
types of products, indoor
products for use in the low
illumination levels common in
indoor environments and outdoor
products for the high illumination
levels common outdoors.
■ Solar cells with a variety of voltages can be created
Since, unlike the fabrication technique used with crystalline solar cells in which cells cut apart and then
connected, multiple cells can be connected in series at the same time as the cells are formed, it is easy to
create batteries with a variety of voltages.
(This series connection idea is the same as that used with regular batteries.)
■ Solar cells with a variety of shapes can be created
The methods used to form amorphous films have special features that allow other substrates, such as
stainless steel or plastic films, to be used in place of the usual glass substrate. This means that previously
unknown solar cells, solar cells that are round, square, or any complex shape, or solar cells that can be
bent, can be created.
It is also possible to create areas in these solar cells that consist of just transparent glass by etching.
■ High sensitivity in the visible light region
The human eye is sensitive to light with wavelengths from about 400 nm to 700 nm.
Since amorphous silicon solar cells are sensitive to light with essentially the same wavelengths, in addition
to solar cells, they can also be used as visible light sensors.
■
Relationship between
illumination level and output
Output (current)
comparison
Current
Voltage
Illumination
[lux]
1
100 1000 10000 100000
500
1000
A
B
C
[Example]
A: 1cm
2
: one row of cell
B: 1cm
2
: two rows of cell
C: 2cm
2
: one row of cell
Dining rooms,
coffee shops
Offices,
meeting rooms
Drafting
tables
Rain
Cloudy Bright
Direct sun
Outdoor products
Indoor products
Electronic
calculators
Wristwatches
(Solar watches)
Clocks
Stopwatches
Garden
lights
Sensor
lights
Car
accessories
Battery
chargers
Mobile
equipment such
as cell phones
POP
products
LED
blinkers
(Curbstone
markers)
SANYO can support other applications as well.
Contact your SANYO representative for consultation.
Place used Substrate Feature Reference
Low price (basic substrate)
Thin, light weight, unbreakable, can easily be
formed in arbitrary shapes, highly precise
dimensions
Thin, light weight, unbreakable, can easily be
formed in arbitrary shapes, highly precise
dimensions
Thin, light weight, unbreakable, bendable,
can easily be formed in arbitrary shapes
Thin, light weight, unbreakable, bendable,
can easily be formed in arbitrary shapes
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Contact your
SANYO
representative.
Contact your
SANYO
representative.
Contact your
SANYO
representative.
Indoors
Outdoors
Visible light
sensor
Glass
Stainless steel
Film
Low price (basic substrate)
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Page 9
Glass
Stainless steel
Film
Contact: The person in charge of Amorton products TEL.03-3837-6306
Support designs with arbitrary sizes and patterns
as required by the application
■
Relationships between number
of rows of the cell and cell area
(Illumination level is constant.)
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