Newer Material For PV Conversion

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Outline:

• Physics Of PV Conversion

• The three generations of solar cells– First Generation

– Second Generation

– Third Generation

• Solar Cell Materials

• Emerging Photovoltaic

• Timeline of Solar Photovoltaic cell

• Conclusion

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n-type semiconductor

p-type semiconductor

+ + + + + + + + + + + + + + +- - - - - - - - - - - - - - - - - -

Physics of Photovoltaic Conversion

Depletion Zone

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Photovoltaic Materials

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First-generation - based on expensive silicon wafers; 85% of the current commercial market.

Second-generation - based on thin films of materials such as amorphous silicon, Nano crystalline silicon, cadmium telluride, or copper indium selenide. The materials are less expensive, but research is needed to raise the cells' efficiency.

Third-generation - the research goal: a dramatic increase in efficiency that maintains the cost advantage of second-generation materials. Their design may make use of carrier multiplication, hot electron extraction, multiple junctions, sunlight concentration, or new materials.

The three generations of solar cells

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Continued…

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Goal: Achieving high efficiency from inexpensive materials with so-called third-generation cells

The horizontal axis represents the cost of the solar module only; it must be approximately doubled to include the costs of packaging and mounting. Dotted lines indicate the cost per watt of peak power.

Solar PV Materials:

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Efficiency Of Cells (Lab)

Amorphous silicon (multijunction) 13.2%

Cadmium Telluride (CdTe) thin film 16.5%

Copper-Indium-Gallium-Selenium (CIGS) 19.9%

Gallium Arsenide (GaAs) Cell 20%

Multi crystalline or polycrystalline silicon 20.3%

Mono crystalline silicon 23.4%

High performance mono-crystalline silicon 24.7%

Triple-junction (GaInP/GaAs/Ge) cell 40.7%

Emerging Photovoltaic:

• Organic Photovoltaic

An organic photovoltaic cell (OPVC) is aphotovoltaic cell that uses organic electronics--abranch of electronics that deals with conductiveorganic polymers or small organic molecules forlight absorption and charge transport.

An organic photovoltaic cell, comprisingan organic photoconductive layer comprising acharge generating substance and a chargetransporting substance, and a protective layercovering the organic photoconductive layer andblocking low-wavelength light of below 450 nm.

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Continued…

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The optical absorption coefficient of organic molecules is high, so a large amount of light can be absorbed with a small amount of materials.

The power plastic(OPVC) itself has low production costs in high volumes.

The main disadvantages associated with organic photovoltaic cells are low efficiency, low stability and low strength compared to inorganic photovoltaic cells.

• Dye-sensitized solar cell

It is based on a semiconductor formed

between a photo-sensitized anode and an electrolyte.

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The DSSC has a number of attractive features:• semi-flexible and semi-transparent• most of the materials used are low-cost

Disadvantages:• Low Efficiency(7-8%)

• Transparent conducting film

Transparent conductive oxides (TCO) are doped metal oxides used in optoelectronic devices such as flat panel displays and Photovoltaic (including inorganic devices, organic devices). Most of these films are fabricated with polycrystalline or amorphous microstructures.

• Quantum dot solar cell

A quantum dot solar cell is a solar cell design that uses quantum dot as the absorbing photovoltaic material. It attempts to replace bulk materials such as silicon, copper indium gallium selenide (CIGS) or CdTe.

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Timeline of Solar Photovoltaic cell

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Conclusion

Many of us believe that photovoltaics could become the major energy source for the world in the later part of this century, but continued research and development are required in several areas:

PV system costs must be reduced significantly

Improved conversion efficiencies

Long-term reliability must be ensured for new PV materials & devices

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Thank You…

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