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What Is A Solar Cell

A solar cell is an electrical device that convertsthe energy of light directly into electricity by thephotovoltaic effect.

It is a form of photoelectric cell which, when

exposed to light, can generate and support anelectric current without being attached to anyexternal voltage source.

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Solar Cells

Solar cells are often electrically connected and encapsulated as amodule.

Photovoltaic modules often have a sheet of glass on the front side.

Various materials display varying efficiencies and have varyingcosts.

Materials for efficient solar cells must have characteristics matchedto the spectrum of available light.

Materials- Si, CIGS, CdTe

Solar cells are made from bulk materials that are cut into wafersbetween 180 to 240 micrometers thick that are then processed likeother semiconductors.

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Disadvantages

Costly to manufacture

Less Efficiency

Storage

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What are NanocrystalSemiconductors

Nanocrystal solar cells are solar cells basedon a substrate with a coating ofnanocrystals.

Nanocrystal solar cells are classed as thirdgeneration solar cells,

They are theoretically expected toovercome the ShockleyQueisser limit.

Materials- Si, CdTe etc.

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Quantum Dots

Quantum dots are semiconductors whoseelectronic characteristics are closelyrelated to the size and shape of theindividual crystal.

They have a diameter in the range of 1-20nm.

Smaller the size of the crystal, the larger theband gap.

The smaller the dot, the closer it is to theblue end of the spectrum, and the largerthe dot, the closer to the red end

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Advantages Over Normal Silicon :-

Multiple electrons can be freed using a single photon.

It also shows increased absorption in the red and infraredwavelengths.

Higher electron mobility, due to the presence of the siliconcrystallites.

Quantum Dots can improve the efficiency of solar cells.

The quantum dot band gap is tunable and can be used to createintermediate bandgaps.

The maximum theoretical efficiency of the solar cell is as high as63.2% with this method.

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Nanocrystal Production Method

Sputtering

19%Ink-jet

Printing

14%

Wet

Synthesis

5%

Spin-

coating

3%

Others

26%

Sputtering is a process wherebyatoms are ejected from a solid targetmaterial due to bombardment of thetarget by energetic particles.

It is commonly used for thin-filmdeposition, etching and analyticaltechniques

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Nanocrystal Production Method

Sputtering

19%Ink-jet

Printing

14%

Wet

Synthesis

5%

Spin-

coating

3%

Others

26%

An inkjet printer is a type of computerprinter that creates a digital image bypropelling droplets of ink onto paper.

The emerging ink jet materialdeposition market uses print headsusing piezoelectric crystals, to depositmaterials directly on substrates.

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Nanocrystal Production Method

Chemical vapor deposition (CVD) isa chemical process used to producehigh-purity, high-performance solidmaterials.

The process is used to produce thin films.

Frequently, volatile by-products are alsoproduced, which are removed by gasflow through the reaction chamber.

Sputtering

19%Ink-jet

Printing

14%

Wet

Synthesis

5%

Spin-

coating

3%

Others

26%

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Future Scope

Liquid Nanocrystals

Synthetic Nanocrystals

Nano-Wires

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Liquid Nanocrystals

Stable liquid solar cells can be painted orprinted onto clear surfaces.

They have a size of around 4nm.

Liquid nanocrystal solar cells are cheaperto manufacture than single-crystal silicon

wafer solar cells Solar cells can be printed on plastic

instead of glass.

Materials- cadmium selenide(CdS)

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Synthetic Nanocrystals

Substitution of the organic molecules withtwo inorganic nanocrystals made fromzinc selenide and cadmium sulfide.

These are highly robust crystals comparedto the organic equivalents

They are less vulnerable to heat, UVradiation, and degradation problems asthe nanocrystals could be revitalized witha methanol wash.

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Nano-Wires

What are Nano-Wires?

Due to some unique physical lightabsorption properties of nanowires, thelimit of how much energy we can utilizefrom the sun's rays is higher thanpreviously believed

Nanowires are more effective for storingsolar energy because they center thesun's rays into a small region in nanowirecrystal

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