Brief discussion on various advanced solar cells

1. Advanced Solar Cell structures
Arpan Deyasi
Kolkata, India
5/16/2021 1
Arpan Deyasi, RCCIIT, India

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Arpan Deyasi, RCCIIT, India
Generation growth
 1st generation
 2nd generation
 3rd generation

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Arpan Deyasi, RCCIIT, India
1st generation solar cell
Conventional, wafer-based solar cell
Made of mono-crystalline and poly-crystalline
Semiconductor materials

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1st generation solar cell
Higher conversion efficiency w.r.t absorbed photons
Most of the photons have energies less or greater
than bandgap
Open-circuit voltage is smaller than bandgap

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Arpan Deyasi, RCCIIT, India
2nd generation solar cell
Based on thin film technology
Materials are CdTe, CIGS, amorphous Silicon

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2nd generation solar cell
Higher absorption coefficient
Lower fabrication cost compared to Si solar cell
Environment contamination starts from
fabrication processes
Materials are not abundant, and hence cost is more

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Arpan Deyasi, RCCIIT, India
3rd generation solar cell
Made by organic or organo-metallic compounds

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Arpan Deyasi, RCCIIT, India
Cost is minimal
3rd generation solar cell
Raw materials are easy to find
Easier fabrication process rather than
other two technology
Due to use of liquid electrolyte, cost is higher

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M S(n)
Ec
EV
EFn
EFi
ΦM > ΦS(n)
Schottky Barrier Solar Cell
Monochromatic
light

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Arpan Deyasi, RCCIIT, India
Schottky Barrier Solar Cell
Principle similar to p-n junction cell
Cheap and easy alternative to traditional cell
Limitations:
Conducting grid on top of metal layer
Surface damage due to high temperature in
grid-attachment technique

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Arpan Deyasi, RCCIIT, India
Grooved Junction Cell
Source: https://www.pveducation.org/

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Arpan Deyasi, RCCIIT, India
Grooved Junction Cell
Higher p-n junction area
High efficiency ( > 20%)

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Arpan Deyasi, RCCIIT, India
Thin Film Solar Cells
Produced from cheaper polycrystalline materials
and glass
High optical absorption coefficients
Bandgap suited to solar spectrum

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Arpan Deyasi, RCCIIT, India
According to the type of photo voltaic material used, the thin
film solar cells are classified into four types:
1) Amorphous silicon (a-Si) and other thin-film silicon (TF-Si)
2) Cadmium Telluride (CdTe)
3) Copper indium gallium deselenide (CIS or CIGS)
4) Dye-sensitized solar cell (DSC) and other organic solar cells
Thin Film Solar Cells

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Arpan Deyasi, RCCIIT, India
Thin Film Solar Cells
Source: https://www.circuitstoday.com/

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Arpan Deyasi, RCCIIT, India
Advantages
1) Easy to handle
2) More flexible than conventional solar cells
3) Available as thin wafer sheets
4) Cheaper than traditional panels
Thin Film Solar Cells
Disadvantages
1) Less efficiency (20 to 30% of light converted into
electricity)
2) Complex structure
3) Need to be very careful in handling
4) Can’t be used in astronomical devices

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Arpan Deyasi, RCCIIT, India
Tandem Solar Cell
One method to increase the efficiency of a solar cell is to
split the spectrum and use a solar cell that is optimised
to each section of the spectrum
Tandem solar cells can either be individual cells or
connected in series.

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Arpan Deyasi, RCCIIT, India
Tandem Solar Cell
Top cell absorbs high
energy photons
Bottom cell absorbs low
energy photons
Source: https://www.pveducation.org/

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Arpan Deyasi, RCCIIT, India
Stacking two solar cells one on top of the other, where
top cell is semi-transparent, which efficiently converts
large energy photons into electricity
The bottom cell converts the remaining or transmitted
low energy photons in an optimum manner
Tandem Solar Cell

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Multiband Solar Cell
3rd generation photovoltaics
At radiative limits, large gains
in efficiency are possible,
primarily because photons
with energies lower than
primary band gap can now
be absorbed and utilized

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Thermophotonic Solar Cell
• Heated semiconductor
emits narrow bandwidth
radiations
• Diode with higher
temperature has lower
voltage

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generates electrical current as it radiates infrared light
(heat) toward the extreme cold of deep space
Thermophotovoltaic Solar Cell

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• Filter passes radiations of energy equal to bandgap of solar
cell material
• Emitter radiation matched with spectral sensitivity of cell
• High Illumination Intensity ( ~ 10 kW/m2 )
Thermophotovoltaic Solar Cell