Foundation of Solar cell

1. Photovoltaic Cell
Part-I: Foundation
Arpan Deyasi
Dept of ECE, RCCIIT, Kolkata, India
Course: EI605D
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2. Region of EM Wave Wavelength [nm] Energy [eV]
Ultraviolet 10-400 3.1-124
Visible (blue) 450-490 2.53-2.76
Visible (red) 635-700 1.77-1.95
Infrared 1000-10000 0.124-1.24
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3. Ozone layer absorbs ultraviolet radiation
Therefore energy bandwidth of available solar
radiation is 0.124 to 3 eV
We require material whose bandgap will be in that
range, i.e., semiconductor
Any device absorbing solar energy should be made by
Extrinsic Semiconductor material
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4. What is Solar Cell?
It is a semiconductor
device which converts
sunlight into electrical
energy
Why solar energy
is required?
•Free
•Non-polluting
•Ready available
Renewable
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5. What is Photovoltaic Effect?
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6. Photovoltaic Effect
Sunlight is
composed
of photons
Photons absorbed
by solar cell
Valence electrons
excite after
absorbing energy
Goes to conduction
band and
become free
Net increase
in potential
difference
Minority carriers
move according
to the direction
of reverse current
Generation of
photo-voltage
is called
photovoltaic effect
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Difference between Photovoltaic Effect & Photoelectric Effect
In the photoelectric effect, the electrons are emitted into a free
space whereas, in photovoltaic effect, the electrons directly enter
another material upon emission.
The emitted electrons via the photovoltaic effect are pushed
through a junction potential in contrast to the photoelectric effect
where there is no junction potential involved.

8. I-VCharacteristicofSolarCell
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I-VCharacteristicofSolarCell

10. I-VCharacteristicofSolarCell
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I-VCharacteristicofSolarCell
Dark
Illuminated

12. Voc & Isc
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13. Fill Factor
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14. Conversion Efficiency
Efficiency is always calculated at AM = 1.5
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Factors affecting Conversion efficiency
1. Wavelength of Light – Decrease of wavelength increases energy of
photons, thereby increasing efficiency
2. Recombination – Increase of recombination produces generation
of light
3. Environmental Temperature – Increase of operating temperature
decreases efficiency of materials
4. Electrical Resistance – Larger electrical contact can minimize
resistance at the cost of blocking incident radiation through larger
metallic contact
5. Absorbing Material – Good quality of absorbing material used at
top surface can reduce amount of reflected photons

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Role of bandgap in determining Efficiency
Open-circuit voltage increases with increase of bandgap
Short-circuit current decreases with increase of bandgap

17. https://www.solpass.org/6-8Science/6s/standards/study6.3.htm
https://www.pveducation.org/pvcdrom/solar-cell-operation/iv-curve
References
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1. Non conventional Energy, A. V. Desai, New Age International
Publishers Ltd.
2. Renewable energy resources and emerging technologies, D.P.
Kothari, Prentice Hall of India Pvt. Ltd.
3. Er. R K Rajput, Non-Conventional Energy Sources and Utilisation
(Energy Engineering), S. Chand Publishing
4. B.H Khan, Non Conventioanl Energy Resources, Tata McGraw-Hill
Education