Solar cells convert sunlight directly into electrical energy through the photovoltaic effect. They are constructed of two layers, an n-type and p-type semiconductor, creating a p-n junction. When light hits the solar cell, photons are absorbed and electrons are released, generating an electrical current. The current can be converted to AC power for applications. The main types of solar cells are monocrystalline, polycrystalline, and amorphous silicon cells, which have different efficiencies depending on their material purity.

1. Solar Cell
DEVELOPED BY:-
VIMAL MANGUKIYA (140940106058)
GUIDED BY:-
DIGVIJAY MAHIDHA

2. Definition
 Solar cell is also called as photo galvanic cell
Photo galvanic cell or solar cell is the one which
converts the solar energy (energy obtained from
the sun) directly into electrical energy.

3. Principle
 The solar cells are based on the principles of
photovoltaic effect.

4. Photovoltaic effect
Definition:
 The generation of
voltage across the PN
junction in a
semiconductor due to
the absorption of light
radiation is called
photovoltaic effect.
The Devices based on
this effect is called
photovoltaic device.
Light
ener
gy
n-type semiconductor
p- type semiconductor
Electri
cal
Power
p-n junction

5. Construction
 Solar cell (crystalline Silicon) consists of n-type
semiconductor (emitter) layer and p-type semi-conductor
layer (base). The two layers are sand-wiched
and hence there is formation of p-n
junction.
 The surface is coated with anti-reflection coating
to avoid the loss of incident light energy due to
reflection.

6. Construction

7. Working
 When a solar panel exposed to sunlight , the light
energies are absorbed by a semi conduction
materials.
 Due to this absorbed energy, the electrons are
liberated and produce the external DC current.
 The DC current is converted into 240-volt AC
current using an inverter for different applications.

8. Working

9.  Thus when this p and n layers are connected to
external circuit, electrons flow from n-layer to p-layer,
an hence current is generated
 The electrons that leave the solar cell as current
give up their energy to whatever is connected to
the solar cell, and then re-enter the solar cell.
Once back in the solar cell, the process begins
again.

10. Types of Solar cell
 Based on the types of crystal used, soar cells can be
classified as,
1. Mono crystalline silicon cells
2. Polycrystalline silicon cells
3. Amorphous silicon cells

11. The Mono crystalline silicon cell
 It is produced from pure silicon (single crystal).
Since the Mono crystalline silicon is pure and
defect free, the efficiency of cell will be higher.

12. Polycrystalline solar cell
 In Polycrystalline solar cell, liquid silicon is used as
raw material and polycrystalline silicon was obtained
followed by solidification process. The materials
contain various crystalline sizes. Hence, the efficiency
of this type of cell is less than Mono crystalline cell

13. Amorphous silicon cells
 Amorphous silicon was obtained by depositing
silicon film on the substrate like glass plate.
 The layer thickness amounts to less than 1μm –
the thickness of a human hair for comparison is
50-100 μm.

14. Comparison of Types of solar cell
Material Efficiency (%)
Mono crystalline silicon 14-17
Polycrystalline silicon 13-15
Amorphous silicon 5-7

15. Advantages
1. It is clean and non-polluting
2. It is a renewable energy
3. Solar cells do not produce noise and they are totally
silent.
4. They require very little maintenance
5. They are long lasting sources of energy which can be
used almost anywhere
6. They have long life time
7. There are no fuel costs or fuel supply problems

16. Disadvantage
1. Solar power can`t be obtained in night time
2. Solar cells (or) solar panels are very expensive
3. Energy has not be stored in batteries
4. Air pollution and whether can affect the
production of electricity
5. They need large area of land to produce more
efficient power supply