Solar PV module

1. PHYSICS OF PV CELLS
SOLAR PV INSTALLATION SUPERVISION
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2. Learning
outcomes
Explain basics of
PV Technology
understand semi
conductors
Explain doping
Understand the
PN-Junction
At the end of this lesson, the participant be able
to:
Participants: Engineers and Technologist
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Course structure
• Theoretical session
• Quiz at intervals
• Practical & Field work
• Group work
CONTENT DELIVERY METHODS:
Presentation Slides, Demonstration, Discussion and Videos
EVALUATION METHOD: Quiz , Group work andTake home assignment

4. Photoelectric Effect
 Exposure to light resulting to generation of electricity
within the molecular structure due to the impact of
photons.
 Mostly exhibited by Group IV element of Periodic table.
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5. Basics of Semiconductors
Conductor
Semiconductor
Insulator
Silicon (Si)
 Mostly occurs as silicate compound such as sand
 Most common element in universe by mass
 2nd most commom element in earth crust
Group IV, III &V, II&VI as in Si, Ge, GaAs, CdTe
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6. Pure Silicon(Instrinsic)
 All valence electrons
used for bonding
 Electrons can break
free by minimum
energy excitation
called band gap
 Intrinsic conductivity is
low (movement of
electrons very limited)
Not usable for PV
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7. Visible Light
Photon
An excited electron from the
valence shell into the
conduction band all through
the molecular structure
Visible Light
Photon
Si Si
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8. Recombination
Parameters for solar cell
operation
 Band gap
 Number of free carriers
(electrons or holes)
available for
conduction.
 “Generation” and
recombination of free
carriers in response to
light shining on the
material
Recombination will
continue unless
direct by an electric
field
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9. Doping(Extrinsic)
Improved extrinsic conductivity by contamination
with phosphorous
N-doping P-doped
Improved extrinsic conductivity by contamination
with boron
Introducing impurities into the lattice structure of an intrinsic semiconductor
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10. Fused together
P-layer(+) N-layer(-)
Movement of electrons to fill holes
PN- Junction formation
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Boron atoms with 6
electrons(-vely charged)
Phosphorus atoms
with 14
electrons(+vely
charged)
Movement of charge Carriers

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P-layer(+) N-layer(-)
-ve charged Due
to excess
electrons at the
boron atoms
+ve charge due to
missing electrons
from the
phosphorus atoms
Electric field opposes movement of further electrons
Electric field directs electrons

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Light, mostly absorbed in p-layer

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Electrons accelerated to n-layer

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Through conductor back to p-layer
When exposed to a radiation of 1
kW/m2, a typical photovoltaic (PV)
cell generates a voltage
and current of approximately 0.6 V
and 7.5 A, respectively (4.5 W).