This project is done by Mr.Balaji padmanaban on Arizona state university
Solar energy is becoming one of the
primary sources of energy replacing fossil
fuels due to its abundance. Its
versatility, abundance and environmental friendly have
made it one of the most promising
renewable sources of energy. Solar cells convert this
solar energy into Electrical Energy
used to drive various appliances. The effort to
improve the efficiency of these cells
and the reduction of their costs has been a major
concern for a long time. Modeling of
various structures of solar cells provides an insight
into the physics involved in its
operation and better understanding of the ways to improve
their efficiency.
In this work a three dimensional Drift
Diffusion Model has been developed and
has been used to simulate Silicon
Solar cells. This model involves the self consistent
solution of the Poisson and Continuity
Equations. A pn silicon solar cell has been
simulated to test the working of the
code. Later a p+-p-n+ and n+-p-p+ structure of
various lengths has been simulated to
understand the physics behind the operation of a
realistic silicon solar cell.
Recombination mechanisms which play a crucial role in the
determination of the cell efficiency
such as Radiative Recombination, SHR
recombination, Auger Recombination
have been included in the code.
Light does not enter through all the
regions of the device since the top metal
contact has some reflectivity and thus
prevents the light to enter the device called the
Shadowing effect. Thus Shadowing
effect tends to reduce the efficiency of the solar cell
as the effective number of electron
hole pairs generated within the device has been
reduced and this is observed during
simulation. The surface recombination effect has also been included for the
surface of the window through which light enters the device and
this also tends to reduce the
efficiency.
Finally the efficiency variation with
the variation in the length of the device has
been simulated. Theoretically the
efficiency increases initially with the increase in the
base length since the capture of
higher wavelength photons or lower energy photons is
possible thus increasing the
efficiency but with increase after a certain length a decrease
in the efficiency takes place due to
the increase in the ratio of the length of the device to
the diffusion length. In this work the
increase in the efficiency with length has been
simulated but the length could not be
increased a lot to observe the decrease in efficiency
due to limitation of simulation time.
To download the full thesis of this project for your references you can go to this site:
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