ECE/OPTI 514A/414A
Problem Set 1
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Please Turn in Problem Set 1 in the D2L Folder under the
Assignment tab;
Scan or take a clear picture of your work. Submit as one document
(not 4).
Answer the questions on a blank sheet of paper clearly labeling your
work for each section. (i.e. 1 a.,… 3 c.,… etc.)
1. A silicon PV cell has a Voc = 0.62V, Isc = 1.30A, m = 1.2 (ideality factor), the
reverse saturation current is 10-9A, and is operating at a temperature of 300K.
a. (1) Assuming that Green’s fill factor approximation is valid and the cell does
not have parasitic resistance compute the fill factor and maximum power for
this cell.
b. (2) If the PV cell now has a parasitic series resistance of 0.025 ohm, compute
the new maximum power and FF.
c. (2) Now assume that the PV cell has a shunt resistance of 100 ohm and no
series resistance. What is the new FF and maximum power?
d. (2) Now assume that both the 0.025 ohm series resistance and the 100 ohm
shunt resistance exist simultaneously. Compute the output current (I) at an
output voltage of 0.6*Voc.
e. (1) i) Sketch the I-V for the ideal PV cell showing the approximate form for the
FF obtained in part a . ii) Assuming that the PV cell now has the 0.025 ohm
series resistance sketch the I-V curve for this cell on the same plot.
f. (2) A PV cell has a short circuit current of 1A with solar irradiance at
500W/m2, a reverse saturation current of 10-9A. If the cell is illuminated with
1000W/m2 and the cell temperature stays the same how much does the open
circuit voltage change?
2. (10) Compute the electron-hole generation rate at a depth of 20µm into a slab of
silicon produced with sunlight at 640 nm within a 10 nm spectral bandwidth about
640 nm (i.e. 640 nm +/-5nm). Assume that the spectral irradiance at 640 nm is
1.465 W/m2-nm (as found in the Lab 2 data). The absorption of silicon at this
wavelength is 5000/cm. Also assume that the light is normally incident and
account for reflection from the surface of the silicon that has a refractive index of
3.6. (Note that in this problem there is no grid contact i.e. s = 0.)
3. a. The diagram below shows the fixed charge distribution in a PV cell when a p-n
junction is formed.
