Page 108 - Mirjam-Theelen-Degradation-of-CIGS-solar-cells
P. 108
Chapter 4
Abstract
Two types of CIGS solar cells, both designed for implementation in CIGS modules, were
subjected to temperatures between 25ºC and 105ºC. Simultaneous exposure to AM1.5
illumination allowed the measurement of their electrical parameters at these temperatures.
These two types of solar cells, deposited with different procedures on soda lime glass (SLG)
and polyimide (PI) substrates, showed large variations in temperature dependency of these
parameters.
It was shown that the temperature dependency of the open circuit voltage (V) was
oc
dependent on its room temperature value: a high V at 25oC leads to a slower loss of V when
oc
oc
the temperature is increased. For the V, the normalised temperature dependency varied
oc
between -0.28%/ºC and -0.47%/ºC, which is in agreement with literature. The temperature
dependency of the short circuit current density (J ) showed more surprising results. While the
sc
PI samples had the expected positive temperature dependency (0.03 to 0.32 %/C) the SLG
o
samples showed a small negative impact of increasing temperature (-0.01 to -0.05 %/C). A
o
correlation between the temperature dependencies of the J and the ideality factor n was
sc
observed. Therefore, this difference could be caused by increased recombination for the SLG
samples.
Furthermore, the temperature coefficients of the fill factor (negative), efficiency (negative), as
well as the series (slightly negative) and shunt (negative) resistances were extracted.
106
Abstract
Two types of CIGS solar cells, both designed for implementation in CIGS modules, were
subjected to temperatures between 25ºC and 105ºC. Simultaneous exposure to AM1.5
illumination allowed the measurement of their electrical parameters at these temperatures.
These two types of solar cells, deposited with different procedures on soda lime glass (SLG)
and polyimide (PI) substrates, showed large variations in temperature dependency of these
parameters.
It was shown that the temperature dependency of the open circuit voltage (V) was
oc
dependent on its room temperature value: a high V at 25oC leads to a slower loss of V when
oc
oc
the temperature is increased. For the V, the normalised temperature dependency varied
oc
between -0.28%/ºC and -0.47%/ºC, which is in agreement with literature. The temperature
dependency of the short circuit current density (J ) showed more surprising results. While the
sc
PI samples had the expected positive temperature dependency (0.03 to 0.32 %/C) the SLG
o
samples showed a small negative impact of increasing temperature (-0.01 to -0.05 %/C). A
o
correlation between the temperature dependencies of the J and the ideality factor n was
sc
observed. Therefore, this difference could be caused by increased recombination for the SLG
samples.
Furthermore, the temperature coefficients of the fill factor (negative), efficiency (negative), as
well as the series (slightly negative) and shunt (negative) resistances were extracted.
106
