Environmental Engineering Reference
In-Depth Information
Table 9.2 Typical solar cell parameters measured under AM1.5
conditions for 0.002 cm
2
and 0.090 cm
2
solar cells
J
sc
(mAcm
−
2
) F
η
/cm
2
)
p
(
/cm
2
)
Device
V
oc
(mV)
(%)
R
s
(
0.002 cm
2
1
1,110
12.6
0.83
11.6
—
—
solar cells 2
1,081
12.3
0.82
11.0
2.3
4,200
3
1,077
12.3
0.82
10.8
2.9
3,000
0.090 cm
2
1
1,148
11.9
0.86
11.7
2.5
10,400
solar cells 2
1,141
11.4
0.86
11.2
4.0
5,100
3
1,150
13.1
0.85
12.7
3.8
—
measured immediately after the removal of the bias voltage. The
same diodes were then exposed to reverse-bias conditions with a
voltageof
∼
0.8VforseveralhoursandI-Vcurveswereimmediately
recorded. Drastic changes inI-Vcharacteristics have been observed,
distorting the high-quality solar cell characteristics presented in
Fig. 9.5. Typical results are summarised in Table 9.3 and shown in
Figs. 9.6to 9.9.
During subsequent I-V measurements after applying electrical
stresses to device structures, measured parameters showed drastic
changes, as shown in Table 9.3. All parameters fluctuate in wide
ranges. The I-V curves showed peculiar kinks, as shown in Fig. 9.6;
sudden discontinuities, as shown in Fig. 9.7(a); and deformed
characteristics, as shown in Fig. 9.7(b). Figure 9.8 graphically
Table 9.3 A summary of solar cell parameters as a function of the applied
external electrical stress
J
sc
(mAcm
−
2
)
Stresses Applied (V)
V
oc
(mV)
FF (%)
I
sc
(mA)
1.
First measurement
1,093
84
0.036
18.0
2.
Forward bias with 1.0 V for 2 hrs
930
73
0.037
18.3
3.
Forward bias with 1.0 V for 3 hrs
855
77
0.023
11.4
4.
Reverse bias with 0.7 V for 17 hrs
855
74
0.032
16.1
5.
Reverse bias with 0.8 V for 3 hrs
888
77
0.021
10.7
6.
Reverse bias with 0.8 V for 19 hrs
1,038
83
0.012
6.0
7.
Reverse bias with 0.8 V for 3 hrs
963
54
0.045
22.5
8.
Reverse bias with 0.8 V for 19 hrs
1,081
81
0.028
14.1
9.
Forward bias with 0.9 V for 66 hrs
1,050
82
0.016
7.8
10.
Forward bias with 0.9 V for 28 hrs
625
62
0.024
12.0
11.
Forward bias with 0.9 V for 25 hrs
1,025
80
0.009
4.6
