Environmental Engineering Reference
In-Depth Information
Fig. 2.3 Absorption spectra
of PC
60
BM and PC
70
BM
Table 2.5 Photovoltaic performance of the fullerene multiadduct acceptors
Donor/acceptor (weight ratio)
J
sc
(mA/cm
2
)
V
oc
(V)
FF
PCE (%)
Refs
P3HT/PC
60
BM(1:0.8)
10.9
0.62
0.62
4.18
[
72
]
P3HT/bisThC
60
BM(1:1.2)
5.91
0.72
0.41
1.73
[
72
]
P3HT/triThC
60
BM(1:1.4)
1.88
0.64
0.28
0.34
[
72
]
P3HT/bisPC
60
BM(1:1.2)
9.14
0.724
0.68
4.5
[
71
]
P3HT/PC
60
BM(1:1)
8.94
0.61
0.60
2.4
[
70
]
P3HT/bisPC
60
BM(1:1.2)
7.30
0.73
0.63
2.4
[
70
]
P3HT/bisPC
70
BM(1:1.2)
7.03
0.75
0.62
2.3
[
70
]
P3HT/bisThC
60
BM(1:1.2)
7.31
0.72
0.66
2.5
[
70
]
2.2.2.2 Indene-C
60
Bisadduct and Indene-C
70
Bisadduct (ICBA)
Indene-fullerene adducts were used as electron acceptor materials in OPVs [
73
-
75
]. This kind of compounds can be synthesized easily by a one-pot reaction. The
solution of indene and fullerene (C60 or C70) in DCB was heated to reflux for
several hours, and a mixture of unreacted fullerene, indene-fullerene monoadduct
(ICMA), indene-fullerene bisadduct (ICBA), and indene-fullerene multiadduct can
be obtained, which can be separated readily through column chromatography.
LUMO levels of ICMA and ICBA are -3.86 and -3.74 eV respectively [
73
]; both
are higher than that of PCBM, and thus ICMA/P3HT- and ICBA/P3HT-based
devices showed higher V
oc
than that of P3HT/PCBM-based devices. ICMA has
poor solubility in CB or DCB, which limits the photovoltaic performance of the
devices; ICBA can be easily dissolved into CB or DCB, and its LUMO level was
higher than ICMA and PCBM.
ICBA was successfully used in P3HT-based solar cells. Typically, V
oc
of
P3HT/PCBM system is *0.6 V; in P3HT/ICBA system, V
oc
of 0.84 V can be
obtained without sacrificing the other parameters, including FF and J
sc
. The great
increase on
V
oc
should be benefited from the high-lying LUMO of ICBA. The
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