Hybrid Solar Cells with Polymer and Inorganic Nanocrystals - Organic Solar Cells: Materials and Device Physics - page 248

Fig. 9.6 XRD pattern of
ZnO prepared from
Dietheylzinc under 110 Cin
air. The appearance of the
peaks shows that ZnO is
crystallized. Reproduced with
permission from Ref. [ 24 ]
(see Fig. 9.6 ); namely, Diethyl Zinc which has been used to fabricate HSCs with
MDMO-PPV [ 24 ] and P3HT [ 27 ] and 1.1 % and 1.4 % conversion efficiencies had
been achieved, respectively. Great breakthrough has been made in 2009,
Oosterhout et al. [ 30 ] were able to study the 3D morphology of the device prepared
from Diethyl Zinc and P3HT via electron tomography. The authors provided a
detailed insight into the role of 3D morphology in charge generation and trans-
porting. The hybrid device showed a PCE up to 2 % when the nanoscale
morphology of the active layer was optimized, Fig. 9.7 shows the structure and
J-V characteristics of the device.
9.3.2 Nanorods and Nanowires
An important achievement in the development of CdSe-based HSCs was reported
by Huynh et al. in 2002 [ 9 ]. CdSe nanorods with aspect ratios ranging from 1 to 10
had been studied and the one with highest aspect ratio showed the most excellent
charge transport property and gave the best performance with a milestone effi-
ciency of 1.7 % under AM 1.5 global condition. After that, many efforts have been
done toward the improvement of CdSe nanorods-based HSCs, Sun et al. [ 67 ] have
studied the influences of solvents on the morphology and photovoltaic property of
CdSe/P3HT blend film and a promising PCE of 2.6 % had been achieved by using
a high boiling point solvent, 1,2,4-trichlorobenzene, for the enhanced hole trans-
port of P3HT, similar PCE was also reported by using a post-treatment method
called chemical vapor annealing [ 68 ]. The efficiency of HSCs was further
improved to 3.2 % by using a new low band gap polymer, poly[2,6-(4,4-bis-(2-
ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b 0 ] dithiophene)-alt-4,7-(2,1,3-benzothiadi-
azole)] (PCPDTBT) [ 47 ] (see Fig. 9.8 ). Except for CdSe, another Cadmium
Chalcogenide, CdSe nanorods were also used to prepared HSCs with polymers