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Abstract
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Herein, three ionic liquid random copolymers (P) containing 1‐vinyl‐3‐
butylimidazolium bromide (VBImBr) and methyl methacrylate (MMA) with various
molar ratios were prepared using conventional free radical polymerization. Afterward,
their corresponding chemically cross‐linked copolymers (XP) were formed similarly in
the presence of polyethylene glycol dimethacrylate (PEGDMA). The synthesized
copolymers were characterized using FT‐IR, 1H NMR, and GPC. Differential scanning
calorimetry (DSC) and thermal gravimetric analysis (TGA) results showed that the
rigidity and thermal stability of the copolymers depended on the ionic liquid content
as well as the degree of cross‐linking. Gel polymer electrolytes were then prepared
via obtained copolymers in the presence of a constant amount of synthesized
imidazolium‐based ionic liquid. Among the copolymers, the P3 with in feed VBImBr:
MMA molar ratio of 70:30 and the cross‐linked 1%‐XP3 copolymer prepared with
1 mol% of PEGDMA exhibited the highest conductivity and diffusion coefficients
for I3
¯ and I¯. The power conversion efficiency of the optimized linear and crosslinked
copolymers (P3 and 1%‐XP3) under the simulated AM 1.5 solar spectrum
irradiation at 100 mW cm−2 were 3.49 and 4.13% in the fabricated dye‐sensitized
solar cells (DSSCs), respectively. The superior long‐term stability and high performance
of the gel electrolyte containing 1%‐XP3 suggested it as commercial gel
electrolyte for future DSSCs.
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