Fabrications of Flexible Solid Electrolytes Composed of Exfoliated Montmorillonite/Multi-walled Carbon Nanotubes/Polymerized Ionic Liquids and Their Applications on Dye-Sensitized Solar Cells
Date Issued
2015
Date
2015
Author(s)
Gu, Yuan-Bin
Abstract
We synthesized the crosslinkable ruthenium complex with styryl groups attached on the bipyridine ligand, denoted as Ru-S which was characterized by NMR and UV-vis spectroscopies for this study. And we also synthesized 1-(2-acryloyloxy-ethyl)-3-methylimidazol-1-ium iodide (AMIMI), a polymerizable ionic liquid. The stability of Ru-S after crosslinking and copolymerization with different concentrations of AMIMI in ACN solutions were investigated by UV-vis spectroscopy through rinsing with NaOH aqueous solution to remove the unreacted RuS. In order to decrease the viscosity of AMIMI ionic liquid electrolyte, EMII was added to prepare five different weight ratios of EMII/AMIMI. The power conversion efficiency (PCE) of resulting DSSCs was increased when the content of EMII was increased. The PCE was increased from 3.99% to 5.87% when the weight ratio of EMII/AMIMI reached 1:1. Then different contents of exMMT were incorporated into the eletrolytes with EMII/AMIMI=1:1 for the DSSC. The Jsc and PCE were both increased with increasing the content of exMMT. The PCE reached up to 5.83% when the content of exMMT was 1 wt%. It is because the presence of exMMT can promote the oxidation of I- to I3-. Moreover, different contents of MWCNT were also incorporated into the eletrolytes with EMII/AMIMI=1:1 for the DSSC. The presnence of MWCNT could also increase the Jsc and PCE of the resulting DSSC . The PCE could reach up to 6.19% as 0.2wt% MWCNT was incorporated. It is because the presence of MWCNT can increase the conductivity of the electrolyte. Then different contents of exMMT was incorporated into the eletrolytes with EMII/AMIMI=1:1 and 0.2wt% MWCNT for DSSC. The best performance of DSSC had the PCE increased from 6.19% to 6.42% as 1 wt% exMMT was incorporated. That is because the MWCNT can increase the conductivity of the electrolyte, and exMMT can promote the oxidation of I- to I3-. When the content of exMMT was more than 1 wt%, the system would be over the gel point and reduce the effects. The long term service inverstingaion of DSSC showed that the stability of the DSSC with MWCNT was much greater than that without MWCNT. The PCE of the devise with MWCNT could remain more than 70% after testing for one month. However the PCE of the devise without MWCNT decreased to only 20%. Then we open the device and investigated the morphology of the electrolyte surface with SEM. More cracks have been produced on the layer of polymerized ionic liquid electrolyte in the device with MWCNT. It indicated that MWCNT with high thermal conductivity might accelerate the polymerization of AMIMI under the exposure of sunlight during long term testing. Keyword: EMII；AMIMI；RuS；Ionic Liquids；exMMT；MWCNT；DSSC; long term
Subjects
AMIMI
Ionic Liquids
exMMT
MWCNT
DSSC
long term
Type
thesis
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