Fabrication of Soft Solid-State Electrolyte with Polyelectrolytes/Multi-walled Carbon Nanotubes for Dye-sensitized Solar Cells
Date Issued
2014
Date
2014
Author(s)
Hsiao, Chun-Han
Abstract
The power conversion efficiency of solid-state dye-sensitized Solar Cells (DSSCs) reported in the recent literature is still low and the flexible solar cells is deemed to be the trend of future. Therefore, to improve the power conversion efficiency of solid-state DSSCs and achieve the goal of flexibility, this research tried to use the copolymers with the glass transion temperatures lower than the room temperature to fabricate the soft solid-state electrolytes for DSSC. We used butyl acrylate (BA) to copolymerize with two kinds of monomers containing carboxylic acid group, acrylic acid (AA) and methacrylic acid (MAA), through emulsifier-free emulsion polymerization. The glass transion temperatures of resulting copolymers measured by differential scanning calorimetry (DSC) were all below room temperature (25℃). Then we used these soft copolymers to prepare the soft solid-state electrolyte for DSSCs.
In the first part of this resreach, we changed the molar ratio of BA and AA (MAA) monomers for copolymerization. By using 1.5AM 100mW/cm2 sunlight, we found the power conversion efficiency of DSSC using P(BA1-co-AA1) electrolyte system was 3.29±0.09％, and its open circuit voltage (Voc) and short circuit current density (Jsc) were 0.65±0.05V and 9.01±0.10 mA/cm2. Whereas, the DSSC using P(BA1-co-MAA1) electrolyte system had power conversion efficiency of 3.71±0.06％, open circuit voltage value of 0.68±0.05 V , and short circuit current density of 11.11±0.12 mA/cm2.
In the second part of this research, due to lower power conversion efficiency for the DSSCs using ionic copolymer systems as a solid-state electrolyte compared to liquid and gelled-type electrolytes, we incorporated MWCNT with above soft solid-state electrolyte to increase the electric conductivity. The results showed that the DSSCs using P(BA1-co-AA1) system containing 0.3 wt% MWCNT had the best performance with the power conversion efficiency increasd to 5.09±0.08％. Voc and Jsc were 0.70±0.09 V and 13.27±0.12 mA/cm2 respectively. Moreover, the DSSCs with P(BA1-co-MAA1) system containing 0.3 wt% MWCNT also showed the best result with the power conversion efficiency increased to 5.15±0.11％. Voc and Jsc were 0.72±0.05 V and 12.55±0.09 mA/cm2 respectively. Apparently, addition of 0.3wt% MWCNT to the solid-state electrolyte increased both Voc and Jsc and also elevated the electric conductivity. The glass transion temperature of P(BA3-co-MAA2) measured by DSC decreased from 9.89℃to 6.90℃ by adding 0.3wt% MWCNT . The glass transion temperature of P(BA3-co-MAA2) containing 0.3wt% MWCNT also decreased from 15.48℃ to -0.79℃. It implies that MWCNT could adsorb the AA segment of P(BA3-co-AA2) and MAA segment of P(BA3-co-MAA2) through carboxylic cationic-π interaction.
Subjects
聚丁基丙烯酸酯
染料敏化太陽能電池
多層奈米碳管
軟質
固態電解質
Type
thesis
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