Nanocomposite Gel Electrolytes Research Articles

Recent research progress of dye-sensitized solar cells in Japan

Recent results of research and development on dye-sensitized solar cells in Japan will be reviewed. Current main issues are the luck of wide absorption organic dyes and high efficient hole transport layers. To solve the issues, various organic dyes and nano-composite ionic gel electrolytes were developed. In parallel to these, mechanism of charge transport and recombination in the solar cells were investigated. These studies provide several strategies to improve the efficiency and durability of the dye-sensitized solar cells. To cite this article: S. Yanagida, C. R. Chimie 9 (2006).

Synthesis of polymer gel electrolyte with high molecular weight poly(methyl methacrylate)–clay nanocomposite

Polymer nanocomposite gel electrolytes consisting of high molecular weight poly(methyl methacrylate) PMMA–clay nanocomposite, ethylene carbonate (EC)/propylene carbonate (PC) as plasticizer, and LiClO 4 electrolyte are reported. Montmorillonite clay was ion exchanged with a zwitterionic surfactant (octadecyl dimethyl betaine) and dispersed in methyl methacrylate, which was then polymerized to synthesize PMMA–clay nanocomposites. The nanocomposite was dissolved in a mixture of EC/PC with LiClO 4, heated and pressed to obtain polymer gel electrolyte. X-ray diffraction (XRD) of the gels indicated intercalated clay structure with d-spacings of 2.85 and 1.40 nm. In the gel containing plasticizer, the clay galleries shrink suggesting intercalation rather than partial exfoliation observed in the PMMA–clay nanocomposite. Ionic conductivity varied slightly and exhibited a maximum value of 8 × 10 −4 S/cm at clay content of 1.5 wt.%. The activation energy was determined by modeling the conductivity with a Vogel–Tamman–Fulcher expression. The clay layers are primarily trapped inside the polymer matrix. Consequently, the polymer does not interact significantly with LiClO 4 electrolyte as shown by FTIR. The presence of the clay increased the glass transition temperature (Tg) of the gel as determined by differential scanning calorimetry. The PMMA nanocomposite gel electrolyte shows a stable lithium interfacial resistance over time, which is a key factor for use in electrochemical applications.

Improved dye-sensitized solar cells using ionic nanocomposite gel electrolytes

In this study, an effect of addition of nanoparticles into a dye-sensitized solar cells (DSCs) ionic liquid electrolyte was explored. Carbon nanotubes, other carbon nanoparticles and titanium dioxide nanoparticles were dispersed individually into a 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIm-TFSI) ionic liquid electrolyte by grinding. It was centrifuged to form an ionic nanocomposite gel electrolyte. The dispersion of nanoparticles resulted in a substantial increase in their viscosity. Their electric conductivity increased as well. Notable effects were obtained in photocurrent density and voltage measurements of the DSC assembled with them. Energy conversion efficiency of them was significantly improved and increased compared with a DSC using a bare ionic liquid electrolyte.

Dye-sensitized solar cells employing a highly conductive and mechanically robust nanocomposite gel electrolyte

Solvent evaporation rate, ionic conductivity, and photovoltaic response were used to compare a traditional organic liquid electrolyte to a gel electrolyte and a nanocomposite gel electrolyte consisting of poly(vinylidenefluoride- co-hexafluoropropylene) (PVdF-HFP) and 12.5 wt.% synthetic layered silicate particles. The addition of layered silicate nanoparticles to the pure gel electrolyte markedly increased solvent retention and improved mechanical strength. The nanocomposite gel electrolyte had a conductivity of 2.6 × 10 −3 S/cm and a power conversion efficiency matching that of the liquid electrolyte.

Improved dye-sensitized solar cells using ionic nanocomposite gel electrolytes

In this study, an effect of addition of nanoparticles into a dye-sensitized solar cells (DSCs) ionic liquid electrolyte was explored. Carbon nanotubes, other carbon nanoparticles and titanium dioxide nanoparticles were dispersed individually into a 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIm-TFSI) ionic liquid electrolyte by grinding. It was centrifuged to form an ionic nanocomposite gel electrolyte. The dispersion of nanoparticles resulted in a substantial increase in their viscosity. Their electric conductivity increased as well. Notable effects were obtained in photocurrent density and voltage measurements of the DSC assembled with them. Energy conversion efficiency of them was significantly improved and increased compared with a DSC using a bare ionic liquid electrolyte.

A High-Performance Solid-State Dye-Sensitized Photoelectrochemical Cell Employing a Nanocomposite Gel Electrolyte Made by the Sol–Gel Route

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A Nanocomposite Gel Electrolyte Made by the Sol-Gel Route for a Solid-State Dye-Sensitized Photoelectrochemical and Electrochromic Cells

AbstractThis work describes the properties of an organic-inorganic hybrid gel with an incorporated I-/I3-redox couple that serves as a solid electrolyte for a dye-sensitized TiO2 photoelectrochemical (DSPEC) cell with an efficiency of 4% [1]. The influence of the AcOH on the hydrolysis and condensation reactions of the gels was studied with the help of infrared spectroscopy, while the presence and the formation of the I3 - species were established from the UV-visible spectra of the gels and independently evaluated from the confocal micro-resonance Raman spectra of the electrolyte encapsulated in the DSPEC during open- and short-circuit conditions. Finally, the same gel electrolyte was used for the construction of an electrochromic (EC) window without a counter electrode with intercalation properties (transmission and reflective configuration).