Long-Term Stability Improvement of Non-Toxic Dye-Sensitized Solar Cells via Poly(ethylene oxide) Gel Electrolytes for Future Textile-Based Solar Cells

Abstract

To overcome the long-term stability problems of dye-sensitized solar cells (DSSC) due to solvent evaporation and leakage, gelling the electrolyte with polymers is an appropriate option. Especially for future applications of textile-based DSSCs, which require cost-effective and environmentally friendly materials, such an improvement of the electrolyte is necessary. Therefore, the temporal progressions of efficiencies and fill factors of non-toxic glass-based DSSCs resulting from different gel electrolytes with poly(ethylene oxide) (PEO) are investigated over 52 days comparatively. Dimethyl sulfoxide (DMSO) proved to be a suitable non-toxic solvent for the proposed gel electrolyte without ionic liquids. A PEO concentration of 17.4 wt% resulted in an optimal compromise with a relatively high efficiency over the entire period. Lower concentrations resulted in higher efficiencies during the first days but in a poorer long-term stability, whereas a higher PEO concentration resulted in an overall lower efficiency. Solvent remaining in the gel electrolyte during application was found advantageous compared to previous solvent evaporation. In contrast to a commercial liquid electrolyte, the long-term stability regarding the efficiency was improved successfully with a similar fill factor and thus equal quality.

Investigation of the Long-Term Stability of Different Polymers and Their Blends with PEO to Produce Gel Polymer Electrolytes for Non-Toxic Dye-Sensitized Solar Cells

“…In addition to polymers, a suitable solvent is of great importance, since evaporation leads to a drying of the GPE and will result in an increasing viscosity and decreasing ionic conductivity [43]. The here used non-toxic solvent DMSO with its high vapor pressure offers a stable alternative to the other most often used solvents and is compatible with our goal of producing non-toxic DSSCs [15,41,44].…”

“…Due to our motivation to produce non-toxic DSSCs, most frequently used toxic solvents like acetonitrile are out of the question [7]. Therefore, an important criterion for the polymers used in this paper is their solvability in the low-toxic solvent dimethyl sulfoxide (DMSO), which proved to be suitable regarding GPEs of environmentally friendly DSSCs [15].…”

Review of State of the Art Recycling Methods in the Context of Dye Sensitized Solar Cells

“…The basis for the DSSC, which is classically used in laboratories to investigate various properties of DSSCs, is two coated glass plates (0). A thin transparent conductive oxide (TCO) layer is deposited on the glass plates, referred to as the front and counter electrodes (0) [14,29]. The main task of these conductive semiconductor layers, which are transparent to visible light, is to transport the charge carriers generated in the cell by the internal photoelectric effect [14,29].…”

“…A thin transparent conductive oxide (TCO) layer is deposited on the glass plates, referred to as the front and counter electrodes (0) [14,29]. The main task of these conductive semiconductor layers, which are transparent to visible light, is to transport the charge carriers generated in the cell by the internal photoelectric effect [14,29]. Light absorption and the resulting induced charge separation takes place in the dye molecules (2) [14,30].…”

“…Therefore, we only use materials for our DSSCs that are non-toxic and abundant [12][13][14][15]. These cells could be reused and recycled and pose no danger to humans or the environment.…”