Quasi‐Solid‐State Dye‐Sensitized Solar Cells Containing a Charged Thermoplastic Elastomeric Gel Electrolyte and Hydrophilic/phobic Photosensitizers

Abstract

As the threat of global climate change due to combustion emissions becomes increasingly alarming, the search for clean and sustainable alternative energy is of paramount importance. With this objective in mind, harnessing solar energy is particularly attractive due to ongoing improvements in silicon‐, perovskite‐, and organic‐based solar cells. Of these, dye‐sensitized solar cells (DSSCs) constitute a promising technology due to their relatively low cost, moderate conversion efficiency, and robust mechanical properties. An important breakthrough in the development of DSSCs is the use of polymer gel electrolytes. In this work, we employ amphi­philic thermoplastic elastomers (TPEs) in the form of sulfonated block ionomer (SBI) homologs for this purpose. Since the midblock of each charged copolymer is hydrophilic, the resultant microphase‐separated nanostructures consist of continuous ionic channels that facilitate electron diffusion. A unique characteristic of the SBI archetype studied here is that the morphology can be solvent‐templated. We exploit this feature by introducing either hydrophilic or hydrophobic photosensitizers into the DSSCs. When the SBI exhibits a primarily lamellar morphology, a hydrophilic dye yields the highest efficiency (7.0%), whereas the opposite is observed when the nanostructure consists of a solvent‐templated nonpolar matrix. Photosensi­tizer tunability is augmented by the intrinsic mechanical and adhesive properties of a TPE.

Microphase-Separated Morphologies and Molecular Network Topologies in Multiblock Copolymer Gels

“…This paradigm naturally extends to include polar diluents such as water and ionic liquids in the case of triblock or higher-order multiblock copolymers possessing hydrophobic end blocks and a hydrophilic midblock. These functional soft materials are of interest in the fabrication of proteinaceous hydrogels, Li-ion batteries, soft robotics, organic photovoltaics, , and water-treatment , or amphoteric gas-separation membranes. An especially attractive attribute of TPEGs is their ability to be (electro)­mechanically strain-cycled with little, if any, hysteresis .…”

Self-Assembly of a Midblock-Sulfonated Pentablock Copolymer in Mixed Organic Solvents: A Combined SAXS and SANS Analysis

“…This solution → solid nanostructural dependence, generally referred to as solvent templating, is especially prevalent in materials that cannot be thermally annealed due to experimentally inaccessible glass or order–disorder transition temperatures ( T g and T ODT , respectively). Block copolymers containing strongly acidic and nonpolar blocks, which are currently of considerable interest due to their applicability as ion- and electron-exchange membranes, − are typically unaffected by thermal treatment due to high T g and interblock incompatibility (χ A–B directly relates to T ODT ). Recent studies − of midblock-sulfonated pentablock copolymers have established an intimate connection between solution and bulk film morphologies.…”

A study of the nanostructure and efficiency of solid-state dye-sensitized solar cells based on a conducting polymer

“…Therefore, the solidification of the electrolyte in DSCs has been one of the most important routes to overcome this problem [8, 9]. A lot of research has been conducted to replace the liquid electrolyte with solid or gel materials [10, 11, 12, 13, 14]. Hole transporting materials (HTM) are usually utilized as solid-state electrolytes in DSCs including inorganic types such as CuI and CuSCN, and organic types such as Spiro-OMeTAD [15, 16].…”