Cellulose Nanocrystal Aerogels as Electrolyte Scaffolds for Glass and Plastic Dye-Sensitized Solar Cells

Abstract

The fabrication, thickness, and structure of aerogel films composed of covalently cross-linked cellulose nanocrystals (CNCs) and poly(oligoethylene glycol methacrylate) (POEGMA) were optimized for use as electrolyte absorbers in dye-sensitized solar cells (DSSCs). The aerogel films were cast directly on transparent conducting counter electrode substrates (glass and flexible poly(ethylene terephthalate) plastic) and then used to absorb drop-cast liquid electrolyte, thus providing an alternative method of filling electrolyte in DSSCs. This approach eliminates the use of electrolyte-filling holes, which are a typical pathway of electrolyte leakage, and furthermore enables a homogeneous distribution of electrolyte components within the photoelectrode. Unlike typical in situ electrolyte gelation approaches, the phase inversion method used here results in a highly porous (>99%) electrolyte scaffold with excellent ionic conductivity and interfacial properties. DSSCs prepared with CNC–POEGMA aerogels reached similar power conversion efficiencies as compared to liquid electrolyte devices, indicating that the aerogel does not interfere with the operation of the device. These aerogels retain their structural integrity upon bending, which is critical for their application in flexible devices. Furthermore, the aerogels demonstrate impressive chemical and mechanical stability in typical electrolyte solvents because of their stable covalent cross-linking. Overall, this work demonstrates that the DSSC fabrication process can be simplified and made more easily upscalable by taking advantage of CNCs, being an abundant and sustainable bio-based material.

Cellulose for Light Manipulation: Methods, Applications, and Prospects

“…[132] The DSSC has the advantages compared to ordinary solar cells in its low cost by using inexpensive materials and the easy way of fabrication due to the variety of suitable materials and preparation methods, for example, by using roll-to-roll processes. [133][134][135][136] Usually the electrolyte is in a liquid form, which is pumped through the cell. There, the liquid is exposed to a porous structure modified with a dye/TiO 2 layer.…”

“…This system showed similar performance and stability as the nonaerogel DSSCs and enables the production of large-area solar cell systems. [134] The beneficial effect of nanoscale microfibrillated cellulose (MFC) was investigated by Chiappone et al For this purpose, nanoscale microfibrillated cellulose was used in photocrosslinked polymer electrolyte membranes. Here, the MFC serves as a source for light scattering and reflection.…”

Performance evaluation of a low-cost, novel vanadium nitride xerogel (VNXG) as a platinum-free electrocatalyst for dye-sensitized solar cells

“…Few studies have been successfully reported demonstrating the enhanced performance of dye-sensitized solar cells with xerogel-structured photoanodes. [44][45][46][47] These results encouraged the present approach to synthesize the vanadium nitride xerogel and investigate its catalytic activity towards the counter electrode for DSSCs.…”

Natural Cellulose Substance Based Energy Materials

“…Hence, a quasi‐solid electrolyte system provides a pathway for the solution of both the above‐mentioned problems, and the hierarchical cross‐link structures of the natural cellulose substances make them the ideal scaffold for the liquid electrolyte to form the quasi‐solid electrolyte system. As an example, a cotton derived cellulose aerogel film was covalently anchored with poly(oligoethylene glycol methacrylate (POEGMA), and then cast on the counter electrode substrate as the electrolyte absorber in the DSSC [87b] . The yielded cellulose aerogel film (CNC‐POEGMA aerogel film) exhibited a three‐dimensionally cross‐link network structure with high porosity that replicated from the initial cellulose substance.…”