Electrolyte membranes based on ultrafine fibers of acetylated cellulose for improved and long-lasting dye-sensitized solar cells

Electrospun nanofibers obtained from cellulose acetate before (CA) and after (DCA) deacetylation were used as electrolyte membranes in dye-sensitized solar cells. As holders of the active components of the device and compared to the reference system, the CA and DCA membranes increased the average device efficiency by as much as 14%. The membranes enhanced the charge transfer at the counter electrode (assessed by the Ohmic and charge transfer resistance and corresponding Helmholtz capacitance). Simultaneously, the photoelectrode did not interfere with the performance as measured by the short-circuit current density, open circuit voltage, fill factor and conversion efficiency. Long-term stability tests (light soaking) showed that the CA- and DCA-based solar cells sustain operation for at least 500 h. For long term use and/or to serve as a scaffold for other purposes, DCA performs better than CA. The proposed active electrolyte membranes are expected to open the way toward rapid and continuous assembly of dye sensitize solar cells using cellulose esters. Graphical abstract: [Figure not available: see fulltext.].