An ion conductive polysiloxane as effective gel electrolyte for long stable dye solar cells

Among various alternatives to liquid electrolytes, ion conductive polymeric gels still offer the greatest potentialities to fill the gap between high energy conversion efficiency and long term stability in several classes of electrochemical and photo-electrochemical devices. We here present the synthesis of an ion conductive polysiloxane, named poly[(3-N-methylimidazoliumpropyl)methylsiloxane-co-dimethylsiloxane]iodide (IP-PDMS), which has been successfully employed to formulate a batch of iodide/triiodide-based gel electrolytes for dye solar cells. They are demonstrated to guarantee a good trade-off among photovoltaic performances and environmental stability. In particular, dyes solar cells embodying a benzothiadiazole-based donor-π-acceptor sensitizer and a 40%wt-IP-PDMS-based gel electrolyte have been revealed to maintain up to 90% of their initial photovoltaic performances over 1000 h of light soaking at 0.4 sun, although sealed with a simple thermoplastic gasket.