Stable ⩾8% efficient nanocrystalline dye-sensitized solar cell based on an electrolyte of low volatility

We demonstrate a $⩾8\%$ efficient nanocrystalline dye-sensitized solar cell retaining over 98% of its initial performance after 1000 h of accelerated tests subjected to thermal stress at 80 °C in the dark. Device degradation was also negligible following 1000 h of visible light soaking at 60 °C. This high performance and stable device was realized by using a robust electrolyte of low volatility in conjunction with the amphiphilic ruthenium sensitizer $\left[\mathrm{Ru}(4,4^{\prime }\text{-dicarboxylic acid-}2,2^{\prime }\text{-bipyridine})(4,4^{\prime }\text{-}\mathrm{bis}\left(p\text{-hexyloxystyryl}\right)\text{-}2,2^{\prime }\text{-bipyridine}){\left(\mathrm{NCS}\right)}_2\right]$ , coded as K-19, which was grafted together with 1-decylphosphonic acid on the mesoporous titania film acting as photoanode.