Flexible counter electrodes based on nitrogen-doped carbon aerogels with tunable pore structure for high-performance dye-sensitized solar cells

Nitrogen-doped carbon aerogels (NCAs) were prepared by introducing tripolycyanamide during the synthesis of organic aerogel precursors, and the effects of the nitrogen content on the pore structure of NCAs and the photovoltaic properties of dye-sensitized solar cells (DSSCs) based on NCA counter electrodes (CEs) were studied. With the increase of nitrogen-doped concentration, the pore size of NCAs decreases, and the mesoporous volume fraction increases, which lead to lower charge-transfer resistance and better electrocatalytic activity. The NCA CE based on polyvinylidene fluoride as binder shows a greater electrocatalytic activity than that based on polytetrafluorethylene because its higher polarity leads to better bonding capacity. Under optimized experimental conditions, the DSSC based on NCA8 flexible CE achieved a photoelectric conversion efficiency of 8.83%, which is 102.6% of that based on platinum CE (8.61%) under the same experimental conditions (AM 1.5, 100 mW cm−2).