Low resistance transparent graphene-like carbon thin film substrates for high performance dye sensitized solar cells

The transparent graphene-like carbon (GLC) thin films were deposited on fluorine doped tin oxide (FTO) glass substrates by hot filament chemical vapor deposition (HFCVD) without using any catalyst. The GLC thin film substrates presented reasonably low sheet resistance with good transparency. The thickness and transparency of GLC thin film substrates were easily controlled by varying the deposition time from 5-30 min at the constant filament temperature 1400 C. The prepared GLC thin film substrates were directly used as conducting substrates to make TiO₂ photoanode for the fabrication of dye sensitized solar cells (DSSCs). A solar-to-electrical conversion efficiency of ∼6.94% was achieved by DSSC fabricated with GLC thin film substrate (10 min) which was reasonably higher than DSSC fabricated with bare FTO substrate. The deposition of GLC thin film on FTO significantly improved the open circuit voltage (V_OC, ∼0.70 V) and fill factor (FF, ∼0.63) of the fabricated DSSC. The enhanced V_OC and FF might attribute to the reduced recombination and improvement of contacts between TiO₂ layer and the conducting layer.