CNT-G-TiO2 layer as a bridge linking TiO2 nanotube arrays and substrates for efficient dye-sensitized solar cells

This study incorporated a 3-D hybrid material comprising graphene and carbon nanotubes (CNTs) into a TiO2 composite paste to adhere TiO2 nanotube arrays (NTAs) as photoanodes. The effect of the proportion of CNTs to graphene on the dye-adsorption ability of bonding layers was investigated and the optimal proportion of 2 : 1 provided a greatest degree of dye absorption. The DSSC efficiencies firstly increased and then decreased with increasing amount of CNT-G hybrid. The optimized DSSC efficiency of 6.17% was achieved at a suitable concentration (0.1 wt%) of CNT-G, which is due to a balance between electron transport and light harvesting in the photoanode.