Carbon nanotube-carbon black hybrid counter electrodes for dye-sensitized solar cells and the effect on charge transfer kinetics

In this work, the catalytic activity of carbon nanotubes (CNTs), carbon black (CB), and CNT-CB counter electrodes in the I − /I 3 − reduction reaction is reported and compared with the Pt counter electrode. The fabricated counter electrodes were evaluated in dye-sensitized solar cells (DSSCs). The results indicate that the best cathodes were made from CNT 10 (240 μm) and CB with a charge transfer resistance ( R CT ) of 2.70 Ω, and when the complete device shows 19.83 Ω of internal series resistance ( R S ), the photovoltaic parameters of these cells were J SC = 10.47 mA cm −2 ; V OC = 0.70 V; and FF = 57.90, with an efficiency of 4.29%, indicating a better interaction between the CNT 10 in the 3D network of the counter electrode, generating a good charge transfer kinetics, in comparison with only CNT 10 or CB.