Highly effective 2D layered carbides counter electrode for iodide redox couple regeneration in dye-sensitized solar cells

In the present study, two typical 2D layered MXenes, i.e., Titanium carbide (Ti 3 C 2 ) and Vanadium carbide (V 2 C) are synthesized via a simple etching method under lower temperature as counter electrode catalysts to achieve the iodide redox couple regeneration in dye-sensitized solar cells. As indicated from the result, Ti 3 C 2 significantly outperforms V 2 C, and the device by exploiting Ti 3 C 2 counter electrode achieves power conversion efficiency (PCE) of 5.3%, while the device by applying V 2 C counter electrode only exhibits a poor PCE of 4.0%. To improve the catalytic activity of the prepared Ti 3 C 2 , the effect of etching time on the catalytic activity has been evaluated, which demonstrates that Ti 3 C 2 etched 24 h exhibits the highest catalytic activity, and the device generates a PCE of 6.2%. Lastly, the catalytic activity of the Ti 3 C 2 is further improved by postprocessing with KOH aqueous solutions, and the PCE value is up-regulated to 7.1%. The high catalytic behavior of Ti 3 C 2 could be attributed to the prominent charge transfer and mass transport properties caused by the specific 2D layer structure, suggesting a potential candidate to the noble metal electrodes.