Effects of TiCTx MXene Addition to a Co Complex/Ionic Liquid-Based Electrolyte on the Photovoltaic Performance of Solar Cells.

Redox mediators comprising I, Co, and TiCTx MXene were applied to dye-sensitized solar cells (DSCs). In the as-prepared DSCs (I-DSCs), wherein hole conduction occurred via the redox reaction of I/I ions, the power conversion efficiency (PCE) was not altered by the addition of TiCTx MXene. The I-DSCs were exposed to light to produce Co/Co-based cells (Co-DSCs), wherein the holes were transferred via the redox reaction of Co/Co ions. A PCE of 9.01% was achieved in a Co-DSC with TiCTx MXene (TiCTx-Co-DSC), which indicated an improvement from the PCE of a bare Co-DSC without TiCTx MXene (7.27%). It was also found that the presence of TiCTx MXene in the redox mediator increased the hole collection, dye regeneration, and electron injection efficiencies of the TiCTx-Co-DSC, leading to an improvement in both the short-circuit current and the PCE when compared with those of the bare Co-DSC without MXene.