Robust carbon dots-wrapped NiCo flower-like nanostructures for enhanced triiodide reduction

Replacing traditional counter electrodes (CEs) with Pt-free electrodes is one of the challenges for developing dye-sensitized solar cells (DSCs). Herein, we successfully synthesized carbon dots-wrapped NiCo flower-like nanostructure (NiCo/Cdots) and evaluated its application as CEs for DSCs. To characterize as-prepared materials, we conducted FESEM and TEM-EDS. Cyclic Voltammetry (CV), electrochemical Impedance Spectroscopy (EIS), Bode, and Tafel plots were then used to investigate the electrocatalytic properties of NiCo/Cdots CE. As a result, the as-prepared sample exhibited high electrocatalytic activity, low charger-transfer resistance, and large exchange current density. DSC based on NiCo/Cdots CE was assembled and showed a slightly lower PCE than Pt CE-based DSCs (8.27 and 8.52 %, respectively). However, it provided excellent stability during a long-term performance. These results indicated that CoNi/Cdots is a low-cost, easy-to-fabricate material with high potential as a CE of DSCs.