High efficiency nitrogen-doped core-shell carbon spheres as counter electrodes for dye-sensitized solar cells

A novel metal-free conductive catalyst is designed based on N-doped core-shell carbon spheres (N-CCS) with rich active sites. Furthermore, the doping of N atoms activated the fully interconnected mesoporous basal planes of carbon spheres. Corresponding electrochemistry (Cyclic voltammetry, electrochemical impedance spectroscopy, and Tafel polarization measurements) test discovered the excellent electrocatalytic activities in the I−/I3− redox reaction of dye-sensitized solar cells (DSSCs), suggesting to result from the improvement of the surface electronic properties of CCS. DSSCs with N-CCS as the counter electrode (CE) achieve power conversion efficiency (PCE) of 7.89%, higher than to Pt's value (7.48%) in the same test environment, demonstrating as a hopeful catalyst for low-cost DSSCs.