Interconnected nitrogen and sulfur dual-doped porous carbon as efficient electrocatalyst for triiodide reduction in dye-sensitized solar cells

Exploiting cost-effective and efficient counter electrodes (CEs) for the reduction of triiodide (I-3(-)) has been a persistent objective for the development of dye-sensitized solar cells (DSSCs). Here, we propose a strategy for the synthesis of nitrogen and sulfur dual-doped porous carbon (N/S-PC) via a thermal annealing approach by using melamine as N source, and basic magnesium sulfate (EMS) whiskers as S source and templates. Benefiting from the high surface area, unique interconnected structural feature and synergistic effects of N/S dual-doping, the N/S-PC shows excellent electrocatalytic activity toward I-3(-) reduction, which has simultaneously been confirmed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Tafel polarization measurements. The DSSC devices with N/S-PC CEs exhibit a PCE up to 7.41%, which is higher than that of DSSC devices with single heteroatom (N or 5) doped CEs and even Pt CEs (7.14%). (C) 2016 Elsevier B.V. All rights reserved.