Design and fabrication of NiCo2S4@rGO as an efficient Pt free triiodide reducing agent for dye-sensitized solar cell application

Abstract

Exploiting efficient Pt-free counter-electrode materials with low cost and highly catalytic property is a hot topic in the field of Dye-sensitized solar cells (DSCs). Here, NiCo₂S₄/reduced graphene oxide (RGO) was prepared via an economical hydrothermal ynthesis route, and the as-prepared composite exhibited comparable electrocatalytic property with the conventional Pt electrode as the counter-electrode. Enhanced optoelectronic, optical and structural characteristics have been attained over the constructed heterojunction. Band gap energy of NiCo₂S₄ (2.35 eV) was suppressed to 2.11 eV owing to its supporting with 10 wt.% rGO bringing about upgraded absorption of visible light. Electrochemical studies confirmed the synergetic effect of nickel and cobalt ions with the high electrical conductive rGO networks that enhance the electrocatalytic activity of NiCo₂S₄ nanostructures. The efficiency achieved for the NiCo₂S₄@rGO counter electrode (CE) based DSSC is 8.17%, which is remarkably higher than that of pristine NiCo₂S₄ (7.31%), and Pt (7.14%) under the same experimental conditions. In outline, given their innovative synthesis approach, affordability, and remarkable electrocatalytic attributes, the newly developed NiCo₂S₄@rGO counter electrodes stand out as potent contenders in future dye-sensitized solar cell applications.