Growth of a WSe₂/W counter electrode by sputtering and selenization annealing for high-efficiency dye-sensitized solar cells

Abstract

A chemically active and stable WSe₂/W structure was prepared by sputtering and selenization annealing in order to replace a high-cost Pt counter electrode in dye-sensitized solar cells. The CV, EIS analysis, and Tafel curve measurements indicated that the WSe₂/W electrode possesses high conductivity, low charge transfer resistance at the electrolyte-electrode interface, good electrocatalytic activity, and fast reaction kinetics for the a iodide/triiodide redox reaction, which are due to the synergistic effect of W and WSe₂ in combination. The DSSC with a novel WSe₂/W counter electrode achieved a high power conversion efficiency of 8.22% under standard light illumination, which is comparable to that with a platinum (Pt)-coated FTO electrode (8.20%).