One-step preparation of 3D hydrangea-like nickel sulfide films as electrocatalysts for efficient dye-sensitized solar cells

Abstract

Hydrangea-like nickel sulfide was directly deposited on indium tin oxide (ITO) substrates via a one-step solvothermal method. The effect of the molar ratio of nickel chloride to thiourea on the morphology of nickel sulfide was systematically investigated. It was demonstrated that a lower nickel-to-thiourea ratio facilitates the formation of hydrangea-like structures. Specifically, when the ratio of nickel chloride to thiourea is 1 : 3, the resulting hydrangea-like nickel sulfide counter electrode (CE) demonstrates superior catalytic activity. Without any additional post-sulfuration or thermal treatment, a dye-sensitized solar cell (DSSC) incorporating this CE exhibits a power conversion efficiency (PCE) of 7.64%, which is comparable to that of a DSSC incorporating a Pt-based CE. These findings indicate a facile and efficient approach for synthesizing nickel sulfide as a promising alternative CE material for DSSCs.