One-Step Hydrothermal Tailoring of NiCo sub(2)S sub(4) Nanostructures on Conducting Oxide Substrates as an Efficient Counter Electrode in Dye-Sensitized Solar Cells

• Published in: Advanced materials interfaces Vol. 2; no. 18; p. np
• Main Authors: Khoo, Si Yun, Miao, Jianwei, Yang, Hong Bin, He, Ziming, Leong, Kam Chew, Liu, Bin, Tan, Timothy Thatt Yang
• Format: Journal Article
• Language: English
• Published: 01.12.2015
• Subjects: Charge transport; Dyes; Electrodes; Nanostructure; Oxides; Photovoltaic cells; Platinum; Solar cells
• ISSN: 2196-7350; 2196-7350
• DOI: 10.1002/admi.201500384

A one-step in situ tailoring of NiCo sub(2)S sub(4) nanostructures is demonstrated on fluorine-doped tin oxide (FTO) as Pt-free counter electrodes (CEs) for dye-sensitized solar cells (DSSCs) with performance surpassing that of a conventional Pt-sputtered CE. An interconnected NiCo sub(2)S sub(4) nanosheet network is successfully constructed on the FTO glass via a hydrothermal method, attributed to the synergistic effect of structure-directing hexamethylenetetramine and L-cysteine. A growth mechanism is proposed, and the effects of nanostructures and sulfur atomic percentages on the electrocatalytic performance are discussed in depth. A DSSC with the optimized interconnected NiCo sub(2)S sub(4) nanosheet CE exhibits higher power conversion efficiency (7.22%) compared to that with a conventional Pt-sputtered CE (6.87%) due to excellent charge transport properties and enhanced electrocatalytic activity of the NiCo sub(2)S sub(4) nanostructures. This work showcases the strong potential of nanostructured ternary chalcogenides, which are composed of earth-abundant elements and prepared through a single-step hydrothermal process without tedious posttreatments, to reduce the dependence of platinum in DSSCs and other electrochemical devices. Network-like NiCo sub(2)S sub(4) nanosheets on conducting oxide substrates are prepared via a simple hydrothermal process. Their use as an effective counter electrode (CE) in dye-sensitized solar cells is demonstrated, with performance surpassing that of a conventional platinum-sputtered CE. The performance can be attributed to its large electrocatalytic surface area, low charge transport resistance, and high electrocatalytic activity.