Electrochemical growth of NiS nanoparticle thin film as counter electrode for quantum dot-sensitized solar cells

Abstract

Abstract The high stability and superior electrocatalytic activity of counter electrodes (CEs) are crucial but important issues in high performance quantum dot-sensitized solar cells (QDSSCs). To address the above issues, nanoparticle-structured nickel sulfide (NiS) thin film electrodes were prepared on F-doped SnO 2 glass (FTO glass) substrates using a facile chemical bath deposition method at different growth times and used directly as the CEs for CdS/CdSe/ZnS QDSSCs. The surface morphology and thickness of the resulting NiS films are greatly affected by the deposition time. By optimizing the growth time of the NiS CE materials, a power conversion efficiency up to 3.25% was achieved for CdS/CdSe/ZnS based QDSSCs, which was much higher than that of the Pt CE (0.79%). In addition, a preliminary durability test of the CE in QDSSCs reveals that the NiS CE exhibited good stability than the Pt CE. The improved performance of the QDSSC was attributed to the resulting electrochemical catalytic activity of the NiS CE with efficient charge transfer at the CE/electrolyte interface, which was verified by the electrochemical impedance spectroscopy and the Tafel polarization measurement results. Therefore, the excellent electrochemical performance of NiS highlights its promising application as a CE for high performance QDSSCs.