Cu2ZnSnS4 nanoplate arrays synthesized by pulsed laser deposition with high catalytic activity as counter electrodes for dye-sensitized solar cell applications

Abstract

In this paper, ligand free vertically aligned Cu₂ZnSnS₄ nanoplates were directly synthesized on a fluorine doped tin oxide substrate using a pulsed laser deposition (PLD) method, forming a nanoplate array. The array follows a two-step growth by first forming a Cu₂ZnSnS₄ thin film (∼100 nm), followed by vertical nanoplate formation. The nanoplates are about 20 nm thick and 300 nm high with a petal-like shape. Furthermore, the nanoplate array was integrated in a dye sensitized solar cell as a counter electrode with a power conversion efficiency of 3.65%, which is comparable to that of a conventional sputtered Pt counter electrode (3.33%) and higher than that fabricated with a “classical” Cu₂ZnSnS₄ thin film (2.83%). The Cu₂ZnSnS₄ nanoplate array is proved to be suitable for counter electrode fabrication to achieve Pt-free dye sensitized solar cells, which could significantly cut down the cell cost and provide environmentally friendly photovoltaic devices.