Solvent-Induced Oriented Attachment Growth of Air-Stable Phase-Pure Pyrite FeS₂ Nanocrystals

Bin-Bin Yu, Xing Zhang, Yan Jiang, Jie Liu, Lin Gu, Jin-Song Hu, and Li-Jun Wan

J. Am. Chem. Soc., 2015, 137 (6), pp 2211–2214

Publication Date (Web): February 3, 2015 (Communication)

DOI: 10.1021/ja512979y

Abstract (click image for pdf file)

Pyrite Iron disulfide (FeS₂), as an eco-friendly and low-cost material composed of earth-abundant elements, has attracted much attention for promising applications in solution-processed photovoltaics, photoelectrochemical cells, and broad spectral photodetectors. The key challenge for its application of pyrite the synthesis of phase-pure pyrite with controlled surface state to inhibit its decomposition in air. Here, we reported the controlled synthesis of atmosphere-stable and phase-pure pyrite FeS₂ nanostructures through oriented attachment in a facile one-step solvothermal process. It was interestingly found that the kinetics and arrangement of the oriented attachment of FeS₂ primary clusters are closely related to the solvent used in the reaction. Nanocubes in a size of ~150 nm, spheroidal NCs in ~50 nm, and microspheres in micrometers assembled by nanoparticles in several nanometers can be selectively prepared via OA by choosing different solvents. Although all three as-synthesized products are phase-pure pyrite, the detailed Raman spectroscopy analysis over time showed that they exhibited distinct stability in air. Both spheroidal FeS₂ NCs and microspheres were stable in air for at least more than 1 year. After the understanding the reason for this long-term stability, air-stable FeS₂ nanocubes was also obtained after solvent exchange. The reported results will not only contribute to develop air-stable phase-pure FeS₂ nanomaterials, also to understand the oriented attachment mechanism in crystal growth.