Anisotropic Growth of Iron Pyrite FeS₂ Nanocrystals via Oriented Attachment

Abstract

Pyrite (FeS2) material is attractive for applications in solar cells, lithium batteries, and hydrogen production because of its abundant, nontoxic features as well as the extraordinary electrical and optical properties. Pyrite (FeS2) nanocrystals (NCs) were synthesized via hot injection method, and the crystalline structure and morphologic evolution of pyrite NCs were investigated. We found that pyrite (FeS2) NCs were generated from a mackinawite FeS0.94 nanosheets template. The initial anisotropic growth of NCs was dominated by oriented attachment mechanism. Ostwald ripening growth became obvious as time progressed, resulting in faceted NCs. In accordance with the analysis of high-resolution transmission electron microscopy (HRTEM) images and surface free energies, we found that the attachment occurs between the opposite facets with high surface free energies including (210)-Fe and (210)-2S as well as (001)-Fe and (001)-2S. The attachment could also happen through a “point-contact” followed by interparticle growth. This study sheds light on a better understanding of the growth mechanism of anisotropic pyrite FeS2 NCs and provides a means to rationally manipulate the morphology of pyrite FeS2 NCs in order to achieve desired physical properties for efficient photovoltaic conversions.

Two-dimensional transition metal dichalcogenide-based counter electrodes for dye-sensitized solar cells

“…Pyrite iron disulfide (NiS 2 ) acquires unique morphological structures including nanocrystals, nanowires, nanosheets, nanocubes, and exhibits interesting electrical, photovoltaic, and catalytic properties. [211][212][213][214][215][216][217][218][219][220] An interesting comparative study was done by Shukla et al 221 In an interesting study, FeS 2 nanorod arrays were fabricated on a FTO substrate after sulfurizing FeO(OH) nanorods, and used as a CE for DSSCs. 222 The FeS 2 nanorods exhibited better electrocatalytic activity than FeS 2 films and Pt-based CEs due to more active sites, which resulted in high J SC value of the DSSCs.…”

Nanocrystalline Pyrite for Photovoltaic Applications

“…The higher sulfur concentration favours higher FeS 2 formation rate that is the rate‐determining step . A very recent investigation of growth mechanism of FeS 2 NCs by Zhu et al . revealed that OLA in replacement with ODA as a solvent leads to the growth of anisotropic pyrite NCs with more branches, chromosome‐like shapes along the ‹210› direction.…”

Morphology controllable syntheses of micro- and nano-iron pyrite mono- and poly-crystals: a review

“…However, it could not provide further information on how the iron pyrite nanocubes or nanospheres form. Hence, Oriented Attachment (OA), which appears to be a suitable mechanism during the development of nanoscale materials, was introduced in iron pyrite crystalline growth by Gong et al 73 and Zhu et al 85 They utilized the OA mechanism (Fig. 5i) to interpret the iron pyrite cubes and spheres 73 and the anisotropic growth of iron pyrite, 85 respectively.…”