Effects of alloying on band gap and morphology of iron pyrite nanoparticles

- Zinc alloyed FeS2 nanoparticles are synthesized first time only in oleylamine.
- Alloying of zinc is confirmed with the blue-shift observed in Raman spectra.
- An increase of 0.08 eV is observed in energy band-gap due to zinc alloying.
- Nanoparticles shape changes from cubic to quasi cubic.

Here, we report the effects of zinc alloying in iron pyrite (FeS2) nanoparticles (NPs). The NPs were synthesized by a hot-injection method using oleylamine (OAm) only, with no other ligand. The band-gap and morphology were found to be strongly dependent on the relative amount of zinc incorporated in the nanoparticles. A blue shift was observed in Raman active modes for FeS2 upon Zn incorporation which has been ascribed to the change in the bond length of (S2)2− dumbbells in the pyrite structure. According to the optical absorption measurements the band-gap (Eg) of NPs increased linearly with the mole fraction of Zn in the precursor solution (Zni) for the NP synthesis, and an enhancement of ∼0.08 eV was achieved for Zni = 40%. Also, the shape of NPs varied from cubic to quasi-cubic with the increase in the mole fraction of Zn in the precursor.