Low temperature synthesis of iron pyrite (FeS2) nanospheres as a strong solar absorber material

Phase pure iron pyrite (FeS2) nanosphere morphology was synthesized by a solvothermal route an alternative to colloidal synthesis by utilizing an ethylene glycol and benzylamine as a solvent and structure directing ligand at 160 degrees C for 12 h in Teflon lined autoclave. The as obtained nanospheres were in average similar to 50 nm diameter with a smooth surface and well mono-disperse as observed by the FESEM images. The XRD analysis shows a typical iron pyrite crystal phase with 20 position at 28.23 degrees, 32.76 degrees, 36.84 degrees, 40.48 degrees, 47.32 degrees and 56.01 degrees without any impurity peaks. The Raman spectra further confirmed the phase pure pyrite structure. The UV-Vis and PL spectra shows excellent solar absorbance with a band gaps of 1.35 eV close to the direct band gap (1.38 eV) of pyrite materials, however the photoluminescence spectra shows a band gap of 1.39 eV close to the direct band gap. The obtained nanosphere morphology was highly promising as an excellent solar absorber material for the photovoltaic application. (C) 2018 Elsevier B.V. All rights reserved.