Synthesis, Structural and Optical Properties of Erbium-Doped α-Fe2O3 Nanoparticles

In this paper, we report the synthesis and optical studies of α -Fe 2 O 3 and erbium (Er 3+ ) ion-doped α -Fe 2 O 3 nanoparticles (NPs). The sol–gel auto-combustion method was employed to synthesize NPs with varying concentrations of Er 3+ ions. The synthesized NPs are thoroughly characterized and discussed. Powder x-ray diffraction analysis confirms the hexagonal (rhombohedral) crystal structure, with no additional phase formation. High-resolution transmission electron microscopy reveals the agglomeration of NPs in the synthesized systems. The average particle size decreases with Er 3+ ion doping in α -Fe 2 O 3 NPs. The elemental composition of doped and undoped systems is confirmed by energy dispersive x-ray spectroscopy (EDAX). The optical band gap was calculated from diffuse reflectance spectroscopy using the Kubelka–Munk relation. Band gap decreases with an increase in Er 3+ ion doping up to a specific doping concentration. Er 3+ ion-doped α -Fe 2 O 3 NPs show enhanced luminescence as compared to pristine α -Fe 2 O 3 NPs. An optimum band gap and enhanced luminescence of these doped systems make them as good candidates for optoelectronic devices.