Synthesis, structural characterization and optical properties of Dy, Ho and Er doped magnesium pyroborate nanoparticles

In this study, Dy3+, Ho3+, Er3+ doped magnesium pyroborates were synthesized with various concentrations at different temperatures by solution combustion synthesis method. The final products were well characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Ultraviolet Visible Spectroscopy (UV-VIS). In the first part of this work, 0.005, 0.010, 0.020, 0.050 mole amount of RE (Dy3+, Ho3+, Er3+) metal ion doped Mg2B2O5 were synthesized using five different fuels; glycine, tartaric acid, citric acid, urea and hexamethylenetetramine (HMTA) with magnesium nitrate (Mg(NO3)2.6H2O) and boric acid (H3BO3) sources via solution combustion technique. The synthesized materials were furtherly subjected to the heating processes at 400oC with 10 min. in which the combustion reaction was completed and followed at 700oC with 2h, 800oC with 1h and 900oC with 1h. to remove organic residues and to obtain pure, crystalline RE doped Mg2B2O5 nanoparticles. In the FTIR study, the strong vibrational bands assigned at 1450-1550 cm-1 and 600-750 cm-1 indicated the characteristic vibrations of Mg2B2O5. Additionally, the crystallite size of the products were calculated using Debye Scherrer equation and founed between 10-19 nm which proved the products were nanoparticles. In the UV-VIS analysis, the effect of temperature and the doping concentration of Dy3+, Ho3+, Er3+ ion on the optical properties of the products was examined due to the changed in wavelengths as red shift and/or blue shift.