Tunable optical properties of some rare earth elements-doped mayenite CaAlO nanopowders elaborated by oxalate precursor route.

Rashad, Mohamed; Mostafa, Ahmed; Mwakikunga, Bonex; Rayan, Diaa

Rare earth (RE) ions-doped mayenite CaAlREO nanopowders (where RE = La and Gd and x = 0-1.0) were synthesized using the oxalate precursor technique. The as-prepared precursors were calcined at 800 °C for 2 h. Obviously, all RE-doped CaAlREO possessed a well-crystalline cubic mayenite phase till RE content of 0.8. The crystallo-chemical aspects including crystallite size, lattice parameters, theoretical X-ray density and bulk density were robustly on RE nature and ratio. The microstructure and the average grain size were significantly influenced by the RE kind and content. The high transparency of CaAlREO over 80% was found to be evinced in the visible wavelength range of 400-800 nm. Besides, the incorporation of RE cation minimized the direct band gap energy from 4.42 eV for pure mayenite to 3.85 and 3.59 eV with x value 1.0 of La and Gd ions. The photoluminescence spectra of pure mayenite nanoparticles showed that the band edge emission ( λ = 248 nm) with an intense visible emission band at 360 nm was detected. Otherwise, the band edge emission showed a slight shift toward short wavelength due to the substitution Al by RE ions. Such results open a new avenue for application of mayenite as a good candidate for transparent low-temperature electron conductor for optoelectronics applications.

RARE earth metals; OPTICAL properties of metals; CALCIUM compounds; OXALATES; METAL powders; NANOSTRUCTURED materials

Applied Physics A: Materials Science & Processing, 2017, Vol 123, Issue 1, p1

0947-8396

Academic Journal

10.1007/s00339-016-0654-y