Rare-earth (Nd and Eu) induced structural transformation and optical properties of brownmillerite-type Sr2ScGaO5 oxide

Towards designing of new advanced optoelectronic materials, we have explored the synthesis of a series of rare earth (RE) substituted (Nd3+ and Eu3+) perovskite compounds, Sr2-x-yNdxEuyScGaO5+δ. The phase purities of three new compounds have been verified by Rietveld refinement, FESEM, EDS and Raman spectroscopic studies. The incorporation of RE ions at A-site leads to the structural transformation from brownmillerite Sr2ScGaO5 to cubic perovskite phase and the additional charge of the RE plays a crucial role for the nonstoichiometric oxygen vacancies in the host system. Interestingly, with the increment of europium dopant percentage, the optical properties significantly changes such as the colour of the emitting light moves from dark blue to red under UV irradiation as well as a change in their decay life time profile is also observed. The density functional theory calculations have been performed to understand the effect of oxygen vacancy in the electronic properties of the title compounds. Three new A-site rare-earth (Nd and Eu) doped cubic (space group Pm-3m) perovskite oxides Sr2-x-yNdxEuyScGaO5+δ (0.45 ​≤ ​x ​≤ ​0.5 and 0 ​≤ ​y ​≤ ​0.05) derived from brownmillerite Sr2ScGaO5 have been synthesized through ceramic method. The present disordered oxides with oxygen vacancies have emerged as a potential candidate for studying photo luminescence properties. [Display omitted] •Three new rare-earth substituted cubic oxides (Sr2-x-yNdxEuyScGaO5+δ) are synthesized.•These oxides adopt cubic structure unlike the orthorhombic structure of the parent.•The trivalent rare-earths go to the twelve coordinated at divalent strontium site.•The europium derivatives emit red light under UV radiation.•Oxygen vacancy play crucial role in the electronic structure.