Transformation of refractory ceramic MgAl2O4 into blue light emitting nanomaterials by Sr2+/Cr3+ activation

[Display omitted] •Synthesis of MgAl2O4:Sr2+/Cr3+ nanomaterials for the applications of LEDs.•Defects such as oxygen vacancies, unfilled lattice sites, and antisite defects are critical in determining the behavior of synthesized material(s).•By adjusting the concentration of the dopant(s), a tunable hue may be produced.•Synthesized MgAl2O4:Sr2+/Cr3+ exhibits colour change from greenish blue to blue. The current research aims at manipulation of physical properties of spinel MgAl2O4 by substitution of Sr2+ cations at tetrahedral and Cr3+ at orthogonal-sites. Synthesized materials were studied by XRD, TGA, SEM, EDX and UV–visible, diffuse reflectance and photoluminescence spectroscopy. A series of Sr2+ and Cr3+ doped derivatives with the general formula Mg1-xSrxAl2-yCryO4 (where x, y = 0.2, 0.4, 0.6, 0.8 and 1.0) have been produced and investigated using the co precipitation technique. Although strain in the cubic crystal structure of magnesium aluminate spinel was seen upon doping due to Sr2+'s higher cationic radius, the structure remained reserved (spinel) for low dopant concentration (x, y = 0.2, 0.4, 0.6). The behavior of activator ions Cr3+ in these derivatives is supposed to be altered due to change in site occupancy. Due to presence of antisites defects activator ions; structural, optical, thermal, electrical properties of MgAl2O4 material were modified.