Concentration-dependent structural modification and color tunability of Sm3+-doped ZnAl2O4 phosphors

This research deals with the synthesis of undoped and Sm3+-doped ZnAl2O4 using the citrate sol-gel method. Various complementary techniques have extensively studied the consequences of samarium ion (Sm3+) doping on the crystallinity and emission mechanism. XRD analysis endorses the formation of Sm3+-doped ZnAl2O4 spinel powder within the size range of 14-26 nm. The granular surface morphology of the prepared samples and their particle size distribution were examined by SEM and TEM, respectively. The direct bandgap of the doped samples was calculated (2.77-3.65 eV) using the Kubelka-Munk function on the diffuse reflectance data. At high concentrations of Sm3+, photoluminescence (PL) results demonstrate orange-red emission at 597 nm after providing energy corresponding to direct excitation (396 nm) of Sm3+ ion. The blue-green emission is obtained first time in Sm3+-doped ZnAl2O4 at lambda(ex) = 320 nm excitation wavelength. The CIE chromaticity coordinates indicated that the prepared samples could be applied as an efficient phosphor in the visible range.

Automated summary

This research focuses on the synthesis of undoped and Sm3+-doped ZnAl2O4 using the citrate sol-gel method. Various techniques were used to investigate the effects of samarium ion (Sm3+) doping on crystallinity and emission mechanism. The results show that doped ZnAl2O4 exhibits good luminescent properties in the visible range and can be used as an efficient phosphor.