Abstract

Research into finding environmentally friendly, efficient and economic viable nanophosphors is still ongoing as the incorporation of radioactive substances into phosphors to improve their short time luminescence poses serious environmental concern. The present paper investigates the effect of particle size on the, morphology and photoluminescence of environmentally friendly CaAl2O4: Mn2+ nanocrystals. The phosphor was prepared by the high temperature reaction technique. X-ray diffraction analysis revealed monoclinic structure. Average crystal size of the unpassivated nanomaterial (CAU) was found to be higher (41.49 nm) than that of the passivated (CAP) one (34.81 nm). Photoluminescence investigation at 345 nm excitation showed emission wavelengths that match Mn2+ emission. Both the emission color and intensity of the nanocrystals were observed to be crystal-size dependent with high luminescence intensity and deep blue emission peaks coming from CAP; while low luminescence intensity, prominent violet peaks and a weak blue emission peak were registered on CAU. Investigation of the samples responds to different excitation wavelengths revealed that both materials received corresponding colour emission and maximum intensity at 465 nm excitation.

Key words: Photoluminescence, morphology, passivation, fluorescence phosphor.