Synthesis, characterization and photoluminescence properties of CaSiO 3:Eu 3+ red phosphor

Abstract

CaSiO 3:Eu 3+ (1–5 mol%) red emitting phosphors have been synthesized by a low-temperature solution combustion method. The phosphors have been well characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and optical spectroscopy. PXRD patterns reveal monoclinic CaSiO 3 phase can be obtained at 900 °C. The SEM micrographs show the crystallites with irregular shape, mostly angular. Upon 254 nm excitation, the phosphor show characteristic fluorescence 5D 0 → 7F J ( J = 0, 1, 2, 3, 4) of the Eu 3+ ions. The electronic transition located at 614 nm corresponding to 5D 0 → 7F 2 of Eu 3+ ions, which is stronger than the magnetic dipole transition located at 593 nm corresponding to 5D 0 → 7F 1 of Eu 3+ ions. Different pathways involved in emission process have been studied. Concentration quenching has been observed for Eu 3+ concentration > 4 mol%. UV–visible absorption shows an intense band at 240 nm in undoped and 270 nm in Eu 3+ doped CaSiO 3 which is attributed to oxygen to silicon (O–Si) ligand-to-metal charge-transfer (LMCT) band in the SiO 3 2− group. The optical energy band gap is widened with increase of Eu 3+ ion dopant.