Tunable Color Emissions upon UV Irradiation from Tb3+:Y2SiO5 Phosphor

A series of terbium-activated yttrium oxyorthosilicate (Tb3+:Y2SiO5) phosphor was prepared through the sol–gel technique at a high calcination temperature of 1100°C. The phase purity was examined by the x-ray diffraction (XRD) analysis and found to be X1 type for all series of samples. The existence of functional groups in the prepared samples was confirmed by Fourier-transform infrared (FT-IR) spectroscopy. The sample exhibited absorption bands of Si-O-Si and Y-O groups at wavenumbers between 717 cm−1 and 550 cm−1 , and the NO3 groups appeared between 800 cm−1 and 1020 cm−1 in the FT-IR spectra. Under 244-nm excitation, the photoluminescence spectra were recorded in the 350 to 650 nm wavelength range. A possible cross-relaxation mechanism between the 5D3 and the 5D4 levels for the concentration quenching of two distinct emission transitions has been described in detail. The dipole–dipole interaction is most responsible for concentration quenching, as evidenced by the Dexter theory. The CIE chromaticity analysis of the Y2SiO5:Tb3+ phosphor was illustrated by a CIE 1931 color calculator. These findings demonstrate the suitability of the Tb3+-activated Y2SiO5 matrix as a UV-excitable, color-tunable emitter with Tb3+ ion variations and an efficient green light-emitting phosphor in the fields of solid-state lighting devices.