Tunable greenish-to-reddish light generation via energy transfer in Tb3+/Sm3+-codoped PbGeO3:PbF2:CdF2 glass under UV excitation

Abstract

Generation of tunable greenish–yellowish–reddish luminescence mediated by energy transfer in Tb3 + / Sm3 + -codoped fluorogermanate glass under UV light excitation is reported. Fluorescence emissions around 487, 542, 561, 582, 600, 620, 645, 650, and 706 nm were obtained in double-doped samples under 355- and 375-nm excitation wavelengths. The relative intensity of the Sm3 + and Tb3 + ions’ individual distinctive emissions depends upon the excitation wavelength, relative ions concentration, and the energy transfer of Tb3 + to Sm3 + mechanism, which lead to the tonality tunable overall luminescent color. The CIE-1931 chromaticity coordinates of the overall luminescence resided in the range (0.31; 0.59) to (0.62; 0.37). Time decay measurements indicated efficient Tb3 + to Sm3 + energy-transfer process with a substantial decrease (1.65 to 0.85 ms) of Tb3 + emitting levels due to the presence of Sm3 + ions in the host matrix.