Up-conversion luminescence and energy transfer mechanisms in Tb 3+ –Yb 3+ co-doped GeO 2 –PbO–PbF 2 oxyfluoride glasses

Abstract

GeO2–PbO–PbF2 glasses doped with rare-earth ions have been widely studied; however, the codoping of Tb3+ and Yb3+ in this glass system has not yet been explored. This work presents a novel approach involving the tailored combination of Tb3+/Yb3+ ions, optimized to enhance up-conversion efficiency under low-power near-infrared (NIR) excitation. To the best of our knowledge, this codoping strategy, together with a comprehensive investigation of the associated energy transfer mechanisms and multicolor emission behavior, has not been previously reported. In this study, the prepared glasses were systematically investigated using X-ray diffraction, absorption, excitation, and emission spectroscopic techniques to examine their structural characteristics and optical performance. Up conversion emission was studied under 976 nm excitation, supported by decay time analysis, while power dependence was probed using a 940 nm laser diode (300–600 mW). Furthermore, multicolor emission characteristics were analyzed through chromaticity coordinate determination and CIE diagram mapping under 375 and 976 nm excitation. These results demonstrate the significant potential of these materials for use in advanced photonic applications, such as bioimaging, photovoltaics, optical data storage, and light-emitting devices.