Manometry Strategy Based on Excitation Spectral Shift Induced by Pressure-Controlled Intervalence Charge Transfer in Tb3+:LiTaO3

Luminescence manometer is of great practical importance when investigating the physical and chemical phenomena under the extreme condition of high pressure. In this work, we propose a manometry strategy based on pressure-induced spectral shift of an excitation band which offers great flexibility for switching the monitoring wavelengths, in contrast to the traditional strategies based on spectral shift of a specific emission band. A significant red-shift of the UV excitation band with maximal pressure sensitivity of 2.12 nm/GPa is observed in Tb3+:LiTaO3, which stems from the susceptibility of the metal-to-metal intervalence charge transfer to surrounding chemical environment. The abnormal intensity variation of emissions in the visual spectral range from 496 to 627 nm and the luminescence mechanism are investigated via studying the pressure dependent structural and spectroscopic properties. Given the widened pressure-monitoring spectral window, relatively intense luminescence signal and competitive pressure sensitivity, the Tb3+ activated LiTaO3 is demonstrated to be a promising candidate for luminescent manometer. The strategy based on varying excitations may provide an alternative path for developing high-performance optical manometers.