Highly Sensitive Optical Manometer Based on the Visible Emissions of Ce³⁺-Doped La₆Sr₄(SiO₄)₆F₂ Multisite Phosphors

For overcoming the unsatisfactory sensitivity of optical manometers and the susceptibility of manometric parameters to temperature changes, a series of Ce3+-doped La6Sr4(SiO4)(6)F-2 phosphors with multicolor emissions are developed. Excited by 375 nm, the resultant compounds exhibit asymmetric and broad emission bands, which can be easily deconvoluted into two peaks originating from seven to ninefold coordinated Ce3+ sites, where their intensities are dependent on the excitation wavelength. Through analyzing the pressure-related luminescence intensity ratio (LIR) derived from these two Ce3+ sites, it is clear that the final manometer exhibits an unprecedentedly high relative sensitivity of approximate to 425% GPa(-1) at 0.76 GPa (the highest value reported to date). As pressure increases, the emitting color tunes from yellow to blue, resulting in the possibility of visual pressure sensing. Furthermore, based on the color coordinates of the phosphor material, its pressure sensing capability is discussed, in which the maximum sensitivities are 24.38 and 27.74% GPa(-1) at 0.76 GPa, when x-coordinate and y-coordinate are employed, respectively. Additionally, the LIR value is only slightly affected by temperature, leading to a thermal invariability manometric factor (TIMF) > 400 K GPa(-1). The findings indicate that Ce3+-doped La6Sr4(SiO4)(6)F-2 phosphors are good luminescent candidates for optical and visual multi-mode manometers.