Undoped Ca ₂ Sb ₂ O ₇ with High Stability and Sensitivity for Multi‐Modal Rapid‐Response Optical Manometer

Abstract Optical manometers demonstrating broad application prospects in high‐pressure physics, materials science, planetary geology, and energy technology. However, current optical manometers based on diverse materials universally require complex doping of the host matrix, which complicates fluorescence mechanisms, significantly limiting their practical applicability. In this work, a pure‐phase undoped oxide material, Ca 2 Sb 2 O 7 , is successfully synthesized and its optical pressure sensing properties are studiede. Ca 2 Sb 2 O 7 shows a single emission peak centered at 440 nm when excited by 335 nm light, which can be monitored and analyzed under high pressure. A high sensitivity (dλ/dP = 0.75 nm GP −1 ) is reported from undoped Ca 2 Sb 2 O 7 . In addition to the emission wavelength, Raman and absorption spectra of Ca 2 Sb 2 O 7 can also be exploited for pressure sensing. The area integral of the PL peak also has a strong linear relationship with pressure. It also shows exceptional pressure reversibility, and robust environmental stability. This work provides an alternative way for optical manometer: material without any doping can play an unique role in this field.