Performance evaluation of Ce3+ doped flexible PVDF fibers for efficient optical pressure sensors

Abstract

This work proposes a highly novel centrifugally spun lanthanide doped nonwoven fibrous mat as a non-contact optical pressure sensor with a wide linear dynamic range and good pressure sensitivity. The sensor properties are based on the spectral shift, broadening and intensity enhancement of Ce3+ ion in Ce doped PVDF fiber upto significantly high pressure. Two different systems: Ce(NO3)3·6H2O and (NH4)4Ce(SO4)4·2H2O doped PVDF flexible fibers (CeN-PF and CeS-PF) were produced using the Forcespinning® technique. Both CeN-PF and CeS-PF fibers displayed violet-blue emission under UV irradiation due to a 5d-4f transition of Ce3+ ions. Our emission results show that both CeN-PF and CeS-PF spectral characteristics are influenced by high pressures, inducing significant spectral ref shift in 5d-4f. The pressure-induced monotonous changes in bandwidth and emission intensity enhancement along with red shift suggesting the potential application of these fibers for pressure sensing applications. The CeN-PF fiber exhibits a high-pressure sensitivity (dλ/dP ≈ 0.28 nm/GPa) under a comprehensive linear dynamic range (0–64 GPa) with no pressure-induced luminescence quenching. The changes in CeS-PF is less pronounced with a lower pressure sensitivity of 0.10 nm/GPa compared to CeN-PF due to large crystal field splitting energy of nitrate ion compared to sulphate ion. This work presents a highly efficient, cost effective, scalable lanthanide doped flexible fibrous based system with negligible high pressure quenching and a wider linear dynamic range for optical pressure sensing applications.