A fluorometric metal-organic framework oxygen sensor: from sensitive powder to portable optical fiber device

Nowadays, the development of high-sensitivity oxygen probes and portable detection devices are urgent required. Lanthanide metal-organic frameworks (MOFs), combining the advantages of lanthanide luminescent features and the inherent porosity of MOFs, show great potential for highly sensitive O2 sensing. At the same time, optical fiber sensors have proven to be a simple and effective detection platform for portable and actual monitoring. In this work, we designed an O2-sensitive porous lanthanide MOF by elaborately selecting organic ligand with the suitable high triplet-state level. The luminescent intensity of as-synthesized EuNDC (1,4-H2NDC = 1,4-naphthalenedicarboxylic acid) can be effectively quenched by O2, giving rise to the most outstanding detection performance than other reported lanthanide MOFs with high sensitivity (93.5% quenched at 1 bar O2, I0/I100 = 15.4, KSV = 13.3 bar-1, LOD = 0.21 mbar), good reversibility, and short response/recovery times (10/70 s). After that, we proposed and developed a reflection type optical fiber sensor by integrating EuNDC and silica fiber in PDMS film for remote, in-field and real-time O2 monitoring.